Neovascular or wet age-related macular degeneration (AMD) is caused by blood vessels growing as a layer of tissue under the central retina (the macula). The disease leads to the development of a blind spot in the centre of the visual field and is the most common cause of legal blindness among the elderly in the western world. Surgery has been used to remove tissue lying beneath the macula, within which grow the small, new blood vessels which are the cause of wet AMD. It was hoped that removal of this tissue might limit the development of AMD, and perhaps even improve vision.
We found two large multicentre studies conducted in 790 people affected by choroidal neovascularisation, with or without extensive blood beneath the macula. The results of these studies suggested that visual loss cannot be prevented using surgery. In addition, complications such as cataract and retinal detachment can arise during follow-up, in patients who have the procedure.
There is no benefit with submacular surgery in most people with subfoveal choroidal neovascularisation due to AMD in terms of prevention of visual loss. Furthermore, the risk of developing cataract and retinal detachment increases after surgery.
Vitreoretinal surgeons proposed submacular surgery to remove the fibrovascular tissue causing damage to the centre of the retina, in the attempt to limit central visual loss in people affected by neovascular age-related macular degeneration (AMD).
This review aims at assessing the effectiveness of submacular surgery for preserving or improving vision in patients with AMD.
We searched CENTRAL, MEDLINE, EMBASE and LILACS. There were no language or date restrictions in the search for trials. The electronic databases were last searched on 11 February 2009.
We included randomised or quasi-randomised controlled trials comparing submacular surgery with any other treatment or observation.
Two authors independently extracted the data. The risk ratio (RR) of visual loss and visual gain was estimated at one year.
Two multicentre studies with a similar design were conducted between 1997 and 2003 and compared submacular surgery with observation in people affected by subfoveal neovascular AMD with (n=336) or without (n=454) extensive blood in the macula. At one year there was high quality evidence of no benefit for preventing visual loss (RR: 0.96; 95% confidence interval (CI): 0.84 to 1.09). No difference could be demonstrated regarding the chance of visual gain (RR: 1.06; 95% CI: 0.75 to 1.51), although this evidence was of low quality because of imprecision. The risk difference was -2% (95% CI: -10% to 5%) and 1% (95% CI: -4% to 6%) for visual loss and visual gain, respectively, thus excluding a large benefit with surgery in terms of absolute risk in this sample. There was high quality evidence that cataract needing surgery (RR: 8.69; 95% CI: 4.06 to 18.61) and retinal detachment (RR: 6.13; 95% CI: 2.81 to 13.38) were more common among operated patients, and detachment occurred in 5% of patients with no extensive blood and in 18% of those with extensive blood beneath the macula.
A pilot study compared submacular surgery with laser photocoagulation in 70 patients. No difference between the two treatments could be demonstrated for any outcome measure, but estimates were very imprecise because of small sample size.