The National Diabetic Retinopathy Laser Treatment Audit. III. Clinical outcomes

To describe the short-term clinical outcomes for a cohort of patients undergoing first photocoagulation treatment for proliferative retinopathy or maculopathy in the United Kingdom.

Nine-month follow-up of the Royal College of Ophthalmologists' national audit of laser treatment for diabetic retinopathy.

For eyes with maculopathy, 9.2% had had a deterioration in visual acuity equivalent to a doubling of the visual angle and 3.3% of eyes had a visual acuity of less than 6/60 at follow-up. There had been an improvement in the macular oedema or exudate in 64.6% and 77.3% respectively. Prognostic factors for a poorer visual acuity at follow-up were worse visual acuity at baseline, the presence of diffuse (vs focal) oedema and grid (vs focal) treatment. For eyes with proliferative retinopathy, the retinal neovascularisation had regressed fully in 50.8% of cases, whilst there had been no change or a deterioration in 10.3%. A visual acuity of less than 6/60 at follow-up was present in 8.6% of eyes. There was a poor morphological outcome at follow-up (as defined by rubeosis, new tractional detachment or having had a vitrectomy) in 7.2%. Risk factors for poor morphological outcome were the presence of 'high-risk characteristics', female sex and the presence of concurrent maculopathy at baseline. Regression of neovascularisation was associated with greater areas of retinal ablation at the initial treatment session. Although some eyes with proliferative retinopathy appeared to be undertreated initially compared with DRS and ETDRS protocols, some of these eyes did respond to lower amounts of treatment.

For maculopathy, poorer outcome was related to worse visual acuity at baseline, diffuse (vs focal) maculopathy, and grid treatment. For proliferative retinopathy, poorer outcome was related to 'high-risk characteristics' and coexistence of maculopathy at baseline, and improvement was related to larger areas of ablation. The relationship of poor outcome with worse initial disease argues for earlier detection of retinopathy.