Abstract
Purpose:
To assess the results of the functional evaluation of glaucoma using the amplitude of the P50-N95 wave of pattern Eletroretinogram (PERG) compared with the mean deviation (MD) of the standard automated perimetry (SAP).
Methods:
A prospective transversal study was performed. A hundred and thirty one eyes of eyes of 74 patients were examined with PERG using the Rolandtm with 100% of contrast, reverse pattern in Black and White with stimulus height of e 4 cm and with SAP using HumphreyTM perimetry (Zeisstm), strategy SITA-Standrd 24-2. The sample was divided in three groups based on SAP: 51 eyes with primary open angle glaucoma (POAG) with MD=-7dB or worse, 58 with POAG with a MD better than -7dB and 30 controls. The statistical analysis was performed using the linear mixed models of the Statistical Package for Social Sciences SPSS, Chicago, IL ,USA version 2.0.
Results:
The estimate marginal mean of P50-N95 wave amplitude of PERG using linear mixed models was 3.83mV in the group with POAG and SAP MD worse than -7dB (mean MD= -16.72dB), 3.79mV in the group with PAOG and SAP MD better than -7dB (mean MD= -2.70dB); and in the control group 7.74mV (mean MD= -1,49 dB). The difference of the N50-P95 wave amplitide of PERG was statistically significant between the POAG with MD worse than -7dB and the control group (p<0.001) and between the POAG with MD better than -7dB and the control group (p<0.001). There was no statistical significant difference between both POAG groups. In our sample no POAG patient had a P50-N95 wave amplitude better than 10mV .
Conclusions:
The objective functional evaluation using the P50-N95 wave amplitude of PERG can be a useful test for the diagnosis and for the follow-up of progression in glaucoma patients. In our sample, there was a significant difference between the control group and the POAG groups, however there was no statistically significant difference between the POAG groups. Prospective longitudinal studies evaluating the correlation between SAP progression and P50-N95 worsening are needed to further evaluate this diagnostic tool.