title: Iris transluminance in type 2 diabetes.
abstract: OBJECTIVE
  Cross-sectional analysis of iris transluminance in type 2 diabetic patients compared with control subjects, all followed in a cohort study.
  
  
  METHODS
  A cohort consisting of a well-characterized group of 82 type 2 diabetic patients were followed for 10 years after diagnosis, as were 125 control subjects. The prevalence of iris transluminance was determined by transscleral transillumination and by grading of black-and-white positive prints at the 10-year examination. The frequency of diabetic retinopathy was prospectively determined by grading of fundus photographs at baseline and after five and 10 years.
  
  
  RESULTS
  Iris transluminance was found in 27% of diabetic patients and 8.0% of control subjects (P = 0.001). The diabetic patients with more severe and short-term retinopathy more commonly had abnormal iris transluminance than those with no or only mild retinopathy (P < 0.05). Iris transluminance was not associated with intraocular pressure or glycemic control.
  
  
  CONCLUSIONS
  In type 2 diabetic patients, abnormal iris transluminance tended to associate with more severe and short-term retinopathy. Therefore we assume that hypoxia is responsible for the defects in the pigment layer of the iris. Thus, abnormal iris transluminance may serve as a marker for rapidly progressive retinopathy.
authors.affiliation: Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Raija
authors.initials: R
authors.lastname: Voutilainen-Kaunisto
authors.forename: Leo
authors.initials: L
authors.lastname: Niskanen
authors.forename: Matti
authors.initials: M
authors.lastname: Uusitupa
authors.forename: Markku
authors.initials: M
authors.lastname: Teräsvirta
mesh_terms: D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D003930:Diabetic Retinopathy / Q000150:complications*; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007429:Intraocular Pressure; D007499:Iris Diseases / Q000150:complications*; D008297:Male; D008875:Middle Aged; D010781:Photography; D011446:Prospective Studies