OSLI Retina

January 2020

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12 Ophthalmic Surgery, Lasers & Imaging Retina | Healio.com/OSLIRetina More recently, methods such as M-CHARTS (Inami & Co., Ltd., Tokyo, Japan), 9,10 D-CHARTS, 11 shape discrimination hyperacuity, 12 and preferential hyperacuity perimetry (PHP) 13 have all been studied and used as means of quantifying metamorphopsia. However, with the exception of PHP testing devices, 14 which are costly 15 and only U.S. Food and Drug Ad- ministration-approved for monitoring of intermediate nonexudative AMD, none of the above tests can yield a spatial representation of patients' distortions that can be subsequently mapped onto corresponding regions of the macula. Some interest has been accruing as a result in methodologies predicated on the "negation" or "nullification" of existing distortion by the patient; in theory, if a patient were able to manipulate visual input (ie, an Amsler grid) in such a way that their distortion was no longer perceptible, the resulting im- age might indicate not only the retinotopic location of any perceived distortion, but also the quantity, direc- tionality, and general shape. To our knowledge, so far only three studies have constructed such tests: two of these studies employed deformable Amsler grids, 16-18 and one proposed a new test in which subjects would construct and straighten a "notional square" out of eight randomly distributed points. 19 Each of these testing methodologies represents opposing extremes in terms of granularity. The deformable Amsler grid provides copious spatial information yet is a relative- ly cumbersome, time-consuming test, and the "no- tional square" method is largely a research tool that only tests the spatial alignment of eight foci in the creation of a distortion map. 19 The aim of the present study is to assess the feasi- bility of a new software-based method of negating vi- sual distortion by way of a deformable dotted line — a method that we believe will be both rapid in practice while remaining granular in output. We hypothesize that subjects with visual distortion will be able to ma- nipulate an objectively straight dotted line at various points until it appears straight to them; the resulting changes made by the user would provide simple, lin- ear "distortion maps" that could be superimposed onto corresponding macular anatomy. The degree of the manipulation might then serve as a useful met- ric of metamorphopsia that could be employed in a clinic or study setting. PATIENTS AND METHODS Study Design and Recruitment This was a prospective, institutional review board- approved, cross-sectional, observational study of 22 subjects who were recruited for participation in this study from the clinics of the Roski Eye Institute of the University of Southern California in Los Angeles, CA. Subjects older than 18 years of age of any bio- logical sex and ethnicity were eligible to participate if they had been diagnosed with a maculopathy in one or both eyes and demonstrated at least one non-zero M-Charts score in the affected eye(s). As our primary Figure 1. (A) Depiction of the objectively straight dotted line displayed on our software platform, which is centered on a central fixation point. (B) Schematic depiction of several foci where a subject may have deformed the straight line using the testing interface. The areas denoted in red represent the areas of space that are cumulatively summed to calculate manipulated area under the curve.

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