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The +10 diopter lens occluder
N Benegas1, B J Kushner, G V Morton
1Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, WI 53705, USA.
Background:
It would be useful to be able to visualize the eye under cover during the cover test. Used as an occluder, a +10 diopter (D) lens will permit such visualization. It is important to know if a +10D lens creates dissociation that is qualitatively similar to an opaque occluder.
Methods:
The angle of strabismus was measured in 33 patients with esotropia. Seventeen had intermittent exotropia, and 15 had dissociated vertical divergence with both an opaque occluder and a +10D lens used as an occluder. The findings were then compared.
Results:
In 64 of the 65 patients participating in this study, the measurements obtained with the 2 occluders agreed within 3 prism diopters on repeated testing. In the remaining patient, the measurements differed by 5 prism diopters. In all patients, the dissociated eye could be clearly visualized through the +10D lens.
Conclusion:
A +10D lens permits excellent visualization of the dissociated eye and provides measurements that are qualitatively similar to those obtained with a standard occluder. Arch Ophthalmol. 2000;118:1071-1073