The Topographical Effect of Optical Zone Diameter in Orthokeratology Contact Lenses in High Myopes



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Carracedo Rodríguez, Juan Gonzalo and Espinosa Vidal, Teresa M. and Martínez Alberquilla, Irene and Batres Valderas, Laura (2019) The Topographical Effect of Optical Zone Diameter in Orthokeratology Contact Lenses in High Myopes. Journal of Ophthalmology, 2019 . p. 1082472. ISSN 2090-004X

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Purpose. To evaluate the effect of the optical zone diameter (OZ) in orthokeratology contact lenses regarding the topographical profile in patients with high myopia (−4.00 D to −7.00 D) and to study its effect over the visual quality. Materials and Methods. Twelve patients (18 eyes) were fitted with overnight orthokeratology (OrthoK) with a randomized 6 mm or 5 mm OZ lens worn for 2 weeks, followed by a 2-week washout period, between both designs. Keratometry (K) readings, optical zone treatment diameter (OZT), peripheral ring width (PRW), higher-order aberrations (HOA), high (HC) and low contrast (LC) visual acuity, and subjective vision and comfort were measured at baseline and after 2 weeks of OrthoK lens wear of each contact lens. Results. No significant differences were found between any measurements for the same subject at both baselines ( value > 0.05). There was no difference between OZ lens designs found in refraction, subjective vision or comfort, and HC and LC visual acuity. Contrast sensitivity was decreased in the 5 mm OZ lens design compared with 6 mm OZ design (-value < 0.05). 5 mm OZ design provoked a greater flattening, more powerful midperipheral ring and 4th-order corneal and total spherical aberration than the 6 mm OZ design, being statistically significant after 7 days, for corneal aberration, and 15 days, for corneal and total, of wearing the lens (-value < 0.05). The OZT obtained were 2.8 ± 0.2 mm and 3.1 ± 0.1 mm for 5 mm and 6 mm OZ design, respectively (-value < 0.05). Regarding PRW, the 5 mm OZ design had a wider ring width in both the nasal and temporal zones (-value < 0.05). Conclusions. A smaller diameter optical zone (5 mm) in orthokeratology lenses produces a smaller treatment area and a larger and more powerful midperipheral ring, increasing the 4th-order spherical aberration that affects only the contrast sensitivity but without differences in visual acuity and subjective vision compared with a larger OZ diameter (6 mm).

Item Type:Article
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Received 18 October 2018; Revised 29 November 2018; Accepted 16 December 2018; Published 2 January 2019

Uncontrolled Keywords:Orthokeratology; Contact lenses; High myopia;
Subjects:Medical sciences > Optics > Contact lenses
Medical sciences > Optics > Optometry
Medical sciences > Optics > Visual perception
ID Code:51540
Deposited On:26 Feb 2019 14:48
Last Modified:26 Feb 2019 14:48

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