title: Microaneurysm turnover at the macula predicts risk of development of clinically significant macular edema in persons with mild nonproliferative diabetic retinopathy.
abstract: OBJECTIVE
  To examine the relationship between microaneurysm (MA) turnover using automated analysis of fundus photographs (RetmarkerDR; Critical Health SA) and development of clinically significant macular edema (CSME) in nonproliferative diabetic retinopathy (NPDR).
  
  
  METHODS
  A prospective, monocenter, observational study was designed to follow eyes/patients with type 2 diabetes and NPDR (Early Treatment Diabetic Retinopathy Study levels 20 and 35) with no prior laser treatment for 2 years or until development of CSME. A total of 410 patients, one eye per patient, fulfilled the inclusion/exclusion criteria and were included in the study. Ophthalmologic examinations including best corrected visual acuity, fundus photography, and optical coherence tomography were performed at baseline, 6 months, and at the last study visit (24 months or before laser treatment).
  
  
  RESULTS
  A total of 348 eyes/patients performed the 24-month visit or developed CSME. Of these 348 eyes/patients, 26 developed CSME. HbA1c levels at baseline and MA turnover (i.e., the sum of the MA formation and disappearance rates) computed during the first 6 months of follow-up were found to be independently predictive factors for development of CSME. MA turnover was 11.2 ± 11.2 in the 26 eyes/patients that developed CSME and 5.0 ± 5.2 in the remaining 322 (P < 0.001). Higher MA turnover values correlated with earlier development of CSME. MA turnover predictive values for CSME development were, for the positive predictive value, 20% and for the negative predictive value, 96%.
  
  
  CONCLUSIONS
  MA turnover calculated with the RetmarkerDR predicts development of CSME in eyes with NPDR. Low MA turnover values identify well the eyes that are less likely to develop CSME in a 2-year period.
authors.affiliation: University of Coimbra, Coimbra, Portugal.
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Ribeiro
authors.forename: Sandrina G
authors.initials: SG
authors.lastname: Nunes
authors.forename: José G
authors.initials: JG
authors.lastname: Cunha-Vaz
mesh_terms: D000328:Adult; D000368:Aged; D000783:Aneurysm / Q000473:pathology*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D003930:Diabetic Retinopathy / Q000150:complications*; D005260:Female; D006801:Humans; D008266:Macula Lutea / Q000473:pathology*; D008269:Macular Edema / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies