Abstract
Purpose :
The pattern electroretinogram (pERG) closely depends on normal RGC activity, and therefore represents an objective and direct measure of RGC function. This functional test has been shown to be altered in ocular hypertension and glaucoma. The purpose of the study is to determine the effect of IOP reduction on pERG of a cohort of early stage glaucoma patients.
Methods :
Twenty three consecutive untreated glaucoma patients (at an early stage of the disease based on a definition using clinical, perimetric and tomographic findings) were assesed by pERG (Diopsys-NOVA contrast sensitivity module; Pine Brook, NJ, E.U.A.), before and after undergoing pharmacological ocular hypotensive therapy. The effect of IOP reduction was compared with functional and structural changes, incuding three pERG variables (magnitude, magnitudeD and magnitudeD/magnitude ratio). Non-parametric statistical methods were used. A P value of less tan 0.05 was considered as statistically significant.
Results :
Participants were predominantly female (69.5%), older than 50 years of age (median, 61 years), and affected by primary open-angle glaucoma (82.6%). No significant changes were observed comparing pre- and post-antiglaucoma treatment moments of perimetric indexes (medians: MD, - 3.72 dB vs. - 3.14 dB; PSD, 4.01 dB vs. 4.18 dB) from a mínimum of four visual fields per eye; as well as of tomographic parameters (medians: average CFNR, 90 µm vs. 92 µm; rim area, 1.15 mm2 vs. 1.11 mm2); in contrast, statistically significant differences were observed at the two different moments regarding IOP (medians, 22 mm Hg vs. 16 mm Hg; P = 0.001), as well is in pERG variables (medians: magnitude, 1.39 µv vs. 2.34 µv, P = 0.014; magnitudeD, 1.01 µv vs. 2.18 µv, P = 0.028; magnitudeD/magnitude ratio, 0.70 µv vs. 0.98 µv, P = 0.049).
Conclusions :
A clinically significant IOP reduction in previously untreated patients with early glaucoma seems to improve electrical activity of ganglion cells measured by pERG which could be used as a sensitive biomarker of therapeutic efficacy in glaucoma patients during its earliest stages.
This is a 2020 ARVO Annual Meeting abstract.