Which test is used to measure corneal thickness in POAG evaluation?

• A. RNFL/GCC OCT
• B. 24-2 HVF
• C. Pachymetry
• D. IOP

Answer: (C)

Measuring corneal thickness is crucial in POAG evaluation because central corneal thickness (CCT) directly affects how we interpret intraocular pressure readings and influences glaucoma risk assessment. The test that directly measures corneal thickness is pachymetry, using either ultrasonic waves or optical methods to determine the distance across the cornea. Knowing the CCT helps adjust IOP measurements from applanation tonometry since thicker corneas can yield higher readings and thinner corneas can mask true IOP, guiding management decisions and risk stratification.

Other tests assess different aspects: imaging of the retinal nerve fiber layer and ganglion cell complex (RNFL/GCC OCT) provides structural information about the optic nerve; visual field testing (24-2 HVF) evaluates functional vision loss; and measuring IOP alone gives pressure but not corneal thickness.