Role of Pattern Electroretinogram in Ocular Hypertension and Early Glaucoma

PURPOSE

• To test if pattern electroretinogram (PERG) can early detect retinal ganglion cells dysfunction in ocular hypertension

METHOD

• Cross-sectional observational study, Visual fields were examined using automated perimetry with central 24-2 program.
• Optical coherent tomography was done to assess the neuroretinal rim area, vertical cup/disc ratio and average superior and inferior retinal nerve fiber layer thickness.
• PERG was recorded using skin electrodes. Amplitude and latency of P50 and N95 were documented.

RESULTS: 

• PERG data: the mean P50 and N95 showed significantly higher latency and  significantly lower amplitude in the POAG group and the OHT group compared to the control group (P<0.001, <0.001, and P<0.001,<0.001, respectively).
• In the POAG group, there was significant negative correlation between pattern standard deviation on one hand and P50 amplitude (r=-0.620, P=0.001) and N95 amplitude (r=-0.61, P<0.001) on other hand. Also, the mean deviation was positively correlated with P50 amplitude (r=0.51, P=0.007) and N95 amplitudes (r=0.50, P=0.002).
• However, there was no significant correlation between PERG parameters and OCT parameters. In the OHT group, PERG parameters did not correlate with visual field and OCT parameters.

CONCLUSION

• PERG can detect the dysfunctional but still live retinal ganglion cells earlier than OCT in OHT cases, allowing the early start of treatment that can restore the ganglion cell function before irreversible damage occurs.

TAKE-HOME MESSAGE

• The authors evaluated three groups of individuals which included healthy controls, patients with primary open angle glaucoma, and patients with ocular hypertension with 30 eyes in each group to determine the efficacy of pattern electroretinogram (PERG) in the early detection of retinal ganglion cells dysfunction in ocular hypertension.
• Results demonstrated that compared with optical coherence tomography, PERG was effective in early diagnosis of many conditions, including nerve and retinal damage.
• Utilization of PERG in combination with glaucoma investigations is recommended to avoid focal defect in retinal nerve fiber layer.
• The authors concluded that PERG is a useful imaging modality for early diagnosis and determining treatment intervals

REFERENCE 

Role of Pattern Electroretinogram in Ocular Hypertension and Early Glaucoma. J. Glaucoma 2019 Jul 12;[EPub Ahead of Print], E Turkey, ZSE Elsanabary, LHM Elshazly, MH Osman