KERATOCONUSDefinition and Incidence
Emily Gottschalk OD, FAAO
What is Keratoconus?
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- A bilateral, asymmetric degenerative thinning of the corneal stroma causing a cone-shaped protrusion.1
- Corneal steepening causes high irregular astigmatism and decrease in quality of vision.1
What is the age of onset?
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- Early adolescence and progresses until the third to fourth decade of life.1,2
How common is Keratoconus?
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- CLEK study: 13.5% of patients with keratoconus had a positive family history.3
- Worldwide prevalence: 1.38 per 1000.4
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- Varies by region from 0.17 per 1000 in the United States to 40 per 1000 in Iran.4
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- 2024 study: 1:334 in ages 3-18 in Chicago.5
Sources
- Krachmer JH, Feder RS, Belin MW. Keratoconus and related noninflammatory corneal thinning disorders. Surv Ophthalmol 1984;28:293–322.
- Wang Y, Rabinowitz YS, Rotter JI, Yang H. Genetic epidemiological study of keratoconus: Evidence for major gene determination. Am J Med Genet 2000;93:403–409.
- Wagner H, Barr JT, Zadnik K. Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study: Methods and findings to date. Contact Lens and Anterior Eye 2007;30:223–232.
- Hashemi H, Heydarian S, Hooshmand E, et al. The Prevalence and Risk Factors for Keratoconus: A Systematic Review and Meta-Analysis. Cornea 2020;39:263.
- Harthan JS, Gelles JD, Block, et al. Prevalence of Keratoconus based on Scheimpflug Corneal Tomography metrics in a pediatric population from a Chicago-based school age vision clinic. Eye & Contact Lens 2024; 50(3):121-125.