Binocular function changes produced in response to overnight orthokeratology



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Felipe Márquez, Gema and Nombela Palomo, María and Palomo Álvarez, Catalina and Cacho Bobillo, Isabel and Nieto Bona, Amelia (2017) Binocular function changes produced in response to overnight orthokeratology. Graefe's Archive for Clinical and Experimental Ophthalmology, 255 (1). pp. 179-188. ISSN 0721-832X

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Purpose: To analyze the binocular function changes produced on subjects undergoing overnight orthokeratology (OK) treatment over short-term (3 months) and long-term (3 years) wear.
Methods: A prospective, longitudinal study on young adult subjects with low to moderate myopia was carried out. Binocular function was assessed by the following sequence of tests: Distance and near horizontal phoria (Von Graefe technique), distance and near horizontal vergence ranges (Risley rotary prisms), accommodative convergence/accommodation (AC/A) ratio (gradient method) and the near point of convergence (standard push-up technique). The short-term sample consisted of: 21 subjects in the control group, 26 in a corneal refractive therapy (CRT) treatment lenses group and 25 in a Seefree treatment lenses group. Those subjects were evaluated at baseline and at a 3-month follow-up visit. Twenty one subjects were old CRT wearers that attended a 3-year follow-up visit (long-term group).
Results: A statistically significant difference over the 3-month treatment was found for divergence at distance: the break point decreased 1.4 Δ (p = 0.0006) in the CRT group and the recovery point increased 1.2 Δ (p = 0.001) in the Seefree group. Also, the Seefree group had an exophoric trend of 2.3 Δ at near (p = 0.02) and a base-out break decrease of 2.3 Δ (p = 0.03). For the long-term group, only the base-out break point at distant vision showed a statistically significant difference of 4.9 Δ (p = 0.02).
Conclusions: OK induces minimal changes in the binocular function for either short-term or long-term periods, apart from a near exophoric trend over the short-term period.

Item Type:Article
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Received: 19 April 2016 /Revised: 7 August 2016 /Accepted: 7 November 2016 /Published online: 21 November 2016

Uncontrolled Keywords:Binocular function; Contact lenses; Fusional vergences; Myopia; Orthokeratology; Phoria
Subjects:Medical sciences > Optics > Contact lenses
Medical sciences > Optics > Optometry
Medical sciences > Optics > Visual perception
ID Code:44379
Deposited On:31 Aug 2017 07:32
Last Modified:31 Aug 2017 07:32

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