Detection of arteriolar narrowing in fundoscopic examination: evidence of a low performance of direct ophthalmoscopy in comparison with a microdensitometric method.
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.
Maestri
Marcelo M
MM
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.
Fuchs
Sandra C
SC
Ferlin
Elton
E
Pakter
Helena M
HM
Nunes
Gerson
G
Moraes
Ruy S
RS
Gus
Miguel
M
Moreira
Leila B
LB
Fuchs
Flávio D
FD
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