Abstract
Purpose: :
To evaluate ocular characteristics, including prevalence of no or mild retinopathy, and established risk factors of retinopathy in patients who have lived 50 or more years with type 1 diabetes mellitus (DM).
Methods: :
Ninety–five patients with type 1 DM diagnosed at least 50 years ago were identified through the Joslin Diabetes Center 50–year Medal program. Patients underwent Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity (VA) testing, dilated fundus exam, ETDRS protocol 7–standard field stereo fundus photography, and HbA1c and lipid measurements. Fundus photos were graded for severity of diabetic retinopathy (DR) and macular edema (ME) and for presence of laser scars. Two readers graded all photos, with discrepancies adjudicated by a third grader.
Results: :
Of 187 eyes with fundus photographs, 24 (12.8%) had no discernible DR, 1 (0.5%) had questionable DR, 77 (41.2%) had mild nonproliferative diabetic retinopathy (NPDR), 11 (5.9%) had moderate NPDR, 2 (1.1%) had severe NPDR, and 67 (35.8%) had proliferative DR (PDR). Photos from five eyes (2.7%) were ungradable due to media opacities or other, nondiabetic pathology. 88.1% of eyes with PDR had received previous panretinal photocoagulation with 97.0% of these achieving quiescence. ME was present in 9.6% of eyes (18) and 7.0% of eyes (13) had clinically significant ME. Of the 190 eyes with evaluated VA, 44.2% (84) and 85.8% (163) were better than or equal to 20/20 or 20/40, respectively. Only 9 (4.7%) eyes had VA of 20/200 or worse. Increasing severity of DR was correlated with the presence of hypertension (p=0.022), worse VA (p=0.004), and the presence of ME (p<0.001). DR severity was not statistically associated with gender, age, duration of DM, or age of onset of DM. Neither DR severity nor VA was related to current HbA1c or lipid levels.
Conclusions: :
In patients with 50 or more years of type 1 DM, more than 50% have mild or no DR and nearly half have 20/20 VA or better. Also, despite the demonstrated association of HbA1c and duration of DM with onset and progression of DR in patients with shorter duration disease, these risk factors did not correlate with severity of DR in long–duration patients. These findings suggest possible retinopathy protective attributes in some patients with long duration DM. Further studies of this patient cohort are warranted to identify biochemical and genetic factors that might protect against the development of retinopathy and other diabetic microvascular complications.
Keywords: diabetic retinopathy • clinical (human) or epidemiologic studies: prevalence/incidence • diabetes