Abstract
Purpose: :
To compare parafoveal retinal thickness and changes in the retinal inner and outer segments in diabetic patients with various stages of diabetic retinopathy.
Methods: :
Fourteen diabetic eyes (10 patients) without clinically significant macular edema and 8 control eyes (4 patients) of patients without diabetes and retinal disease were studied. Diabetic eyes were further subdivided into those with no diabetic retinopathy (NDR) (5 eyes), mild DR (5 eyes) and moderate DR (4 eyes). Total retinal, inner segment and outer segment thickness measurements were obtained 1.0mm from the foveal center using spectral-domain optical coherence tomography (SD-OCT). Temporal and nasal measurements were averaged to obtain mean thicknesses. Additional patient records are to be evaluated in the above manner to verify our preliminary results.
Results: :
Mean total retinal thickness 1.0mm from the foveal center was significantly thinner in NDR eyes when compared to controls (308∝m vs. 348∝m, p<0.0001). Mean retinal thickness in NDR eyes was also significantly thinner when compared to eyes with mild DR (334∝m, p<0.01) and moderate DR (334∝m, p<0.01). Significant thinning of the inner segment was observed consistently in all diabetic eyes within the study group (NDR 130∝m, p<0.0001; mild DR 146∝m, p<0.0001; moderate DR 150∝m, p<0.01) compared to controls (176∝m). The outer segment was significantly thicker in eyes with mild (191∝m, p<0.0001) and moderate (185∝m, p<0.001) DR compared to controls (166∝m).
Conclusions: :
The inner segment and outer segment of the parafoveal retina are affected differently in patients with various stages of diabetic retinopathy. We found that the inner segment was thinner in patients with NDR, mild DR and moderate DR, while thickening of the outer segment was observed in those with mild DR and moderate DR. These changes may be related to the vascular supply and abnormalities that occur in the retinas diabetic patients.
Keywords: diabetic retinopathy • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina