Definition

Corneal topography measures the shape, curvature, and power of the cornea. 
Alternative Names: Orbscan, VK

What to Expect

  • The patient is seated in front of the instrument with the chin placed in a chin rest, and the forehead against a support.
  • The patient gazes at a central red fixation light and a bright flash photograph is taken.  
  • The patient will be asked to hold still and not blink while the photograph is taken.
  • The test will take approximately two minutes per eye.

How the Test Feels

Patients may experience momentary blurry vision immediately after the test due to the bright flash photography.

Why the Test is Performed

This test is useful in determining if vision is decreased due to a corneal disorder. 

Results

  • Normal Values
    A computerized printout displays the shape and curvature of the cornea.
  • Abnormal Results
    Abnormal corneal topography may detect underlying corneal disease such as:
    • Keratoconus
    • Astigmatism
    • Corneal thinning
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