Clinical And Electrophysiological Photostress Recovery Times In Distinguishing Demiyelinating Optic Neuritis And Maculopathy (P6.292)

OBJECTIVE: We aim to investigate the contribution of clinical measurement of PRT(photostress recovery time) and electrophysiological evaluations by Visual Evoked Potentials (VEP) in distinguishing MDs from optic neuritis(ON) and to explicate differences between groups. BACKGROUND: Optic neuropathies and macular disease(MD) may sometimes have similar clinical presentations. PRT can be evaluated to differentiate MDs from optic nerve disorders, because the distinction is difficult. METHODS: Study involved 10 healthy control(20 eyes),12 patients with ON(22 eyes) and 9 patients(18 eyes) with MD. Clinical opthalmological and neuro-opthalmological examinations with optic coherence tomography(OCT) were performed on all patients. PRTs were clinically measured in each eye.VEPs were recorded before clinical photostress and in every 20 seconds after the stress for 2 minutes and P100 latencies were measured in all eyes. PRTs according to P100 latencies were determined in each group.Clinical and electrophysiological recovery times of each group were compared with the others. Correlations between PRTs,VEPs,clinical features and retinal nerve fibres layer9 thickness(RNFLT) in OCT were investigated. RESULTS: PRT for the affected eyes of all patients were longer than the nonaffected eyes of patients and controls (p<0.002).In basal conditions,VEPs latencies were longer in MS patients9 both eyes (MSON or MSWON) than MDs9 and controls9 eyes (p<0.002,p<0.0001). In MSON and MSWON eyes,VEPs were observed to have delayed P100 latencies compared to controls (P< 0.0001) and MDs immediately after photostress.20 seconds after bleaching, VEPs P100 latency delays were observed only in the MSON eyes.VEPs latencies of all MS patients recovered to basal conditions at 120th seconds. The correlations between the evaluations of visual Acuity(VA), RNFLT, PRT and VEP showed that an increase of RNFLT was associated with low VA in the MDs with macular oedema(p<0.01) and a decrease of RNFLT caused delayed VEP latencies in all patients(p<0.03). CONCLUSIONS: The results suggest that the co-use of these tests may be useful in differential diagnosis ON between MD’and the differences may be resulting from the involvement of different functional structures. Disclosure: Dr. Idiman has nothing to disclose. Dr. Keskin has nothing to disclose. Dr. Kaya has nothing to disclose. Dr. Idiman has nothing to disclose. Dr. Bulut has nothing to disclose.