Automated grating contrast-sensitivity: The easy test for hidden visual loss in recovered optic neuritis patient

PURPOSE: Residual visual loss is an important predictor of optic neuritis relapse and progression. This study aimed to investigate the hidden residual visual loss in patients with optic neuritis using automated contrast-sensitivity (CS) function testing. MATERIALS AND METHODS: This cross-sectional study investigated 29 recovered optic neuritis patients (age: 27.69 ± 13.32 years, range: 13–51). Twenty age-matched controls with normal visual acuity (VA, in LogMAR) were recruited, for comparison with patients' VA and CS function after stable recovery from optic neuritis (6 months of follow-up). CS tests used a novel software that displays a single set of Gabor patches (2 cycles per degree at 10° ×10° of visual angle) with contrasts grating from 100% to 0.1%. RESULTS: There were 13 adolescent patients (63.6%: retrobulbar neuritis [RN]; 36.4%: papillitis), 14 adult patients (50%: RN; 42.9%: papillitis), and only 2 older patients (all with neuroretinitis). There was improvement of VA in the patient group at first diagnosis and follow-up (VA initial vs. final: 1.438 ± 1.134 vs. 0.235 ± 0.272, P < 0.001). This VA improvement was similar to control group (P = 0.052). In CS, there were significant differences in patient versus control groups (69.069% ± 70.235% vs. 27.215% ± 25.27%, P = 0.025). Linear regression showed that initial VA and CS function could not predict final VA (P = 0.183 and P = 0.138, respectively). CONCLUSIONS: Patients with optic neuritis showed decreased CS compared to control group which indicated the residual visual loss. Automated CS testing is useful in detecting residual visual loss in patients who recovered from optic neuritis.