title: Macular and peripapillary choroidal thickness in diabetic patients.
abstract: OBJECTIVE
  To investigate macular and peripapillary choroidal thickness (CT) in diabetic patients with and without diabetic retinopathy (DR).
  
  
  METHODS
  One hundred and fifty subjects were enrolled: 102 diabetic patients (102 eyes) and 48 normals, as controls. Exclusion criteria were previously treated DR, refractive error higher than ± 3 diopters, and treated or untreated glaucoma. All patients underwent full ophthalmic examination, stereoscopic color fundus photography, and spectral domain optical coherence tomography (RS-3000; Nidek). Spectral domain optical coherence tomography examination consisted of linear scans, 6 mm in length, centered onto the fovea, and circle scan positioned around the optic disk (3.46 mm in diameter). Choroidal thickness was measured manually at the fovea and at 1, 2, and 3 mm distance along all scans in the macula. Peripapillary CT was measured at eight points along the circle scan. All measurements were performed independently by 2 masked graders.
  
  
  RESULTS
  Mean age was not significantly different between patients with diabetes and controls. In the macular area, CT was significantly lower in the nasal quadrant versus all other quadrants (P < 0.0001), in both groups. In the peripapillary area, CT was significantly lower in the inferior quadrant versus all other quadrants (P < 0.05), in both groups. Mean macular and peripapillary CT progressively and significantly decreased with increasing level of DR (nonproliferative and proliferative DR vs. controls, P < 0.05). No significant CT difference was found between controls and diabetic eyes without detectable DR. Diabetic macular edema did not influence CT. Interobserver coefficient of repeatability was 28.8 (95% confidence interval, 24.8-32.8) for foveal measurements and 13.0 (95% confidence interval, 11.2-14.8) for peripapillary measurements. Pearson correlation coefficient was 0.99, and P <0.0001 for all measurements.
  
  
  CONCLUSIONS
  Choroidal thickness is reduced in diabetic eyes and parallels appearance and evolution of DR. Spectral domain optical coherence tomography clearly confirms in vivo previously reported histopathologic observations. The role of choroid in the pathophysiology of DR needs to be adequately investigated.
authors.affiliation: Fondazione G. B. Bietti, IRCCS, Roma, Italy.
authors.forename: Stela
authors.initials: S
authors.lastname: Vujosevic
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Martini
authors.forename: Fabiano
authors.initials: F
authors.lastname: Cavarzeran
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Pilotto
authors.forename: Edoardo
authors.initials: E
authors.lastname: Midena
mesh_terms: D001786:Blood Glucose / Q000378:metabolism; D002829:Choroid / Q000473:pathology*; D003922:Diabetes Mellitus, Type 1 / Q000150:complications; D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D003930:Diabetic Retinopathy / Q000097:blood / Q000145:classification / Q000150:complications*; D005260:Female; D005451:Fluorescein Angiography; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009898:Optic Disk; D009929:Organ Size; D012160:Retina; D012720:Severity of Illness Index; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human