Keratometry is most commonly used to help with which of the following?

• A. Intraocular pressure measurement
• B. Color vision testing
• C. Visual acuity testing
• D. Contact lens fitting

Answer: (D)

Keratometry measures the curvature of the clear front surface of the eye by analyzing the reflected pattern on the cornea. Those measurements give corneal power, which is essential for predicting how a contact lens will fit on the eye. Because a lens must match the corneal curvature to sit properly, move appropriately, and avoid irritation, keratometry is most commonly used to guide contact lens fitting, including selecting an appropriate base curve and assessing fit. It’s not used to measure eye pressure, color vision, or visual acuity—the tests for those are tonometry, color plates, and acuity charts, respectively.