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An Approach to Oculomotor Anomalies in a Child
Published in Vivek Lal, A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
Accommodative esotropia is an esotropia caused partially or entirely by the use of accommodation to clear vision in the presence of hyperopia. Typically, accommodative esotropia is a comitant esotropia that presents later than infantile esotropia (typically onset within ages 2–5 years) and is intermittent initially becoming more constant with time. Accommodative esotropia is typically associated with moderate-to-high hyperopia (mean +4.75D)1 and may be associated with a high accommodative convergence to accommodation (AC/A ratio).
Etiology of accommodative esotropia — current concepts
Published in Jan-Tjeerd de Faber, 28th European Strabismological Association Meeting, 2020
In accommodative esotropia, uncorrected hypermetropia causes a blurred retinal image. This stimulates the accommodation in order to give a focussed image. Through the near vision complex this leads to an accommodative convergence.
Rehabilitation and management of visual dysfunction following traumatic brain injury
Published in Mark J. Ashley, David A. Hovda, Traumatic Brain Injury, 2017
Visual system input, or reception, is dependent on formation of a focused optical image on the retina; healthy eyes; and healthy, intact pathways to primary visual cortex. Accommodation (the internal focusing of the eye mediated by the ciliary muscle) and vergence (the ability to make disjunctive or inward and outward movements of the eyes) are also an important part of getting visual input to the visual cortex without confusion. These two functions are tied together by neural feedback loops. As one expends accommodative effort (trying to focus closer), the accommodative effort drives convergence, pulling the eyes inward. As accommodation is relaxed, the eyes diverge, or relax outward, as for viewing distant targets. There is a similar, but lower, amplification loop from convergence to accommodation: As one exerts convergence effort, it drives accommodation. It should be obvious that a disruption in the balance between these two interacting systems—accommodative–convergence and convergence–accommodation—can cause serious dysfunction in eye teaming and focusing. There are useful models of such disturbances88 reviewed by Ciuffreda.89
Prism adaptation response and surgical outcomes of acquired nonaccommodative comitant esotropia
Published in Strabismus, 2023
Noriko Nishikawa, Yuriya Kawaguchi, Rui Fushitsu
The refraction in the builder group showed greater myopia than the non- builder group, even after adjusting for age at surgery. Bielschowsky-type acute esotropia has been associated with uncorrected myopia and prolonged near work.26 In patients involving uncorrected or under-corrected myopia with esodeviation, accommodative convergence is reduced and patients easily maintain esophoria at near vision. Therefore, even if the patient has appropriate eyeglasses or contact lenses, they will see better without them at near work. It is possible that this might be a consequence of esotropia rather than its pathogenic mechanism.11,27 Furthermore, many of these patients tend to be insensitive to diplopia until their symptoms worsen while looking far away,27 resulting in a delay in seeking medical care. We speculate that the persistence of these conditions may increase the angle of deviation latently, which could be detected using the PAT in patients with myopia, especially at near. However, no previous studies have reported the relationship between refraction and the PAT response. This contradiction may be attributable to differences in patient demographics since this cohort included many myopic patients of relatively older ages, while most patients in the previous reports were children and adolescents with hyperopia or emmetropia.7,8,28
Forty-five Years of Studying Intermittent Exotropia — What Have I Learned? The WSPOS Keynote Strabismus Lecture, October 3, 2020
Published in Journal of Binocular Vision and Ocular Motility, 2022
In 1952, Scobee reported that in many patients who appear at first to have a divergence excess pattern, prolonged monocular occlusion will unmask a larger near deviation, which will approach or equal the distance deviation.24 At first, Scobee recommended 24 h of occlusion, but he later shortened it to 1 h. Patients who demonstrated this increase in the near deviation were said to have a simulated (or pseudo) divergence excess. The literature subsequently became confusing with respect to diagnosing a simulated divergence excess pattern, as Brown advocated the use of +3D lenses to bring out the larger near deviation.25,26 He considered this to be a substitute for prolonged monocular occlusion. However, +3D lenses and prolonged monocular occlusion work on different mechanisms, the former suspending accommodative convergence and the latter fusional convergence; they should not be interchangeable.19,27 Yet seemingly paradoxically, 1/3 of patients with IXT will have a similar response to prolonged monocular occlusion and +3D lenses at near.4 This apparent contradiction needs to be explained, which I will do shortly.
Accommodative and convergence anomalies in patients with opioid use disorder
Published in Clinical and Experimental Optometry, 2022
Mohaddeseh Ghobadi, Payam Nabovati, Hassan Hashemi, Ali Talaei, Hamid Reza Fathi, Yeganeh Yekta, Hadi Ostadimoghaddam, Abbasali Yekta, Mehdi Khabazkhoob
The present study is the first study to investigate the prevalence of accommodative and convergence anomalies specifically in patients with OUD. According to the results, the prevalence of the accommodative and convergence disorders was 33.75% and 25.00%, respectively. Among accommodative disorders, accommodative insufficiency had the highest prevalence (22.5%) and among convergence disorders, the highest prevalence was related to convergence insufficiency (18.75%). The overall prevalence of combined accommodative-convergence dysfunctions was 7.50%. Among combined disorders, the combined accommodative insufficiency-convergence insufficiency had the highest prevalence (5%). Table 4 shows a list of previous studies that have examined the prevalence of accommodative and convergence anomalies in normal young adult populations.