Keratoconus
The cornea gradually thins and bulges into a cone shape, causing severe irregular astigmatism and vision distortion.
A way to think about it
Your cornea is normally dome-shaped, like a mountain peak. In keratoconus, that dome becomes thinner and weaker, gradually bulging outward into a cone shape—like the peak gets stretched and droops. This irregular shape creates weird, changing vision distortions and makes the eye increasingly astigmatic (blurry). It's like your eye's shape is slowly warping.
What's happening in the eye
Keratoconus is a progressive thinning of the cornea (front surface of the eye) due to collagen breakdown. The cornea loses its structural strength and gradually bulges forward into a cone. As it progresses, the shape becomes increasingly irregular. This extreme astigmatism causes blurred, distorted, and sometimes double vision. Thankfully it usually stabilizes by age 30-40.
Common symptoms
- Progressive blurred or distorted vision, objects look wavy or streaky
- Frequent changes in eyeglass or contact prescription
- Increased sensitivity to light and glare, halos around lights
- Mild eye irritation or discomfort, worse with dry eyes
- In advanced cases: scarring of cornea, vision loss despite correction
Risk factors
- Family history—if your parent has it, you have 5-10% risk
- Connective tissue disorders: Down syndrome, Ehlers-Danlos, Marfan syndrome
- Chronic eye rubbing—can accelerate progression significantly
- Atopy (allergic disease): asthma, eczema, hay fever
- Age—typically appears in teens to early 20s
- More common in Asian, African, and Hispanic populations
Warning signs - seek care immediately
- Rapid vision changes over weeks or months—may signal acute hydrops (cornea swelling), see doctor urgently
- Corneal scarring or opacity forming—can indicate advanced disease or past hydrops
- Persistent discomfort despite lenses—may signal lens fit problem or infection
- Vision loss that doesn't improve with contacts—may need surgical intervention
Questions to ask your doctor
- 1.Am I a candidate for corneal cross-linking right now? How urgent is it?
- 2.Should my family members be screened for keratoconus?
- 3.What scleral lens prescription is best? Can I try different fits before committing?
- 4.If my disease progresses despite cross-linking, what's my next step?
- 5.Are there medications or supplements that slow progression?
Keratoconus is serious but manageable, especially if caught early. Cross-linking stops progression in most patients. Scleral lenses provide excellent vision for many. Corneal transplant, if needed, has good outcomes.
Sources
Information on this page is based on the following authoritative sources:
- American Academy of Ophthalmology
- National Eye Institute (NIH)
- American Optometric Association
- Mayo Clinic
Last updated: April 2026