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Horopter deviations and distortions.

R W Reading
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Abstract

Previously gathered data from 3 subjects, judged to show usually very steady binocular fixation, were selected for retrospective analysis. This consisted of determining the means and standard error of the means of as many control runs as were available. The role of the fluctuation of vergence eye movement responses in producing the results is discussed. It is concluded that the longitudinal horopter most likely always conforms to the locus of a circle constructed through the two entrance pupils and the point of fixation.

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AniseikoniaEye MovementsFixation, OcularHumansRefractive ErrorsRetrospective StudiesVisual PerceptionJournal ArticleResearch Support, U.S. Gov't, P.H.S.

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R W Reading. 1985. Horopter deviations and distortions.. https://doi.org/10.1111/j.1755-3768.1985.tb05251.x

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PubMed2005

Compensation of aniseikonia with toric intraocular lenses and spherocylindrical spectacles.

BACKGROUND AND PURPOSE: Magnification disparity between the two eyes (aniseikonia) is one of the major unresolved problems in modern cataract surgery, potentially degrading binocular visual function or causing diplopia. The purpose of this study is to describe a paraxial computing scheme using 4x4 system matrices to simulate a corrected pseudophakic 'optical system eye' with a meridional magnification that matches the magnification of a given contralateral eye. METHODS: Based on the definition of a centred optical system in the paraxial Gaussian space containing astigmatic surfaces using 4x4 refraction and translation matrices, we derived a methodology for calculating the refractive power and axis of toric intraocular lenses and spherocylindrical spectacle corrections for (i) fully correcting the optical system eye and (ii) realizing an arbitrary meridional magnification by solving a linear equation system. RESULTS: The capabilities of this computing scheme are demonstrated with two examples. In example 1 we calculate a toric lens and a spherocylindrical spectacle correction for compensation of a corneal astigmatism to realize a predefined iso-meridional magnification. In example 2 we first determine the meridional magnification of the contralateral eye, which has been treated with cataract surgery and toric lens implantation, and then we compute the appropriate combination of a fully correcting toric lens and spherocylindrical spectacle refraction, which exactly matches the meridional magnification of the contralateral eye. CONCLUSION: We presented an en bloc matrix based strategy for the calculation of an optical system eye containing an astigmatic cornea, a toric lens implant and a spherocylindrical spectacle correction, where the toric lens and the spherocylindrical spectacle correction are determined to fully correct the system and to realize an arbitrary meridional magnification i.e. to eliminate aniseikonia.

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