scholarly journals Determination of Oxygen Permeability in Soft Contact Lenses Using a Polarographic Method:  Estimation of Relevant Physiological Parameters

2008 ◽  
Vol 47 (10) ◽  
pp. 3619-3629 ◽  
Author(s):  
J. M. Gonzalez-Meijome ◽  
V. Compañ-Moreno ◽  
E. Riande
Keyword(s):  
Oxygen Permeability ◽  
Contact Lenses ◽  
Physiological Parameters ◽  
Polarographic Method ◽  
Soft Contact ◽  
Soft Contact Lenses

Determination of the Lysozyme Deposit Curve in Soft Contact Lenses

2003 ◽  
Vol 29 (2) ◽  
pp. 79-82 ◽  
Author(s):  
David J. Keith ◽  
Mike T. Christensen ◽  
Jacqueline R. Barry ◽  
Jerry M. Stein
Keyword(s):  
Contact Lenses ◽  
Soft Contact ◽  
Soft Contact Lenses

scholarly journals The Effectiveness of Different Optical Correction Methods in Children and Adolescents with Progressive Myopia Based on a Comparative Evaluation of the Accommodation and Axial Length of Eyes

2018 ◽  
Vol 15 (2S) ◽  
pp. 65-72 ◽  
Author(s):  
M. M. Sitka ◽  
S. G. Bodrova ◽  
N. A. Pozdeyeva
Keyword(s):  
Children And Adolescents ◽  
Axial Length ◽  
Contact Lenses ◽  
Control Group ◽  
Soft Contact ◽  
Axial Elongation ◽  
Soft Contact Lenses ◽  
Optical Correction ◽  
Progressive Myopia

Objective: to determine optimal method of progressive myopia optical correction in children and adolescents.Patients and methods. Conducted 5-year prospective clinical and instrumental examination of 494 children with myopia using orthokeratology lenses, soft contact lenses and glasses. 61 children (the average age 11.7 ± 2.36 years) with myopia –2.87 ± 1.1 D and astigmatism –0.58 ± 0.27 D used orthokeratological lens. 92 children (the average age 12.8 ± 1.51 years) with myopia –3.66 ± 1.07 D, astigmatism –0.53 ± 0.18 D wore soft contact lens. 79 children (the average age 11.52 ± 1.78 years) with myopia –1.59 ± 1.08 D, astigmatism –0.71 ± 0.54 D used glasses with monofocal lenses, with full correction. The control group consisted of 249 children (the average age 9.1 ± 1.14 years) with initial emmetropia. Determination of refraction, subjective and objective determination of accommodation, and axial length of the eye (“IOL-master”) was conducted in children.Results. The maximum progression of myopia was observed in younger children (8–9 years). Correction of myopia with orthokeratology lenses (OKLs) was accompanied by the lowest dynamics of changes in axial length (axial elongation 0,44 ± 0,32 mm) compared to the correction with soft contact lenses (SCLs) (axial elongation 0,73 ± 0,36 mm), spectacle correction (axial elongation 1,39 ± 0,47 mm) and the control group (axial elongation 0,6 ± 0,41 mm). In all children with myopia, at the beginning of the study, there were reduced values reserve of relative accommodation and an objective accommodative response. Correction of myopia with OKLs (p = 0,0002) and SCLs (p = 0,036) provides the normalization of subjective and objective reserve indication of relative accommodation in both age group in comparison of spectacles correction.Conclusion. Correction with orthokeratology lens in children with progressive myopia contributes to the minimum growth length of the eye. Correction of myopia OKLs and MKL improves of subjective and objective indicators of relative accommodation reserve. 

scholarly journals Refractive behavior changes with six months daily wear of high and low oxygen permeability hydrogel contact lenses

2006 ◽  
Vol 65 (2) ◽  
Author(s):  
W.D.H. Gillan
Keyword(s):  
Oxygen Permeability ◽  
Contact Lenses ◽  
The Other ◽  
Behavior Changes ◽  
Low Oxygen ◽  
Soft Contact ◽  
Silicone Hydrogel ◽  
Refractive State ◽  
Soft Contact Lenses ◽  
Silicone Hydrogels

Introduction: The investigation of myopia and soft contact lenses is not new. Many reports show  that  the  wearing  of  silicone  hydrogel lenses as opposed to conventional disposable hydrogel lenses results in little progression of myopia in the eyes wearing silicone hydrogels. Method: Six subjects wore a silicone hydro-gel lens on one eye while the other eye wore a habitual disposable hydrogel lens for six months of daily wear. Fifty measurements of refractive state in each eye were taken prior to the subjects wearing a silicone lens in one eye and a conven-tional hydrogel lens in the other eye. After six months of daily wear another fifty measurements of refractive state were taken for each subject. Results:  Although  there  is  no  statisti-cal  support  for  the  findings  of  this  study, comet stereo-pairs are used to show the chang-es in refractive state for each subject. Four of  the  six  subjects  showed  an  increase  in myopia in the eye wearing the silicone lens. Discussion:  The  increase  in  myopia in eyes wearing a silicone hydrogel lens is contrary  to  the  findings  of  other  studies.

Effect of the medicine “Cationorm” on lacrimal film in obstructive dysfunction of meibomyus glands among users of soft contact lenses

2020 ◽  
pp. 39-45
Author(s):  
Ekaterina B. GORSHENYOVA ◽  
Nataliya M. SUTORMINA
Keyword(s):  
Hyaluronic Acid ◽  
Contact Lenses ◽  
Control Group ◽  
Delayed Effect ◽  
Soft Contact ◽  
Silicone Hydrogel ◽  
Soft Contact Lenses ◽  
Pathogenetic Therapy ◽  
Tear Substitute

There are more than 80 million users of soft contact lenses in the world - 10-15 % of the population. The prevalence of meibomyus gland dysfunction is 43-61 % with the prevalence of obstructive form and the development of lipodeficiency in lacrimal film. At the same time, the use of traditional tear substitutes based on hyaluronic acid is ineffective and the problem of finding a tear substitute with exposure to all 3 layers of lacrimal film becomes relevant. Nanoemulsion “Cationorm” is created as a means of pathogenetic therapy of dry eye syndrome against the background of lipodeficiency, however, there weren't any studies of its effectiveness in obstructive form of meibomyus gland dysfunction among users of soft contact lenses. We examined 3 layers of lacrimal film with the help of Norn's sample with determination of time of lacrimal film break, bio-measurement of lacrimal meniscus and biomicoscopy of eyelid edge region at painting of lissamino-om green. The study involved 28 young carriers of silicone-hydrogel contact lenses with signs of obstructive form of meibomyus gland dysfunction, who we divided into two groups: a control group used to eliminate the symptoms of a hyaluronic acid-based tear substitute, and an experimental group using the drug “Cationorm”. We revealed prolonged effect of nanoemulsion “Cationorm” on all three layers of lacrimal film, which hasn't only symptom lacrimal, but has pathogenetic therapeutic delayed effect among users of soft contact lenses with obstructive form of dysfunction of meibomyum glands, and nanostimer of lipid microspheres provides full compatibility even with material of silicone-hydrogel soft contact lenses. We proved the protective effect of the preparation on ocular epithelium cells.

scholarly journals Influence of Tear Protein Deposition on the Oxygen Permeability of Soft Contact Lenses

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Se Eun Lee ◽  
So Ra Kim ◽  
Mijung Park
Keyword(s):  
Oxygen Permeability ◽  
Contact Lenses ◽  
Boundary Effect ◽  
Soft Contact ◽  
Silicone Hydrogel ◽  
Artificial Tear ◽  
Protein Deposition ◽  
Soft Contact Lenses ◽  
Tear Proteins ◽  
Tear Protein

Purpose. To investigate the effect of tear protein deposition on the change in oxygen permeability (Dk) of soft contact lenses (SCL). Methods. Three hydrogel lenses (polymacon, nelfilcon A, and etafilcon A) and two silicon hydrogel lenses (lotrafilcon A and balafilcon A) were investigated. Etafilcon A lenses were incubated in artificial tear solution for 1, 6, 12, and 48 h, whereas the other SCL were incubated for 1, 3, 7, and 14 days. Oxygen permeability was measured using the polarographic method, and lenses were stacked in four layers to correct the boundary effect. Results. The Dk of all investigated SCL was decreased by the protein deposition. Silicone hydrogel lenses showed a smaller deposition of artificial tear proteins than conventional hydrogel lenses. However, their Dk was reduced twofold than those of 3 conventional hydrogel lenses when compared at the same level of protein deposition. Despite a large amount of total deposited protein in etafilcon A lenses, their Dk was more stable than other SCL. Conclusions. From the results, it was revealed that the Dk of SCL is different from the value provided by manufacturers because of the tear protein deposition on surface and/or in pore of SCL; however, the degree of Dk change in SCL was not simply correlated with the amount of tear protein deposition. Thus, it is considered that the correlation between tear protein deposition and properties of lens materials affects Dk change.

Oxygen Permeability of Disposable Soft Contact Lenses

1990 ◽  
Vol 110 (3) ◽  
pp. 269-273 ◽  
Author(s):  
Barry A. Weissman ◽  
Steven D. Schwartz ◽  
Nina Gottschalk-Katsev ◽  
David A. Lee
Keyword(s):  
Oxygen Permeability ◽  
Contact Lenses ◽  
Soft Contact ◽  
Soft Contact Lenses
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