Visual acuity measurement in exceptional children.

BACKGROUND

Numerous reports have been published describing the determination of visual acuity in infants using forced-choice preferential-looking (FPL) methods. Results confirm the effectiveness of this technique for evaluating the child who is unable to respond to conventional clinical methods of visual acuity measurement (e.g., Snellen Letter or Symbol Acuity).

METHODS

Using a FPL acuity apparatus and discrimination paradigm similar to that developed and modified by Held, Gwiazda, Mohindra et al., and also used by Atkinson et al., we used grating acuity assessment with binomial method of rapid endpoint determination as well as luminance matched targets (+/- 3.4 percent) with grating regularity controlled (+/- 2.35 percent) in studies of 105 full-term infants with normally developing vision and six exceptional children.

CONCLUSIONS

The results of these investigations show that monocular grating acuity thresholds measured in infants in a clinically useful way were also measurable in exceptional children when conventional visual acuity testing failed, thereby enabling the monitoring of improvements in visual acuity and performance for five of the six exceptional children studied.