title: Progression of retinopathy and alteration of the blood-retinal barrier in patients with type 2 diabetes: a 7-year prospective follow-up study.
abstract: BACKGROUND
  The study was carried out to evaluate the correlation between blood-retinal barrier (BRB) permeability and the progression of diabetic retinopathy (DR), defined by development of "need for photocoagulation", over a 7-year period by means of vitreous fluorometry (VF).
  
  
  METHODS
  Forty type 2 diabetic patients with minimal or no retinopathy, aged 40-65 years (mean 53.9 + 7.3 years), were followed up prospectively for 7 years. Investigations including standard ophthalmological examination, fundus photography, fluorescein angiography and VF were performed at entry and 1, 4, 5 and 7 years later. Only one eye per patient was included in the study. Need for photocoagulation was based on Early Treatment Diabetic Retinopathy Study protocols and decided by the attending ophthalmologist.
  
  
  RESULTS
  After 7 years of follow-up a total of 22 of the 40 eyes had received photocoagulation. The eyes that needed photocoagulation were those that had higher VF values at the entry of the study and showed higher rates of deterioration (initial values 5.1 + 1.9 vs 2.8 + 1.5 x 10(-6) min-1, P < 0.001; annual increase in leakage for the first year, 1.5 + 0.8 vs 0.5 + 1.0 x 10(-6) min-1, P < 0.001,). The eyes that did not need photocoagulation during the 7 years of follow-up showed stable VF readings (-0.1 + 1.2 x 10(-6) min-1, difference between initial values and 7 years later).
  
  
  CONCLUSIONS
  Abnormally high VF values and their rapid increase over time are good indicators of progression and worsening of the retinopathy in diabetes type 2.
authors.affiliation: Department of Ophthalmology, University Hospital and Institute for Biomedical Research in Light and Image, Coimbra, Portugal.
authors.forename: J
authors.initials: J
authors.lastname: Cunha-Vaz
authors.forename: C
authors.initials: C
authors.lastname: Lobo
authors.forename: J C
authors.initials: JC
authors.lastname: Sousa
authors.forename: B
authors.initials: B
authors.lastname: Oliveiros
authors.forename: E
authors.initials: E
authors.lastname: Leite
authors.forename: J R
authors.initials: JR
authors.lastname: de Abreu
mesh_terms: D000328:Adult; D000368:Aged; D001813:Blood-Retinal Barrier; D002199:Capillary Permeability; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D003930:Diabetic Retinopathy / Q000209:etiology / Q000473:pathology* / Q000601:surgery; D018450:Disease Progression; D005451:Fluorescein Angiography; D015590:Fluorophotometry; D005500:Follow-Up Studies; D005654:Fundus Oculi; D006801:Humans; D008028:Light Coagulation; D008875:Middle Aged; D011446:Prospective Studies