Binocular anomalies and reading problems.

H D Simons; J D Grisham

Home/Archive/PubMed

PubMed · 3312379

Binocular anomalies and reading problems.

H D Simons·J D Grisham

View original source ↗Export metadata ↓

Abstract

This paper reviews and evaluates the research literature on the relationship of binocular anomalies to reading problems. The weight of the evidence supports a positive relationship between certain binocular anomalies and reading problems. The evidence is positive for exophoria at near, fusional vergence reserves, aniseikonia, anisometropia, convergence insufficiency, and fixation disparity. There is some weak positive evidence for esophoria at near and mixed evidence for stereopsis. The evidence on lateral phorias at distance is negative.

Explore related subjects

Aniseikonia Convergence, Ocular Dyslexia, Acquired Fixation, Ocular Humans Ocular Physiological Phenomena Refractive Errors Strabismus Vision Disorders Vision, Ocular Comparative Study Journal Article Review

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

H D Simons, J D Grisham. 1987. Binocular anomalies and reading problems.. https://pubmed.ncbi.nlm.nih.gov/3312379/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2005

Field-dependent aniseikonia associated with an epiretinal membrane a case study.

PURPOSE: Aniseikonia is a binocular anomaly in which the two eyes perceive images of different sizes and/or shapes. It is usually assumed to be constant as a function of visual field angle (VFA) (i.e., angular distance from the line of sight). This is correct for optically induced aniseikonia, such as the aniseikonia that is associated with anisometropia and probably also pseudophakia. The purpose of this article is to show that if the aniseikonia is of retinal origin, then the aniseikonia may no longer be constant as a function of VFA (i.e., field-dependent aniseikonia). DESIGN: Case report, with the patient having a unilateral epiretinal membrane. METHODS: The aniseikonia was measured in vertical and horizontal directions with a customized version of the Aniseikonia Inspector software. The VFA was made variable by changing the dimensions of the comparison targets in the direct comparison procedure. MAIN OUTCOME MEASURE: Aniseikonia as a function of VFA. RESULTS: The patient exhibited good repeatable aniseikonia, ranging from 23% to 2.5% for VFAs ranging from 0.36 degrees to 5.7 degrees . Higher angles had lower aniseikonia. A control subject did not show this field-dependent aniseikonia. CONCLUSIONS: Aniseikonia may vary with VFA due to a retinal cause such as an epiretinal membrane. The problem with field-dependent aniseikonia is that it cannot be corrected fully with conventional optics, which exhibit an approximately constant magnification as a function of VFA. Nevertheless, by correcting 5% to 10% aniseikonia, which showed up in the VFA measurement range at 2 degrees to 3 degrees , our patient had improved visual comfort, especially for reading.

Aniseikonia↗

PubMed2005

Contact lens management of aniseikonia and photophobia induced by trauma.

PURPOSE: To describe a case of a contact lens fitting to relieve aniseikonia and photophobia resulting from trauma. METHODS: A 61-year-old man suffered a blunt injury to his left eye resulting in glaucoma and a traumatic cataract with a fixed pupil and iris defects. A vitrectomy, lensectomy, and iris repair were performed leaving him with significant anisometropia. RESULTS: The patient was fitted with a prosthetic contact lens. CONCLUSIONS: Contact lenses can provide significant visual improvement in cases of aniseikonia and photophobia.

Aniseikonia↗

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.

Aniseikonia↗