Objective Assessment of Photoreceptor Displacement and Metamorphopsia

Abstract

Background : We have developed a binocular perimetry technique for the quantitative assessment of retinal photoreceptor displacement and metamorphopsia.Objective: To study the direction and amplitude of retinal photoreceptor displacement in eyes with idiopathic macular holes using our binocular perimetry technique.Subjects: Five healthy control subjects and 10 patients with unilateral stage 3 to 4 macular holes in one eye and a healthy fellow eye.Method: Kinetic perimetry using red and green filter glasses, black binocular fixation targets, red and green selective monocular stimuli (Goldmann III-4-e), and fundus image superimposition of perimetry data. Results:We found no discrepancy between the 2 visual fields in any healthy subjects. In patients with a unilateral macular hole, the central scotoma invariably extended beyond the rim of the hole. In 8 patients, each point on the rim of the scotoma had a perceptually corresponding location in the visual field of the fellow eye that was closer to the center of the visual field. In the 2 patients with the longest duration of symptoms (Ͼ2 years), no such discrepancy was found.Conclusions: Differential perimetry enables the objective study of retinal photoreceptor displacement and metamorphopsia. We found objective evidence for radial centrifugal photoreceptor displacement in most patients with idiopathic macular holes.

Spontaneous Closure of Large Base Idiopathic Full Thickness Macular Hole

“…Positive Watzke-Allen test in this patient during slit lamp examination gave the evidence of displacement of the photoreceptors centrifugally at the macular hole and supported that he has FTMH (Jensen & Larsen 1998).…”

Metamorphopsia: An Overlooked Visual Symptom

“…Differential perimetry was proposed by Jensen and Larsen [48] in 1998 to assess the amplitude of PR displacement. This technique is based on a theory that a local displacement of a group of PRs causes a shift in the visual field projection of the involved PRs.…”

“…This technique is based on a theory that a local displacement of a group of PRs causes a shift in the visual field projection of the involved PRs. A healthy fellow eye and normal binocular vision are required, as in this way unilateral displacement of the PR will lead to loss of visual field correspondence with the cortically paired receptor element in the fellow eye [48]. As the brain continues to assign the original visual field projection to a stimulus reaching the displaced receptor, metamorphopsia, micropsia, and macropsia are all induced by the discrepancy between real and perceived visual field projection.…”

“…As the brain continues to assign the original visual field projection to a stimulus reaching the displaced receptor, metamorphopsia, micropsia, and macropsia are all induced by the discrepancy between real and perceived visual field projection. Differential perimetry was performed with Goldmann kinetic perimetry (50 cm working distance), using red and green filter glasses, black binocular fixation targets, and red and green selective monocular stimuli (Goldmann III and IV) with fundus image superimposition of perimetry data [48]. The authors reported that macular holes are accompanied by metamorphopsia, micropsia, and central scotoma due to the presence of radial centrifugal PR displacement away from the center of the retina [48].…”

“…Differential perimetry was performed with Goldmann kinetic perimetry (50 cm working distance), using red and green filter glasses, black binocular fixation targets, and red and green selective monocular stimuli (Goldmann III and IV) with fundus image superimposition of perimetry data [48]. The authors reported that macular holes are accompanied by metamorphopsia, micropsia, and central scotoma due to the presence of radial centrifugal PR displacement away from the center of the retina [48]. As stated by the authors, differential perimetry was shown to be a valid and objective test for accurate and detailed study of macular diseases characterized by mechanical attenuation or crowding of PRs, such as macular holes or puckers [48].…”