Quantification of Metamorphopsia in Patients with Macular Hole

¹ Department of Ophthalmology, Glostrup Hospital, Glostrup, Denmark
² Department of Ophthalmology, Glostrup Hospital, Glostrup, Denmark; National Eye Clinic, Kennedy Center, Copenhage, Denmark

^* To whom correspondence should be addressed. E-mail: kroyers{at}yahoo.com.

	Abstract

Purpose. To describe a novel method for the evaluation of metamorphopsia within the central 10 degrees of visual field in 55 patients with idiopathic macular hole. Our test evaluates metamorphopsia in terms of interocular disparity between the two eyes. Methods. We applied semicircular test- and reference-stimuli of variable diameters in a binocular test that measured interocular size disparity between perceptually iseikonic stimuli in subjects with a unilateral macular hole. A group of 11 healthy subjects was used as reference. Results. In 55 patients with a macular hole, interocular disparity demonstrated a mean value of 0.71 degrees for stimuli in the range 1.0 - 2.5 degrees in diameter. This number declined to 0.41 degrees for stimuli in the range of 9.0 - 10.0 degrees in diameter. Both hole diameter and eccentricity had a significant effect on mean disparity (P < 0.001). Conclusions. Metamorphopsia level declined as a function of eccentricity and affected the central 10 degrees of visual field. Macular hole size had an independent effect on interocular disparity. These results confirm reports that visuospatial distortion in macular hole, is primarily the result of radial displacement of photoreceptors.

Key Words: psychophysics, macular hole, binocular vision, photoreceptor morphology, metamorphopsia, retinal disparity