[Preliminary report of contrast sensitivity in idiopathic optic neuritis patients after recovery]

To explore the changes of contrast sensitivity (CS) in patients recovered from idiopathic optic neuritis (ION).

It was a case-control study. We screened 22 idiopathic optic neuritis patients who underwent treatment and obtained normal visual acuity. No nervous system abnormalities were found in MRI scan. Twenty four healthy individuals were enrolled as the control group. OPTEC 6500 contrast sensitivity tester was used to examine near- and far-distance CS values on 1.5, 3.0, 6.0, 12 and 18 cycles/degree (c/d), separately. T-test or u-test was used to compare the mean of CS values between these two groups. ANOVA or H-test was adopted on CS values at the different frequencies in each group. Simple linear correlation was used to analyze the correlation between CS values and age, duration and gender, separately.

The maximum CS values in both far- and near-distance appeared in 6.0 c/d in these two groups were 70.27 +/- 40.44, 53.32 +/- 29.50, 78.86 +/- 36.37 and 109.39 +/- 44.98, respectively. The minimum CS values in both far- and near-distance appeared in 18 c/d in these two groups were 8.27 +/- 6.11, 12.09 +/- 8.57, 15.67 +/- 9.02 and 22.22 +/- 14.56, respectively. Far- and near-distance CS values in ION group and control group had very significant differences at these five spatial frequencies (From 1.5 to 18.0 c/d, the test values on far-distance were 4.19, 5.59, 3.06, 2.50, 3.13, P values were 0.00, 0.00, 0.00, 0.01, 0.00. The test values on near-distance were 3.54, 3.98, 2.72, 3.20, 3.39, P values were 0.00, 0.00, 0.01, 0.00, 0.00). CS values had no relation to the duration of ION. Significant difference in CS values existed on most frequencies (In far- and near-distance, H values in ION group were 52.38 and 64.96, in control group were 64.77 and 60.53, P values were both less than 0.01). The maximum H value appeared on near-distance in ION group. The maximum H value was 64.96 of near-distance in ION group. Far- and near-distance CS values in ION group itself and control group itself had very significant differences at these 5 spatial frequencies (From low to high frequencies, F values were 6.36, 0.03, 2.52, 1.53, 2.90; P values were 0.02, 0.87, 0.12, 0.22, 0.10 in ION group. In control group, F values were 5.31, 5.69, 6.06, 0.61, 3.14; P values were 0.03, 0.02, 0.02, 0.44, 0.08 respectively).

CS values at different frequencies in ION patients with normal visual acuity descend significantly. Contrast sensitivity examination can be an important technique to evaluate vision quality in patients after ION.