Keratoconus - Related Disorders

Related Disorders

Several other noninflammatory eye disorders, generally rarer than keratoconus, also cause thinning of the cornea:

• Keratoglobus is a very rare condition that causes corneal thinning primarily at the margins, resulting in a spherical, slightly enlarged eye. It may be genetically related to keratoconus.
• Pellucid marginal degeneration causes thinning of a narrow (1–2 mm) band of the cornea, usually along the inferior corneal margin. It causes irregular astigmatism that, in the early stages of the disease can be corrected by spectacles. Differential diagnosis may be made by slit-lamp examination.
• Posterior keratoconus, a distinct disorder despite its similar name, is a rare abnormality, usually congenital, which causes a nonprogressive thinning of the inner surface of the cornea, while the curvature of the anterior surface remains normal. Usually only a single eye is affected.