Corneal Topography: What To Expect & How To Interpret Results (2024)

What is corneal topography?

Corneal topography is a painless test that produces color-coded maps of your cornea. Your cornea is the clear, outer surface of your eye. It has a slightly curved shape that refracts (bends) light as it enters your eye, allowing you to see the world around you. Corneal topography evaluates the shape of your cornea to diagnose and manage various eye conditions.

The word “topography” usually refers to surface features on land (like mountains or rivers), or maps that describe those features. So, you might wonder what this term has to do with your eyes.

Think of your cornea as a miniature version of a sprawling stretch of land. Like land, your cornea can be smooth or dotted with bumps or other unusual features. On land, you can spot trees or elevation changes. But you normally can’t see such surface features on your cornea. That’s where corneal topography comes in. This technology allows eye care specialists to map and measure your cornea, including its thickness and elevation changes.

Corneal topography is the gold standard for mapping subtle changes in your cornea that occur suddenly or over time. Computerized corneal topography is another name for this test.

What is corneal topography used for?

Corneal topography serves many purposes. This test helps eye care specialists:

• Diagnose and monitor conditions that affect your cornea.
• Plan for surgery on your cornea and evaluate the surgery’s results.
• Fit contact lenses to the shape of your eyes.

Diagnosing and monitoring conditions

Corneal topography plays an essential role in diagnosing and checking the progression of:

• Astigmatism.
• Keratoconus.
• Pellucid marginal degeneration (PMD).
• Scarring from injuries or infections.
• Growths, such as pterygium (surfer’s eye).

Surgical planning and evaluation

Corneal topography allows providers to identify issues that could affect the success of certain eye surgeries. For example, this test can diagnose conditions like keratoconus in the early stages, even before you have symptoms. People with keratoconus face a higher risk of complications after refractive eye surgeries such as LASIK.

Corneal topography helps providers plan:

• Refractive surgery, such as LASIK or PRK, to correct your vision.
• Cataract surgery to replace your eye’s natural lens with an intraocular lens.
• Cornea transplant to give you a new cornea.
• Corneal cross-linking surgery to treat keratoconus and other conditions that weaken your cornea.

Fitting contact lenses

Corneal topography provides precise measurements of your cornea. These measurements allow your provider to find the best fit for contact lenses. They’re especially helpful for fitting rigid gas-permeable (RGP) lenses. These are hard, durable contacts that help people with irregularly shaped eyes or conditions like keratoconus.

Who needs corneal topography?

You may need corneal topography if:

• You’d like to have laser refractive surgery (like LASIK). This test is a crucial part of pre-operative evaluations to make sure you’re a good candidate for the surgery. Underlying problems with your cornea can lead to complications after your surgery.
• You need surgery to treat corneal disease. This test helps your provider plan your surgery to give you the best possible outcomes.
• You’ve already had surgery. Providers use this test to evaluate the results of your surgery.
• You need contact lenses. This test allows your provider to fit contact lenses to the shape of your eyes. Such testing is especially important if your corneas have an irregular shape.

Who performs this procedure?

An eye care specialist, often an ophthalmologist, performs corneal topography.