What is keratoconus?
In keratoconus, the cornea’s structural collagen fibres weaken, and the cornea progressively thins and bulges outward into a cone-like shape. This creates irregular astigmatism — light focuses unevenly — so images appear distorted, shadowed or doubled even with glasses.
It usually begins in the teens or twenties and may progress for a decade or more before stabilising. Both eyes are typically affected, though often asymmetrically. Rubbing the eyes is a known aggravating factor, and there is frequently a family history or association with allergic eye disease.
Symptoms and how it is detected
Common early signs: frequent changes in spectacle power (especially increasing astigmatism), blurred or distorted vision, ghosting around letters, glare and halos at night, and sensitivity to light. Because glasses change so often, young patients may visit several opticians before the true cause is found.
Diagnosis is made with corneal topography and tomography — scans that map curvature and thickness and detect the characteristic cone. Early or “forme fruste” keratoconus can be detected before obvious symptoms, which matters because treatment to halt progression works best when started early.
Management options
Glasses: correct vision in early, regular cases but cannot stop progression.
Specialty contact lenses: rigid gas-permeable, scleral or hybrid lenses vault over the cone to create a smooth optical surface — often the best vision solution in moderate disease.
Corneal collagen cross-linking (CXL): the only established treatment that halts progression by strengthening corneal collagen. It does not reverse existing distortion — its job is to stabilise.
Intrastromal corneal ring segments: in selected cases, these can regularise shape and improve lens tolerance.
Transplantation: reserved for advanced cases where clarity or thickness can no longer support function — in suitable eyes, deep anterior lamellar keratoplasty preserves more of the patient’s own tissue.
The sequence and combination are individual. The guiding principle is: stabilise first, then optimise vision.
Why early detection matters
Cross-linking changes the disease’s course only while it is still progressing. Once the cornea has scarred or become very thin, options narrow. Regular topography (typically every 6–12 months in at-risk patients) tracks progression and times treatment. Patients with a family history, allergic eye disease or habitual eye rubbing benefit from screening.
Keratoconus and refractive surgery
Standard LASIK is unsafe in keratoconus because removing tissue weakens an already weak cornea. Some carefully selected, stable post-CXL eyes may be considered for surface procedures or implantable lenses under specialist guidance. Any refractive-corrective decision in keratoconus requires expert review of topography and stability over time.