title: Comparison of Optic Nerve Head Topographic Parameters in Patients With Primary Open-Angle Glaucoma With and Without Diabetes Mellitus.
abstract: OBJECTIVE
  To evaluate the optic nerve head (ONH) parameters of primary open-angle glaucoma (POAG) patients with and without diabetes and to investigate the effect of the metabolic control of diabetes on ONH topography.
  
  
  METHODS
  A study group of 60 eyes of 60 POAG patients with type 2 diabetes mellitus and a control group of 41 eyes of 41 POAG patients without diabetes were recruited for the study. Complete ophthalmic examinations of all patients were performed and the quantitative optic disc parameters were evaluated with Heidelberg retina tomography (HRT) III. HbA1c measurements of diabetic patients were assessed on the same day when the ophthalmic assessments were performed.
  
  
  RESULTS
  Mean rim area and rim volume of the study group was statistically higher than the control group (P=0.04 for rim area and P=0.02 for rim volume). The difference in other parameters of the HRT between the groups were insignificant (P>0.05). In the study group, the duration of the diabetes was not significantly correlated to rim area and rim volume (r=0.03, P=0.81 for rim area; r=0.03, P=0.79 for rim volume). Analysis of covariance showed insignificant effects of age, sex, MD, and PSD values over rim area and rim volume (P>0.05). There were weak but statistically significant correlations between HbA1c levels and some HRT parameters including disc area, cup area, cup volume, and cup shape measure (r=0.35 and P=0.006 for disc area; r=0.35 and P=0.006 for cup area; r=0.32 and P=0.01 for cup volume; r=0.32 and P=0.01 for cup shape measure).
  
  
  CONCLUSIONS
  The results of this study imply the protective effect of diabetes over glaucomatous optic nerve damage in POAG patients. However, larger and controlled studies are warranted to confirm those findings.
authors.affiliation: *Department of Ophthalmology, Dişkapi Yildirim Beyazit Training and Research Hospital ‡Department of Ophthalmology, Faculty of Medicine, Yildirim Beyazit University, Ankara †Department of Ophthalmology, Faculty of Medicine, Ondokuz Mayis University, Samsun, Turkey.
authors.forename: Serkan
authors.initials: S
authors.lastname: Akkaya
authors.forename: Ertuğrul
authors.initials: E
authors.lastname: Can
authors.forename: Faruk
authors.initials: F
authors.lastname: Öztürk
mesh_terms: D000368:Aged; D063171:Corneal Pachymetry; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis / Q000503:physiopathology*; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D021621:Imaging, Three-Dimensional; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology; D009887:Ophthalmoscopy; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis / Q000503:physiopathology*; D011446:Prospective Studies; D012165:Retinal Ganglion Cells / Q000473:pathology; D019371:Topography, Medical
chemical_list: D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human