Certified Ophthalmic Assistant Practice Exam

In keratometry, what does a measurement typically indicate?

1. The astigmatism degree

2. The corneal curvature

3. The lens power

4. The eye's overall health

The correct answer is: The corneal curvature

The correct answer is that keratometry measures the corneal curvature. Keratometry is a diagnostic procedure that primarily determines the shape and curvature of the cornea, which is vital for understanding how light is focused in the eye. Since the cornea is responsible for the majority of the eye's refractive power, knowing its curvature helps in assessing the eye's optical performance, particularly in relation to fitting contact lenses and planning for refractive surgery. While keratometry can provide insights into astigmatism because it measures the difference in curvature between the steep and flat meridians of the cornea, it does not directly measure the degree of astigmatism but rather indicates factors that contribute to its presence. Other options like lens power and the eye's overall health are not directly measured by keratometry; lens power is related to the lens itself and requires different assessments, while overall ocular health encompasses a broader evaluation beyond the corneal shape alone.