A patient ordered glasses online after an exam. The glasses are blurry. In order to confirm the glasses were made correctly, you would use the:

• A. Phoropter
• B. Lensometer
• C. Tonometer
• D. Autorefractor

Answer: (B)

To confirm that the glasses were made correctly, you measure the actual lenses with a lensometer (also called a focimeter). This instrument determines the optical power of each lens and reveals the sphere, cylinder, and axis, as well as the axis orientation and prism if present. By placing the finished glasses on the lensometer, you can see whether the powers match what was prescribed and whether the lenses are correctly labeled and centered. If there’s a mismatch—wrong power, wrong axis, incorrect cylinder value, or mislabeling—you’ll identify exactly what needs to be corrected.

Other tools aren’t used for this verification. A phoropter is used during the eye exam to determine the prescription, not to verify finished lenses. A tonometer measures intraocular pressure, and an autorefractor estimates prescription, but neither is used to confirm that a completed pair of glasses matches the patient’s prescription.