Comparison of Microvascular and Electrophysiological Findings of Normal-Tension Glaucoma and Chronic Non-Arteritic Ischemic Optic Neuropathies.

OBJECTIVES

To compare microvascular alterations in the optic nerve head between non-arteritic anterior ischemic optic neuropathy (NAION) and normal-tension glaucoma (NTG) and assess the correlation between vascular density (VD) and pattern electroretinography (PERG) changes.

MATERIALS AND

METHODS

Patients with NTG and NAION underwent comprehensive ophthalmologic examinations, including optic coherence tomography angiography and PERG imaging. Demographic and clinical data were collected, and groups were matched for age, intraocular pressure, mean deviation, and global retinal nerve fiber layer thickness.

RESULTS

The study included 25 eyes from the NAION group, 24 eyes from the NTG group, and 30 eyes from the control group. VD was significantly lower in the peripapillary, inferior hemi, inferior temporal, and temporal inferior regions in NAION patients compared to NTG patients (p=0.004, p=0.003, p=0.002, p=0.006, respectively). Analysis of PERG parameters revealed that the P50 amplitudes in both NAION and NTG patients were lower than those in the control group (p=0.001, p=0.012, respectively). A statistically significant difference between the NAION and NTG groups was observed only in N95 amplitude (p=0.035). N95 amplitude emerged as the most sensitive discriminator, while inferior temporal VD was the most specific discriminator. VD correlated with P50 latency, P50 amplitude, and N95 amplitude (p<0.050 for all).

CONCLUSION

Our findings highlight the diagnostic value of peripapillary vessel density and PERG parameters in distinguishing NAION from NTG. The observed correlations between PERG and VD suggest a complementary role for these measures in evaluating retinal ganglion cell function and microvascular alterations.