title: [The sub-classification and long-term prognosis of preproliferative diabetic retinopathy].
abstract: OBJECTIVE
  We followed eyes with preproliferative diabetic retinopathy(PPDR) for 2 or more years, and then evaluated the proportion of patients developing proliferative diabetic retinopathy(PDR) and the period from diagnosis of PPDR until development of PDR.
  
  
  METHODS
  We divided 95 eyes affected by PPDR into 75 eyes with mild type and 20 eyes with moderate type based on our previously proposed sub-classification, and evaluated the long-term prognosis of 2 or more.
  
  
  RESULTS
  The proportion developing PDR was 24% in mild type and 60% in moderate type. The average period from diagnosis of PPDR until development of PDR was 6 years and 5 months in the mild type and 2 years in the moderate type. The accumulative occurrence rates of PDR at two, 5, and 10 years were estimated to be 0%, 14%, and 39% in the mild type and 35%, 58%, and 79% in the moderate type, respectively. The proportion developing PDR was significantly higher and the average period until PDR development significantly shorter in the moderate than in the mild type. In mild type eyes, the rate of progression to moderate type was 56% and further progression from moderate type to PDR was noted in 43%.
  
  
  CONCLUSIONS
  The above results again verify the usefulness of our sub-classification, and also provide useful information about the long-term prognosis of PPDR.
authors.affiliation: Department of Ophthalmology, Surugadai Hospital of Nihon University, 1-8-13 Surugadai, Kanda, Chiyoda-ku, Tokyo 101-8309, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Sato
authors.forename: Z
authors.initials: Z
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D003929:Diabetic Neuropathies / Q000145:classification* / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D008875:Middle Aged; D011379:Prognosis; D013997:Time Factors; D018630:Vitreoretinopathy, Proliferative / Q000145:classification* / Q000453:epidemiology / Q000209:etiology