What measurement does a tonometer primarily assess?

A tonometer is an instrument specifically designed to measure intraocular pressure (IOP). This measurement is crucial in the evaluation and management of eye conditions, particularly glaucoma, which is characterized by elevated intraocular pressure that can lead to optic nerve damage and vision loss.

Monitoring IOP is essential for diagnosing and tracking the progression of glaucoma, as well as assessing the effectiveness of treatments. A tonometer can utilize various methods, such as applanation tonometry or non-contact tonometry, to accurately gauge the pressure within the eye.

Other options relate to different aspects of eye health: corneal curvature is assessed through keratometers, visual acuity is tested using an eye chart, and retinal thickness can be measured using optical coherence tomography (OCT), none of which are the primary purpose of a tonometer. Thus, the role of a tonometer centers specifically on assessing intraocular pressure.