Effectiveness of a pinhole method for visual acuity screening
J. I. Loewenstein, P. F. Palmberg, J. E. Connett and D. N. Wentworth
Visual acuity screening was performed in the home in an adult population,
using a standardized, retroilluminated chart. A pinhole disk was utilized
to retest those subjects who initially failed the screening. All subjects
failing the screening with the pinholes, and an equal number of age-matched
subjects passing the screening (controls), were asked to have a complete
ophthalmologic examination, including a protocol refraction in an eye
clinic (clinic examination). Without use of the pinhole disk, 14.4% of
subjects failed to read a 20/40 line. Use of the pinholes reduced the
failure rate to 6.9%. Fifty-seven percent of those failing and 55% of
controls had the clinic examination. Determination of best-corrected visual
acuity after protocol refraction in the clinic indicated that the
false-positive rate (the percentage of subjects who failed the screening
but had visual acuity of 20/40 or better on the clinic examination) for the
screening was 26%, and the false-negative rate (the percentage of subjects
who passed the screening but had visual acuity of worse than 20/40 on the
clinic examination) was 1.5%. Use of a pinhole disk is highly effective for
visual acuity screening, reducing the false-positive rate by more than
half.
