How Corneal Thickness Can Affect Your Eye Treatments

The cornea is the transparent outer layer at the front of your eye. It does more than protect your eye from debris and infection. It also bends incoming light so your eye can focus properly. How thick that corneal tissue measures affects which eye treatments and vision correction procedures are safe for you and how accurately certain diagnostic tests work.

At his practice in Rapid City, South Dakota, Stephen Khachikian, MD, measures corneal thickness as part of comprehensive eye exams and uses that information to determine which treatments are safe and effective for your eyes.

How pachymetry measures your corneal thickness

Corneal thickness refers to how thick the tissue is from the front surface of your eye to the back surface of the cornea. The average adult cornea measures about 540 microns in the center, though normal thickness ranges from person to person.

Dr. Khachikian measures corneal thickness using a test called pachymetry. The process is quick and painless — a probe gently touches your cornea after Dr. Khachikian applies numbing drops, or an optical device scans your eye without direct contact. The measurement takes seconds per eye.

Corneal thickness affects glaucoma screening and disease detection

Corneal thickness affects several aspects of eye health and treatment planning, including:

Accurate eye pressure readings

Corneal thickness influences how Dr. Khachikian measures eye pressure during glaucoma screening. Thicker corneas can make pressure readings appear higher than they actually are, while thinner corneas can make readings appear lower.

Detecting corneal diseases

Certain corneal conditions cause progressive thinning. Keratoconus, a condition where the cornea gradually bulges outward into a cone shape, causes the tissue to thin over time. Tracking corneal thickness helps Dr. Khachikian detect these conditions early and monitor their progression.

Determining eligibility for laser vision correction

Laser-assisted in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) both alter corneal tissue to reshape the eye and correct vision. Your cornea needs enough thickness to safely remove tissue without compromising structural integrity.

Thin corneas might rule out LASIK but not vision correction

LASIK creates a thin flap in the corneal surface, lifts it, reshapes the tissue underneath with a laser, and repositions the flap. Eyes with thin corneas don’t have enough tissue to support both the flap and the necessary reshaping. Performing LASIK on a cornea that’s too thin increases the risk of ectasia, where the cornea becomes unstable and bulges forward.

PRK corrects the same vision problems but skips the flap. Instead, your surgeon removes the thin outer layer of corneal cells, reshapes the exposed tissue with a laser, and lets the cells regenerate over the following week. Because PRK doesn’t create a flap, it preserves more corneal thickness and works for patients whose corneas are too thin for LASIK.

How unusually thick corneas affect glaucoma treatment

Very thick corneas may require adjustments to glaucoma medication dosing because pressure readings can appear falsely elevated. In some cases, thick corneas are associated with certain types of corneal dystrophies — inherited conditions that affect corneal clarity — though thickness alone doesn’t diagnose these conditions.

Schedule a comprehensive eye exam

Corneal thickness measurements are part of thorough eye evaluations and help determine which treatments are safe and appropriate for your vision needs. If you’re considering laser vision correction or you’ve been told your corneas are too thin for LASIK, a consultation with our experienced ophthalmologist can clarify your options.

Call Stephen Khachikian, MD, at 605-203-4256 or schedule an appointment online today.