Keratoconus – Epidemiologia

Keratoconus
Epidemiologia

Keratoconus to postępująca, nieinfekcyjna ektazja rogówki, charakteryzująca się stożkowym uwypukleniem i ścieńczeniem, prowadzącym do nieregularnego astygmatyzmu i upośledzenia widzenia. Choroba rozpoczyna się zwykle w okresie dojrzewania, z progresją do 30-40 roku życia. Globalne rozpowszechnienie wynosi około 138 na 100 000 mieszkańców, jednak dane różnią się znacznie geograficznie i etnicznie – od 0,3 na 100 000 w Rosji do 2300 na 100 000 w centralnych Indiach, a w niektórych regionach Bliskiego Wschodu nawet do 5% populacji. Czynniki środowiskowe, takie jak ekspozycja na promieniowanie UV i zanieczyszczenie powietrza (PM2.5, PM10, NO2), oraz genetyczne (historia rodzinna, pokrewieństwo) odgrywają istotną rolę w etiologii. Pocieranie oczu jest kluczowym modyfikowalnym czynnikiem ryzyka. Choroba jest zwykle obustronna, często asymetryczna, a u dzieci przebiega ciężej i szybciej. Wczesne wykrycie, zwłaszcza w populacjach wysokiego ryzyka, jest kluczowe ze względu na dostępność skutecznego leczenia – sieciowania kolagenu rogówki (CXL), które zatrzymuje progresję w 98,3% przypadków.

Epidemiologia Keratoconus

Globalne rozpowszechnienie keratoconus
Różnice geograficzne w epidemiologii keratoconus
Czynniki środowiskowe wpływające na epidemiologię keratoconus
Różnice etniczne w epidemiologii keratoconus
Wpływ płci i wieku na epidemiologię keratoconus
Czynniki ryzyka w epidemiologii keratoconus
Aspekty kliniczne istotne dla epidemiologii keratoconus
Korzyści z wczesnego wykrywania w kontekście epidemiologii
Wyzwania epidemiologiczne w badaniach nad keratoconus

Znaczenie ekonomiczne epidemiologii keratoconus
Przyszłość epidemiologii keratoconus

Kolejne rozdziały

Epidemiologia Keratoconus

Keratoconus to postępująca, nieinfekcyjna choroba ektazji rogówki, charakteryzująca się stopniowym ścieńczeniem oraz stożkowym uwypukleniem rogówki, prowadzącym do nieregularnego astygmatyzmu i upośledzenia widzenia. Choroba ta zazwyczaj rozpoczyna się w okresie dojrzewania i postępuje przez drugą i trzecią dekadę życia, zwykle stabilizując się około czwartej dekady.¹² Epidemiologia keratoconus wykazuje znaczące zróżnicowanie geograficzne i etniczne, co czyni ją fascynującym obiektem badań epidemiologicznych.

Globalne rozpowszechnienie keratoconus

Częstość występowania keratoconus na świecie wykazuje znaczną zmienność. Według niedawnej metaanalizy, która objęła ponad 50 milionów osób z 15 krajów, globalne rozpowszechnienie keratoconus wynosi około 138 na 100 000 mieszkańców.¹ Starsze dane wskazywały na częstość występowania 1 na 2000 osób (50 na 100 000).² Jednak najnowsze badania wykorzystujące zaawansowane technologie diagnostyczne sugerują, że rzeczywista częstość występowania może być znacznie wyższa.

Rozpowszechnienie keratoconus waha się w szerokim zakresie, od tak niskiego jak 0,3 na 100 000 w Rosji do nawet 2300 na 100 000 w centralnych Indiach (0,0003%-2,3%).³ W niektórych regionach Bliskiego Wschodu wskaźnik chorobowości sięga nawet 5% populacji.⁴⁵ Innym niezwykłym przykładem jest Arabia Saudyjska, gdzie jedno z badań wykazało częstość występowania na poziomie 4,79% (1:21) wśród pediatrycznych pacjentów w wieku 6-21 lat.⁶

W niedawnym badaniu przeprowadzonym w Niemczech z wykorzystaniem nowoczesnej technologii obrazowania Scheimpfluga, częstość występowania keratoconus w głównie kaukaskiej populacji oszacowano na 0,49% (1:204), co jest około dziesięciokrotnie wyższe niż wcześniej raportowano.⁷⁸ Badanie z Australii wykazało, że około 1 na 84 młodych dorosłych (1,19%) ma keratoconus.⁹

Różnice geograficzne w epidemiologii keratoconus

Istnieją wyraźne różnice geograficzne w występowaniu keratoconus. Najwyższą częstość występowania obserwuje się w krajach Bliskiego Wschodu, Azji Południowej oraz w niektórych regionach Indii.¹⁰¹¹ Dla przykładu:

W Arabii Saudyjskiej, prowincja Najran wykazała częstość występowania 87,3 przypadku na 100 000 osób z zapadalności 28,47 na 100 000.¹²
W Izraelu wśród młodych arabskich studentów częstość występowania wyniosła 3,18%.¹³
W centralnych Indiach badanie oparte na populacji wykazało częstość występowania keratoconus na poziomie 2,3%.¹⁴
W Kolumbii zapadalność w populacji ogólnej wynosiła 10,36 na 100 000 mieszkańców.¹⁵
W Szwecji oszacowana częstość występowania keratoconus wyniosła 169,5 na 100 000 osób, z roczną zapadalnością 11,8 na 100 000.¹⁶
W Meksyku badanie wśród młodzieży wykazało częstość występowania na poziomie 1,8%.¹⁷
W Trynidadzie badanie wśród uczniów szkół średnich wykazało częstość występowania 0,46%, przy czym 47,7% uczestników było zagrożonych rozwojem keratoconus.¹⁸

Czynniki środowiskowe wpływające na epidemiologię keratoconus

Czynniki środowiskowe mogą przyczyniać się do znacznej zmienności w częstości występowania keratoconus. Lokalizacje geograficzne z dużą ilością słońca i gorącym klimatem, takie jak Indie i Bliski Wschód, mają wyższą częstość występowania niż miejsca z chłodniejszym klimatem i mniejszą ilością słońca, takie jak Finlandia, Dania, Minnesota, Japonia i Rosja.¹⁹

Kraje Bliskiego Wschodu oraz części Indii charakteryzują się gorącym i słonecznym klimatem z bardzo małą ilością opadów, co odróżnia je od innych regionów. Klimat może więc wpływać na rozwój keratoconus, szczególnie poprzez uszkodzenia oksydacyjne spowodowane nadmierną ekspozycją na promieniowanie ultrafioletowe, które może powodować zmiany enzymatyczne lub modulację enzymów, prowadzące stopniowo do zmian w kolagenie.²⁰

Najnowsze badania wskazują również na związek między zanieczyszczeniem powietrza a keratoconus. Drobne cząstki stałe (PM2.5 i PM10) oraz dwutlenek azotu (NO2) mogą nasilać tę chorobę. Badania potwierdziły pozytywną korelację między poziomem drobnych cząstek a częstością występowania keratoconus.²¹²²

Różnice etniczne w epidemiologii keratoconus

Różnice etniczne mogą wyjaśniać rozbieżności w raportowanej częstości występowania keratoconus. Raporty z dwóch badań w Wielkiej Brytanii wykazały częstość występowania 4,4 i 7,5 razy większą u osób pochodzenia azjatyckiego (indyjskiego, pakistańskiego i bangladeskiego) w porównaniu z białymi Europejczykami.²³

W Stanach Zjednoczonych keratoconus jest częstszy wśród osób czarnoskórych i pochodzenia latynoamerykańskiego niż wśród białych, z ilorazami szans odpowiednio 1,57 i 1,43.²⁴ Badania przeprowadzone w USA na podstawie danych Medicaid i CHIP wykazały, że keratoconus występuje częściej w populacji czarnoskórych, zwłaszcza wśród kobiet, a diagnoza często jest opóźniona u tych pacjentów.²⁵

Warto zauważyć, że w Nowej Zelandii osoby pochodzenia z wysp Pacyfiku miały wyższe ryzyko rozwoju ostrego obrzęku rogówki (komplikacji keratoconus) w porównaniu z osobami pochodzenia europejskiego.²⁶

Wpływ płci i wieku na epidemiologię keratoconus

Keratoconus dotyka obu płci, choć nie jest jasne, czy istnieją znaczące różnice między mężczyznami a kobietami.²⁷ Niektóre badania sugerują brak istotnych różnic w częstości występowania i zapadalności między płciami,²⁸ podczas gdy inne wskazują na przewagę jednej płci:

W badaniu kolumbijskim ogólny stosunek zapadalności mężczyzn do kobiet wynosił 1,60.²⁹
W Szwecji 74,2% zarejestrowanych pacjentów stanowili mężczyźni.³⁰
W badaniu z Meksyku keratoconus dotykał 66% kobiet i 33,3% mężczyzn wśród zdiagnozowanych pacjentów.³¹
Inne badanie wykazało, że po dostosowaniu do wieku, współczynnik ryzyka dla keratoconus był 1,295 razy wyższy u kobiet w porównaniu z mężczyznami.³²

Jeśli chodzi o wiek, keratoconus typowo pojawia się we wczesnej młodości i postępuje przez drugą i trzecią dekadę życia. Początek choroby zazwyczaj przypada na okres dojrzewania, a progresja trwa do około 30-40 roku życia.³³³⁴

Najwyższą zapadalność obserwuje się w grupie wiekowej 20-30 lat. W Szwecji średnia roczna zapadalność była najwyższa w dekadzie 21-30 lat, wynosząc 26,1 na 100 000.³⁵ Progresja choroby jest zazwyczaj szybsza u młodszych pacjentów.³⁶

Czynniki ryzyka w epidemiologii keratoconus

Wyższą częstość występowania keratoconus stwierdzono u pacjentów z następującymi czynnikami ryzyka:

Pocieranie oczu – Uważane za jeden z najważniejszych czynników ryzyka keratoconus.³⁷ Liczne badania potwierdzają związek między pocieraniem oczu a rozwojem lub progresją keratoconus.³⁸³⁹
Historia rodzinna – Większość przypadków keratoconus pojawia się spontanicznie, chociaż około 14% przypadków przedstawia dowody na genetyczną transmisję. Pacjent z keratoconus ma 15-67 razy większe ryzyko rozwoju keratoconus niż osoba bez rodzinnej historii tej choroby.⁴⁰
Spokrewnienia krewniacze – Badania wykazały znaczący bezpośredni związek między keratoconus a pokrewieństwem, z wyższym ryzykiem rozwoju i większą ciężkością choroby u pacjentów, których rodzice byli spokrewnieni w pierwszym stopniu.⁴¹
Atopia i alergie – Istnieją dowody sugerujące potencjalny związek między schorzeniami atopowymi a keratoconus.⁴²
Powiązane choroby – Keratoconus może współistnieć z innymi chorobami oka i schorzeniami ogólnoustrojowymi. Powszechnie rozpoznane powiązania oczne obejmują wiosenne zapalenie rogówki i spojówek, barwnikowe zwyrodnienie siatkówki i wrodzoną ślepotę Lebera. Systemowe powiązania mogą obejmować choroby tkanki łącznej (np. zespoły Ehlersa-Danlosa i Marfana), wypadanie zastawki mitralnej, atopowe zapalenie skóry i zespół Downa.⁴³

Aspekty kliniczne istotne dla epidemiologii keratoconus

Keratoconus jest zwykle chorobą obustronną, choć często asymetryczną.⁴⁴ W badaniu z Meksyku wykazano obustronność u 88,8% pacjentów, chociaż była ona asymetryczna.⁴⁵

W pediatrycznej populacji keratoconus ma unikalne cechy, które odróżniają go od keratoconus u dorosłych – jego prezentacja, postęp, biomechaniczna sztywność rogówki i jego związek z alergią i pocieraniem oczu. U dzieci keratoconus jest znacznie cięższy w momencie diagnozy w porównaniu do dorosłych. Pediatryczny keratoconus ma również wyższy wskaźnik i szybkość progresji.⁴⁶

Korzyści z wczesnego wykrywania w kontekście epidemiologii

Wczesne wykrywanie keratoconus stało się coraz bardziej istotne od czasu wprowadzenia sieciowania kolagenu rogówki (CXL). Jest to fotochemiczne leczenie rogówki światłem UV-A po zastosowaniu ryboflawinny (witaminy B2), które może zatrzymać postęp keratoconus w 98,3% oczu, nawet w relatywnie zaawansowanych przypadkach.⁴⁷

Badania przesiewowe wśród populacji wysokiego ryzyka, takich jak młodzież na Bliskim Wschodzie, mogą być uzasadnione w celu poprawy wczesnego wykrywania i interwencji.⁴⁸ W kontekście zapobiegania progresji choroby, szczególnie ważne jest monitorowanie młodszych pacjentów, u których choroba zazwyczaj postępuje szybciej.⁴⁹

Region/Kraj	Częstość występowania	Najważniejsze czynniki
Arabia Saudyjska (Riyadh)	4,79% (1:21) u dzieci i młodzieży	Genetyka, klimat, ekspozycja na słońce
Bliski Wschód	Do 5% populacji	Gorący klimat, ekspozycja na UV, czynniki genetyczne
Centralne Indie	2,3% (2300 na 100 000)	Ekspozycja na słońce, czynniki genetyczne
Australia	1,19% (1:84) u młodych dorosłych	Palenie tytoniu, wiek
Niemcy	0,49% (1:204)	Nowoczesna diagnostyka (obrazowanie Scheimpfluga)
Szwecja	169,5 na 100 000	Wyższa zapadalność w grupie 21-30 lat
USA	54,5 na 100 000	Wyższa częstość u osób czarnoskórych i pochodzenia latynoamerykańskiego
Rosja	0,3 na 100 000	Chłodniejszy klimat, mniejsza ekspozycja na słońce

Wyzwania epidemiologiczne w badaniach nad keratoconus

Próby ustalenia szacunków częstości występowania i zapadalności na keratoconus w populacji wykazały dużą zmienność w ostatnim stuleciu.⁵⁰ Wiele czynników przyczynia się do tej zmienności:

Różnice w kryteriach diagnostycznych i metodologii badań⁵¹
Różnice w zastosowanych technologiach diagnostycznych (nowoczesne metody wykrywają więcej przypadków)⁵²
Różnice w źródłach danych (rejestry szpitalne vs. badania populacyjne)⁵³
Brak świadomości choroby u pacjentów (60% pacjentów z keratoconus w jednym badaniu nie było świadomych swojej diagnozy)⁵⁴

Badania populacyjne oparte na przesiewowych są najlepszą metodologią do oceny prawdziwej częstości występowania choroby.⁵⁵ Większość badań dotyczących częstości występowania przeprowadzono w szpitalach lub klinikach ze względu na możliwość zbierania danych. Jednak zwykle niedoszacowują one częstość występowania choroby, ponieważ pacjenci są zazwyczaj objawowi, a wczesne i bardziej subtelne formy mogą być przeoczone.⁵⁶

Znaczenie ekonomiczne epidemiologii keratoconus

Aspekty ekonomiczne keratoconus są istotnym elementem jego epidemiologii. W 2019 roku w Stanach Zjednoczonych średni skorygowany o inflację dożywotni koszt leczenia keratoconus wynosił 28 766,69 USD, z łącznym obciążeniem ekonomicznym wynoszącym 3,8 miliarda USD.⁵⁷ Ze względu na wczesny początek, keratoconus może wpływać na edukację, pracę, życie społeczne i rodzinne, jeśli nie jest leczony.⁵⁸

Zrozumienie prawdziwej częstości występowania tej choroby jest ważne z perspektywy zdrowia publicznego, ponieważ może wpływać na decyzje dotyczące alokacji zasobów i przyszłe programy przesiewowe.⁵⁹

Przyszłość epidemiologii keratoconus

Nasza wiedza na temat patofizjologii keratoconus znacznie się rozwinęła i będzie nadal rozwijana dzięki niedawno opracowanym technologiom genetycznym, takim jak sekwencjonowanie całego eksonu lub genomu oraz technologie asocjacji genomowej. Ostatecznie informacje te pomogą w opracowaniu ukierunkowanych terapii, lepszej wczesnej diagnostyki, a potencjalnie nawet lepszego rokowania.⁶⁰

Zwiększona świadomość na temat keratoconus wśród okulistów doprowadziła do wzrostu liczby diagnoz i częstości występowania.⁶¹ Z wcześniejszą diagnozą i szybką interwencją z wykorzystaniem sieciowania rogówki, pacjenci mogą zachować odpowiednią funkcję wzrokową przy użyciu soczewek okularowych lub kontaktowych przez całe życie.⁶²

Podsumowując, epidemiologia keratoconus wykazuje znaczną zmienność geograficzną i etniczną, z najwyższą częstością występowania na Bliskim Wschodzie i w Azji Południowej. Czynniki środowiskowe, genetyczne i behawioralne wpływają na jego rozwój, z pocieraniem oczu jako ważnym modyfikowalnym czynnikiem ryzyka. Wczesne wykrywanie staje się coraz ważniejsze ze względu na dostępność skutecznych terapii zatrzymujących progresję choroby.

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Materiały źródłowe

#1 Keratoconus – UpToDate
https://www.uptodate.com/contents/keratoconus
Keratoconus is a noninflammatory disorder of the cornea with genetic and environmental risk factors. It is characterized by progressive thinning and cone-shaped protrusion of the cornea leading to visual impairment. Patients present at puberty or early adulthood and experience disease progression through the fourth decade. Prevalence in the general population is reported as ranging from 50 to 230 per 100,000. There is no significant sex difference in incidence and prevalence. Some evidence suggests a higher incidence in Asian people from the Indian subcontinent. Another study did not support the association between Asian persons and keratoconus, but did find that Black and Latino persons have approximately 50 percent higher odds of having keratoconus when compared with White persons.
#1
https://journals.lww.com/sjop/fulltext/2022/36010/keratoconus_epidemiology__a_review.2.aspx
Keratoconus is an ectatic corneal disease that affects both men and women, usually at a young age. Risk factors such as eye rubbing, environmental and genetic factors contribute to its pathogenesis. Keratoconus presents a variable prevalence, being as high as 5% of the population in the Middle East. […] Over the last years, researchers have found that the prevalence and incidence of keratoconus cases in the population presented a high variability. There are different explanations for this variability, including the heterogeneity of epidemiological studies and the lack of well-defined criteria for the definition and classification of keratoconus. […] The true prevalence of the disease can be determined more accurately by population-based screening studies. […] A recent meta-analysis that included more than 50 million individuals from 15 countries determined that the global prevalence of keratoconus was 138/100,000.
#2
https://journals.lww.com/ijo/fulltext/2013/61080/epidemiology_of_keratoconus.4.aspx
Ethnic differences may account for the differences in the reported prevalence of keratoconus. The reports of two surveys in the UK indicated a prevalence 4.4 and 7.5 times greater for Asian (Indian, Pakistani, and Bangladeshi) subjects compared with white Caucasians. […] Family history of keratoconus has been found to be very variable and a high prevalence of keratoconus in a sample population can change the reported rate of a positive family history. […] Keratoconus affects both genders, although it is unclear whether significant differences between males and females exist. […] A higher prevalence of keratoconus has been found in patients with eye rubbing. […] Keratoconus usually occurs bilaterally but asymmetry is common. […] The natural history of disease is variable. Typically at about the age of puberty, the keratoconic process starts and usually, over a period of next 10-20 years, the process continues until the progression gradually stops.
#2 Keratoconus | Theialife
https://www.theialife.com/keratoconus
1 in 2000 affected by keratoconus globally […] The global prevalence of keratoconus was found to be 138 per 100,000 people, based on a study that involved over 50 million individuals from 15 different countries. […] Ongoing management and monitoring are crucial to address any changes in visual acuity and corneal morphology.
#3
https://journals.lww.com/ijo/fulltext/2013/61080/epidemiology_of_keratoconus.4.aspx
Prevalence of keratoconus is variable in different parts of the world. Environmental and ethnic factors and the cohort of patients selected for such studies may explain the wide variation in the reported rates. […] The reported prevalence of keratoconus varies widely depending upon the geographic location, diagnostic criteria used, and the cohort of patients selected. The prevalence in studies can range from 0.3 per 100,000 in Russia to 2300 per 100,000 in Central India (0.0003%-2.3%). […] Environmental factors may contribute to the wide variation in prevalence. Geographical locations with plenty of sunshine and hot weather such as India and the Middle East have higher prevalence than locations with cooler climates and less sunshine such as Finland, Denmark, Minnesota, Japan, and Russia.
#4 Keratoconus epidemiology: A review
https://pmc.ncbi.nlm.nih.gov/articles/PMC9375461/
Keratoconus presents a variable prevalence, being as high as 5% of the population in the Middle East. […] The true prevalence of the disease can be determined more accurately by population-based screening studies. […] A recent meta-analysis that included more than 50 million individuals from 15 countries determined that the global prevalence of keratoconus was 138/100,000. […] The prevalence of keratoconus is variable and affects up to 5% of the population in some regions of the world, as the Middle East.
#5
https://journals.lww.com/sjop/fulltext/2022/36010/keratoconus_epidemiology__a_review.2.aspx
The prevalence of keratoconus is variable and affects up to 5% of the population in some regions of the world, as the Middle East. Both sexes are affected, reaching different ethnic groups. Environmental factors such as sunlight exposure and dry weather, eye rubbing, and genetic factors contribute to its pathogenesis.
#6 Epidemiology of Keratoconus | Ento Key
https://entokey.com/epidemiology-of-keratoconus-2/
An important population-based study including 4667 subjects was conducted in central India. Using keratometric values of more than 48 diopters (D) as a cutoff, the authors found a prevalence of keratoconus of 2.3%. […] Other prevalence studies, including population-based surveys from Asia and the Middle East using corneal topographic and tomographic values, found a higher prevalence of keratoconus in these parts of the world, ranging from 0.9% to 3.3%. […] In 2018 performed a cross-sectional, observational, multicenter study collecting data from 522 pediatric patients from 6 years to 21 years of age who were seen at multiple nonophthalmic emergency departments in Saudi Arabia. Bilateral corneal measurements were performed using a Scheimpflug corneal tomography system. Two masked examiners established the diagnosis of keratoconus using both objective and subjective screening criteria. Final keratoconus prevalence was 4.79% (95% confidence interval [CI]: 2.96 6.62) or 1:21 patients, the highest reported so far.
#7
https://link.springer.com/article/10.1007/s00417-023-06132-y
Keratoconus appears to be a rare corneal disease with a prevalence previously estimated at 1:2000. The aim of our study was to investigate the prevalence of keratoconus in a large German cohort and to evaluate possible associated factors. […] The prevalence for keratoconus in the German cohort was 0.49% (1:204; 95% CI: 0.360.64%) and was approximately equally distributed across the age decades. […] The prevalence of keratoconus disease in a mainly Caucasian population is approximately tenfold higher than previously reported in the literature using latest technologies (Scheimpflug imaging). […] The prevalence of keratoconus varies in the literature between 1:20 and 1:2000 in different regions and study designs. […] In our predominantly Caucasian cohort, the prevalence was 0.49%, which was much lower than in the Arab population and approximately 23 times higher than in the analyses using health claim data.
#8
https://link.springer.com/article/10.1007/s00417-023-06132-y
The population-based prevalence of Keratoconus was estimated in a Norwegian register study using data from the Norwegian Patient Registry and resulting in a prevalence estimate of 0.19%. […] We conducted a population-based study and systematically examined a large Caucasian cohort at age 40 years and above regarding keratoconus prevalence using modern Scheimpflug imaging and consecutive double grading of conspicuous cases. […] In conclusion, the prevalence of keratoconus in the German population is approximately tenfold higher (0.49%) than previously reported in the literature using latest technologies, namely Scheimpflug imaging.
#9 How common is an eye condition called Keratoconus among young Australian adults? The Raine Study | The Raine Study
https://rainestudy.org.au/research-paper/how-common-is-an-eye-condition-called-keratoconus-among-young-australian-adults-the-raine-study/
Keratoconus is a condition of the eye that affects the cornea, the clear 'window’ or 'covering’ at the very front of the eye. Keratoconus tends to start off relatively mild and may not be noticeable; however, it does gradually get worse and will eventually reduce the quality of vision and lead to vision loss. […] This manuscript aims to determine how many young Australian adults have keratoconus and investigate what factors might increase an individuals risk of developing keratoconus. […] The study found that approximately 1 in 84 participants of the Raine Study Gen2-20 follow-up were classified as having keratoconus. […] Keratoconus was associated with cigarette smoking and older age. Keratoconus was also associated with poorer vision, a requirement for a stronger glasses prescription (more astigmatism and more short-sighted) and various measures of the cornea (not surprising given keratoconus is known to affect cornea).
#10 Epidemiology of Keratoconus Worldwide
https://openophthalmologyjournal.com/VOLUME/12/PAGE/289/FULLTEXT/
In our paper, we will discuss the epidemiological differences that are present around the world as it is expected that the difference may be due to the genetic environment or habitual and nutritional causes. […] As we know that the cause is unknown until present day but there is a large epidemiological difference between different areas of the world and different ethnicities, and there is an increase in the number of cases occurring nowadays in the world which may be due to technology advancement or better methods of diagnosis. […] The incidence of keratoconus differs according to different publications and paper and also it differs according to the geographical location around the world. […] Higher incidence in other geographical areas was detected in New Zealand and Asir province in Saudi Arabia, and in another study, the prevalence in population based in Israeli Arabs was recorded to be 3.18%.
#11 Keratoconus – EyeWiki
https://eyewiki.org/Keratoconus
Keratoconus is the most common corneal ectatic disorder where the central or paracentral cornea undergoes progressive thinning and steepening, causing high irregular astigmatism and poor quality of vision. […] It was thought to be rare, but more awareness among ophthalmologists about the disease led to an increase in diagnosis and prevalence, which varies between regions. It is considerably higher in the Middle East, India, China, and Australia. […] The prevalence of keratoconus is often reported to be 1 in 700. […] The majority of cases of keratoconus are bilateral, but often asymmetric. […] Onset is typically in early adolescence and progresses into the mid-20s and 30s. However, cases may begin much earlier or later in life, and progression may also persist beyond the 30s. […] Since the availability of corneal collagen crosslinking, patients are usually followed on a 3- to 6-month basis to monitor the progression of the corneal thinning and steepening and the resultant visual changes.
#12 Keratoconus Epidemiology Presentations in Najran Province | OPTO
https://www.dovepress.com/keratoconus-epidemiology-presentations-at-najran-province-saudi-arabia-peer-reviewed-fulltext-article-OPTO
Keratoconus prevalence in Najran Province was found to be 87.3 cases per 100,000 people with an incidence of 28.47 per 100,000 cases. […] Genetic and environmental factors could have a substantial role in the increased rate of keratoconus presentation in Najran Province. Screening programmes should dedicate more attention to late presentation to improve prevention and early detection. More studies on keratoconus epidemiology in Saudi Arabia are needed. […] The prevalence and incidence of KC in Najran Province is high in comparison to figures reported in other studies. The presentation of KC in Najran could be influenced by numerous factors, including genetics and environmental aspects. Knowledge of the epidemiology of KC is important for treatment plans and management of the disease.
#13 Epidemiology of Keratoconus Worldwide
https://openophthalmologyjournal.com/VOLUME/12/PAGE/289/FULLTEXT/
However, different studies have illustrated that there is a difference in incidence according to ethnicity. […] In another study, the prevalence of Keratoconus among Young Arab Students in Israel Data of 314 participants was analyzed and found to be 3.18%. […] The understanding of the epidemiology will help us later in the treatment of the disease so important step is to identify the cause and the most important is preventing the visual impairment in this important part of the society.
#14 Epidemiology of Keratoconus | Ento Key
https://entokey.com/epidemiology-of-keratoconus-2/
An important population-based study including 4667 subjects was conducted in central India. Using keratometric values of more than 48 diopters (D) as a cutoff, the authors found a prevalence of keratoconus of 2.3%. […] Other prevalence studies, including population-based surveys from Asia and the Middle East using corneal topographic and tomographic values, found a higher prevalence of keratoconus in these parts of the world, ranging from 0.9% to 3.3%. […] In 2018 performed a cross-sectional, observational, multicenter study collecting data from 522 pediatric patients from 6 years to 21 years of age who were seen at multiple nonophthalmic emergency departments in Saudi Arabia. Bilateral corneal measurements were performed using a Scheimpflug corneal tomography system. Two masked examiners established the diagnosis of keratoconus using both objective and subjective screening criteria. Final keratoconus prevalence was 4.79% (95% confidence interval [CI]: 2.96 6.62) or 1:21 patients, the highest reported so far.
#15 Colombian Ocular Diseases Epidemiology Study (CODES): incidence and sociodemographic characterisation of keratoconus between 2015 and 2020 | BMJ Open Ophthalmology
https://bmjophth.bmj.com/content/8/1/e001238
Objective To estimate the incidence and describe the demographic characteristics of keratoconus (KC) in Colombia using national health registry data between January 1st 2015 and December 31th 2020. […] We performed the first nationwide, population-based study of KC in Latin America, finding distribution patterns similar to those reported in the literature. This study provides valuable information on the epidemiology of KC in Colombia, which is helpful in the development of policies for the diagnosis, prevention and treatment of the disease. […] The incidence rate in the general population was 10.36 (95% CI 10.08 to 10.64) per 100000 inhabitants. […] The overall male to female incidence rate ratio was 1.60. […] The incidence of KC increased from 9.62 (95% CI 9.52 to 9.71) in 2015 to 14.02 (95% CI 13.95 to 14.08) in 2019. […] We found an incidence of 10.36 (95% CI 10.08 to 10.64) cases per 100000 inhabitants, an expected incidence for a Latin American population (Hispanic heritage) compared with Asian populations which report higher incidences.
#16
https://open.lnu.se/index.php/sjovs/article/view/3654
The purpose of this study was to estimate the prevalence and incidence of keratoconus in Sweden. […] From 2010 to 2020, 16,055 patients were registered with keratoconus in the Swedish Patient Register, giving a total estimated keratoconus prevalence of 169.5 per 100,000 (95% CI: 144.9-194.1), 74.2% were male. The estimated annual incidence of keratoconus was 11.8 per 100,000 (95% CI: 5.1-18.5). The average annual incidence was highest in the decade 21 to 30 years, 26.1 per 100,000 (95% CI: 16.1-36.1). For the age group 0 to 40 years, the estimated incidence of keratoconus was 22.5 per 100,000 (95% CI: 13.7-32.3). […] Keratoconus should not be regarded as an uncommon condition. The prevalence of keratoconus may be even higher because of under-registration among older citizens. The estimated prevalence and incidence of keratoconus in Sweden is comparable to estimated prevalence in Norway.
#17 Prevalence of keratoconus in an adolescent population | Revista Mexicana de OftalmologÃa
https://www.elsevier.es/es-revista-revista-mexicana-oftalmologia-321-articulo-prevalence-keratoconus-in-an-adolescent-S0187451914000316
Keratoconus is an idiopathic and progressive disease, where the cornea develops an irregular and conical shape, being the most common form of dystrophy or corneal ectasia, developing between the age of 12 and 20. In Mexico, the epidemiological information about the pathology is scarce. […] The prevalence rate of keratoconus was 1.8%, affecting 66% of females and 33.3% of males. The mean age of presentation was 16.1 years. […] In Mexico, the research on keratoconus is scarce; the articles published show statistics that are similar to those in international literature, which indicates a higher prevalence in male patients with a mean age of 24.5 years. […] Our study demonstrated bilaterality in 8 (88.8%) patients, although it was asymmetric. […] The relevance of the management of these patients is important to note, as 33.3% of patients ended their treatment in penetrating keratoplasty in our study, clearly indicating that patients are being subjected to radical treatments. […] The importance of performing similar protocols in populations of this age group is necessary to establish statistics that can help identify the incidence and prevalence of keratoconus in populations of similar geographic areas (this study was conducted in the north of Mexico).
#18 Epidemiology of Keratoconus and Associated Risk Factors in High School Students in Couva, Trinidad.
https://uwispace.sta.uwi.edu/items/bc8e518b-a5d6-4108-bcc7-bb181227eecf
Aim: To determine the prevalence of keratoconus and associated risk factors of keratoconus among high school students in Couva. […] Results: The prevalence of keratoconus was 0.46% (2/432) and 47.7% of the participants were at risk of having keratoconus. […] Family history was found to be significantly associated with keratoconus (OR = 142.333, 95% CI: 7.1192845.711; p=0.00). […] Conclusion: This prevalence of keratoconus and those at risk of having keratoconus among high school students in Couva was significantly high when compared with global findings. […] Awareness about keratoconus among high school children in Trinidad is highly advised for early detection of keratoconus and those at risk.
#19
https://journals.lww.com/ijo/fulltext/2013/61080/epidemiology_of_keratoconus.4.aspx
Prevalence of keratoconus is variable in different parts of the world. Environmental and ethnic factors and the cohort of patients selected for such studies may explain the wide variation in the reported rates. […] The reported prevalence of keratoconus varies widely depending upon the geographic location, diagnostic criteria used, and the cohort of patients selected. The prevalence in studies can range from 0.3 per 100,000 in Russia to 2300 per 100,000 in Central India (0.0003%-2.3%). […] Environmental factors may contribute to the wide variation in prevalence. Geographical locations with plenty of sunshine and hot weather such as India and the Middle East have higher prevalence than locations with cooler climates and less sunshine such as Finland, Denmark, Minnesota, Japan, and Russia.
#20 Epidemiology of Keratoconus Worldwide
https://openophthalmologyjournal.com/VOLUME/12/PAGE/289/FULLTEXT/
This difference in keratoconus between different populations is probably multifactorial in terms of genetic, nutrition and environmental factors. […] The Middle East countries in particular, as well as parts of India, are characterized by hot and sunny climates with very little rain which is distinctive from the other countries. Therefore, the climate may influence the development of keratoconus, especially the oxidative damage caused by excessive sun exposure to ultraviolet light rays that may cause enzymatic change or modulation of the enzymes which gradually lead to change in collagen or there may be a difference in genetic or inheritance factor in these societies, or there could be a variety in different styles of life with nutrition that plays a role? […] Keratoconus is a worldwide disorder and the prevalence is different among different ethnic groups in the same geographical part of the world. This has been supported by numerous epidemiological studies that show ethnicity and environmental factors are likely to play a major cause in the etiology of the disease.
#21 New Evidence Strengthens the Link Between Air Pollution and Keratoconus
https://www.reviewofoptometry.com/article/new-evidence-strengthens-the-link-between-air-pollution-and-keratoconus
A recent study published in Ophthalmic Epidemiology highlights the connection between air pollution and keratoconus, revealing that fine particulate matter (PM2.5 and PM10) and nitrogen dioxide (NO2) may aggravate the condition. […] With keratoconus prevalence varying globally, the findings underscore the importance of understanding environmental influences on ocular health and disease progression. […] Researchers specifically investigated the effects of particles matter (PM) of 2.5m and 10m, but also nitrogen dioxide (NO2) and the correlation with the prevalence in the scientific literature. […] The prevalence of keratoconus ranged from 4.29 per 100,000 inhabitants (Taiwan) to 6,690 per 100,000 (Saudi Arabia). […] These current analyses confirm the positive correlation between the fine particles levels and the prevalence of keratoconus, The authors stated in their paper.
#22 New Evidence Strengthens the Link Between Air Pollution and Keratoconus
https://www.reviewofoptometry.com/article/new-evidence-strengthens-the-link-between-air-pollution-and-keratoconus
This research suggests pollution can affect the cornea both directly and indirectly, they said. […] Although further research is needed, this study appears to show that air pollution influences keratoconus development indirectly by stimulating eye rubbing and atopy, and that fine particles may directly affect corneal structures and increase cell apoptosis, the authors concluded.
#23
https://journals.lww.com/ijo/fulltext/2013/61080/epidemiology_of_keratoconus.4.aspx
Ethnic differences may account for the differences in the reported prevalence of keratoconus. The reports of two surveys in the UK indicated a prevalence 4.4 and 7.5 times greater for Asian (Indian, Pakistani, and Bangladeshi) subjects compared with white Caucasians. […] Family history of keratoconus has been found to be very variable and a high prevalence of keratoconus in a sample population can change the reported rate of a positive family history. […] Keratoconus affects both genders, although it is unclear whether significant differences between males and females exist. […] A higher prevalence of keratoconus has been found in patients with eye rubbing. […] Keratoconus usually occurs bilaterally but asymmetry is common. […] The natural history of disease is variable. Typically at about the age of puberty, the keratoconic process starts and usually, over a period of next 10-20 years, the process continues until the progression gradually stops.
#24 Keratoconus: Practice Essentials, Background, Pathophysiology
https://emedicine.medscape.com/article/1194693-overview
Keratoconus’s rate of prevalence varies from 0.2 and 4,790 per 100,000 persons. The great variance depends upon the diagnostic criteria, better detection technology, different research protocols, geographic location and ethnicity of the people studied. The middle east has the highest prevalence whereas areas like Russia and Finland reported very low prevalences. The prevalence of keratoconus varies by ethnicity. Keratoconus is more common in blacks and Latinos than in whites, with odds ratios of 1.57 and 1.43, respectively. […] It is commonly an isolated ocular condition but sometimes coexists with other ocular and systemic diseases. Commonly recognized ocular associations have included vernal keratoconjunctivitis, retinitis pigmentosa, and Leber congenital amaurosis. Systemic putative associations include many of the connective tissue disorders (eg, Ehlers-Danlos and Marfan syndromes), mitral valve prolapse, atopic dermatitis, and Down syndrome, although none of these was found in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) study.
#25 Prevalence and Economic Burden of Keratoconus in the United States | Harvard Medical School Department of Ophthalmology
https://eye.hms.harvard.edu/publications/prevalence-and-economic-burden-keratoconus-united-states
In 2019, the average inflation-adjusted lifetime cost of keratoconus treatment was USD 28,766.69, with a cumulative economic burden of USD 3.8 billion. […] In the United States, keratoconus is most prevalent in individuals 18 to 39 years of age. The keratoconus prevalence is higher in the Black population, specifically female individuals, and the diagnosis is often delayed in these patients.
#26 Acute Corneal Hydrops – EyeWiki
https://eyewiki.org/Acute_Corneal_Hydrops
In patients with keratoconus, the incidence of acute corneal hydrops is reported to be between 0.2% and 2.8%. […] Acute corneal hydrops presents most commonly between 20 and 40 years of age. […] Males may have up to double the risk of females to develop ACH. […] The role of family history in its etiology is highly variable. […] In New Zealand, individuals of Pacific Island ethnicity were found to have a higher risk of hydrops compared to individuals of European descent. […] In the UK, there was a higher prevalence of keratoconus and ACH among South Asian and Black patients.
#27
https://journals.lww.com/ijo/fulltext/2013/61080/epidemiology_of_keratoconus.4.aspx
Ethnic differences may account for the differences in the reported prevalence of keratoconus. The reports of two surveys in the UK indicated a prevalence 4.4 and 7.5 times greater for Asian (Indian, Pakistani, and Bangladeshi) subjects compared with white Caucasians. […] Family history of keratoconus has been found to be very variable and a high prevalence of keratoconus in a sample population can change the reported rate of a positive family history. […] Keratoconus affects both genders, although it is unclear whether significant differences between males and females exist. […] A higher prevalence of keratoconus has been found in patients with eye rubbing. […] Keratoconus usually occurs bilaterally but asymmetry is common. […] The natural history of disease is variable. Typically at about the age of puberty, the keratoconic process starts and usually, over a period of next 10-20 years, the process continues until the progression gradually stops.
#28 Keratoconus – UpToDate
https://www.uptodate.com/contents/keratoconus
Keratoconus is a noninflammatory disorder of the cornea with genetic and environmental risk factors. It is characterized by progressive thinning and cone-shaped protrusion of the cornea leading to visual impairment. Patients present at puberty or early adulthood and experience disease progression through the fourth decade. Prevalence in the general population is reported as ranging from 50 to 230 per 100,000. There is no significant sex difference in incidence and prevalence. Some evidence suggests a higher incidence in Asian people from the Indian subcontinent. Another study did not support the association between Asian persons and keratoconus, but did find that Black and Latino persons have approximately 50 percent higher odds of having keratoconus when compared with White persons.
#29 Colombian Ocular Diseases Epidemiology Study (CODES): incidence and sociodemographic characterisation of keratoconus between 2015 and 2020 | BMJ Open Ophthalmology
https://bmjophth.bmj.com/content/8/1/e001238
Objective To estimate the incidence and describe the demographic characteristics of keratoconus (KC) in Colombia using national health registry data between January 1st 2015 and December 31th 2020. […] We performed the first nationwide, population-based study of KC in Latin America, finding distribution patterns similar to those reported in the literature. This study provides valuable information on the epidemiology of KC in Colombia, which is helpful in the development of policies for the diagnosis, prevention and treatment of the disease. […] The incidence rate in the general population was 10.36 (95% CI 10.08 to 10.64) per 100000 inhabitants. […] The overall male to female incidence rate ratio was 1.60. […] The incidence of KC increased from 9.62 (95% CI 9.52 to 9.71) in 2015 to 14.02 (95% CI 13.95 to 14.08) in 2019. […] We found an incidence of 10.36 (95% CI 10.08 to 10.64) cases per 100000 inhabitants, an expected incidence for a Latin American population (Hispanic heritage) compared with Asian populations which report higher incidences.
#30
https://open.lnu.se/index.php/sjovs/article/view/3654
The purpose of this study was to estimate the prevalence and incidence of keratoconus in Sweden. […] From 2010 to 2020, 16,055 patients were registered with keratoconus in the Swedish Patient Register, giving a total estimated keratoconus prevalence of 169.5 per 100,000 (95% CI: 144.9-194.1), 74.2% were male. The estimated annual incidence of keratoconus was 11.8 per 100,000 (95% CI: 5.1-18.5). The average annual incidence was highest in the decade 21 to 30 years, 26.1 per 100,000 (95% CI: 16.1-36.1). For the age group 0 to 40 years, the estimated incidence of keratoconus was 22.5 per 100,000 (95% CI: 13.7-32.3). […] Keratoconus should not be regarded as an uncommon condition. The prevalence of keratoconus may be even higher because of under-registration among older citizens. The estimated prevalence and incidence of keratoconus in Sweden is comparable to estimated prevalence in Norway.
#31 Prevalence of keratoconus in an adolescent population | Revista Mexicana de OftalmologÃa
https://www.elsevier.es/es-revista-revista-mexicana-oftalmologia-321-articulo-prevalence-keratoconus-in-an-adolescent-S0187451914000316
Keratoconus is an idiopathic and progressive disease, where the cornea develops an irregular and conical shape, being the most common form of dystrophy or corneal ectasia, developing between the age of 12 and 20. In Mexico, the epidemiological information about the pathology is scarce. […] The prevalence rate of keratoconus was 1.8%, affecting 66% of females and 33.3% of males. The mean age of presentation was 16.1 years. […] In Mexico, the research on keratoconus is scarce; the articles published show statistics that are similar to those in international literature, which indicates a higher prevalence in male patients with a mean age of 24.5 years. […] Our study demonstrated bilaterality in 8 (88.8%) patients, although it was asymmetric. […] The relevance of the management of these patients is important to note, as 33.3% of patients ended their treatment in penetrating keratoplasty in our study, clearly indicating that patients are being subjected to radical treatments. […] The importance of performing similar protocols in populations of this age group is necessary to establish statistics that can help identify the incidence and prevalence of keratoconus in populations of similar geographic areas (this study was conducted in the north of Mexico).
#32 Ten-year incidence of keratoconus in relation to sex, age, and thyroid gland dysfunction: a nationwide population-based cohort study (2009–2018)
https://atm.amegroups.org/article/view/124629/html
Keratoconus is a corneal ectatic disorder that often leads to visual impairment and may require corneal transplantation. However, its age and gender-based incidence and potential association with thyroid gland dysfunction (TGD) remain poorly understood. This study aims to clarify these aspects and investigate the possible connection between keratoconus and TGD. […] During the review period, 2,334 patients developed keratoconus before the 10-year mark. Females exhibited a higher keratoconus incidence (7.101 per 100,000 person-years) compared to males (5.559) (P0.001). After adjusting for age, the hazard ratio (HR) for keratoconus was 1.295 times higher [95% confidence interval (CI): 1.1931.406] in females compared to males. […] This study emphasizes a female predominance in keratoconus incidence and suggests a possible connection between hyperthyroidism and keratoconus. Furthermore, it affirms a higher incidence of keratoconus among young individuals.
#33 Keratoconus – EyeWiki
https://eyewiki.org/Keratoconus
Keratoconus is the most common corneal ectatic disorder where the central or paracentral cornea undergoes progressive thinning and steepening, causing high irregular astigmatism and poor quality of vision. […] It was thought to be rare, but more awareness among ophthalmologists about the disease led to an increase in diagnosis and prevalence, which varies between regions. It is considerably higher in the Middle East, India, China, and Australia. […] The prevalence of keratoconus is often reported to be 1 in 700. […] The majority of cases of keratoconus are bilateral, but often asymmetric. […] Onset is typically in early adolescence and progresses into the mid-20s and 30s. However, cases may begin much earlier or later in life, and progression may also persist beyond the 30s. […] Since the availability of corneal collagen crosslinking, patients are usually followed on a 3- to 6-month basis to monitor the progression of the corneal thinning and steepening and the resultant visual changes.
#34 Keratoconus: Practice Essentials, Background, Pathophysiology
https://emedicine.medscape.com/article/1194693-overview
Most keratoconus cases appear spontaneously, although approximately 14% of cases present with evidence of genetic transmission. A patient with keratoconus has a 15 to 67 times greater risk of developing keratoconus than an individual with no family history of keratoconus. […] Personal income, access to health care, and education levels have no known correlation with keratoconus. […] Keratoconus affects both males and females though the rate of prevalence is ambiguous given mixed results from various studies. […] KC typically presents in the early 20’s, though it can develop earlier, and then stabilizes by the fourth decades of life. KC progresses at various rates but tends to progress more rapidly in younger patients and stabilizes approximately 20 years after initial onset.
#35
https://open.lnu.se/index.php/sjovs/article/view/3654
The purpose of this study was to estimate the prevalence and incidence of keratoconus in Sweden. […] From 2010 to 2020, 16,055 patients were registered with keratoconus in the Swedish Patient Register, giving a total estimated keratoconus prevalence of 169.5 per 100,000 (95% CI: 144.9-194.1), 74.2% were male. The estimated annual incidence of keratoconus was 11.8 per 100,000 (95% CI: 5.1-18.5). The average annual incidence was highest in the decade 21 to 30 years, 26.1 per 100,000 (95% CI: 16.1-36.1). For the age group 0 to 40 years, the estimated incidence of keratoconus was 22.5 per 100,000 (95% CI: 13.7-32.3). […] Keratoconus should not be regarded as an uncommon condition. The prevalence of keratoconus may be even higher because of under-registration among older citizens. The estimated prevalence and incidence of keratoconus in Sweden is comparable to estimated prevalence in Norway.
#36 Keratoconus: Practice Essentials, Background, Pathophysiology
https://emedicine.medscape.com/article/1194693-overview
Most keratoconus cases appear spontaneously, although approximately 14% of cases present with evidence of genetic transmission. A patient with keratoconus has a 15 to 67 times greater risk of developing keratoconus than an individual with no family history of keratoconus. […] Personal income, access to health care, and education levels have no known correlation with keratoconus. […] Keratoconus affects both males and females though the rate of prevalence is ambiguous given mixed results from various studies. […] KC typically presents in the early 20’s, though it can develop earlier, and then stabilizes by the fourth decades of life. KC progresses at various rates but tends to progress more rapidly in younger patients and stabilizes approximately 20 years after initial onset.
#37
https://scite.ai/reports/10.4103/sjopt.sjopt_204_21
Keratoconus is an ectatic corneal disease that affects both men and women, usually at a young age. Risk factors such as eye rubbing, environmental and genetic factors contribute to its pathogenesis. Keratoconus presents a variable prevalence, being as high as 5% of the population in the Middle East. […] The prevalence of KC, a bilateral and asymmetric progressive corneal thinning and steeping, was 138 per 100,000 people worldwide according to a recent meta-analysis. However, the prevalence of KC varied, being as high as 5% in the Middle East. In this study, the prevalence of KC among participants was high at 4%. […] In Saudi Arabia, it was discovered that KC has been the main reason for corneal transplantation in the past 20 years. Eye rubbing is considered one of the most significant risk factors for KC based on available data.
#38 Epidemiology of Keratoconus | SpringerLink
https://link.springer.com/chapter/10.1007/978-981-19-4262-4_1
Keratoconus is a progressive disease characterized by thinning of the corneal stroma leading to irregular astigmatism and defective vision. It is mostly bilateral. The incidence of the condition is rising with various screening tools available for laser refractive surgery. The prevalence varies in different parts of the world. Various local and systemic conditions are associated with keratoconus. Recently, eye rubbing has been attributed as an aggravating factor. […] Krachmer JH. Eye rubbing can cause keratoconus. Cornea. 2004;23(6):53940. […] Weed KH, MacEwen CJ, Giles T, Low J, McGhee CN. The Dundee University Scottish Keratoconus study: demographics, corneal signs, associated diseases, and eye rubbing. Eye (Lond). 2008;22(4):53441. […] McMonnies CW. Mechanisms of rubbing-related corneal trauma in keratoconus. Cornea. 2009;28(6):60715.
#39 Epidemiology of Keratoconus | SpringerLink
https://link.springer.com/chapter/10.1007/978-981-19-4262-4_1
Jafri B, Lichter H, Stulting RD. Asymmetric keratoconus attributed to eye rubbing. Cornea. 2004;23(6):5604. […] Koenig SB. Bilateral recurrent self-induced keratoconus. Eye Contact Lens. 2008;34(6):3434. […] Carlson AN. Expanding our understanding of eye rubbing and keratoconus. Cornea. 2010;29(2):245.
#40 Keratoconus: Practice Essentials, Background, Pathophysiology
https://emedicine.medscape.com/article/1194693-overview
Most keratoconus cases appear spontaneously, although approximately 14% of cases present with evidence of genetic transmission. A patient with keratoconus has a 15 to 67 times greater risk of developing keratoconus than an individual with no family history of keratoconus. […] Personal income, access to health care, and education levels have no known correlation with keratoconus. […] Keratoconus affects both males and females though the rate of prevalence is ambiguous given mixed results from various studies. […] KC typically presents in the early 20’s, though it can develop earlier, and then stabilizes by the fourth decades of life. KC progresses at various rates but tends to progress more rapidly in younger patients and stabilizes approximately 20 years after initial onset.
#41
http://www.pakistanbmj.com/journal/index.php/pbmj/article/view/212
To determine the relation between consanguinity and keratoconus (KC). […] Relation between consanguinity and KC was obtained with P 0.05, showing the results were significant. Results showed that the patients whose parents had consanguinity of first degree were more susceptible to the disease and had more severe keratoconus than rest of the population. […] This study supports the hypothesis that a significant direct association between keratoconus and consanguinity persists. Results show, risk of Keratoconus development is much higher in parental consanguinity of first degree than other type of intermarriages. KC in such susceptible group was observed to be more progressive.
#42 Understanding Keratoconus: Munsonâs Sign and Treatment – medtigo Journal
https://journal.medtigo.com/a-32-year-old-female-with-a-sudden-onset-of-vision-loss/
The prevalence and incidence rates of keratoconus have been estimated to be between 0.2 and 4,790 per 100,000 persons and 1.5 and 25 per 100,000 persons/year, respectively, with the highest prevalence and incidence rates typically occurring in 20- to 30-year-olds. Epidemiological studies show substantial global variation in these rates […] Consanguinity and a positive family history of keratoconus are believed to contribute to its incidence. Consequently, this case can be reclassified as a familial instance of keratoconus. In familial cases of keratoconus, it is increasingly evident that the condition follows a Mendelian inheritance pattern, where specific genetic mutations play a causative role. Furthermore, environmental factors have emerged as potential contributors to keratoconus, including contact lens usage, habitual eye rubbing, magnesium deficiency, and ocular atopy. A growing body of evidence notably supports a potential link between atopic conditions and keratoconus
#43 Keratoconus: Practice Essentials, Background, Pathophysiology
https://emedicine.medscape.com/article/1194693-overview
Keratoconus’s rate of prevalence varies from 0.2 and 4,790 per 100,000 persons. The great variance depends upon the diagnostic criteria, better detection technology, different research protocols, geographic location and ethnicity of the people studied. The middle east has the highest prevalence whereas areas like Russia and Finland reported very low prevalences. The prevalence of keratoconus varies by ethnicity. Keratoconus is more common in blacks and Latinos than in whites, with odds ratios of 1.57 and 1.43, respectively. […] It is commonly an isolated ocular condition but sometimes coexists with other ocular and systemic diseases. Commonly recognized ocular associations have included vernal keratoconjunctivitis, retinitis pigmentosa, and Leber congenital amaurosis. Systemic putative associations include many of the connective tissue disorders (eg, Ehlers-Danlos and Marfan syndromes), mitral valve prolapse, atopic dermatitis, and Down syndrome, although none of these was found in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) study.
#44
https://journals.lww.com/ijo/fulltext/2013/61080/epidemiology_of_keratoconus.4.aspx
Ethnic differences may account for the differences in the reported prevalence of keratoconus. The reports of two surveys in the UK indicated a prevalence 4.4 and 7.5 times greater for Asian (Indian, Pakistani, and Bangladeshi) subjects compared with white Caucasians. […] Family history of keratoconus has been found to be very variable and a high prevalence of keratoconus in a sample population can change the reported rate of a positive family history. […] Keratoconus affects both genders, although it is unclear whether significant differences between males and females exist. […] A higher prevalence of keratoconus has been found in patients with eye rubbing. […] Keratoconus usually occurs bilaterally but asymmetry is common. […] The natural history of disease is variable. Typically at about the age of puberty, the keratoconic process starts and usually, over a period of next 10-20 years, the process continues until the progression gradually stops.
#45 Prevalence of keratoconus in an adolescent population | Revista Mexicana de OftalmologÃa
https://www.elsevier.es/es-revista-revista-mexicana-oftalmologia-321-articulo-prevalence-keratoconus-in-an-adolescent-S0187451914000316
Keratoconus is an idiopathic and progressive disease, where the cornea develops an irregular and conical shape, being the most common form of dystrophy or corneal ectasia, developing between the age of 12 and 20. In Mexico, the epidemiological information about the pathology is scarce. […] The prevalence rate of keratoconus was 1.8%, affecting 66% of females and 33.3% of males. The mean age of presentation was 16.1 years. […] In Mexico, the research on keratoconus is scarce; the articles published show statistics that are similar to those in international literature, which indicates a higher prevalence in male patients with a mean age of 24.5 years. […] Our study demonstrated bilaterality in 8 (88.8%) patients, although it was asymmetric. […] The relevance of the management of these patients is important to note, as 33.3% of patients ended their treatment in penetrating keratoplasty in our study, clearly indicating that patients are being subjected to radical treatments. […] The importance of performing similar protocols in populations of this age group is necessary to establish statistics that can help identify the incidence and prevalence of keratoconus in populations of similar geographic areas (this study was conducted in the north of Mexico).
#46 Study The Epidemiology Of Paediatric Keratoconus And Its Association With Vernal Keratoconjunctivitis, IJSR – International Journal of Scientific Research(IJSR), IJSR | World Wide Journals
https://www.worldwidejournals.com/international-journal-of-scientific-research-(IJSR)/article/study-the-epidemiology-of-paediatric-keratoconus-and-its-association-with-vernal-keratoconjunctivitis/NTQ5MQ==/?is=1
Study the epidemiology of Paediatric Keratoconus and its association with Vernal KeratoConjunctivitis. […] Keratoconus is a disorder that produce marked thinning and conical shape of the cornea. […] When keratoconus manifest in childhood i.e.less than 18 years of age, it is known as Pediatric keratoconus or Adolescence keratoconus (between 10 to 19 years of age). […] Paediatric keratoconus have unique characteristics by which it differs from adult keratoconus â its presentation, progress, biomechanical rigidity of cornea and its association with allergy and eye rubbing. […] In children Keratoconus was significantly more severe at diagnosis as compare to adult. […] Pediatric keratoconus have higher rate and speed of progression. […] Children with keratoconus have more co-existing Vernal KeratoConjunctivitis (VKC), children with keratoconus require early intervention to halt the progression and prevent visual disability.
#47 JMIR Medical Informatics – Machine Learning Algorithms to Detect Subclinical Keratoconus: Systematic Review
https://medinform.jmir.org/2021/12/e27363/
Keratoconus is a disorder characterized by progressive thinning and distortion of the cornea. The prevalence of keratoconus varies from 1 in 375 people in Northern Europe to as high as 1 in 48 in some ethnic groups, with studies suggesting a higher incidence in Middle-Eastern, West Indian, and Asian populations with faster progression. The onset of the disease typically occurs after puberty, with subsequent progression at a variable rate over 2 to 3 decades. A recent meta-analysis found that patients 17 years are likely to progress more than 1.5 D in Kmax over 12 months, and those with steeper Kmax of more than 55 D are likely to have at least 1.5 D Kmax progression. […] The detection of keratoconus at an earlier stage has become increasingly relevant since the introduction of corneal collagen cross-linking (CXL). This is a photochemical treatment of the cornea with UV-A light following the application of riboflavin (vitamin B2), which can arrest the progression of keratoconus in 98.3% of the eyes even in relatively advanced cases.
#48 (PDF) Screening for Keratoconus in a High-Risk Adolescent Population
https://www.academia.edu/100041797/Screening_for_Keratoconus_in_a_High_Risk_Adolescent_Population
Purpose: To estimate the prevalence of keratoconus (KC) in a majority-Emirati adolescent population and to demonstrate the feasibility of screening using a dual Scheimpflug and Placido imaging device. […] The prevalence of KC and KC suspect was estimated to be 2.7% (95% CI [1.2%, 5.0%]) and 19.8% (95% CI [15.7%, 24.4%]), respectively. […] KC is highly prevalent in Emirati adolescents. Screening secondary school students for keratoconus appears to be feasible and may be indicated in this population to improve early detection and intervention. […] The prevalence rate of keratoconus was 1.8%, affecting 66% of females and 33.3% of males. […] The prevalence of keratoconus among all subjects was 2.34% (95% confidence interval [CI] 1.4-3.3). […] The keratoconus prevalence in Najran Province was found to be 87.3 cases per 100,000 people with an incidence of 28.47 per 100,000 cases.
#49 Keratoconus – EyeWiki
https://eyewiki.org/Keratoconus
Crosslinking is indicated at the onset of documented progression of keratoconus to improve prognosis and preserve visual function. […] With early diagnosis and prompt intervention with corneal crosslinking, patients may retain adequate visual function with spectacle lenses or contact lenses throughout their lifetime.
#50 Epidemiology of Keratoconus | Ento Key
https://entokey.com/epidemiology-of-keratoconus-2/
Epidemiological studies describe the distribution of disease, identify factors that influence that distribution, and measure the impact and morbidity of disease in a defined population. […] Population-based screening studies are the best methodology to assess the true prevalence of the disease. […] Attempts to establish prevalence and incidence estimates of keratoconus in the population have shown great variability over the last century. […] Most of the prevalence studies have been carried out in hospitals or clinics, because of the ability to collect data. However, they usually underestimate the prevalence of the disease, as patients are commonly symptomatic, and the early and more subtle forms can be missed. […] Population-based screening studies are the best methodology to assess the true prevalence of the disease.
#51
https://journals.lww.com/sjop/fulltext/2022/36010/keratoconus_epidemiology__a_review.2.aspx
Keratoconus is an ectatic corneal disease that affects both men and women, usually at a young age. Risk factors such as eye rubbing, environmental and genetic factors contribute to its pathogenesis. Keratoconus presents a variable prevalence, being as high as 5% of the population in the Middle East. […] Over the last years, researchers have found that the prevalence and incidence of keratoconus cases in the population presented a high variability. There are different explanations for this variability, including the heterogeneity of epidemiological studies and the lack of well-defined criteria for the definition and classification of keratoconus. […] The true prevalence of the disease can be determined more accurately by population-based screening studies. […] A recent meta-analysis that included more than 50 million individuals from 15 countries determined that the global prevalence of keratoconus was 138/100,000.
#52
https://link.springer.com/article/10.1007/s00417-023-06132-y
The population-based prevalence of Keratoconus was estimated in a Norwegian register study using data from the Norwegian Patient Registry and resulting in a prevalence estimate of 0.19%. […] We conducted a population-based study and systematically examined a large Caucasian cohort at age 40 years and above regarding keratoconus prevalence using modern Scheimpflug imaging and consecutive double grading of conspicuous cases. […] In conclusion, the prevalence of keratoconus in the German population is approximately tenfold higher (0.49%) than previously reported in the literature using latest technologies, namely Scheimpflug imaging.
#53 Different keratoconus definitions can lead to substantial prevalence disparities in population-based studies | Scientific Reports
https://www.nature.com/articles/s41598-025-87532-4
This report explores the prevalence of keratoconus in a population-based cohort of adults aged 40 or older according to ten different definitions. […] The reported prevalence of keratoconus varies widely across studies, ranging from as low as 0.0002% in the Urals in Russia to as high as 4.79% amongst Saudi adolescents in Riyadh. […] Understanding the real prevalence of this condition is important from a public health perspective, as it can inform resource allocation decisions and future screening programs. […] A sizable percentage of keratoconus patients may be unaware of having the disease. […] This suggests that studies using hospital or insurance data may underestimate the true prevalence, as they primarily capture patients at more advanced stages. […] When appropriately designed, these studies are less prone to methodological biases and less likely to be affected by low unawareness or variations in referral patterns.
#54 Different keratoconus definitions can lead to substantial prevalence disparities in population-based studies | Scientific Reports
https://www.nature.com/articles/s41598-025-87532-4
We aim therefore to describe the prevalence of keratoconus cases in a population-based setting according to a new tomography-based definition that can be easily applied in epidemiological research. […] The prevalence of probable keratoconus was 2.71% (72/2660, 95%CI: 2.16-3.40%), and the prevalence of manifest (i.e., definite) keratoconus was 0.38% (10/2660, 95%CI: 0.20-0.69%). […] Checking ophthalmic history records of the confirmed keratoconus cases revealed that 6(60%) patients were unaware of their diagnosis or did not report it. […] The prevalence of keratoconus in Europe was estimated at 0.38% in our study, 0.49% in Germany, 0.55% in Poland and 0.75% among male military recruits in France. […] These numbers seem notably higher than other European studies based on hospital or healthcare registries.
#55 Epidemiology of Keratoconus | Ento Key
https://entokey.com/epidemiology-of-keratoconus-2/
Epidemiological studies describe the distribution of disease, identify factors that influence that distribution, and measure the impact and morbidity of disease in a defined population. […] Population-based screening studies are the best methodology to assess the true prevalence of the disease. […] Attempts to establish prevalence and incidence estimates of keratoconus in the population have shown great variability over the last century. […] Most of the prevalence studies have been carried out in hospitals or clinics, because of the ability to collect data. However, they usually underestimate the prevalence of the disease, as patients are commonly symptomatic, and the early and more subtle forms can be missed. […] Population-based screening studies are the best methodology to assess the true prevalence of the disease.
#56 Epidemiology of Keratoconus | Ento Key
https://entokey.com/epidemiology-of-keratoconus-2/
Epidemiological studies describe the distribution of disease, identify factors that influence that distribution, and measure the impact and morbidity of disease in a defined population. […] Population-based screening studies are the best methodology to assess the true prevalence of the disease. […] Attempts to establish prevalence and incidence estimates of keratoconus in the population have shown great variability over the last century. […] Most of the prevalence studies have been carried out in hospitals or clinics, because of the ability to collect data. However, they usually underestimate the prevalence of the disease, as patients are commonly symptomatic, and the early and more subtle forms can be missed. […] Population-based screening studies are the best methodology to assess the true prevalence of the disease.
#57 Prevalence and Economic Burden of Keratoconus in the United States | Harvard Medical School Department of Ophthalmology
https://eye.hms.harvard.edu/publications/prevalence-and-economic-burden-keratoconus-united-states
In 2019, the average inflation-adjusted lifetime cost of keratoconus treatment was USD 28,766.69, with a cumulative economic burden of USD 3.8 billion. […] In the United States, keratoconus is most prevalent in individuals 18 to 39 years of age. The keratoconus prevalence is higher in the Black population, specifically female individuals, and the diagnosis is often delayed in these patients.
#58 Keratoconus | CERAKeratoconus | CERA
https://www.cera.org.au/conditions/keratoconus/
Keratoconus is a common eye condition that affects the cornea â the front window of the eye. The cornea helps to bend and focus light to help us see. […] In most cases, keratoconus appears between the ages of 16 and 30 years and stabilises by middle age. Due to its early onset, it can impact school, work, social and family life if itâs not treated. […] One in every 84 Australian 20-year-olds has keratoconus. It affects men and women equally. […] Itâs the most common reason for corneal transplant in Australia. […] Our Corneal Research Unit is working to better understand the causes of keratoconus and potential treatments. […] The Keratoconus International Consortium is led by CERA and brings together over 40 keratoconus research groups around the world.
#59 Different keratoconus definitions can lead to substantial prevalence disparities in population-based studies | Scientific Reports
https://www.nature.com/articles/s41598-025-87532-4
This report explores the prevalence of keratoconus in a population-based cohort of adults aged 40 or older according to ten different definitions. […] The reported prevalence of keratoconus varies widely across studies, ranging from as low as 0.0002% in the Urals in Russia to as high as 4.79% amongst Saudi adolescents in Riyadh. […] Understanding the real prevalence of this condition is important from a public health perspective, as it can inform resource allocation decisions and future screening programs. […] A sizable percentage of keratoconus patients may be unaware of having the disease. […] This suggests that studies using hospital or insurance data may underestimate the true prevalence, as they primarily capture patients at more advanced stages. […] When appropriately designed, these studies are less prone to methodological biases and less likely to be affected by low unawareness or variations in referral patterns.
#60 Understanding Keratoconus: Munsonâs Sign and Treatment – medtigo Journal
https://journal.medtigo.com/a-32-year-old-female-with-a-sudden-onset-of-vision-loss/
Genetic and environmental factors play a role in the pathogenesis of kidney cancer. The understanding of its epidemiology and etiology has advanced significantly. Our understanding of the pathophysiology of keratoconus has been advanced. It will continue to be enhanced by recently developed genetic technologies such as whole-exome or genome sequencing and genome-wide association technologies. Eventually, this information will help develop targeted therapies, better early diagnostics, and possibly even a better prognosis.
#61 Keratoconus – EyeWiki
https://eyewiki.org/Keratoconus
Keratoconus is the most common corneal ectatic disorder where the central or paracentral cornea undergoes progressive thinning and steepening, causing high irregular astigmatism and poor quality of vision. […] It was thought to be rare, but more awareness among ophthalmologists about the disease led to an increase in diagnosis and prevalence, which varies between regions. It is considerably higher in the Middle East, India, China, and Australia. […] The prevalence of keratoconus is often reported to be 1 in 700. […] The majority of cases of keratoconus are bilateral, but often asymmetric. […] Onset is typically in early adolescence and progresses into the mid-20s and 30s. However, cases may begin much earlier or later in life, and progression may also persist beyond the 30s. […] Since the availability of corneal collagen crosslinking, patients are usually followed on a 3- to 6-month basis to monitor the progression of the corneal thinning and steepening and the resultant visual changes.
#62 Keratoconus – EyeWiki
https://eyewiki.org/Keratoconus
Crosslinking is indicated at the onset of documented progression of keratoconus to improve prognosis and preserve visual function. […] With early diagnosis and prompt intervention with corneal crosslinking, patients may retain adequate visual function with spectacle lenses or contact lenses throughout their lifetime.