Visual function correlates with nerve fiber layer thickness in eyes affected by ocular hypertension

Area of Science:

• Ophthalmology
• Neuroscience
• Medical Imaging

Background:

• Ocular hypertension presents a risk for glaucoma, characterized by elevated intraocular pressure.
• Variability in electrophysiological tests (PERG, VEP) and contrast sensitivity (SCS) is noted in ocular hypertension.
• Optical coherence tomography (OCT) allows for precise measurement of the retinal nerve fiber layer (NFL) thickness.

Purpose of the Study:

• To investigate the association between high variability in PERG, VEP, and SCS measurements and NFL thickness in ocular hypertensive eyes.
• To determine if NFL thickness, as measured by OCT, explains the observed variability in visual function tests.

Main Methods:

• 32 untreated eyes with ocular hypertension and normal visual fields were included.
• SCS, OCT, PERG, and VEP recordings were performed on all participants.
• Linear and Spearman's rank regression analyses were used to correlate NFL thickness with electrophysiological and SCS data.

Main Results:

• Overall NFL thickness ranged from 113 to 169 micrometers.
• Significant correlations were found between NFL thickness and PERG amplitude/latency, VEP amplitude/latency, and SCS at 3 cyc/deg.
• Thinner NFL was associated with reduced PERG amplitude, prolonged PERG latency, reduced VEP amplitude, prolonged VEP latency, and reduced SCS.

Conclusions:

• The variability in PERG, VEP, and SCS testing in ocular hypertension is significantly associated with variations in NFL thickness.
• A thinner nerve fiber layer is linked to poorer visual function outcomes in these tests.
• NFL thickness is a critical factor influencing the results of electrophysiological and psychophysical visual function tests in ocular hypertension.