Peripheral retinal ablation in the treatment of proliferative diabetic retinopathy: a three-year interim report of a randomised, controlled study using the argon laser.

Abstract

SUMMARY A randomised controlled trial is reported of 94 patients with a symmetrical proliferative diabetic retinopathy involving the optic disc, who were treated by a peripheral retinal ablation technique using the argon laser. A highly significant difference in mean cumulative deterioration of visual acuity and blindness was shown in all but the late stages of the disease process between treated and untreated eyes. The untreated eyes exhibited far worse results. The earlier photocoagulation is initiated in the course of the proliferative process in this disease to control or preferably eliminate optic disc neovascularisation, the better the visual prognosis.In England and Wales diabetic retinopathy is responsible for 7% of all new blind registrations and up to 20% in the middle-aged (Sorsby, 1972 (1970) noted that their patients with proliferative retinopathy had an incidence of optic disc neovascularisation of 68 to 73-25 %.Visual prognosis is far worse if the proliferative retinopathy involves the optic disc region (Deckert et al., 1967); 50% of patients in this category are blind within two to three years. Neovascularisation of the optic disc frequently leads to vitreous haemorrhage and blindness (Patz and Berkow, 1968). In their three-year study Beetham et al. (1970) showed that 85% (29 patients) of untreated eyes with vitreous haemorrhage bled from new vessels at the optic disc. Caird et al. (1968) showed that after a vitreous haemorrhage one-third of involved eyes were blind within one year and one-third had vision which was permanently impaired. Patz and Berkow (1968) found that the second (good) eye in patients blind in the other eye frequently became blind through extension of the proliferative process in a short period of time (50 % within one year). Meyer- (1971a, b); and Taylor and Dobree (1970) noted regression of disc neovascularisation occasionally when extensive xenon-arc photocoagulation of the diabetic retina had been undertaken.A circumferential ablation technique using the ruby laser was described first by Aiello et al. (1969). In a subsequent series (Beetham et al., 1970) 30% of patients with optic disc neovascularisation showed significant reduction of new vessels after treatment. James and L'Esperance (1974) treated 52 eyes with proliferation at the optic disc by a retinal ablation technique with the argon laser. After treatment 42% of eyes showed obliteration of disc neovascularisation, and 33% showed a significant response.Interim reports from a multicentre study in the United States using both xenon arc and argon laser (Diabetic Retinopathy Study Research Group, 1976) and England (British Multicentre Photocoagulation Trial, 1977)

Photocoagulation for optic disc new vessels in diabetes mellitus

“…In the more severely affected group (in which fibrous tissue is found on the optic disc) we have found improvement in visual acuity and regression of disc new vessels in 30% and 70% of eyes respectively. Our findings are in accord with Hercules et al (9), who found improvement in vision and regression of disc new vessels in patients with retinal fibrosis but no evidence of traction. These authors noted no improvement where macular traction already existed.…”

“…The prognosis is worse still if the new vessels arise from the optic disc, the risk of blindness rising to 70% over five years (5,10). In recent years a number of randomised controlled clinical trials have shown conclusively that in diabetic retinopathy both argon laser and xenon arc photocoagulation are effective in causing regression of new vessels (9,11) and in improving or maintaining visual acuity (6,7,9,11). In these studies the advantage of treatment was found to be particularly striking in eyes with new vessels arising from the optic disc.…”

Interventions for relieving pain associated with panretinal photocoagulation: a prospective randomized trial

“…[1][2][3][4] The Diabetic Retinopathy Study (DRS) recommended that treatment consists of 800-1600 argon laser burns of 500 mm size to the peripheral retina in a scatter fashion. 1 However, previous studies have shown that PRP is a painful procedure for most patients.…”

The national diabetic retinopathy laser treatment audit III. Clinical outcomes

“…For eyes with diffuse oedematous maculopathy at baseline, focal treatment alone had been given in 28.9% (11), grid treatment alone in 65.7% (25) and both grid and focal treatment in 5.3% (2). For those eyes where the diffuse oedema had improved and proliferative retinopathy had not developed, the median number of burns given was 125 (44-3218, SD 647).…”