Reproducibility of Full-field Electroretinogram Measurements in Birdshot Chorioretinopathy Patients: An Intra- and Inter-visit Analysis.

Purpose: Aims to determine the variability of ffERG measurements in patients with clinically stable birdshot chorioretinopathy (BCR).Methods: Repeatability coefficients (RC) of ffERG amplitudes and implicit times were calculated from 11 BCR patients. Jackknife resampling estimated 95% confidence intervals of each ERG parameter's RC and the percentage change explained by variability alone was calculated.Results: Intra-visit variability in ffERG parameters was lower than inter-visit. Intravisit RCs demonstrated that for intravisit ERG testing, there was less than 30% variation in ERG amplitude for most parameters. For inter-visit ERG testing, a greater than 40% reduction in ERG amplitude may be clinically meaningful for 6 of 8 ERG parameters. Photopic single flash responses have <2 msec of test-retest variability both within and across visits.Conclusions: A 40% reduction in ERG amplitude and/or a delay of >2 msec in the photopic single flash response may be suitable criteria for meaningful change in BCR patients.

Oscillatory potentials in patients with birdshot chorioretinopathy.

PURPOSE: The electroretinogram (ERG) has proven to be useful in the evaluation and monitoring of patients with posterior uveitis. ERG oscillatory potentials (OPs) are sometimes reduced in many uveitic eyes with otherwise grossly normal ERG responses. This study compares ERG parameters, including OPs, between patients with birdshot chorioretinopathy, other posterior uveitis, and controls. METHODS: This was a retrospective case-control study. Sixty-four patients seen at a clinical practice had a total of 93 visits during which ERG was performed on both eyes. ERG data from 93 age-matched controls were also collected. Root-mean-squared (RMS) energy of the OPs was calculated using Fourier analysis for 88 patients and 88 age-matched controls for whom complete data were available. Photopic flicker amplitudes, photopic flicker latencies, scotopic b-wave amplitudes, and OP RMS values were compared between patients and controls. Diagnostic performance was assessed using receiver operating characteristic (ROC) curves. RESULTS: The mean ages of patients and controls were 55.9 ± 10.8 (SD) years and 55.1 ± 11.5, respectively. 83% of the patients had a diagnosis of BCR. The mean OP RMS value was significantly different in patients (15.6 µV ± 9.7 µV) versus control eyes (33.0 µV ± 12.7 µV), p < 0.001. Area under the ROC curves (AUROC) was 0.75 for photopic flicker amplitudes, 0.77 for photopic flicker latencies, 0.72 for scotopic b-wave amplitudes, and 0.88 for OP RMS. AUROC was significantly different between OP RMS and photopic flicker amplitudes (p < 0.001), between OP RMS and flicker latencies (p = 0.0032), and between OP RMS and scotopic b-wave amplitudes (p < 0.0001). CONCLUSION: Analysis of OPs shows greater sensitivity and specificity in the diagnosis and evaluation of patients with birdshot chorioretinopathy than photopic and scotopic ERG amplitudes and photopic flicker latencies.

Long-term outcomes of systemic corticosteroid-sparing immunomodulatory therapy for Birdshot Retinochoroidopathy.

PURPOSE: To report the visual prognosis, electroretinography (ERG) and perimetry outcomes of systemic corticosteroid-sparing immunomodulatory treatment (IMT) for birdshot retinochoroidopathy (BSRC). METHODS: Retrospective non-comparative case series of 132 patients (264 eyes) with BSRC treated with IMT from Massachusetts Eye Research and Surgery Institution. RESULTS: The average follow-up time was 60.1 months. After one year on IMT, 39.4% showed no clinically active inflammation. After 5 years of IMT, 78.0% had no signs of clinical inflammation. No significant differences were observed on best-corrected visual acuity (BCVA), ERG parameters, and perimetry parameters between baseline and subsequent visits on IMT. CONCLUSION: Long-term systemic corticosteroid-sparing IMT was associated with a low rate of BSRC disease exacerbation. While differences were seen on testing parameters, they were not consistent trends and difference were attributed to variability of testing or fluctuation of inflammation that may be expected in the course of the disease.

Five-Year Trends in Multifocal Electroretinogram for Patients With Birdshot Chorioretinopathy.

PURPOSE: The aim of this study is to investigate temporal trends in multifocal ERG (mfERG) parameters and analyze their relationships with anatomic and functional markers in patients with birdshot chorioretinopathy (BSCR). DESIGN: Prospective observational case series. METHODS: Sixteen BSCR patients were include and underwent 2 standardized follow-up (FU) visits within 5 years following a baseline examination, including mfERG, visual acuity (VA), visual field (VF), Lanthony desaturated panel D-15 test for color vision, quality of life (QoL), fluorescein and indocyanine green angiography, and optical coherence tomography (OCT). RESULTS: A significant trend toward a decrease in absolute N1 amplitude values was observed over the follow-up period (P < .001) while N1 implicit time remained unchanged. In contrast, P1 amplitude decreased (P < .001) and P1 implicit time increased (P < .001) over the same period. No significant temporal change was found for VA, color vision score, foveal threshold, mean deviation of VF, and QoL. After adjusting for time to FU, increasing N1 and P1 IT were both associated with decreasing values of logMAR, foveal threshold, and QoL and with increasing color vision score and mean deviation of VF. A significant relationship was observed between decreasing P1 amplitude values and increasing mean deviation of VF. Lower absolute values of N1 amplitude were associated with venous vasculitis, whereas lower P1 amplitude values correlated with alteration of the outer retina in OCT. CONCLUSIONS: Progressive deterioration in mfERG during a 5-year period is detected in BSCR, whereas classical functional test results were unchanged. This study suggests a better sensitivity of mfERG in monitoring the retinal function of BSCR patients.