What part of the cornea does the keratometer measure?

The keratometer is an instrument specifically designed to measure the curvature of the anterior surface of the cornea, particularly the area known as the optic cap, which is the central part of the cornea responsible for refracting light. The keratometer helps in evaluating corneal topography, which is crucial for various ophthalmic applications such as fitting contact lenses, assessing keratoconus, and planning refractive surgeries.

The optic cap is significant because it influences how light is focused within the eye, and understanding its curvature directly impacts the assessment of visual acuity and overall eye health. While other layers of the cornea, such as the endothelium, stroma, and Descemet's membrane, play essential roles in corneal health and function, they are not the focus of measurements taken by the keratometer. The device specifically targets the surface curvature to provide valuable data for vision correction and eye care practices.