Table 2: Features of Typical ON in Adults

• 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]*

* Demyelinating ON does not obey Kollner's rule:
Red-Green color vision defects are characteristic of optic nerve disease and blue-yellow defects are characteristic of retinal disease (especially macular disease) [7,19].