Abstract
Purpose:
The standard Octopus™ G2 protocol (STAP) may not be optimal for structure function correlation to the multifocal eletroretinogram (mfERG) in glaucoma. In a first step, a new automated perimetry (AP) protocol (mf103AP, Octopus, Haag-Streit) related to the mfERG stimulus grid was compared to STAP and to optical coherence tomography (OCT) in primary open angle glaucoma patients (POAG) and controls.
Methods:
One eye from 18 POAG and 15 controls underwent: STAP, the mf103AP protocol and OCT fast macular thickness protocol (Cirrus SD-OCT, Carl Zeiss). mf103AP: 103 stimulus points (size III/ 3e), positioned to correspond to the center of each hexagon in the 103 mfERG grid (55° retinal stimulation). Analysis: AP: MS, MD, sLV , values in dB. OCT: full macular thickness (mT) from the 6 mm diameter area as per Cirrus software, transformed into logarithmic scale. SPSS (IBM, version 22) was used for t-Tests. The statistical package R (version 3.0.2) was used to analyze the relationship between exams using linear mixed effects models and to compare the areas under the receiver operating characteristic curves (AUC). All calculations were adjusted to age.
Results:
Mean age and IOP were 59.6 years (SD 13.5) and 13.2 mmHg (SD 2.7) for POAG and 49.2 years (SD 7.2) and 12.5 mmHg (SD 1.9) for controls. Mean mT was 283.6 µ (SD 14.3) for POAG and 293.7 µ (SD 12.4) for controls (p=0.038, t-Test). Both AP could significantly differentiate glaucoma patients from controls. Mean MD was 3.95 dB (SD 3.8) in POAG and 0.59 dB (SD 1.5) in controls with mf103AP (p= 0.004). With STAP mean MD was 3.47 dB (SD 4.0) in POAG and 0.13 dB (SD 1.7) for controls (p= 0.006). There was a positive significant relationship between MD from STAP and mf103AP (regressive slope 0.853, p<0.001). AUC was similar for STAP MD (0.84) and mf103AP MD (0.83; p=0.878). Both AP protocols showed a statistically significant relationship with full macula thickness (p<0.001, both MD).
Conclusions:
Both AP parameters demonstrated a good predictive performance to identify patients from controls. The mf103AP had comparable parameters in relation to STAP. This held true also for structure function relationship. The mf103AP protocol may be used as a complementary tool in future studies relating structure and function in electrophysiology.