The effect of low vision rehabilitation in diabetic eye disease: a randomised controlled trial protocol.

ABSTRACT

PURPOSE: Current research highlights a rising incidence of diabetes and its complications. Diabetic retinopathy is the leading cause of blindness within the working-age population of the United Kingdom. Increasing severity of retinopathy is associated with reduced visual function and participation in daily living. Only 8% of those referred to Moorfields Eye Hospital's low vision clinic have diabetic eye disease, a value less than prevalence figures for diabetes would predict. The lack of evidence for effectiveness of low vision intervention in this patient group could be responsible. Therefore, in line with CONSORT guidance, we present the methodology of the first randomised controlled trial to quantify the effect of low vision rehabilitation on people with diabetic eye disease. METHODS: One hundred participants were recruited into four retinopathy severity groups based on their diagnosis according to the English National Screening Programme Grading Protocol. Participants were randomised to either immediate intervention (1-2 weeks after enrollment) or delayed (control) intervention (3 months after enrollment). Intervention was a standard low vision assessment performed in a hospital clinic. The Activity Inventory (AI), was administered to all participants by telephone within 1 week of enrollment (before any intervention) and repeated at 3 and 6 months. RESULTS: One hundred participants (Type 1 28, Type 2 72; male 62, female 38) have been recruited. Median habitual distance acuity was 0.19 logMAR (6/9, 20/30), with an interquartile range of 0.06-0.30 logMAR (6/7.5-6/12, 20/25-20/40). AI responses were scored by Rasch analysis, providing a measure of visual ability. Median baseline visual ability was 1.64 logits, with an interquartile range of 0.60-3.75 logits. Difference in mean change in visual ability between intervention groups will be assessed 3 months (primary outcome) and 6 months (secondary outcome) after enrollment. CONCLUSIONS: This is the first randomised controlled trial investigating the effectiveness of low vision rehabilitation for people with diabetic eye disease. With recruitment already complete, it is hoped this work will be the first step in guiding referral criteria for those with diabetic eye disease into the low vision service.