Tribological classification of contact lenses – From coefficient of friction to sliding work: Can contact lens wear help you burn calories?

2018 ◽  
Vol 41 ◽  
pp. S41
Author(s):  
Samuele Tosatti ◽  
Olof Sterner ◽  
Rudolf Aeschlimann ◽  
Stefan Zuercher ◽  
Charles Scales ◽  
...  
Keyword(s):  
Coefficient Of Friction ◽  
Contact Lens ◽  
Contact Lenses ◽  
Contact Lens Wear ◽  
Lens Wear

scholarly journals Preliminary Clinical Exploration of Scleral Lens Performance on Normal Eyes

2018 ◽  
Vol 2 (2) ◽  
pp. e14-e21
Author(s):  
Melissa Barnett ◽  
Jonathon Ross ◽  
Blythe Durbin-Johnson
Keyword(s):  
Visual Acuity ◽  
Contact Lens ◽  
Healthy Subjects ◽  
Contact Lenses ◽  
Front Surface ◽  
Contact Lens Wear ◽  
Factors Associated ◽  
Rigid Contact ◽  
Lens Wear ◽  
Spectacle Correction

Abstract Objectives: The purpose of this study was to evaluate the performance (i.e. vision, comfort and fit) of spherical and front-surface toric scleral lenses in subjects with regular, healthy corneas. Methods: Scleral lenses were fitin the eyes (n = 16) of healthy subjects (n = 9) with regular corneas, absent of pathology, and studied using an observational, multi-visit design. Lens fit was objectively evaluatedby an experienced practitioner.Following 1 month of successful lens wear, participants completedsubjective satisfaction surveys regarding the scleral lens wearing experience. Results:  According to participant surveys, scleral lenses were subjectively preferred over soft toric or gas permeable contact lenses in 88% of eyes, including in all eyes fit with a front-surface toric scleral lens (n = 3). Seventy-five percent (75%) of eyes achieved visual acuity of 0.1 logMAR or better, while all eyes with prior spectacle wear achieved visual acuity with a scleral lens within 1 Snellen line of spectacle correction. Seventy-five percent (75%) of eyes achieved good subjective comfort with a scleral lens. No participants reported poor subjective vision and/or comfort. Conclusions:  Our findings suggest that subjects preferred the performance of a scleral lens (spherical or front-surface toric) compared to a soft toric or gas permeable contact lens. Moreover, scleral lenses may provide a viable, alternative contact lens modality option for patients considering discontinuation of traditional soft toric and/or rigid contact lens wear; so long as the factors associated with hypoxia remain minimized. Key Words:  scleral lens; scleral contact lens; front-surface toric scleral lens; lens performance; normal eyes; healthy eyes

scholarly journals Personal hygiene risk factors for contact lens-related microbial keratitis

2020 ◽  
Vol 5 (1) ◽  
pp. e000476
Author(s):  
Anna Stellwagen ◽  
Cheryl MacGregor ◽  
Roger Kung ◽  
Aristides Konstantopoulos ◽  
Parwez Hossain
Keyword(s):  
Risk Factors ◽  
Risk Factor ◽  
Contact Lens ◽  
Contact Lenses ◽  
Healthcare Services ◽  
University Hospital ◽  
Personal Hygiene ◽  
Microbial Keratitis ◽  
Contact Lens Wear ◽  
Lens Wear

ObjectiveMicrobial keratitis is a sight-threatening complication of contact lens wear, which affects thousands of patients and causes a significant burden on healthcare services. This study aims to identify compliance with contact lens care recommendations and identify personal hygiene risk factors in patients who develop contact lens-related microbial keratitis.Methods and analysisA case–control study was conducted at the University Hospital Southampton Eye Casualty from October to December 2015. Two participant groups were recruited: cases were contact lens wearers presenting with microbial keratitis and controls were contact lens wearers without infection. Participants underwent face-to-face interviews to identify lens wear practices, including lens type, hours of wear, personal hygiene and sleeping and showering in lenses. Univariate and multivariate regression models were used to compare groups.Results37 cases and 41 controls were identified. Showering in contact lenses was identified as the greatest risk factor (OR, 3.1; 95% CI, 1.2 to 8.5; p=0.03), with showering daily in lenses compared with never, increasing the risk of microbial keratitis by over seven times (OR, 7.1; 95% CI, 2.1 to 24.6; p=0.002). Other risks included sleeping in lenses (OR, 3.1; 95% CI, 1.1 to 8.6; p=0.026), and being aged 25–39 (OR, 6.38; 95% CI, 1.56 to 26.10; p=0.010) and 40–54 (OR, 4.00; 95% CI 0.96 to 16.61; p=0.056).ConclusionThe greatest personal hygiene risk factor for contact lens-related microbial keratitis was showering while wearing lenses, with an OR of 3.1, which increased to 7.1 if patients showered daily in lenses. The OR for sleeping in lenses was 3.1, and the most at-risk age group was 25–54.

scholarly journals Impact of Rigid Gas Permeable Contact Lenses Removal on Anterior and Posterior Corneal Surfaces in Keratoconus Patients

2019 ◽  
Author(s):  
Motohiro Itoi ◽  
Koji Kitazawa ◽  
Hisayo Higashihara ◽  
Chie Sotozono
Keyword(s):  
Contact Lens ◽  
Contact Lenses ◽  
Corneal Thickness ◽  
Anterior Segment ◽  
Corneal Surface ◽  
Contact Lens Wear ◽  
Surface Areas ◽  
The Impact ◽  
Lens Wear ◽  
Anterior Posterior

AbstractPurposeTo evaluate the impact of removal of rigid gas-permeable (RGP) contact lenses on the anterior and posterior cornea surfaces of eyes with keratoconus.MethodsEight eyes of 8 patients with keratoconus (KC) (age 34.3 ± 15.3 years; range 19–60 years) were enrolled. Anterior segment optical coherence tomography (AS-OCT) was performed at 1, 5, 10, 20, and 60 minutes after the patients removed their RGP contact lenses. Measurements included anterior and posterior best-fit sphere (BFS); elevation values and corneal surface areas; corneal thickness at the thinnest point; and the anterior-posterior ratio of the corneal surface (As/Ps) between 1 minute and 60 minutes after RGP contact lens removal.ResultsAnterior and posterior elevation values and corneal surface areas showed significant increases, whereas anterior and posterior BFS and central corneal thickness decreased significantly (P < 0.01) between 1 minute and 60 minutes after RGP contact lens removal. No statistically significant differences were found in the As/Ps ratio during the first hour after suspending RGP contact lens wear.ConclusionsWe found that the patients with keratoconus experienced significant changes in both the anterior and posterior corneal shape for 60 minutes after removal of RGP contact lenses.

scholarly journals The Risk of Contact Lens Wear and the Avoidance of Complications

2013 ◽  
Vol 1 (2) ◽  
pp. 80-85 ◽  
Author(s):  
Farihah Tariq ◽  
Peter Koay
Keyword(s):  
Risk Factors ◽  
Contact Lens ◽  
Contact Lenses ◽  
Health Concern ◽  
Refractive Errors ◽  
Microbial Keratitis ◽  
Contact Lens Wear ◽  
Good Contact ◽  
Number Of Individuals ◽  
Lens Wear

Contact lenses are lenses placed on the surface of the cornea to correct refractive errors such as myopia (short-sightedness), hyper­metropia (far-sightedness) and astigmatism. Lens-related complications are becoming a greater health concern as increasing number of individuals are using them as an alternative to spectacles. Contact lenses alter the natural ocular environment and reduce the efficacy of the innate defences. Although many complications are minor, microbial keratitis is potentially blinding and suspected cases should be rapidly diagnosed and referred to an ophthalmologist for treatment. Several risk factors have been identified with extended wear, poor hand hygiene, inadequate lens and lens-case care being the most significant. Promotion of good contact lens hygiene and practices are essential to reduce the adverse effects of contact lens wear.

scholarly journals Life on contact lenses: Exploiting a modern habitat

2009 ◽  
Vol 31 (4) ◽  
pp. 26-27
Author(s):  
James Lonnen
Keyword(s):  
Contact Lens ◽  
Contact Lenses ◽  
Risk Of Infection ◽  
Microbial Keratitis ◽  
Corneal Epithelial ◽  
Contact Lens Wear ◽  
The World ◽  
Micro Organisms ◽  
And Storage ◽  
Lens Wear

There are an estimated 125 million contact lens wearers across the world, and the majority experience few complications; however, it is well known that contact lens wear is a risk factor for microbial keratitis (infection of the cornea of the eye). Owing to the ubiquitous distribution of micro-organisms, it is extremely di cult to prevent them from colonizing contact lens storage cases. Bacteria, fungi and protozoa have all been found in contact lens storage cases; these micro-organisms can adhere to the contact lens, which then acts as a vector to transport the microbes on to the surface of the eye. Bacteria such as Pseudomonas aeruginosa, fungi such as Fusarium solani and the protazoan parasite Acanthamoeba–to name but a few–can cause infection of the corneal epithelial cells, which, if untreated, can lead to blindness. It is therefore essential that wearers clean and disinfect their contact lenses and storage cases e ectively to minimize the risk of infection.

The Development of an Antimicrobial Contact Lens – From the Laboratory to the Clinic

2020 ◽  
Vol 21 (4) ◽  
pp. 357-368 ◽  
Author(s):  
Mark D.P. Willcox ◽  
R. Chen ◽  
P. Kalaiselvan ◽  
M. Yasir ◽  
R. Rasul ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Contact Lens ◽  
Ocular Surface ◽  
Contact Lenses ◽  
Research Progress ◽  
Clinical Testing ◽  
Contact Lens Wear ◽  
Loss Of Vision ◽  
Infection And Inflammation ◽  
Lens Wear

Contact lens wear is generally safe and provides excellent vision. However, contact lens wear is often associated with the risk of developing ocular surface infection and inflammation, and in severe cases, the infection can result in loss of vision. Antimicrobial peptide-coated contact lenses have been made to help reduce the incidence of infection and inflammation. This paper reviews the research progress from conception, through the laboratory and preclinical tests to the latest information on clinical testing of an antimicrobial contact lens. We provide insights into the pathways followed and pitfalls that have been encountered. The journey has not always been linear or smooth, but has resulted in some of the first published clinical testing of antimicrobial peptide-coated contact lenses in humans. We hope this may help lead to the development and commercialisation of antimicrobial contact lenses in the future.

scholarly journals The short-term effects of PMMA contact lens wear on keratometric behaviour: results for a single keratoconic cornea*

2010 ◽  
Vol 69 (2) ◽  
Author(s):  
E. Chetty ◽  
W. D. H. Gillan
Keyword(s):  
Contact Lens ◽  
Contact Lenses ◽  
Corneal Curvature ◽  
Short Term ◽  
Multivariate Statistical ◽  
Contact Lens Wear ◽  
Rigid Contact ◽  
Dioptric Power ◽  
Control Study ◽  
Lens Wear

Keratometric behaviour is a multifaceted issue that many researchers have investigated for years. Many internal and external influences can have an effect on the cornea’s keratometric behaviour. This investigation forms a small part of a larger study that aims at determining the effects that rigid contact lenses might have on keratometric behaviour. This pilot study examined the keratometric behaviour of a single, mildly keratoconic cornea that was fitted with a polymethyl methacrylate (PMMA) contact lens. Sixty successive auto-keratometric measurements were taken immediately before and immediately after three hours of contact lens wear. The data obtained was transformed to dioptric power matrices and were analysed using multivariate statistical methods. This study showed that, at least in one keratoconic cornea, there appeared to be a statistically significant change in corneal curvature under the influence of a PMMA contact lens. The contact lens had also appeared to decrease variation in corneal curvature. There was no control study done on this eye therefore the effects of diurnal variation, if any, could not be established. (S Afr Optom 2010 69(2) 69-76)

scholarly journals Effect of Soft Contact Lens Wear on Tear Film Break up Time

2020 ◽  
Vol 36 (2) ◽  
Author(s):  
Syeda Rushda Zaidi ◽  
Mohammad Ali A Sadiq ◽  
Shua Azam ◽  
Uzma Sattar ◽  
Samia Iqbal ◽  
...  
Keyword(s):  
Contact Lens ◽  
Contact Lenses ◽  
Tear Film ◽  
Soft Contact ◽  
Contact Lens Wear ◽  
Soft Contact Lens ◽  
History Of ◽  
Break Up ◽  
Medical University ◽  
Lens Wear

Purpose:  To see the effect of soft contact lens wears on tear breakup time. Study Design:  Descriptive Observational study. Place and Duration of Study:  College of Ophthalmology and Allied Vision Sciences, King Edward Medical University, Mayo Hospital, Lahore. From January to March 2016. Material and Methods:  Students of King Edward Medical University Lahore wearing soft contact lens for more than 3 months with no  known ocular pathology were selected by non-probability convenient sampling technique. Subjects with history of using any eye drops, history of oral drugs, which could cause dry eye and individuals any ocular disease, were excluded from the study. Tear film BUT was tested by using Fluorescein sodium dye and examinig under cobalt blue filter of slit lamp.SPSS version 20 is used to analyze the data. Results:  There were 30 participants with mean age of 24.5 ± 5 years. All were females. Sixty percent were wearing corrective lenses, and 40% were wearing cosmetic lenses. Out of 30 patients wearing contact lenses, only 6.67% had marginal tear film BUT and none of the patients has shown dry eyes. Individuals using contact lenses for 9 – 12 years had decreased BUT as compared to subjects using lenses for 3 – 6 months. 33.33% of extended lens wearers had reduced BUT as compared to disposable and daily wearers of contact lenses. Discomfort with contact lenses was observed in only 4 patients. Conclusion:  As the duration of contact lens wear increases, the tear film break up time decreases. Individuals using extended wear contact lenses are more prone to develop decreased TFBUT.

scholarly journals Using Nanoparticle Drug Delivery Mechanisms to Improve Eye Moisture Over Extended Periods of Contact Lens Wear

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Hasan Zaidi
Keyword(s):  
Drug Delivery ◽  
Contact Lens ◽  
Contact Lenses ◽  
Tear Film ◽  
Eye Drops ◽  
Three Solutions ◽  
Polyethylene Glycol 400 ◽  
Dry Eyes ◽  
Contact Lens Wear ◽  
Lens Wear

Millions of people around the world suffer from dry eye symptoms as a result of extended contact lens wear. The objective of this design document is to engineer a solution for chronic dry eyes. The solution must be safe, effective, easy to use, and affordable. The goal of the treatment is to decrease tear film osmolarity by 20 mOsmol/L. Three types of nanotechnologies were considered for this task. The candidate solutions were 1) hydrogel contact lenses infused with lubricant-loaded liposomes, 2) lubricant-loaded microemulsions applied as eye drops, and 3) lubricant-loaded niosomes applied as eye drops. All solutions use polyethylene glycol 400 as the primary active ingredient in the lubricant. The three solutions provide a safe treatment option that allows increased bioavailability of drug and increased retention time, as well as controlled release of drug. A combination of candidates 1 and 3 – namely, hydrogel contact lenses infused with lubricant-loaded niosomes – seems to be the best solution because of excellent drug delivery kinetics and minimal safety concerns. The success of this project would encourage further research in niosome-based and contact lens-based drug delivery. It would also allow this company to expand research and development and further specialize in ocular drug delivery.

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