title: Retinal nerve fiber layer defect as an early manifestation of diabetic retinopathy.
abstract: OBJECTIVE
  An incidence of and risk factors for retinal nerve fiber layer defect were investigated in patients with type II diabetes mellitus and compared with that of age-matched control subjects.
  
  
  METHODS
  The authors photographed the retinal nerve fiber layer of the right eye in each of 137 patients with diabetes and 144 healthy control subjects. The level of diabetic retinopathy ranged from levels 1 (no microaneurysm) to 4 (eyes with localized intra-retinal microvascular abnormalities or venous beading). Risk factors for the nerve fiber layer defect analyzed were age of patients, visual acuity, axial length, optic disc size, glycosylated hemoglobin, systolic blood pressure, and level of diabetic retinopathy.
  
  
  RESULTS
  Defects of the retinal nerve fiber layer were found in 6/30 (20%) eyes with level 1 retinopathy, 8/14 (57%) eyes with level 2 retinopathy, 24/47 (51%) eyes with level 3 retinopathy, and 36/46 (78%) eyes with level 4 retinopathy. These defect incidences were significantly higher than that of the control group, which had 5/144 (3.5%) defects (P < or = 0.001). Risk factors for this nerve defect were level of diabetic retinopathy (P = 0.002), high systolic blood pressure (P = 0.0232), and patient's age (P = 0.0478). Not correlated with the incidence of the retinal nerve fiber layer defect were visual acuity, disc size, axial length, and glycosylated hemoglobin level at the time of examination.
  
  
  CONCLUSIONS
  These findings suggest that the retinal nerve fiber layer defect is common in patients with early diabetic retinopathy. Risk factors for this defect were higher level of diabetic retinopathy, systemic hypertension, and advanced age.
authors.affiliation: Department of Ophthalmology, Faculty of Medicine, Kyoto University, Japan.
authors.forename: E
authors.initials: E
authors.lastname: Chihara
authors.forename: T
authors.initials: T
authors.lastname: Matsuoka
authors.forename: Y
authors.initials: Y
authors.lastname: Ogura
authors.forename: M
authors.initials: M
authors.lastname: Matsumura
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D003930:Diabetic Retinopathy / Q000453:epidemiology / Q000209:etiology / Q000473:pathology*; D006801:Humans; D006973:Hypertension / Q000150:complications; D015994:Incidence; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D012160:Retina / Q000473:pathology*; D012307:Risk Factors