Abstract
Purpose :
Strabismus is a visual condition in which the eyes are misaligned and cyclodeviation is the angular misalignment between the eyes. The double Maddox rod test is used clinically to measure cyclodeviations in patients with strabismus. This test requires operator expertise, specialized equipment, and cannot be performed independently by the patient. A self-monitoring device might be useful for diagnosis and monitoring of cyclodeviations by both patients and medical professionals. Our goal is to develop and validate the use of an iPhone application to perform quantitative cyclodeviation measurements independently.
Methods :
A customized double Maddox rod simulation was programmed on an iPhone for use in a virtual reality(VR) viewer. Similar to the traditional double Maddox test, the iPhone application displays two lines: a white horizontal reference line is displayed to the left eye and an angled red line is displayed to the right eye. The subject rotates the axis of the red line using touch inputs on the phone until the lines are perceived to be parallel. The relative cyclodeviation is the ending angle between the two lines. 1 subject with strabismus, 72 years of age and 5 control subjects between the ages of 22-43 completed 3 trials each of traditional and iPhone double Maddox rod tests, each varying with starting angles of the red line. Repeatability of and difference between traditional and iPhone cyclodeviation measurements were compared within subjects.
Results :
The iPhone application was independently operated by all subjects. All subjects preferred the iPhone application to the traditional exam for its ease of use and comfort.Iphone cyclodeviations were repeatable in all subjects with maximum 1° variation.For control subjects, the average difference of cyclodeviation between the traditional examand the iPhone application ranged from 0° to 1°.For the subject with strabismus, the difference of cyclodeviation between the two examinations was 2.67°.
Conclusions :
The measurements obtained for cylcodeviations using the iPhone application were repeatable and reliable when compared to the traditional Double Maddox Rod test. The user experience of the iPhone application was uniformly positive. Future studies are necessary to further validate the iphone app in a diseased population.
This is a 2020 ARVO Annual Meeting abstract.