Abstract
Purpose :
The electroretinogram (ERG) test has proven to be useful in the evaluation and monitoring of patients with uveitis.1,2 ERG oscillatory potentials (OPs) – small oscillations seen superimposed on the larger ERG signal deflections – are believed to be reduced in many uveitic eyes with grossly normal ERG responses. Here we compare ERG parameters, including OPs, in patients with posterior uveitis and controls.
Methods :
64 posterior uveitis patients seen between 2003 and 2018 had a total of 93 visits during which ERG was performed on both eyes. 17 of these patients had repeat visits (mean 1.7 repeat visits, range 1-6). ERG data from the 93 visits were collected, along with data from 93 age-matched controls. Root-mean-squared (RMS) energy of the OPs was calculated using Fourier analysis.3 Photopic flicker amplitudes, scotopic b-wave amplitudes, and OP RMS values were compared between patients and controls. The diagnostic performance of these three parameters was evaluated by comparison of the area under the receiver operating characteristic (ROC) curves.
Results :
The mean ages of patients and controls were 56.2 ± 10.7 (std. dev) years and 55.4 56 ± 11.4, respectively. 50 of the 64 patients (78%) had a diagnosis of birdshot chorioretinopathy. The mean OP RMS value was significantly different in patients (15.7 µV ± 9.3 µV) versus control eyes (33.4 µV ± 13.3 µV), p <0.0001. In the ROC analysis, the area under the curves (AUCs) was 0.75 for photopic flicker amplitudes, 0.72 for scotopic b-wave amplitudes, and 0.88 for OP RMS. AUCs were significantly different between OP RMS and photopic flicker amplitudes (p=0.0001) and between OP RMS and scotopic b-wave amplitudes (p=0.0001).
Conclusions :
Analysis of oscillatory potentials may be more useful in the diagnosis and evaluation of patients with posterior uveitis than photopic and scotopic ERG amplitudes.
1.Moschos M, Gouliopoulos N, Kalogeropoulos. Electrophysiological examination in uveitis: a review of the literature. Clinical Ophthalmology. 2014;8:199-214.
2. Sobrin L, Lam BL, Liu M, Feuer WJ, Davis J. Electroretinographic Monitoring in Birdshot Chorioretinopathy. AJO. 2005;140(1):52e1-52e18.
3. Van der Torren K, Groeneweg G, van Lith G. Measuring oscillatory potentials: Fourier analysis. Doc Ophthalmol. 1988 Jun;69(2):153-9.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.