Early panretinal photocoagulation for ERG-verified ischaemic central retinal vein occlusion

We have previously shown that photopic cone b-wave implicit time ≥ 35.0 ms in 30 Hz flicker electroretinography (ERG) predicts ocular neovascularization (NV) in central retinal vein occlusion (CRVO). Here, we evaluate the effects of early panretinal photocoagulation (PRP) in patients with ERG-verified ischaemic CRVO.

Patients with CRVO, admitted to our department between 2000 and 2008, were classified as having ischaemic or non-ischaemic CRVO based on the ERG-results. In a first group of 71 patients, 18 patients had ischaemic CRVO and were assigned to standard treatment that is regular examinations and PRP as soon as NV was found. In a consecutive group of 65 patients, 18 patients with ischaemic CRVO received early PRP. In this group, ERG was performed on average 6 weeks after the first symptoms of CRVO. The patients underwent PRP as soon as possible after the ERG-examination, and the treatment was completed within one to three sessions.

Twelve patients in the standard treatment group developed neovascular glaucoma during a mean period of 5 months after the CRVO. In the early treatment group, one patient developed subtle iris rubeosis 7 months after PRP. Otherwise, none of the patients showed any signs of ocular NV, and the intraocular pressure remained within normal range, without the necessity of supplementary medication, during a mean follow-up of 41 months.

This study indicates that ocular NV in patients with CRVO can be predicted by photopic 30 Hz flicker ERG and that early PRP in ERG-verified ischaemic CRVO could be suggested as standard treatment.