Related Experiment Video
Updated: Jun 4, 2026

Binocular Dynamic Visual Acuity in Eyeglass-Corrected Myopic Patients
Published on: March 29, 2022
Variability of rarebit and standard perimetry sizes I and III in normals
Jesse M Vislisel1, Carrie K Doyle, Chris A Johnson
1Department of Ophthalmology and Neurology, University of Iowa, College of Medicine, Iowa City, IA, USA.
Purpose:
To compare test-retest variability in rarebit perimetry (RBP) and conventional standard automated perimetry (SAP) using Goldmann size I and III stimuli.
Methods:
Seventeen normal subjects underwent RBP, size I SAP, and size III SAP on five separate visits within a 5-week period. Test-retest variability could not be directly compared because of differences in units. Instead, data were transformed to lie on the same scale by calculating a percentile range to mean ratio for each test.
Results:
Percentile range to mean ratio was highest for size I (3.42 ± 0.62), followed by size III (2.29 ± 0.55), and RBP (0.29 ± 0.10). Results for all three tests were significantly different from each other.
Conclusions:
Comparison of tests with different scales is problematic, but RBP's retest variability appears to be significantly less than both sizes I and III SAP in the measurement of normal subjects.
Related Concept Videos
Empirical Method to Interpret Standard Deviation
This rule is used widely in statistics to calculate the proportion of data values...
Variation: Normal Distribution, Range, and Standard Deviation
One-Way ANOVA: Unequal Sample Sizes
One-Way ANOVA: Equal Sample Sizes
Different sample means can result in different values for the variance estimate: variance between samples. This is because the variance between samples is calculated as the product of the sample size and the variance between the...
Unusual Results
According to the range rule of thumb, any value above or below two standard deviations, 2σ from the mean, μ is considered unusual.
Maximum unusual value = μ + 2σ
Minimum unusual value...
What is Variation?
The range, standard deviation, standard error, and variance are the different measures of variation.
Range: The range is the difference between its maximum and...