Researchers in Egypt have determined that pattern electroretinogram (ERG) testing can detect retinal ganglion cell (RGC) dysfunction early in ocular hypertension (OHT)—even before cellular and axonal loss. This could allow for early treatment that may be able to restore cell function before irreversible damage, the researchers noted.

The study compared pattern ERG findings with visual field and OCT in controls, OHT and primary open-angle glaucoma (POAG) cases (30 eyes in each group). The researchers were assessing pattern ERG’s efficacy in detecting OHT abnormalities and select cases of increased IOP that benefit from glaucoma treatment. 

Significantly higher latencies and lower amplitudes of P50 and N95 were found in both POAG and OHT groups compared with the control group, meaning pattern ERG detected impaired RGC response not evident in the visual field or OCT of some patients. The study found no significant correlation between visual field and pattern ERG parameters in the OHT group, and the researchers now know that is because RGC dysfunction at this disease stage can only be detected using pattern ERG, while the visual field was still normal. However, they did find significant moderate correlation between visual field and pattern ERG parameters for POAG patients—an increase in pattern standard deviation and decrease in mean deviation accompanied a reduction in pattern ERG amplitudes.  

Emna T, Elsanabary ZSE, Elshazly LHM, Osman MH. Role of pattern electroretinogram in ocular hypertension and early glaucoma. Glaucoma. July 12, 2019. [Epub ahead of print].