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Background The combined corticosteroid regimen of the original Optic Neuritis Treatment Trial (ONTT) is used in many centers to treat optic neuritis. Though pattern reversal visual evoked potentials (PRVEPs) are a sensitive, standard measure of visual conduction in optic neuritis, no studies hitherto have investigated the effect of combined ONTT regimen on PRVEPs. We aimed to determine the effect of combined corticosteroid regimen of the ONTT on changes of PRVEPs in patients with first-episode optic neuritis over 3 months post-treatment. Methods This is a prospective, observational study in which 44 patients with optic neuritis were seen pre-treatment (baseline) and follow-up, at 1 month (FU1) and 3 months (FU2). Twenty-nine patients were treated with ONTT combined regimen (ONTT+ Group) while 15 were conservatively managed without corticosteroids (ONTT- Group). The median latency and amplitude values of the P100 PRVEP component and the visual acuity (i.e. LogMAR values) at pre-treatment, FU1 and FU2 were compared in the two groups using Friedman’s rank test and Wilcoxon Signed Ranks test. Results Median P100 latency improved significantly (to the normal range) as early as by 1 month after the commencement of treatment in the ONTT+ Group, and then remained significantly lower than the baseline over next 2 months. In the ONTT- Group, the median P100 latency improved more slowly over the two follow up assessments and reached the normal range by 3 months. Median visual acuity values also improved significantly at 1 and 3 months after the commencement of treatment in the ONTT+ Group but not in the ONTT- Group. Conclusion ONTT combined corticosteroid regimen improves conduction in the visual pathways of patients with first-episode optic neuritis earlier than does conservative management. We provide electrodiagnostic evidence that combined ONTT regimen–compared with conservative management–results in early remission of visual conduction abnormalities in first-episode optic neuritis.

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Objective: Effect of bilateral, optic neuropathy on the function of retinal pigment epithelium has not been investigated extensively to date. This study aimed to determine the effect of bilateral, optic neuropathy on light peak:dark trough ratio, light peak and dark trough values of electro-oculography. Thirty-seven patients with a clinical diagnosis of bilateral optic neuropathy and 40 control subjects were recruited in this observational, cross-sectional study, carried out at the Neurophysiology unit, Teaching Hospital, Peradeniya, Sri Lanka. Pattern reversal visual evoked potentials, pattern electroretinography and electro-oculography were recorded in all of them. Results: Twenty-four patients (64.9%) had reduced light peak:dark trough ratio values. The median light peak:dark trough ratio ± inter quartile range of the patient group (1.50 ± 0.4) was significantly lower than that of the controls (1.80 ± 0.2), (p < 0.001). Median dark trough value was significantly higher in patients compared to the control value. These changes may be due to higher conductance of ion channels in the retinal pigment epithelium, sub retinal space creation, changes in choroidal circulation or secondary to photoreceptor abnormalities in the macular region. These results indicate that retinal pigment epithelium might be affected in bilateral optic neuropathy.

Background: The effect of various risk factors on hearing impairment (HI) in infants has not been studied extensively in Sri Lanka until now. Objectives:To determine the influence of perinatal risk factors on the brainstem auditory evoked potentials (BAEP) in infants in Sri Lanka and to assess the follow up BAEP waveforms of infants with elevated hearing thresholds after 6 months. Method:We recorded BAEP waveforms of 100 eligible at-risk infants using auditory click stimuli. Prematurity, prolonged neonatal intensive care unit (NICU) stay >5 days, very low birth weight (VLBW), hyperbilirubinaemia, ototoxic medications, mechanical ventilation, meningitis and sepsis were the perinatal risk factors considered. Risk factors of HI were determined using multiple logistic regression modeling. We did a follow up assessment after 6 months in 26 infants with elevated hearing thresholds and compared the data of the two assessments.Results: Prematurity (odds ratio: 3.08, 95% CI: 1.05-9.04, p=0.04) and prolonged NICU stay (odds ratio: 3.67, 95% CI: 1.00-13.49, p=0.05) were the significant risk factors for developing HI as indexed by increased BAEP threshold levels. Seventeen out of 26 infants attended the follow up study and five improved.