A comparative study between visual functions of affected and unaffected eyes in acute unilateral optic neuritis

Optic neuritis causes some deficits in visual function in the affected eye and there are some differences in these functions between the affected and unaffected eyes. The purpose of the study is to compare visual functions of both eyes to demonstrate the minimum and maximum value of affection in patients with acute unilateral optic neuritis. Thirty patients (23 female، 7 male aged between 18 and 45 years) who 22 patients with retro-bulbar and 8 patients with anterior optic neuritis، enrolled in the study and their affected and unaffected eyes underwent visual function assessments. Visual acuity (VA)، contrast sensitivity (CS)، color vision (CV)، and visual field (VF) (consist of MA and PSD) were examined for both eyes of all the patients and the significance of the differences between two eyes were calculated and compared by Independent T-test. According to our results، all the investigated visual functions consist of VA (t-test، t=7. 29، P=0. 00)، CS (t-test، t=9. 20، P=0. 00)، CV (t-test، t= -21. 95، P=0. 00)، MD (t-test، t=5. 29، P=0. 01) except PSD (t-test، t=0. 67، P=0. 71) were affected by optic neuritis and there was a significant difference between the affected and unaffected eyes (P<0. 01). The most significant difference were found for contrast sensitivity with letters (P=0. 00) and there wasn`t any significance in the difference between two eyes for PSD parameter in VF (P=0. 71). Considering the most significant difference of contrast sensitivity between affected and unaffected eyes in patients with acute unilateral optic neuritis، it is suggested to pay more attention to the test in evaluating، diagnosis and follow up patients with acute unilateral optic neuritis.