What method measures the front surface of the cornea?

Keratometry is the method used to measure the curvature of the front surface of the cornea. This measurement is crucial in various fields, especially in optometry and ophthalmology, because it helps determine the appropriate fit for contact lenses and assess the cornea's shape, which can be important for diagnosing conditions such as astigmatism.

Keratometers utilize a principle that involves shining a light onto the cornea and reflecting it to measure the radius of curvature. This provides valuable data regarding the cornea’s power and overall health.

While the other methods mentioned focus on different aspects of eye health—tonometry measures intraocular pressure, corneal scans provide detailed images of the cornea's structure, and ophthalmodynamometry assesses blood flow in the eye—none of these methods specifically measure the curvature of the front surface of the cornea as keratometry does. This distinction makes keratometry the correct answer for the question at hand.