Effects of DTL electrode position on the amplitude and implicit time of the electroretinogram.

PURPOSE: This study sought to investigate whether there is an optimal position of the Dawson, Trick, and Litzkow (DTL) electrodes when measuring the full-field electroretinogram (ERG) for monitoring purposes. METHODS: In 200 uveitis patients, an extended light-adapted (LA) ERG protocol was measured twice, incorporating the International Society for Clinical Electrophysiology of Vision standards. First, a LA ERG was measured with the DTL in the lower lid position (LLP) and thereafter in the fornix position. Differences in amplitudes and implicit times of a-waves, b-waves, and the 30 Hz peak were investigated. Intraclass correlation coefficients (ICCs) as well as coefficients of variation (CoV) were calculated, to assess both reliability and relative variability between the two DTL positions. RESULTS: Implicit times showed no statistically significant differences between the two DTL positions. As expected, amplitudes at the different stimulus strengths were 1.12-1.19 higher in the LLP, but there were no significant differences in the CoV between the two DTL positions. The ICC was high for the b-wave and 30 Hz flicker response (0.842-0.979), but lower for the a-wave, especially for amplitudes (0.584-0.716). CONCLUSIONS: For monitoring purposes in patients, we conclude that based on relative variability, no position is preferable above the other. However, because in most diseases amplitudes are decreased, the LLP may be chosen because it yields higher amplitudes. Whatever the choice, it is important to ensure that the DTL position remains stable during an ERG recording.

Electroretinogram abnormalities in non-infectious uveitis often persist.

PURPOSE: In uveitis, a prolonged implicit time of the cone b-wave is a characteristic electroretinogram (ERG) abnormality. We investigated whether this can improve or deteriorate over time and which clinical factors are associated with change. METHODS: Prospective cohort study. Patients with a non-infectious uveitis were included. An ERG was measured in the first year of uveitis onset and a follow-up ERG one year later. Changes in the implicit time of the cone b-wave were investigated in relation to clinical parameters including the following: demographics, uveitis characteristics, treatment, best-corrected visual acuity, optical coherence tomography parameters and fluorescein angiography scores. RESULTS: Of 98 eyes (63 patients), 40 showed a prolonged cone b-wave on the first ERG, which improved in 10 eyes. Eyes with an improved ERG more often had a panuveitis with initially a higher incidence of cells in the anterior chamber during the first ERG, which resolved at the time of their follow-up ERG. Five of the 58 eyes with a normal first ERG had a deteriorated follow-up ERG. These eyes had more frequently an active uveitis at the time of the follow-up ERG. Of the 78 eyes with a stable cone b-wave, 16 had a quiescent inflammation during follow-up. There were no differences in age or treatment. CONCLUSION: In most patients with non-infectious uveitis, ERG abnormalities appear to be irreversible, even when the inflammation becomes quiescent. However, some ERGs improved, which was associated with reduction in inflammation of the anterior chamber due to panuveitis. In contrast, a worsened ERG was associated with a persistence of inflammation.

Electroretinogram abnormalities in nonanterior childhood uveitis.

PURPOSE: A major point of concern in uveitis is the development of irreversible retinal changes after inflammation. In this study, we assess how nonanterior childhood uveitis affects retinal function using full-field electroretinography (ERG). METHODS: Cross-sectional study. ERGs of 63 uveitis eyes (33 children) were measured according to extended International Society for Clinical Electrophysiology of Vision (ISCEV) protocols. ERG abnormalities were investigated in relation to the following clinical parameters: demographics, uveitis characteristics, including severity of inflammation, treatment, best corrected visual acuity (BCVA), cystoid macular oedema (CME) on optical coherence tomography and fluorescein angiography score. RESULTS: The ERG showed abnormalities in 34 eyes (54%). The most frequent ERG abnormalities were prolonged implicit times of the cone b-wave (37%; n = 23/63) and an abnormal 30-Hz flicker response (implicit time and/or amplitude) (33%; n = 21/63). Factors associated with these ERG abnormalities were CME (p = 0.021) and 3+ vitreous cells (p = 0.021). BCVA in eyes with and without these ERG abnormalities did not statistically differ and was relatively good (median: 0.05 LogMAR, IQR: 0.00-0.15 LogMAR). CONCLUSION: The ERG is frequently affected in childhood uveitis indicating a global retinal dysfunction. ERG abnormalities seem to be associated with a more severe posterior segment inflammation and a younger age. If an association between ERG abnormalities and long-term visual outcome can be made in the future, these early ERG findings during the course of childhood uveitis have significance for treatment strategies.

Prolonged Cone b-Wave on Electroretinography Is Associated with Severity of Inflammation in Noninfectious Uveitis.

PURPOSE: This study sought to investigate retinal function in patients with noninfectious uveitis by using full-field electroretinography (ERG) and correlate the ERG to disease duration and severity of inflammation. DESIGN: Prospective cohort study. METHODS: Patients (n = 200) with noninfectious uveitis and a disease duration of <1 year (group A [n = 80]) and those with a disease duration of >5 years (group B [n = 120]) were included. ERGs of the total 355 uveitis eyes were measured according to an extended International Society for Clinical Electrophysiology of Vision protocol. ERG abnormalities were related to demographics and uveitis characteristics, including anatomical classification, duration of uveitis, severity of inflammation, best corrected visual acuity (BCVA), cystoid macular edema (CME), and the highest fluorescein angiography (FA) score during the course of the disease. RESULTS: ERGs showed abnormalities in 235 eyes (66.2%). The most frequent and pronounced ERG abnormality was a prolonged implicit time of the cone b-wave (151 eyes [42.5%]), which was associated with vitritis (P = .005); cells in the anterior chamber (P = .007); the highest fluorescein angiography score (P = .011); age (P < 0.001); and pupil diameter (P < 0.001). BCVA was relatively good (0.05 logMAR [interquartile range {IQR}, 0.011, 0.22]) and not associated with this ERG abnormality. There were no differences between the ERG abnormalities in group A and those in group B and no significant associations between ERG abnormalities and anatomical classification or specific diagnoses. CONCLUSIONS: ERG results are frequently affected in cases of noninfectious uveitis of all anatomic subtypes, including anterior uveitis without apparent inflammation of the posterior segment. ERG abnormalities appear to be associated with the severity of inflammation from both the present and the past and therefore may be seen even when signs of retinal inflammation have disappeared.

Potential Predictors of Poor Visual Outcome in Human Leukocyte Antigen-B27-Associated Uveitis.

PURPOSE: To identify potential predictors of permanent vision loss in patients with human leukocyte antigen (HLA)-B27-associated uveitis in a tertiary referral center. DESIGN: Retrospective case-control study. METHODS: The charts of 212 patients (338 eyes) with HLA-B27-associated uveitis that visited the University Medical Center Utrecht with a follow-up of at least 6 months were retrospectively studied. Clinical features at presentation and during follow-up were compared to final visual outcome in quiescent state. Eyes with (sub-) normal vision (>20/50) were compared with visually impaired (≤20/50) and blind (≤5/50, or a visual field of <10 degrees) eyes, using survival analysis. A multivariate Cox proportional hazards analysis was performed to analyze potential predictors for permanent vision loss. RESULTS: Median follow-up was 10.4 years (range, 0.5-44.7 years). During follow-up 226 eyes (66%) experienced vision loss up to 20/50, but most recovered. Twenty patients (9%) became permanently visually impaired or blind in at least 1 eye because of uveitis, after a median of 9.7 years (range, 0-20.9 years). The main cause was secondary glaucoma or related to glaucoma surgery (12/22 eyes, 55%). Survival analysis showed, after adjustment for age and sex, an ocular pressure of >21 mm Hg, hypotony, and panuveitis to be potential predictors at presentation, and the development of secondary glaucoma or hypotony to be predictors of blindness or visual impairment during follow-up. CONCLUSIONS: The long-term visual prognosis of HLA-B27-associated uveitis is relatively good, but the true incidence of permanent vision loss is probably still underestimated. Our findings highlight the importance of proper control of intraocular pressure.