Date of Award

2011

Degree Type

Thesis

Degree Name

Master of Science in Vision Science (MSVS)

Committee Chair

James Kundart, O.D., M.Ed., F.A.A.O.

Second Advisor

John R. Hayes, Ph.D.

Third Advisor

Lorne Yudcovitch, O.D., M.S., F.A.A.O.

Abstract

Introduction
This paper is a review of some of the most common modes of both measurement and treatment of aniseikonia along with a case series involving 10 subjects. While aniseikonia can be caused by various factors such as the spacing between retinal photoreceptors, epiretinal membranes, or cataract surgery, this paper deals primarily with iatrogenic aniseikonia from the correction of anisometropia. Measurements were taken of the subjects’ axial length, keratometric readings, autorefraction, and amount of aniseikonia under two conditions: with contact lenses, and with spectacles. The results are put forth in this paper along with a brief analysis.


Methods
A literature review was performed using the following databases: VisionCite, Medline-OVID, and Google Scholar. Pertinent papers are cited along with monograph references, and personal observation from performing the tests mentioned. Autorefraction, keratometry, and A-scan ultrasonography were all performed. The program Aniseikonia InspectorTM by Optical Diagnostics was used on a laptop computer and all tests were performed by the same examiner with the testing order being changed after each subject (pseudo-randomization). A latin square was not used to randomize the order.


Results
The data from each subject is put forth in a table and noteworthy information is explained in subsequent paragraphs. Less aniseikonia was experienced with contact lenses verses spectacles. This finding was upheld in 7 out of the 10 subjects participating, regardless of the cause of their anisometropia.


Conclusion
This paper is in accordance with common trends from other studies, in that patients with axial anisometropia, despite Knapp’s law, are best treated with contact lenses. A future study with a larger set of subject utilizing the same measurement parameters, should be able to draw more definitive conclusions in each of the following categories: axial anisometropia, refractive anisometropia, and a combination of the two.

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