Keratoconus

Key clinical points

• Early keratoconus can masquerade as routine astigmatism; tomography is essential for detection.
• Progression is most common in younger patients and those with eye rubbing or atopy.
• Corneal cross-linking halts progression and is most valuable when performed early.
• Rigid gas permeable and scleral lenses provide the best visual rehabilitation for irregular corneas.
• Advanced disease with scarring may require corneal transplantation.

Presentation and diagnosis

Patients often report frequent changes in their spectacle prescription, increasing astigmatism, and reduced quality of vision. Clinical signs include corneal thinning, Vogt striae, Fleischer ring, and in advanced cases scarring or acute hydrops.

Corneal tomography is the cornerstone of diagnosis and screening, revealing inferior steepening, thinning, and posterior elevation before the disease is clinically obvious. Serial tomography documents progression and guides intervention.

Halting progression

Corneal collagen cross-linking uses riboflavin and ultraviolet light to strengthen corneal stromal bonds and arrest ectasia. It does not typically reverse the condition, so early detection and treatment of documented progression—especially in younger patients—preserve the best possible cornea for future vision.

Counseling patients to avoid eye rubbing and managing coexisting allergy and ocular surface disease are important adjuncts.

Visual rehabilitation

Spectacles and soft toric lenses may suffice in mild disease, but as irregularity increases, rigid gas permeable and scleral lenses become the mainstay because they create a smooth refracting surface over the irregular cornea.

When contact lens tolerance fails or significant scarring develops, surgical options include intrastromal corneal ring segments and, ultimately, deep anterior lamellar or penetrating keratoplasty.