| • Acute to sub-acute onset [2,8] promoting over a several hours 6 to 2 weeks [2,9,10] |
| • Young adult patient with peak manifestation between 15-50 years of age [2,3,9] |
| • Females > males [2,3,9] |
| • Periocular pain (90%) [2,5,16-18], especially with eye movement [2,3,8-10,18] |
| • Unilateral loss of visual acuity [2,4,8-10,18] variable in severity (from 20/20 in 10.5% to no light perception in 3.1% [4,5,16]), or may be bilateral usually in children often associated with a post or para infectious demyelination [2,4,8,10] |
| • Reduced contrast sensitivity [1,8,9,18] |
| • Uhthoff’s phenomenon (Exercise or heat-induced deterioration of visual symptoms) [2,5,8,18] |
| • Pulfrich phenomenon (misperception of the direction of movement of an object) [2,5,8,18] |
| • Ipsilateral relative afferent pupillary defect (RAPD). lack of the defect suggests a preexisting or concurrent optic neuropathy in the fellow eye [2,4,8-10,18] |
| • Normal (65%) or swollen (35%) (more common in children) optic nerve head [2,5,9,10,18] |
| • Possibility of mild uveitis [9,18] and retinal periphlebitis [2,9,18] |
| • Visual field defect [2,4,10], any type [9,18]; ranging from commonly seen diffuse depression and central or centrocecal scotoma [2,5,8,16], to rarely seen quadrantic [2,4,16] and altitudinal defects [4] |
| • Spontaneous visual improvement in >90% [2,3,9,18] |
| • No deterioration in vision after steroids discontinuation [2,9] |
| • Pallor of the optic disc [2,11] |
| • Previous history of ON or MS [9,18] |
| • Reduction in vision in bright light [2] |
| • Phosphenes or photopsias (spontaneous flashes of light in vision) provoked by eye movement [8,18] |
| • Dyschromatopsia [2,8-10,18] (any type) [2,7]* |