[Clinical analysis of radiation optic neuropathy]

To investigate the clinical features, risk factors, diagnostic methods, treatment regimens and outcomes of Chinese adult patients with radiation optic neuropathy (RON).

Retrospective case series. Clinical data with RON admitted to Zhongshan Ophthalmic Center from June 1999 to October 2010 were investigated retrospectively.

Thirty-five cases (61 eyes) with RON were analyzed. All cases manifested as sudden binocular or monocular painless vision decrease. In 18 cases (51.4%), symptoms occurred within 36 months after the completion of radiation. In 43 eyes (70.5%), the visual acuity was less than 0.05 and/or with a visual field less than 10 degrees. In 52 eyes which the fundus could be examined, 41 eyes (78.8%) showed a clear boundary of optic papilla, including 6 eyes (14.6%) with normal appearance of optic papilla, 30 eyes (73.2%) with lighter color, 5 eyes (12.2%) with pale optic papilla, and 11 eyes (21.2%) with edematous or hemorrhagic and/or exudative optic papilla. Only 14 eyes showed abnormal visual field examination, mainly manifested as nerve bundle defect scotoma. Seven eyes (50%) manifested as arcuate scotoma, 3 eyes (21.4%) manifested as central scotoma and/or paracentral scotoma, 2 eyes accompanied by blind spot enlargement, 1 eye showed paracentral scotoma and 1 eye with quadrantanopia. Twenty-three eyes received fluorescein angiography (FFA), the major manifestations were low fluorescence at the optic nerve and areas of capillary nonperfusion. Pattern visual evoked potential revealed reduced amplitude and/or extended incubation period in 83.3% eyes. Treatment regimens including systemic corticosteroids, hyperbaric oxygen therapy, hyperbaric oxygen in combination with corticosteroid and laser photocoagulation, the visual acuity of 10 eyes (16.4%) had merely been improved.

The prognosis of visual function in RON is poor resulting from devastating visual loss and/or visual field defect. The main damage of the fundus is retinal vascular occlusion and optic atrophy at different degrees. No adequately effective therapies are proved currently. The treatment aimed on the complication could only provide a short-term improvement of the vision.