title: Early Neurodegeneration of the Inner Retinal Layers in Type 1 Diabetes Mellitus.
abstract: OBJECTIVE
  This study explores retinal structural changes in type 1 diabetes without clinically diagnosed diabetic retinopathy (DR).
  
  
  METHODS
  Peripapillary retinal nerve fiber layer (RNFL) thickness, macular ganglion cell complex (GCC) thickness, and macular thickness (MT) were measured in 90 type 1 diabetic patients by using spectral domain optical coherence tomography. The values were compared with 100 sex- and age-matched healthy controls. The independent t test was used to assess differences in the mean age, mean diabetic and ocular parameters, and the thickness values between the diabetic and control groups. Multiple linear regression analysis was performed to investigate the correlation between the thickness values and diabetic and ocular parameters.
  
  
  RESULTS
  Whole-RNFL, the superior and inferior quadrants, and the superior half of the peripapillary RNFL thicknesses were significantly thinner in diabetic patients compared with controls (p < 0.05). GCC thicknesses in the average macular, outer temporal superior and outer temporal inferior sectors were significantly thinner in diabetic patients (p < 0.05). Central and average MTs were similar in both groups (p > 0.05). There were significant negative correlations of the duration of type 1 diabetes with the inner nasal MT, inner temporal superior GCC thickness, inner nasal inferior GCC thickness, and outer nasal superior GCC thickness (p < 0.05). Similarly, there were significant negative correlations of the level of HbA1c with the whole-RNFL thickness, superior-half-RNFL thickness, and superior-quadrant-RNFL thickness (p < 0.05).
  
  
  CONCLUSIONS
  Type 1 diabetic patients without clinically diagnosed DR had neurodegeneration in the inner retinal layers compared with healthy controls.
authors.affiliation: Department of Ophthalmology at GATA Medical School, Ankara, Turkey.
authors.forename: Fatih C
authors.initials: FC
authors.lastname: Gundogan
authors.forename: Fahrettin
authors.initials: F
authors.lastname: Akay
authors.forename: Salih
authors.initials: S
authors.lastname: Uzun
authors.forename: Umit
authors.initials: U
authors.lastname: Yolcu
authors.forename: Eylem
authors.initials: E
authors.lastname: Çağıltay
authors.forename: Sami
authors.initials: S
authors.lastname: Toyran
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D003922:Diabetes Mellitus, Type 1 / Q000175:diagnosis*; D003930:Diabetic Retinopathy / Q000175:diagnosis; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D009412:Nerve Fibers / Q000473:pathology*; D011446:Prospective Studies; D012162:Retinal Degeneration / Q000175:diagnosis*; D012165:Retinal Ganglion Cells / Q000473:pathology*; D041623:Tomography, Optical Coherence; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human