Significant characteristics related to visual field (VF) advancement in primarily normal tension glaucoma (NTG) patients included reduced P50-N95 amplitude on pattern electroretinography (PERG) and the presence of microvasculature dropout (MvD) on optical coherence tomography angiography (OCT-A) at baseline. Researchers looked into the patient demographics and ocular markers (such as PERG and OCT-A readings) that are predictive of glaucoma progression at the outset. Over the course of 3 years, 140 eyes with open-angle glaucoma were prospectively enrolled and monitored with at least 5 serial VF examinations. Latencies and amplitudes for the N35, P50, and N95 were measured with a baseline PERG.
Baseline OCT-A pictures were analyzed to determine the microvasculature loss in the deep retinal layer of the parapapillary region (MvD) and the density of the superficial vessels in the macula. Isolated central scotoma was defined as an eye with a glaucomatous VF defect in both hemifields within 24 points of a central 10 degrees of fixation but no VF abnormality in the nasal periphery outside 10 degrees of fixation. Hemorrhages in the discs were documented as part of the follow-up process. The Glaucoma Progression Analysis (GPA) software on the Humphrey Field Analyzer was used to conduct a linear regression analysis on the MD values and an event-based analysis to find parameters associated with VF progression. Glaucoma progression was defined as a GPA of 0.5 or higher. About 107 eyes (76.4% of the total 140) were classified as non-troublesome glaucoma, while 57 eyes (40.7% of the total 140) showed advancement of glaucoma as measured by the Humphrey VF Glaucoma Progress Assessment.
The MD slopes for the progressors were -0.43±1.11 dB/y, while those for the nonprogressors were 0.59±1.27 dB/y (P<0.001). Patients with advanced glaucoma had more MvD on OCT-A, isolated central scotoma, more DH, and lower P50-N95 amplitude at baseline than those without advancement. There were statistically significant correlations between the MD slope and both age at diagnosis (P=0.038) and baseline P50-N95 amplitude (P=0.019). Both the existence of MvD on OCT-A (P<0.001) and baseline P50-N95 amplitude (P=0.037) were substantially linked with VF development on GPA. In patients with primarily NTG, VF development was significantly correlated with the existence of MvD and retinal ganglion cell dysfunction as measured by PERG at baseline, DH, or central scotoma. These people need closer observation.