Impact of Incidence and Progression of Diabetic Retinopathy on Vision-Specific Functioning.

PURPOSE: To investigate the independent impact of the incidence and progression of diabetic retinopathy (DR) on visual functioning (VF).

DESIGN: Population-based cohort study.

PARTICIPANTS: A total of 518 participants aged 40 to 80 years (baseline visit 2007-2009 and second visit 6 years later, 2013-2015), with diabetes, clinical data, and VF information at both visits.

MAIN OUTCOME MEASURES: VF-7 scores, converted to interval-level person measures (in logits) using Rasch analysis.

METHODS: Incident DR was defined using the Modified Airlie House classification as "none or minimal" DR at baseline and at least mild nonproliferative DR at follow-up; incident vision-threatening DR (VTDR; severe nonproliferative DR, proliferative DR, and/or clinically significant macular edema) as no VTDR at baseline, and present at follow-up; and DR progression as at least a 1-step worsening in DR at follow-up from mild or worse status at baseline. The longitudinal associations between incident DR, VTDR, and DR progression, as well as change in composite and individual item scores of VF, were assessed using multivariable linear regression models.

RESULTS: Of the 518 participants (mean age ± standard deviation [SD] 59.8±9.0 years; 47.7% female), 42 (9.8%), 14 (2.8%), and 32 (42.7%) had incident DR, incident VTDR, and DR progression, respectively, at follow-up. In models adjusting for traditional confounders, persons with incident DR and VTDR had a 13.7% (β = -0.60; 95% confidence interval [CI], -0.96 to -0.24; P = 0.001) and 23% (β = -1.00; 95% CI, -1.61 to -0.38; P = 0.001) reduction in mean VF scores at follow-up. Furthermore, individuals with incident DR had similar independent reductions in scores for 7 individual items of the VF-7, whereas those with incident VTDR had the largest reductions for activities like cooking (31%; P = 0.003), reading the newspaper (29.6%; P < 0.001), and seeing street signs (28%, P = 0.001) at follow-up. Progression of DR was not independently associated with change in overall VF (β = -0.18; 95% CI, -1.00, 0.64; P = 0.660).

CONCLUSIONS: Incident DR, particularly vision-threatening stages, has a substantial negative impact on people's overall vision-dependent functioning and specific activities such as cooking, seeing street signs, and reading the newspaper. Our findings reinforce the need for strategies to prevent or delay the development of DR.