Are Myopic Eyes Less Likely to Have Diabetic Retinopathy?

PurposeEyes with myopia may be less likely to develop diabetic retinopathy (DR). The relationship between refractive error, ocular biometry, and DR therefore was investigated.DesignPopulation-based, cross-sectional study.ParticipantsPersons with diabetes from the Singapore Malay Eye Study (SiMES).MethodsDiabetes mellitus was defined as random glucose of 11.1 mmol/l or more, use of diabetic medication, or a physician diagnosis of diabetes. Spherical equivalent refraction (SE) was assessed using an autokeratorefractometer and subjective refraction. Axial length (AL) and anterior chamber depth (ACD) were measured by IOLMaster (Carl Zeiss Meditec AG, Jena, Germany). Diabetic retinopathy was graded from retinal photographs.Main Outcome MeasuresAny DR was defined by characteristic lesions defined by the Early Treatment Diabetic Retinopathy Study (ETDRS); moderate DR by ETDRS retinopathy severity scores of 43 or higher; and vision-threatening retinopathy by severe nonproliferative retinopathy, proliferative DR, or clinically significant macular edema.ResultsOf 3280 adult Malay participants (78.7% response), 629 persons with diabetes contributed to this analysis. In multivariate analyses adjusting for age, gender, education, height, cataract, hypertension, hemoglobin A1c, and other factors, eyes with myopic SE were less likely to have any DR (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.84–0.96; P = 0.002, per 1-diopter [D] decrease), moderate DR (OR, 0.83; 95% CI, 0.73–0.93; P = 0.001, per 1-D decrease), and vision-threatening DR (OR, 0.77; 95% CI, 0.67–0.88; P<0.001, per 1-D decrease). Eyes with longer AL were less likely to have any DR (OR, 0.86; 95% CI, 0.75–0.99; P = 0.041, per 1-mm increase), moderate DR (OR, 0.80; 95% CI, 0.62–1.05; P = 0.11, per 1-mm increase), and vision-threatening DR (OR, 0.63; 95% CI, 0.40–0.99; P = 0.044, per mm increase). Eyes with deeper ACD were less likely to have moderate DR (OR, 0.32; 95% CI, 0.16–0.64; P = 0.001, per 1-mm increase) and vision-threatening DR (OR, 0.14; 95% CI, 0.06–0.36; P = 0.001, per 1-mm increase).ConclusionsMyopic refraction and longer AL are associated with a lower risk of DR, particularly vision-threatening retinopathy, without any evidence of a threshold.Financial Disclosure(s)The author(s) have no proprietary or commercial interest in any materials discussed in this article.