Illumination, optics, and clinical performance of a hand-held magnified visual inspection device (AviScope): a comparison with colposcopy.
OBJECTIVE
Colposcopy is the reference standard for a visual inspection device in terms of illumination, optics, and clinical performance. A hand-held magnification device such as the AviScope, developed as an alternative to naked eye visual inspection with acetic acid, is also of interest as a low-cost, more portable alternative to a colposcope in low-resource settings within the context of cervical cancer prevention programs and for microbicides research.


METHODS
A performance comparison of the AviScope, visual inspection with acetic acid, and three colposcopes.


METHODS
An analysis was carried out of the optics and illumination of the colposcopes and the AviScope prototype and of the evidence for the reproducibility and clinical accuracy of visual methods for histologically confirmed high-grade cervical intraepithelial neoplasia. Using the findings, the feasibility of increasing the performance and reducing the cost of a hand-held scope was examined.


RESULTS
Published studies have found the AviScope to have slightly higher sensitivity than visual inspection with acetic acid (60.7 versus 55.7%, P < 0.05) without loss of specificity. Despite the variability among the colposcopes, the field of view, resolution, depth of field, magnification, and quality of the illumination beam pattern and spectral output exceeded that of the AviScope. The clinical sensitivity and specificity of colposcopy were higher than that of the AviScope. The availability of improved materials for optics and illumination suggests that a hand-held scope with enhanced performance is feasible.


CONCLUSIONS
Although the performance of the AviScope prototype was suboptimal compared with the colposcopes, it appears possible to design a hand-held magnification device at a reasonable price with better optics and illumination.
Sellors
John W
JW
Program for Appropriate Technology in Health, Seattle, WA, USA. jsellors@path.org
Winkler
Jennifer L
JL
Kreysar
Douglas F
DF
D020681:Colposcopes / Q000706:statistics & numerical data; D003127:Colposcopy / Q000379:methods / Q000592:standards / Q000706:statistics & numerical data; D004867:Equipment Design; D005260:Female; D006801:Humans; D008029:Lighting; D055095:Optics and Photonics / Q000295:instrumentation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis / Q000517:prevention & control