Purchase this article with an account.
Y. Shimada, M. Horiguchi; A New Psychophysical Test for Studying Dislocation of the Photoreceptors in Macular Diseases. Invest. Ophthalmol. Vis. Sci. 2010;51(13):1327.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Dislocation of the photoreceptors causes distortion of the image and affects vision. We developed a new technique for evaluating dislocation of the photoreceptors, which provides both direction and magnitude of the receptor displacement in central visual field.
Eight and 3 patients with unilateral macular hole (MH) and epiretinal membrane (ERM), respectively, without anisophoria nor anisometropia served as subjects. The tenets of the Declaration of Helsinki were followed. A green filter was placed in front of the affected eye and a red filter in front of the fellow eye. Subjects fixed binocularly on a white cross at the center of the CRT monitor located at a distance of 0.33 m from the subject. The background was black. A red circle, the reference target, that cannot be seen by the affected eye was displayed at some point in the central field. A green circle, the active target, that can be seen only by the affected eye was moved around the reference target by an examiner until the subject could see it overlapped exactly on the reference target. This procedure was repeated at 32 different locations of the reference target, 1-8 degree in 8 directions from the fixation point, and each time, the location of the active target was plotted.
In MH cases, metamorphopsia assessed monocularly with the Amsler's Chart was mild or nearly undetectable, however the locations of the active target were displaced centrifugally relative to the that of the reference target. The magnitudes of displacements were larger at points closer to the center. Two patients of stage II MH, centripetal displacements were observed at one direction that was corresponding to the centripetal traction of vitreous on a hole edge analyzed by an OCT. In cases of ERM, displacements were centripetal in general, however, the direction and magnitude were varied so much among the observation points, some displacements were circumferential and even centrifugal.
Dislocation of the receptors can be evaluated precisely using our technique in macular diseases. It seems that this provide us more accurate information on distortion than Amsler's chart or M-CHARTS(R).
This PDF is available to Subscribers Only