What instrument is used to measure the thickness of the cornea and the depth of the anterior chamber?

The pachymeter is the correct instrument for measuring the thickness of the cornea and the depth of the anterior chamber. This instrument uses ultrasound or optical methods to accurately assess corneal thickness, which is critical for diagnosing and managing various ocular conditions, such as glaucoma and corneal diseases.

By determining corneal thickness, practitioners can evaluate the structural integrity of the cornea and gain insights into the risk factors for glaucoma, as thinner corneas are often associated with a higher susceptibility to this condition. Additionally, measuring the anterior chamber depth can help in determining the risk of angle-closure glaucoma.

In contrast, other options serve different purposes: an ophthalmoscope is primarily used for examining the interior of the eye, specifically the retina and optic nerve; a Schirmer test measures tear production; and a tonometer measures intraocular pressure, which is essential for assessing glaucoma risk but does not provide information about corneal thickness or anterior chamber depth.