The Effects of Atropine Eyedrops on Ocular Alignment and Binocular Vision

2022C-PEDIG-Atropine

Atropine is a non-selective muscarinic acetylcholine (M) receptor antagonist that paralyzes the ciliary muscle, dilates the pupil, and reduces the power of accommodation. Current studies have confirmed the effect of low concentrations of atropine drops in slowing the progression of myopia. In the atropine treatment for myopia (ATOM2) study, there was a rapid and dose-dependent decrease in accommodation after atropine drops: after 2 weeks of use, accommodation decreased from baseline 16.2D to 11.3D (4.9D) in the 0.01% atropine drops group, from baseline 16.7D to 3.8D (12.9D) in the 0.1% atropine group, and from baseline 15.8 D to 2.2 D (13.6 D) in the 0.5% atropine group; one year after withdrawal, there was some recovery of the accommodation in all the three groups, but it was still lower than the baseline values for each group, with a mean decrease of 2.56 D.Similar results were found in the Low-concentration Atropine for Myopia Progression (LAMP) Study by Janson C. Yam, 0.05% atropine drops reduced the accommodation by approximately 2D on average after 1 year of treatment. In general, if accommodation decreases by 2D or more compared to normal values, accommodation insufficiency is considered. There is a linkage between accommodation and convergence called accommodative convergence-to-accommodation (AC/A) which is closely related to exotropia. It was reported that the amount of accommodation required to maintain binocular fusion in patients with intermittent exotropia was greater than that of normal controls. In addition, pupil size and visual acuity are also factors that affect accommodation. In summary, the reduced accommodation amplitude, pupil dilation, and blurred near vision caused by atropine drops would affect the progression of intermittent exotropia and the ocular alignment after the surgery. In most cases, the reduced accommodation and convergence might induce exotropia, but in some patients, they may use more accommodative stimuli to compensate the insufficiency of accommodation, and there may be an increase in convergence or even esotropia. Taken together, due to the effect of atropine drops on pupil size, near visual acuity, and accommodation amplitude, the investigators hypothesize that atropine drops are likely to affect binocular vision and ocular alignment in patients with exotropia and exophoria.

2024-03-02

2025-02-01

2027-02-01

Recruiting

339

Inclusion Criteria: * The age ranged from 5 to 14 years; * Astigmatism \< 2.5D, spherical power: - 1.00D \~ -6.00D; difference between eyes in spherical power \< 1.5D, difference between eyes in astigmatism \< 1.00D; * Intraocular pressure \< 21mmHg; * Ocular alignment fulfilling the following criteria：Exophoria with an exodeviation at near \> 6PD12; Intermittent exotropia with an exodeviation ≤25 PD both at distance and at near, Titmus \<=400 arc seconds; Intermittent exotropia patients underwent strabismus surgery, 6 months after operation, fulling the criteria of exophoria and intermittent exotropia mentioned before. * Subjects and their parents or legal guardians have signed informed consent and are willing to accept randomized grouping and regular follow-up. Exclusion Criteria: * Amblyopia * Have heart disease or serious respiratory disease * Allergic to atropine, cyclopentantone, propoxybenzocaine and benzalkonium chloride; * Those who have used contact lenses, bifocal lenses, or other measures to control myopia (including atropine); * No binocular vision; * Combined with vertical strabismus≥5PD, abnormal oblique muscle function≥ 2+, cyclodeviation, DVD or A-V pattern, paralytic and restrictive strabismus, comitant esotropia； * Previous history of other ocular surgery; * Severe complications during or after strabismus surgery, such as perforation of the sclera, tear and detachment of extraocular muscle; postoperative eye movement limitation; visual acuity decreased after operation; * Combined with other ocular diseases; * Craniofacial malformations affecting the orbits; * significant neurological disorders; * Birth less than 34 weeks or birth weight less than 1500 g; * Intraocular pressure \> 21mmhg; * Unable to cooperate with the examination.

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2024-04-17