Normal values for Octopus tendency oriented perimetry in children 7 through 13 years old.

BACKGROUND

The purpose of this study was to determine age-dependent values for mean sensitivity, mean deviation, and loss variance for normal children age 6 through 13 years, using the Octopus 301 perimeter and the Tendency Oriented Perimetry 32 (TOP-32) program.

METHODS

Healthy children from 6 through 13 years of age with a visual acuity of 20/20 OU and at least 60 arc seconds of stereopsis were recruited. They were tested on the Octopus 301 perimeter using the TOP-32 program, and each eye was tested twice during one session. Results for all four tests were averaged for each subject, and the average was used for statistical analysis. The main outcome measures were mean sensitivity, mean deviation, and loss variance by age. The test duration, learning and fatigue effects, and the influence of false positive responses on the average mean sensitivity were also analyzed.

RESULTS

There were 142 subjects tested. Six-year-old children showed high intersubject variability and were excluded (N=23). The average age of the remaining 7- to 13-year-old cohort (N=119) was 9.8 +/- 1.7 years. The average test duration was 2.9 +/- 0.3 min. The average mean sensitivity was 28.7 +/- 1.9 dB. The mean sensitivities for tests 1 through 4 were 28.14, 28.63, 28.96, and 28.92 dB, respectively. The average mean deviation was 0.4 +/- 1.9 dB. The slope of the regression line for mean sensitivity vs age was -0.018 +/- 0.165 dB/year, which was not significantly different from zero (two-tailed t test, p=0.83). The false positive catch trial rate was high (mean 26%) and was independent of age. When the data from subjects who had more than two false positive catch trial responses on any one test were eliminated, the mean sensitivity decreased to 28.3 +/- 1.9 dB.

CONCLUSIONS

When testing patients age 7 through 13 years on the Octopus 301 perimeter using the TOP-32 program, comparison against the programmed normal mean sensitivity value for 20-year-old subjects (29.0 dB) is appropriate. During a sequence of four tests, both learning and fatigue effects are evident. The false positive response rate is naturally high regardless of age, and children should not be overencouraged to respond during testing.