Keratoconus and specialty lenses
Keratoconus reshapes the cornea so ordinary lenses stop correcting vision well. Scleral and tricurve lenses rest on the white of the eye and create a regular surface, which usually restores sharpness. Fitting takes several measurements and follow-up visits.
Some corneas are not regularly shaped. When that happens, ordinary lenses do not correct well no matter how carefully the prescription is refined: light enters distorted and the image never quite comes into focus.
That is what specialty lens designs are for.
Who it is for
- You have been diagnosed with keratoconus.
- You have an irregular cornea from previous surgery, scarring or a transplant.
- You see halos, glare or double images even with your glasses on.
- Your prescription shifts a lot and quickly, and you are told something different every year.
- You tried regular contact lenses and cannot tolerate them.
What gets fitted
- Scleral lenses — they rest on the sclera, the white of the eye, instead of on the cornea. They hold a chamber of fluid over the eye that creates a new, regular optical surface. Usually the most comfortable option when the cornea is very irregular.
- Tricurve and other specialty designs — geometries made to sit on corneas that are not spherical.
- Combinations — when it makes sense to split the work between a contact lens and glasses.
What to expect
Fitting these lenses is not like buying ordinary contacts. It takes more than one visit, and that is normal.
- The actual shape of your cornea is measured, not just your prescription.
- A diagnostic lens is tried and how it sits is observed.
- The geometry is adjusted until it rests where it should and you see comfortably.
- You are taught to insert, remove and care for them, which with these lenses has its own technique.
- You are rechecked after days and weeks, because real comfort is measured in use.
Frequently asked questions
Do they hurt? They should not. A well-fitted scleral lens rests on an area with very little sensitivity. Discomfort is a sign that it needs adjusting.
How long does the fitting take? Several visits over a few weeks. It is a process, not a purchase.
Are they useful if I have already had surgery? Often yes, and that is one of the cases where they help most. Bring your surgical report.
Does insurance cover them? Some plans cover medically necessary contact lenses, which is different from cosmetic ones. Check with your office before the appointment.