title: Detection of arteriolar narrowing in fundoscopic examination: evidence of a low performance of direct ophthalmoscopy in comparison with a microdensitometric method.
abstract: BACKGROUND
  Retinal abnormalities, particularly arteriolar narrowing, are powerful predictors of cardiovascular events. The precision of internists and ophthalmologists in the assessment of retinal vessels widths has been disputed but not evaluated against a technology of edge detection.
  
  
  METHODS
  Fifty-two patients with hypertension had optic fundi examination done by an internist and an ophthalmologist, and had retinographies taken and digitized to determine vessel diameters by a new technology of edge detection (microdensitometric method). Physicians asserted the presence of arteriolar narrowing (<or=0.67) through direct ophthalmoscopy and projected retinography. The microdensitometric method measures automatically the vessel widths based on the subpixel resolution of the edge of vessel walls. Sensitivity (SE), specificity (SP), positive (PPV) and negative predictive values (NPV), and kappa statistics were calculated, taken the microdensitometric method as reference.
  
  
  RESULTS
  The performance of the direct examination by the internist to detect arteriolar narrowing was SE: 68.7 (67.0-70.4); SP: 72.7 (68.0-77.4); PPV: 88.0 (85.9-90.0); and NPV: 44.4 (41.5-47.4). For the ophthalmologist the figures were: SE: 74.4 (72.9-75.7); SP: 53.8 (49.8-57.8); PPV: 82.9 (81.3-84.4); and NPV: 41.2 (38.0-44.3). Kappa statistics were 0.34 (0.07-0.62) for the internist, and 0.26 (-0.03-0.53) for the ophthalmologist.
  
  
  CONCLUSIONS
  The performance of internists and ophthalmologists to detect hypertensive microangiopathy based on low arteriolar venous ratio is low and casts doubt about the usefulness of this examination in clinical practice.
authors.affiliation: Post-graduate Program in Medical Sciences, School of Medicine, Division of Ophthalmology, Hospital de Clinicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Brazil, Brazil.
authors.forename: Marcelo M
authors.initials: MM
authors.lastname: Maestri
authors.forename: Sandra C
authors.initials: SC
authors.lastname: Fuchs
authors.forename: Elton
authors.initials: E
authors.lastname: Ferlin
authors.forename: Helena M
authors.initials: HM
authors.lastname: Pakter
authors.forename: Gerson
authors.initials: G
authors.lastname: Nunes
authors.forename: Ruy S
authors.initials: RS
authors.lastname: Moraes
authors.forename: Miguel
authors.initials: M
authors.lastname: Gus
authors.forename: Leila B
authors.initials: LB
authors.lastname: Moreira
authors.forename: Flávio D
authors.initials: FD
authors.lastname: Fuchs
mesh_terms: D000328:Adult; D002196:Capillaries / Q000473:pathology; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D005654:Fundus Oculi; D006801:Humans; D006973:Hypertension / Q000150:complications*; D008297:Male; D008875:Middle Aged; D009887:Ophthalmoscopy / Q000592:standards*; D010781:Photography / Q000379:methods*; D012171:Retinal Vessels / Q000473:pathology*; D012680:Sensitivity and Specificity