Diagnosing keratoconus

Early diagnosis of keratoconus is decisive: the sooner the disease is identified, the more it can be stabilized before it lastingly affects vision. Keratoconus is first suspected from certain signs, then confirmed by corneal imaging tests.

• Blurred or distorted vision that is not fully corrected by glasses.
• An irregular astigmatism that increases, with frequent changes of prescription.
• Sensitivity to light, halos, or double vision perceived in a single eye.
• A drop in vision in a teenager or young adult, especially with eye rubbing or allergies.

Corneal topography (or mapping) is the key examination. It draws a precise map of the curvature and thickness of the cornea and can detect keratoconus, sometimes at a very early stage, even before vision is clearly affected. It is also the examination used to monitor theprogression over time.

• The pachymetry, which measures the thickness of the cornea.
• Theanterior segment OCT, which finely analyzes the layers of the cornea.
• Examination with the slit lamp, which looks for the characteristic signs.
• Theaberrometry, which assesses the optical quality of the eye.

These examinations are painless and quick; they are performed during a specialized work-up.

Screening is particularly recommended in teenagers, in people with a family history of keratoconus, and before any refractive surgery (LASIK). Identifying early keratoconus makes it possible to offer, if needed, a stabilization treatment at the right time.