Related Experiment Video
Updated: Jul 18, 2026

Isokinetic Robotic Device to Improve Test-Retest and Inter-Rater Reliability for Stretch Reflex Measurements in Stroke Patients with Spasticity
Published on: June 12, 2019
The validity and repeatability of the New Aniseikonia Test
Beatriz Antona1, Francisco Barra, Ana Barrio
1Departamento de Optica II (Optometria y Vision), Universidad Complutense, Madrid, Spain. bantona@opt.ucm.es
Purpose:
Aniseikonia has been traditionally measured using the New Aniseikonia Test (NAT) based on red/green anaglyphs. This study was designed to establish whether the NAT is a valid and reliable test.
Methods:
The NAT was tested on three groups of subjects: a control group (n = 45) and two groups of participants at risk of experiencing aniseikonia, those with anisometropia greater than or equal to 1.00 D (n = 29) and those with bilateral pseudophakia (n = 26). The validity of the test was established by comparing the measured aniseikonia with that simulated with size lenses in a double-blind study. Repeatability was evaluated by comparing the results obtained at two different time points.
Results:
Our results indicate that the NAT underestimates aniseikonia and more so in the horizontal than in the vertical direction. Repeatability was poor, although biases were clinically insignificant. However, the 95% limits of agreement were around +/-2%. The behavior of the test was similar in the three groups of subjects.
Conclusions:
We conclude that the repeatability of the NAT is not very high and recommend that clinicians be cautious when interpreting the results of this test.
Related Concept Videos
Reliability and Validity
Comparing Experimental Results: Student's t-Test
Accuracy and Errors in Hypothesis Testing
In hypothesis testing, the probability of making a Type I error, denoted as α, is commonly set at 0.05. This significance level indicates a 5% chance...
Significance Testing: Overview
McNemar's Test
Amines to Sulfonamides: The Hinsberg Test
Generally, a primary amine reacts with the Hinsberg reagent to produce an N-substituted benzenesulfonamide. The electron-withdrawing sulfonyl...
