Increasing negative spherical aberration with soft contact lenses improves high and low contrast visual acuity in young adults

2009 ◽  
Vol 29 (6) ◽  
pp. 593-601 ◽  
Author(s):  
Sheila M. Rae ◽  
Peter M. Allen ◽  
Hema Radhakrishnan ◽  
Baskar Theagarayan ◽  
Holly C. Price ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Young Adults ◽  
Contact Lenses ◽  
Spherical Aberration ◽  
Soft Contact ◽  
Low Contrast ◽  
Soft Contact Lenses

Use of orthokeratology contact lenses in the treatment of progressive myopia

2020 ◽  
pp. 18-22
Author(s):  
Mariya Olenich
Keyword(s):  
Visual Acuity ◽  
Children And Adolescents ◽  
Optical System ◽  
Contact Lenses ◽  
Spherical Aberration ◽  
Soft Contact ◽  
Soft Contact Lenses ◽  
Vision Correction ◽  
Progressive Myopia ◽  
Biomechanical Changes

Orthokeratology is a method of non-surgical correction of refraction, which is based on the principle of biomechanical changes in the curvature of the cornea under the influence of «reverse geometry». This method was developed more than 50 years ago, however, it became widely used only in the early 2000s. The basis of this method is the use of special orthokeratology lenses that patients wear during the night. Peculiarity of these lenses is the ability to change curvature of the cornea, resulting in a flattening of its central part and thickening of the paracentral and peripheral sections, which leads to the formation of positive spherical aberration of the optical system. Such changes in the cornea resulting from partial desquamation of keratocytes and changes in their shape during 7–8 hours of influence during the night, lead to the normalization of refraction, which persists for the next 24 hours. Most often this method of vision correction is used in children and adolescents, since it allows not only to optimize visual acuity for a certain period of time, but also to stop the progression of myopia. Another indication for the correction of vision using orthokeratology lenses includes active sports and situations that exclude the possibility of wearing glasses or soft contact lenses.

scholarly journals Peripheral Refraction, Wave Front of the Eye and Visual Performance in the Correction of Myopia in Children with Bifocal Soft Contact Lenses with High Addition

2021 ◽  
Vol 18 (3) ◽  
pp. 518-526
Author(s):  
E. P. Tarutta ◽  
S. V. Milash ◽  
M. V. Epishina
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Contact Lenses ◽  
Spherical Aberration ◽  
Sharp Decrease ◽  
Soft Contact ◽  
Wavefront Aberrations ◽  
Soft Contact Lenses ◽  
Soft Contact Lens

Purpose: to study the effect of bifocal soft contact lens (BSCL) with an ADD of 4 diopters on peripheral refraction (PR), optical and ergonomic eye parameters in children with myopia.Patients and methods. 26 patients (52 eyes) with myopia –3.09 ± 1.13 diopters at the age of 10.04 ± 1.5 years without correction and with correction by BSCL Prima BIO Bi-focal ( Okay Vision Retail, Russia). All patients underwent a horizontal and vertical PR study on an open field autorefractometer Grand Seiko WAM-5500 (Japan), wavefront aberrations were studied on OPD-Scan III aberrometer (Nidek, Japan), contrast sensitivity under mesopic conditions were studied on a Mesotest 2 instrument (Oculus, Germany) and visual productivity was studied using test tables.Results. The visual acuity of the distance with a BSCL correction of 0.98 ± 0.04 did not differ (p = 0.26) from the maximum visual acuity corrected by spherocylindrical glasses of 0.99 ± 0.04. BSCL induces myopic defocus in all peripheral zones, with a maximum value of 15° and a sharp decrease of 30°. Peripheral myopic defocus induced by the lens at a horizontal and vertical angle of 15 degrees did not depend on the initial degree of myopia. BSCL increases the total RMS from 0.07 ± 0.02 μm to 0.19 ± 0.07 μm in the 3 mm zone (p < 0.01) and from 0.27 ± 0.09 μm to 1.18 ± 0, 23 μm in the 6 mm zone (p < 0.01), mainly due to an increase in spherical aberration from –0.0005 ± 0.006 μm to 0.06 ± 0.01 μm (p < 0.01) and from 0.01 ± 0.09 μm to 0.58 ± 0.14 μm (p < 0.01) in the 3 mm and 6 mm zones, respectively. An increase in the overall RMS in BSCL reduces the quality of eye optics and contrast sensitivity under mesopic conditions, but does not impair visual productivity.Conclusion. BSCLs with a high ADD of 4 diopters are capable of inducing significant myopic peripheral defocus due to the induction of spherical aberration, while maintaining high visual acuity and not changing ophthalmic ergonomics, which makes them a pathogenetically substantiated method for correcting myopia and preventing its progression in children and adolescents.

scholarly journals Accommodation in emmetropic and myopic young adults wearing bifocal soft contact lenses

2008 ◽  
Vol 28 (1) ◽  
pp. 62-72 ◽  
Author(s):  
Janice Tarrant ◽  
Holly Severson ◽  
Christine F. Wildsoet
Keyword(s):  
Young Adults ◽  
Contact Lenses ◽  
Soft Contact ◽  
Soft Contact Lenses

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

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
G. Carracedo ◽  
T. M. Espinosa-Vidal ◽  
I. Martínez-Alberquilla ◽  
L. Batres
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Contact Lenses ◽  
Spherical Aberration ◽  
Ring Width ◽  
Treatment Area ◽  
Low Contrast ◽  
Zone Diameter ◽  
Peripheral Ring ◽  
Optical Zone

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 (p 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 (p-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 (p-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 (p-value < 0.05). Regarding PRW, the 5 mm OZ design had a wider ring width in both the nasal and temporal zones (p-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).

Contrast Sensitivity with Soft Contact Lenses Compensated for Spherical Aberration in High Ametropia

1998 ◽  
Vol 75 (1) ◽  
pp. 37-43 ◽  
Author(s):  
JOHN DE BRABANDER ◽  
NICOLAS CHATEAU ◽  
FLORENCE BOUCHARD ◽  
SANDRINE GUIDOLLET
Keyword(s):  
Contrast Sensitivity ◽  
Contact Lenses ◽  
Spherical Aberration ◽  
Soft Contact ◽  
Soft Contact Lenses

scholarly journals “OKVision OKV-SL” customizable soft contact lenses fitting guide

The Eye ◽  
2020 ◽  
Vol 22 (4(132)) ◽  
pp. 61-68
Author(s):  
A. V. Myagkov ◽  
Zh. N. Poskrebysheva
Keyword(s):  
Visual Acuity ◽  
Contact Lens ◽  
Contact Lenses ◽  
Soft Contact ◽  
Soft Contact Lenses ◽  
Vision Correction

The purpose of this guide is to introduce ophthalmologists and optometrists to the basics of fitting of customizable soft contact lenses, which is an important knowledge that enhances practitioners’ skills and helps provide a high visual acuity for many patients.Material and methods. This guide sets forth the principles of calculation of contact lens parameters, defines parameters specific to customizable lenses as well as assessment of the fit and the rules of lens handling and care.Conclusions. Following the fitting guide ensures a successful vision correction with customizable soft contact lenses for both doctor and the patient.

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