Highly specific photoscreening at the Alaska State Fair. Valid Alaska Blind Child Discovery photography and interpretation.

During the Alaska State Fair, from 1999 through 2001, experienced MTI photoscreeners from the District 49-A Lions Club screened 1844 children as a part of the Alaska Blind Child Discovery. Physician interpretation produced the following recommendations: normal 93.8%, "normal +" 3.4%, "positive" 2.7% and inconclusive 0.2%. Extrapolating from 53 confirmatory follow-up exams estimates the specificity of this screening (true negatives/all normal follow-up exams) from 97% to 100%, with a positive predictive value (true positive/all positive screenings) greater than 90%. High specificity increases the cost-effectiveness of screening. We derived "ABCD-Specificity" equals true negatives/(exam negatives plus inconclusives). In 2002, an additional 655 children were screened yielding 22 "positive" (3.4%), 28 N+ (4.3%), 605 "normal" (92.4%) and no "inconclusive." This brings the total ABCD State Fair Effort to 2499 screened with 2.8% "positive," 3.6% N+, 93.4% "normal" and only 0.12% "inconclusive."