Keratoconus is a progressive eye disorder that changes the normal shape of the cornea. Instead of staying round and clear, the cornea gradually thins and bulges into a cone-like shape. This change disrupts the way light enters the eye, often leading to blurred or distorted vision.
Many people ask a simple but important question: Is keratoconus rare? The answer is more complex than it seems. While it is not as common as nearsightedness or astigmatism, modern studies suggest keratoconus is more widespread than previously believed.
We will explore the prevalence, epidemiology, and incidence of keratoconus. We will examine global statistics, look into regional variations—including what this means for Filipinos—and dispel common misconceptions.
Epidemiology of Keratoconus: What the Numbers Show
Global Prevalence
Older textbooks often stated that keratoconus affected about 1 in 2,000 people. That figure was based on limited data and diagnostic tools available decades ago.
Recent epidemiology studies paint a different picture. A 2025 global meta-analysis reviewing more than 50 studies estimated the pooled prevalence at 0.24%, or about 1 in every 417 people worldwide. This is significantly higher than traditional figures.
In other words, keratoconus is not extremely rare, but rather an uncommon corneal disease that can affect thousands in a single country.
Incidence: New Cases Each Year
The same meta-analysis found an incidence rate of about 4 cases per 100,000 people annually. While this number seems small, it means thousands of new cases are diagnosed globally each year.
Regional Variations
Epidemiology also shows that keratoconus is not evenly distributed. Prevalence varies greatly depending on geography, ethnicity, and environment:
- Middle East & South Asia: Higher rates, possibly due to genetic predisposition and environmental factors such as UV exposure.
- Europe: Moderate prevalence, with population studies reporting between 0.2% and 0.6%.
- United States: Insurance database analyses suggest lower numbers, around 0.04%, but these may underestimate true occurrence because many mild cases go undiagnosed.
- Philippines & Southeast Asia: Limited large-scale studies exist, but based on global patterns, prevalence here is likely similar to other Asian countries.
How Prevalence Differs by Age and Gender
Keratoconus usually appears in the teenage years or early twenties, when the cornea is more vulnerable to thinning. The highest prevalence is often reported among people aged 20–29.
Gender patterns are mixed. Some studies suggest men may be slightly more affected, while others show no major difference. What remains consistent is that early detection is crucial because the disease tends to progress more rapidly in younger patients.
Risk Factors for Keratoconus
While the exact cause is still not fully understood, several risk factors increase the likelihood of developing keratoconus:
- Genetic Predisposition: A family history of keratoconus raises the risk.
- Environmental Factors: Chronic eye rubbing, allergies, and exposure to strong sunlight have all been linked.
- Syndromic Associations: Conditions like Down syndrome show higher rates of keratoconus.
- Ethnicity: Studies suggest a higher prevalence in Middle Eastern, South Asian, and certain Asian populations compared to European cohorts.
For Filipinos, the tropical climate, high UV exposure, and common allergic eye conditions may contribute to increased risk.
Signs and Symptoms
Keratoconus often develops slowly, but early detection is key. Common signs include:
- Blurred or distorted vision.
- Frequent changes in eyeglass prescription.
- Sensitivity to light and glare.
- Double vision in one eye.
Because these symptoms overlap with other eye conditions, many cases remain undiagnosed until progression becomes noticeable.
Diagnosis: How Eye Doctors Detect Keratoconus
Modern diagnosis relies on corneal topography and tomography. These tools create detailed maps of the cornea, showing early corneal thinning and subtle cone-shaped bulging.
Routine eye exams may not always detect early keratoconus, which is why specialized testing at an eye center is recommended, especially for high-risk individuals.
Why Awareness Matters in the Philippines
In the Philippines, many people still consider keratoconus unfamiliar. Awareness campaigns can help Filipinos understand that:
- It is not as rare as once thought.
- Early detection through eye screening is critical.
- Environmental factors like sun exposure and eye rubbing should not be ignored.
By increasing awareness, more patients can seek timely diagnosis and prevent long-term vision impairment.
Conclusion
Keratoconus is often described as a rare disease, but modern epidemiology shows it is more common than once believed. With global prevalence estimates around 1 in 400 people, it may not always fit the strict definition of “rare.” Still, it remains an uncommon corneal disease that requires serious attention.
For Filipinos, awareness of keratoconus is especially important. Recognizing risk factors, understanding symptoms, and seeking early eye care can protect long-term vision.
At Shinagawa Lasik & Aesthetics, we combine medical expertise, advanced diagnostic tools, and proven treatments like corneal collagen cross-linking to help patients manage keratoconus effectively. Our commitment is not only to treatment, but also to patient education—because informed patients make stronger decisions for their eye health.
For inquiries, questions, and appointments, call our Patient Care Lines:
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Citations and Resources
Shinagawa LASIK & Aesthetics strives to provide accurate and reliable information regarding LASIK procedures and eye health. We utilize primary sources to support our content, including peer-reviewed scientific studies, data from reputable medical organizations, and expert opinions. We also reference established publications and research where appropriate.
Our commitment to evidence-based information ensures that you receive trustworthy and up-to-date details to make informed decisions about your eye care.
Resources Used in This Article
- Science Direct. “Quality of life of a sample of people with keratoconus in KSA, https://www.sciencedirect.com/science/article/pii/S1658361223000458“
- Philippine Journal of Ophthalmology. “Clinical Profile of Keratoconus Patients at the Philippine General Hospital, https://paojournal.com/index.php/pjo/article/view/17/422“
- PubMed. “Prevalence and clinical profile of keratoconus in patients presenting at a provincial hospital in KwaZulu, Natal, South Africa: A case study, https://pmc.ncbi.nlm.nih.gov/articles/PMC10628798/“
- PubMed Central. “Prevalence of keratoconus in persons with Down syndrome: a review, https://pmc.ncbi.nlm.nih.gov/articles/PMC8061858/“
- Science Direct. “Cross-national comparative study of orphan drug policies in Saudi Arabia, the United States, and the European Union, https://www.sciencedirect.com/science/article/pii/S1319016423002335“