OCT-A, PERG Parameters Predict Visual Field Progression in Glaucoma

The presence of microvasculature dropout (MvD) and retinal ganglion cell (RGC) dysfunction at baseline, disc hemorrhage (DH), and central scotoma are predictive of visual field (VF) progression in patients with glaucoma, according to research published in the Journal of Glaucoma. Researchers employed pattern electroretinography (PERG) and optical coherence tomography angiography (OCT-A) parameters to obtain baseline demographics and ocular characteristics of patients with normal-tension glaucoma.

The researchers prospectively enrolled patients with open-angle glaucoma and followed up with them for at least 3 years. All patients underwent at least 5 serial VF tests. The team performed baseline PERG and obtained N35, P50, and N95 latencies and amplitudes. They also evaluated superficial vessel density (VD) at the macula and MvD (defined as complete loss of microvasculature within the deep retinal layer of the parapapillary region) using baseline OCT-A images, assessed patients for isolated central scotoma, and recorded instances of DH. In combination with an event-based analysis, the team used linear regression analysis to determine which parameters were associated with VF progression.

Of the 140 eyes of 140 patients (mean age, 55.92±10.06 years), the researchers found that 76.4% had normal-tension glaucoma and 40.7% displayed glaucoma progression. The mean deviation slopes were -0.43±1.11 decibels per year in eyes with progression and 0.59±1.27 decibels per year in eyes with no progression (P <.001). 

They also demonstrated that eyes with progression showed frequent MvD on OCT-A, isolated central scotoma, frequent DH, and reduced baseline P50-N95 amplitude compared with eyes without progression. 

The analyses revealed that age at diagnosis (P =.038) and baseline P50-N95 amplitude (P =.019) were significantly associated with the mean deviation slope. It also showed that the presence of MvD on OCT-A (P <.001) and baseline P50-N95 amplitude (P =.037) were significantly associated with VF progression.

“In this study on predominantly [normal-tension glaucoma] patients, patients with vascular features, who presented with central scotoma, or possessed RGC dysfunction detected by PERG, tended to show progression and should be monitored closely,” according to the researchers.

Limitations of the study included a sample population with predominantly normal-tension glaucoma and a large proportion of eyes with isolated central scotoma as well as a possible influence of the projection artifacts of OCT-A.