Information
Editors
Keratoconus (Conical Degeneration of the Cornea)
Essentials
- Keratoconus (conical degeneration or conical bulging of the cornea) is a disease in which the cornea becomes thinner and more fragile.
- The pressure in the eye makes the thinned cornea bulge conically outward.
- Keratoconus often begins at the age of 12-20 years and typically progresses for 10-15 years.
- In most cases, progression will stop before any significant impairment of visual acuity.
- Keratoconus may also result from laser-assisted refractive surgery (usually LASIK surgery). In that case, it is called corneal ectasia.
- The patients should be treated and monitored by an ophthalmologist.
Prevalence
- 1 in 1 500-2 000 people
- There are differences between countries; check local epidemiology.
Symptoms and findings
- Reduced visual acuity
- Increased astigmatism and myopia
- Simultaneous perception of several images of a single object
- Impaired contrast sensitivity (difficulty distinguishing between various shades of black and white)
- Thinning cornea
- Visible protrusion of the corneal surface
Workup
- Visual acuity
- Inspection of the eye: is there conical bulging of the cornea visible on lateral inspection (often best detectable if the patient looks down)?
- Examinations by an ophthalmologist include corneal tomography and biomicroscopy.
Treatment
- Corneal cross-linking strengthens the structure of the cornea and prevents it from protruding forward.
- Hard contact lenses
- In advanced cases, corneal transplantation may be considered.