Which eye condition can a keratometer help diagnose?

A keratometer is a diagnostic instrument specifically designed to measure the curvature of the anterior surface of the cornea. This measurement is crucial because the shape of the cornea directly affects how light is focused onto the retina. In the case of astigmatism, the curvature of the cornea is irregular, leading to blurred or distorted vision. By using a keratometer, an eye care professional can determine the degree and axis of the curvature, providing essential information to diagnose astigmatism accurately and inform appropriate corrective measures, such as glasses or contact lenses.

In contrast, other conditions such as cataracts, glaucoma, and retinal detachment involve different pathological processes and diagnostics that do not rely on corneal curvature measurements. Cataracts are characterized by lens clouding, glaucoma involves intraocular pressure and optic nerve damage, and retinal detachment requires imaging techniques and assessments of the retina. Therefore, while a keratometer is essential for diagnosing astigmatism, it is not applicable for diagnosing the other listed conditions.