title: Retinal tissue thickness in type 1 and type 2 diabetes.
abstract: BACKGROUND
  The objective was to investigate full retinal and inner retinal thickness in individuals with type 1 and type 2 diabetes.
  
  
  METHODS
  Eighty-four individuals with type 1 diabetes (T1DM), 67 individuals with type 2 diabetes (T2DM) and 42 non-diabetic individuals (control group) were enrolled. Participants underwent full retinal thickness evaluation in the central retinal, parafoveal and perifoveal zones and in the retinal nerve fibre layer (RNFL) and ganglion cell complex (GCC), using spectral domain optical coherence tomography. As a preliminary step, the key variables of interest - age, sex, diabetic retinopathy (DR), duration of diabetes and HbA1c levels - were analysed and compared between the three groups. Full retinal thickness, RNFL and GCC thicknesses were also compared between the groups. The relationship between the type of diabetes and retinal tissue thickness was explored, adjusting for the five potential confounders.
  
  
  RESULTS
  Compared to individuals with T1DM, individuals with T2DM had significantly reduced full retinal thickness in the parafovea and perifovea and reduced RNFL and GCC thickness. The mean differences were six (p = 0.020), seven (p = 0.008), six (p = 0.021) and four micrometres (p = 0.013) for the parafovea, perifovea, RNFL and GCC thicknesses, respectively. Thicknesses within the central zone (p = 0.018) and at the parafovea (p = 0.007) were significantly reduced in T2DM when compared to the control group. After adjusting for age, sex, diabetic retinopathy, duration of diabetes and HbA1c levels, the relationship between type of diabetes and retinal tissue thickness was not statistically significant (p > 0.056).
  
  
  CONCLUSIONS
  Retinal tissue thickness is not significantly different between type 1 and type 2 diabetes, when adjusted for age, sex, diabetic retinopathy, duration of diabetes and HbA1c levels.
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia.
authors.forename: Sangeetha
authors.initials: S
authors.lastname: Srinivasan
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia.
authors.forename: Nicola
authors.initials: N
authors.lastname: Pritchard
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia.|Deakin University, Geelong, Victoria, Australia.
authors.forename: Geoff P
authors.initials: GP
authors.lastname: Sampson
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia.
authors.forename: Katie
authors.initials: K
authors.lastname: Edwards
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Vagenas
authors.affiliation: Princess Alexandra Hospital, Woolloongabba, Queensland, Australia.|School of Medicine, University of Queensland, Woolloongabba, Queensland, Australia.
authors.forename: Anthony W
authors.initials: AW
authors.lastname: Russell
authors.affiliation: Centre for Endocrinology and Diabetes, Institute of Human Development, University of Manchester, United Kingdom.|Weill Cornell Medical College in Qatar, Doha, Qatar.
authors.forename: Rayaz A
authors.initials: RA
authors.lastname: Malik
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia. n.efron@qut.edu.au.
authors.forename: Nathan
authors.initials: N
authors.lastname: Efron
mesh_terms: D000368:Aged; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000473:pathology*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000473:pathology*; D003930:Diabetic Retinopathy / Q000175:diagnosis; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008875:Middle Aged; D012160:Retina / Q000473:pathology*
chemical_list: D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human
keywords: diabetic retinopathy; ganglion cell complex; retinal nerve fibre layer; retinal thickness; type 1 diabetes; type 2 diabetes