title: Quantitative spectral domain optical coherence tomography thickness parameters in type II diabetes.
abstract: OBJECTIVE
  To elucidate the changes in retinal thickness and individual layer thickness in subjects with diabetic retinopathy (DR) using spectral domain optical coherence tomography (SDOCT).
  
  
  METHODS
  A total of 251 eyes from 170 subjects were included in this study. The study sample was subdivided into nondiabetic subjects; subjects with diabetes but no DR; subjects with mild, moderate, and severe nonproliferative DR (NPDR); and proliferative DR. Various retinal thickness parameters were assessed using SDOCT.
  
  
  RESULTS
  The mean age of the study population was 55.34 ± 9.02 years (range: 32-80 years) and 56.6% of the subjects were males. Men had significantly greater central foveal thickness, central subfield thickness, retinal nerve fiber layer thickness, and retinal thickness in all the quadrants of 3 mm and 6 mm zones compared to women (P < 0.001). Superior (293.11 ± 25.46 vs. 285.25 ± 19.17; P = 0.044) and temporal (282.10 ± 25.26 vs. 272.46 ± 16.21; P = 0.011) quadrants showed an increased retinal thickness in any DR group when compared with diabetic subjects without DR. Photoreceptor layer thickness was significantly reduced in diabetic subjects with no DR when compared with nondiabetic subjects and also in cases of severe NPDR when compared with mild and moderate NPDR.
  
  
  CONCLUSIONS
  Here, we analyze the quantitative retinal thickness parameters in diabetic subjects using SDOCT. Neuronal degenerative changes such as photoreceptor and retinal pigment epithelial thinning in case of DR are also reported.
authors.affiliation: Department of Optometry, Elite School of Optometry, Elite School of Optometry, Chennai, Tamil Nadu, India; Department of Optometry, Birla Institute of Technology and Science, Pilani, Rajasthan, India.
authors.forename: Laxmi
authors.initials: L
authors.lastname: Gella
authors.affiliation: Sankara Nethralaya, Shri Bhagwan Mahavir Vitreoretinal Services, Chennai, Tamil Nadu, India.
authors.forename: Rajiv
authors.initials: R
authors.lastname: Raman
authors.affiliation: Sankara Nethralaya, Shri Bhagwan Mahavir Vitreoretinal Services, Chennai, Tamil Nadu, India.
authors.forename: Tarun
authors.initials: T
authors.lastname: Sharma
keywords: Diabetic retinopathy; retinal thickness; spectral domain optical coherence tomography