Vitrectomy and radial optic neurotomy for central retinal vein occlusion: effects on visual acuity and macular anatomy.

BACKGROUND: Central retinal vein occlusion (CRVO) is a common retinal vascular disorder and a leading cause of visual loss. It is thought to arise from vascular obstruction at the level of the lamina cribrosa. The purpose of the study reported here was to evaluate the potential benefit of radial optic neurotomy (RON) and determine its effect on foveal thickness and macular volume in patients with CRVO.
METHODS: We conducted a prospective pilot study of ten patients with CRVO. Visual acuity (VA) score measured with the Early Treatment Diabetic Retinopathy Study chart and the corresponding Snellen equivalent were assessed before and 6 months after surgery. Colour fundus photography, fluorescein angiography (FA) and optical coherence tomography (OCT) were carried out before and at 2, 6, 12 and 24 weeks after surgery. Foveal thickness and macular volumes were assessed using OCT.
RESULTS: Visible reperfusion was observed in four of the ten patients at the time of surgery. VA score improved in eight of the ten patients from a median score of 11.50 (range 0-68) to a median score of 35.00 (range 3-79). Macular volumes decreased in six of seven patients from a median of 4.99 mm3 (range 2.68-6.77) to a median of 3.11 mm3 (range 1.11-5.02). Foveal thickness decreased in six of seven patients from a median of 596.50 microm (range 338.50-745.50) to a median of 330.50 microm (range 118-634.50). Six of ten patients developed a chorioretinal venous anastomosis. Macular oedema on OCT persisted in six of ten patients.
CONCLUSIONS: We observed an improvement in VA score and a corresponding reduction in foveal thickness and macular volume following RON, but macular oedema persisted in 60% of patients. Whilst optimisation of patient selection criteria remains a challenge, this pilot study suggests that RON has a beneficial effect on VA in patients presenting with CRVO.