Diabetic retinopathy is the most common cause of blindness in the UK, with older people and those with worse diabetes control, hypertension, and hyperlipidaemia being most at risk. Diabetic retinopathy can cause microaneurysms, haemorrhages, exudates, changes to blood vessels, and retinal thickening.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments in people with diabetic retinopathy? What are the effects of treatments for vitreous haemorrhage? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2010 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
We found 58 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
In this systematic review we present information relating to the effectiveness and safety of the following interventions: peripheral retinal laser photocoagulation, focal and grid laser photocoagulation for maculopathy, corticosteroids for macular oedema, vascular endothelial growth factor inhibitors, and vitrectomy for vitreous haemorrhage.
Diabetic retinopathy is the most common cause of blindness in the UK, with older people and those with worse diabetes control, hypertension, and hyperlipidaemia most at risk.
Diabetic retinopathy can cause microaneurysms, haemorrhages, exudates, changes to blood vessels, and retinal thickening.
Peripheral retinal laser photocoagulation reduces the risk of severe visual loss compared with no treatment in people with preproliferative (moderate/severe non-proliferative) retinopathy and maculopathy.
We don't know if any one type of laser treatment is superior to another.We don't know whether peripheral laser photocoagulation is effective in people with background or preproliferative (non-proliferative) retinopathy without maculopathy because we found no RCTs assessing it in this population.
The benefits of laser photocoagulation are more notable in people with proliferative retinopathy than in those with maculopathy.
Focal macular laser photocoagulation reduces the risk of moderate visual loss in eyes with clinically significant macular oedema plus mild to moderate preproliferative (moderate/severe non-proliferative) diabetic retinopathy, compared with no treatment.
Grid photocoagulation to zones of retinal thickening may improve visual acuity in eyes with diffuse maculopathy.
Photocoagulation is unlikely to be beneficial in eyes with maculopathy but without clinically significant macular oedema.
Intravitreal triamcinolone acetonide improves visual acuity and reduces macular thickness in eyes with macular oedema refractory to previous macular laser photocoagulation, but repeated injections are needed to maintain benefit.
Secondary ocular hypertension and progression of cataract are common complications with intravitreal triamcinolone; infectious endophthalmitis is rare.
Intravitreal vascular endothelial growth factor (VEGF) inhibitors pegaptanib and bevacizumab improve visual acuity and reduce macular thickness in eyes with centre-involving diabetic macular oedema and vision loss, but repeat intravitreal injections are needed to maintain benefit.
Bevacizumab is not licensed for intraocular use.We don't know the long-term ocular and systemic safety of bevacizumab.We don't know if any one intravitreal VEGF inhibitor or treatment regimen is superior to another.We don't know whether combination treatment with VEGF inhibitor injection plus macular laser photocoagulation is effective as we found only one trial assessing ranibizumab as part of combined treatment.
Vitrectomy can reduce visual loss if performed early in people with vitreous haemorrhage, especially if they have severe proliferative retinopathy.
We don't know whether vitrectomy is effective in people with vitreous haemorrhage plus maculopathy as we found no RCTs assessing it.