Abstract
Purpose:
The Diabetes Control and Complications Trial demonstrated that a mean of about 6 years of intensive therapy aimed at near normal glucose levels reduced the risk of retinopathy by as much as almost 80% compared to conventional therapy. Therefore the purpose of this trial was to evaluate the prevalence and stage of diabetic retinopathy (DR) and diabetic macular edema (DME) in a cohort of Swiss adults with type 1 diabetes who had been treated with intensified insulin therapy aiming at near normal glucose levels from the beginning of their disease.
Methods:
A cross-sectional analysis of 153 adult persons with diabetes type 1 for 5 to 25 years duration who had been treated at an University-based diabetic center with intensified insulin therapy aiming at near normal glucose levels from the beginning of their disease. Screening included: best corrected visual acuity (BCVA) and contrast sensitivity testing, biomicroscopic ophthalmic examination, ETDRS 7-field color stereoscopic photography and fluorescein angiography, SD-OCT (optical coherence tomography). Grading of color, angiography and SD-OCT images was carried out by the Vienna Reading Center.
Results:
The prevalence of any DR as assessed by ETDRS 7-field color stereoscopic photography was 61.3%. There were no cases of sight-threatening DR. Proliferative DR (PDR) was observed in 0% and non-proliferative DR in 61.3% of eyes, with no signs of DR being present in the remaining 38.7% of the eyes. ETDRS 7-field color stereoscopic fluorescein angiography revealed any signs of DR in 58.5% of examined eyes. The presence of DR was strongly associated with increased duration of diabetes and correlated to long-term mean HbA1c and blood pressure values. Mean central retinal thickness was 280±22µm. Within the 9 ETDRS fields intraretinal cysts were detectable in 1.6% and hyperreflective intraretinal foci in 7.4% of eyes. None of the eyes showed subretinal fluid at SD-OCT. Mean central point choroidal thickness was 310±76µm.
Conclusions:
The prevalences of DR and DME in a population with long term type 1 diabetes who had been treated with intensified insulin therapy aiming at near normal glucose levels from the beginning of their disease are low compared to the data in the literature for conventional treatment.