Evaluation of retinal, retinal nerve fiber layer and choroidal thicknesses in diabetic patients without diabetic retinopathy

Purpose: Comparison of retinal, retinal nerve fiber layer (RNFL) and choroidal thicknesses in healthy subjects and diabetic patients without retinopathy. Materials and Methods: The study included 133 diabetic patients without diabetic retinopathy and 60 healthy subjects aging 37-78 years of age. Horizontal line scan of retina and choroid were performed using enhanced depth imaging mode of Fourier domain optical coherence tomography. The retinal and choroidal thicknesses were measured at the central fovea and at 1500 µm nasal and 1500 µm temporal from the center of the fovea. RNFL thickness measurements were performed using default RNFL thickness measurement mode provided by the device. Results: The mean age of diabetic group and control group were 52.75±12.74 and 53.83±5.95 years, respectively. Intraocular pressure (IOP) of diabetic group and control group were 16.26±2.90 and 13.18±2.13 mmHg, respectively (p<0.001). Central retinal thickness of diabetic group and control group were 226.24±18.78 and 216.37±14.79 µm, respectively (p<0.001). Subfoveal choroidal thickness of diabetic group and control group were 301.95±76.20 and 346.62±82.14 µm, respectively (p=0.001). We did not determine statistically significant difference between RNFL thicknesses of the groups (p=0.494). Correlation analysis using Spearman test revealed presence of diabetes showed association with increased foveal retinal thickness, decreased subfoveal choroidal thickness and increased IOP (range of rho values were -0.262 and 0.543, p<0.001). Conclusions: Diabetic group had higher retinal thickness, lower choroidal thickness and higher IOP values compared to healthy subjects. No significant RNFL thickness difference was determined between the groups. Results of the current study demonstrated that IOP and posterior segment of diabetic patients without retinopathy should be evaluated cautiously. © 2015 Gazi Eye Foundation. All Rights Reserved.