Keratoconus

Keratoconus is a progressive disease of the cornea in which it increasingly thins and bulges into a cone shape. The deformation leads to irregular refraction of light and thus to progressive deterioration of vision. Keratoconus typically begins in puberty or young adulthood and almost always affects both eyes, although often to a different extent.

Symptoms

The complaints usually develop gradually:

• Increasingly blurred vision that becomes ever harder to correct with glasses
• Distorted or "smeared" vision
• Increased sensitivity to glare
• Ghost images or double contours (especially at night)
• Frequent changes of the glasses prescription
• Increasing nearsightedness and irregular corneal curvature (irregular astigmatism)

Causes and risk factors

The exact cause of keratoconus is not fully understood. Both genetic and environmental factors play a role:

• Genetic predisposition: in some families keratoconus occurs more frequently
• Eye rubbing: considered an important risk factor, as it mechanically weakens the cornea
• Allergies: chronic itching and frequent rubbing promote the disease
• Associated conditions: trisomy 21 (Down syndrome), Marfan syndrome, and Leber congenital amaurosis are associated with an increased risk

Diagnosis

The diagnosis is made by corneal topography, a painless imaging procedure that precisely measures the surface shape and thickness of the cornea. Even early stages that are not noticeable during a normal eye examination can be detected with it.

Treatment

Glasses and contact lenses

In early stages, glasses can still correct vision sufficiently. As the disease progresses, the corneal surface becomes increasingly irregular, so that glasses are no longer enough. Rigid (hard) contact lenses compensate for the irregular surface and often enable significantly better vision than glasses.

Special types of contact lenses for keratoconus include:

• Rigid contact lenses
• Scleral lenses (large lenses that rest on the white part of the eye)
• Hybrid lenses (combination of a hard center and a soft edge)

Corneal cross-linking (CXL)

Cross-linking is a minimally invasive procedure that links the collagen fibers of the cornea together using riboflavin (vitamin B2) and UV-A light, thereby stabilizing the cornea. The goal is to stop the progression of keratoconus. CXL is particularly important in children and adolescents with documented progression, as the disease often advances more quickly at a young age.

Corneal transplant

In advanced stages, when contact lenses are no longer tolerated or the cornea is too heavily scarred, a corneal transplant (keratoplasty) may be necessary. The chances of success in keratoconus are overall good.

Not recommended: LASIK

Laser correction (LASIK) is not suitable for keratoconus, as it further weakens the already thinned cornea and can worsen the disease.

Important: do not rub the eyes!

Eye rubbing is considered a significant risk factor for the development and progression of keratoconus. If your child rubs their eyes frequently, for example due to allergies or habit, this should definitely be treated or broken. Anti-allergic eye drops can relieve the itching and thus reduce rubbing.

Our advice

If your child complains of increasingly blurred vision, the glasses prescription has to be changed frequently, or ghost images are described, corneal topography should be performed. The earlier keratoconus is detected, the better its progression can be halted by cross-linking.