Hemifield patter electroretinogram and macular thickness asymmetry parameters in ocular hypertension patients

Abstract

AbstractPurpose To assess which is the most sensitive and specific exam for detecting an early retinal ganglion cells (RGC) damage between hemifield test pattern electroretinogram (PERG HF) and the posterior pole asymmetry analysis with optical coherence tomography (OCT‐PPAA) in ocular hypertensive patients (OH).Methods Forty‐two OH patients (mean age of 56.0±5.6 yrs.) with an intraocular pressure (IOP)>21mmHg and forty healthy controls (mean age of 55.2±6.4 yrs.) with IOP<21mmHg were assessed. All patients had normal visual acuity, normal optic disc appearance and normal standard achromatic perimetric (SAP) indices. All subjects underwent an OCT‐PPAA with the OCT‐Spectralis and PERG HF examination. Data were analyzed with Wilcoxon test and Receiver Operating Characteristic (ROC) curve analysis taking p < 0.05 as significant.Results We found that OH patients compared to healthy controls with full field PERG had a not significant decrease of the N95 wave amplitude (p<0.097) with a significant increase of its peak‐time (103.88 ± 11.11 vs 92.78 ± 4.30 msec; p<0.027). With PERG HF we found a significant intraeye asymmetry of the N95 wave (‐1.99±1.58 vs ‐0.67± 0.35 µVolt; p<0.023). With OCT‐PPAA in OH patients we found a decrease in macular thickness but not a statistical significant intraeye hemispheric asymmetry (3.94± 2.89 vs 5.98±4.74 µ; p<0.116). ROC curve analysis revealed a sensitivity of 80% and specificity of 87.6% for PERG HF whereas by using OCT‐PPAA we found a sensitivity of 70% and a specificity of 74%.Conclusion Our study shows that at the moment the PERG HF is the most sensitive and specific technique than OCT‐PPAA for detecting early RGC damages in eyes with ocular hypertension.