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The Twentieth Century
Published in Arturo Castiglioni, A History of Medicine, 2019
The curiosity of a lawyer, Adelbert ames, who asked himself if the two eyes see alike, led to the discovery of aniseikonia, a condition in which the retinal image of one eye differs in size and shape from that of the other eye. The cerebral effort to fuse with two different images then causes headaches, nervousness, and even digestive disturbances. Aniseikonia cannot be considered a rare condition; more than two per cent of all patients with asthenopic symptoms are affected by it. A special instrument (the eikonometer) is used for its diagnosis, and special lenses to correct it, as evolved in the Dartmouth laboratories.
Aniseikonia: A 21st Century Look
Published in Journal of Binocular Vision and Ocular Motility, 2019
A long time ago, around 2008, I saw two adult patients, both of whom complained of aniseikonia. They did not know each other, nor were they referred to me from the same clinic. One gentleman came via the retina department. The second gentleman came via the glaucoma department. These two individuals broadened the landscape of my Orthoptic practice and served as the genesis of this lecture today. Table 1 summarizes the findings of these two patients. Both men are of the same age range, both with complaints of a 25% image size difference between their eyes, and both have retinal edema on optical coherence testing (OCT). The story of their individual ocular histories now diverges. Patient 1 has good vision in each eye, and an equal refractive error. He has an intermittent exotropia, which was not helped by prism offset during prism adaptation testing. On aniseikonia testing, using the New Awaya Aniseikonia Test, actual image size disparity was 5%. Patient 1 was not helped by contact lens trial, prisms or manipulation of his refractive error. He remains relatively symptom free to this day.
Aniseikonia and anisometropia: implications for suppression and amblyopia
Published in Clinical and Experimental Optometry, 2019
Jayshree South, Tina Gao, Andrew Collins, Jason Turuwhenua, Kenneth Robertson, Joanna Black
Aniseikonia is a condition where there is a perceived difference in image size or shape between the eyes. Perceived image sizes are determined by a combination of factors, including the angular sizes of images falling on each retina, the distribution of the retinal receptive fields and the cortical mapping of the visual fields in the brain. Aniseikonia can result when there are substantial differences between the two eyes or in the visual pathways for any of these factors. Aniseikonia can disrupt binocular vision, but currently, it is not routinely screened for in most optometric settings.