Radial optic neurotomy in central retinal vein occlusion: preliminary results.

BACKGROUND: To investigate the efficacy of radial optic neurotomy (RON) on visual prognosis and clinical findings in central retinal vein occlusion (CRVO).

METHODS: Prospective, non-randomised, self-controlled comparative trial. Six patients with ischemic CRVO who had visual acuity (VA) less than or equal to 0.1 and duration of CRVO at least 1 month, and 6 patients with non-ischemic CRVO who maintained their VA less than or equal to 0.1 during the minimal follow-up of 3 months underwent pars plana vitrectomy and RON. LogMAR VA measurement and fluorescein angiography were performed before and after surgery. Automated perimetry was obtained from 4 patients at the last visit. Main outcome measures were VA and clinical changes in fundus appearance of CRVO evaluated with fundus photography and fluorescein angiography.

RESULTS: Radial optic neurotomy was successfully performed in all 12 patients without serious complications. All patients were of clinical improvement of fundus findings. In 11 (92%) patients, a visual improvement of at least 2 lines was observed. After mean follow-up of 9.3 months, mean improvement in VA was 5.1 +/- 3.1 lines (range, 2-14 lines). Cystoid macular oedema and degeneration were observed in 8 (67) patients. Four patients, two of whom had preoperative ocular hypertension had raised intraocular pressure controlled with topical antiglaucoma medication. In late postoperative period, one ischemic eye developed vitreous haemorrhage necessitating vitrectomy and endolaser photocoagulation. Automated perimetry revealed segmental visual field defects in all the examined eyes.

CONCLUSIONS: Radial optic neurotomy in CRVO yields clinical and visual improvement in majority of the patients. Cystoid macular oedema and degeneration are the major factors responsible for restriction of VA improvement. Further randomised and controlled studies with longer follow-up are essential to establish the appropriate timing and indications of RON in CRVO.