Frequency Doubling Technology Perimetry in Normal Children

Purpose

To test visual field thresholds of normal children with frequency doubling technology (FDT) perimetry to quantify testing times and reliability characteristics in a pediatric population and to determine whether current methods of stratifying adult threshold values need revision for children.

Design

Prospective cross-sectional study.

Methods

Ninety-four children, ages 5 to 17 years, were recruited from local pediatric clinics and the general community and were tested at one center. Children likely to have abnormal visual fields or abnormal test taking ability because of ophthalmic, neurologic, or behavioral problems were excluded. Children were asked to perform a threshold FDT visual field with each of their eyes. Threshold results were gathered, analyzed, and compared with the standards that have been established for tests in adults. Results were validated by testing a further 72 children, with the same protocol, at a different center.

Results

For children older than 14 years, threshold mean deviation values were within normal limits according to the adult normative database that is used currently in FDT perimetry. Below 15 years of age, mean deviations for normal children decreased with decreasing age. The best linear fit was given by a mean deviation of −11.43 ± 0.82 dB × age (R² = 0.18; P < 10⁻⁵).

Conclusion

This research establishes a normative model for pediatric visual field testing with FDT and, by a comparison of threshold results for normal children to established adult norms, provides evidence that parameters for normal sensitivity must be revised for children younger than 15 years.