RE-PERG, a new procedure for electrophysiologic diagnosis of glaucoma that may improve PERG specificity.
OBJECTIVE
A significant variability of the second harmonic (2ndH) phase of steady-state pattern electroretinogram (SS-PERG) in intrasession retest has been recently described in glaucoma patients (GP), which has not been found in healthy subjects. To evaluate the reliability of phase variability in retest (a procedure called RE-PERG or REPERG) in the presence of cataract, which is known to affect standard PERG, we tested this procedure in GP, normal controls (NC), and cataract patients (CP).


METHODS
The procedure was performed on 50 GP, 35 NC, and 27 CP. All subjects were examined with RE-PERG and SS-PERG and also with spectral domain optical coherence tomography and standard automated perimetry. Standard deviation of phase and amplitude value of 2ndH were correlated by means of one-way analysis of variance and Pearson correlation, with the mean deviation and pattern standard deviation assessed by standard automated perimetry and retinal nerve fiber layer and the ganglion cell complex thickness assessed by spectral domain optical coherence tomography. Receiver operating characteristics were calculated in cohort populations with and without cataract.


RESULTS
Standard deviation of phase of 2ndH was significantly higher in GP with respect to NC (P<0.001) and CP (P<0.001), and it correlated with retinal nerve fiber layer (r=-0.5,P<0.001) and ganglion cell complex (r=-0.6,P<0.001) defects in GP. Receiver operating characteristic evaluation showed higher specificity of RE-PERG (86.4%; area under the curve 0.93) with respect to SS-PERG (54.5%; area under the curve 0.68) in CP.


CONCLUSIONS
RE-PERG may improve the specificity of SS-PERG in clinical practice in the discrimination of GP.
Social Health District, Glaucoma Center, Azienda Sanitaria Locale, Brindisi.
Alberto
A
Mavilio
Department of Ophthalmology and Otolaryngology, University of Bari, Bari, Italy.
Dario
D
Sisto
Department of Ophthalmology and Otolaryngology, University of Bari, Bari, Italy.
Paolo
P
Ferreri
Department of Ophthalmology and Otolaryngology, University of Bari, Bari, Italy.
Nicola
N
Cardascia
Department of Ophthalmology and Otolaryngology, University of Bari, Bari, Italy.
Giovanni
G
Alessio
ganglion cells; glaucoma; optical coherence tomography; pattern electroretinogram; visual field