[Clinical study on optic neuropathy and retinopathy subsequent to radiotherapy of nasopharyngeal carcinoma].

OBJECTIVE

To explore the characteristics of optic neuropathy and retinopathy subsequent to radiotherapy of nasopharyngeal carcinoma (NPC).

METHODS

Sixty-eight eyes from 34 patients with fundus disease and visual disturbance after NPC radiotherapy were studied by vision testing, fundus examination, fundus fluorescein angiography (FFA) and computer analysis of visual field.

RESULTS

There were two types of fundus diseases: optic neuropathy and retinopathy. The former mainly showed edema, pale and atrophy of the optic disc. The latter showed mainly cotton-wool spots, bleeding, abnormal vessels or maculopathy of the retina. In 65.7% (22/34) of the patients fundus disease and visual disturbance occurred within 3 years after radiotherapy. FFA revealed that 88.1% (59/67) of the cases showed intense fluorescence, 65.7% of the cases (44/67) showed extensive flaw on macula, 71.9% of the cases (53/67) showed microaneurysm, and 53.7% of the cases (36/67) showed lack of perfusion of the retinal capillary network. Visual field test showed quadrant defect and irregular scotoma.

CONCLUSIONS

Early damage of the fundus subsequent to radiotherapy of NPC is the occlusion of capillary vessels or microcirculation, followed by occlusion of the small artery or vein, which causes chronic anoxemia on the optic disk, the macula, and the retina. The atrophy of the optic nerve, ischemic maculopathy, and retinal neo-vascular membrane may cause hemorrhage in the vitreous and retinal detachment, which can result in blindness. These changes are similar to the changes of ischemic optic neuropathy and diabetic retinopathy, which might offer a clue about the prevention and treatment of fundus damage subsequent to radiotherapy of NPC.