Certified Ophthalmic Assistant Practice Exam

Which instrument is used to measure corneal thickness and anterior chamber depth?

1. Ophthalmoscope

2. Tonometry

3. Pachymeter

4. Rheometer

The correct answer is: Pachymeter

The correct answer is the pachymeter, which is an instrument specifically designed to measure the thickness of the cornea. This measurement is important in various clinical practices, particularly in assessing patients at risk for glaucoma or those considering refractive surgery like LASIK. The pachymeter can also provide valuable data regarding the anterior chamber depth, which is essential in various diagnostic and therapeutic decision-making processes. In contrast, the ophthalmoscope is primarily used for examining the interior of the eye, particularly the retina and the optic nerve. It does not measure corneal thickness or anterior chamber depth. Tonometry assesses intraocular pressure but does not directly measure corneal thickness or the depth of the anterior chamber. The rheometer measures the flow properties of materials and is not relevant in ocular measurements. Therefore, the pachymeter is the only instrument listed that accurately provides the necessary measurements concerning corneal thickness and anterior chamber depth.