Centering Mechanism for Soft Contact Lenses

1999 ◽  
Vol 121 (2) ◽  
pp. 188-195 ◽  
Author(s):  
Guo Ming T. Funkenbusch ◽  
Richard C. Benson
Keyword(s):  
Potential Energy ◽  
Contact Lens ◽  
Energy Method ◽  
Contact Lenses ◽  
Soft Contact ◽  
Soft Contact Lenses ◽  
Soft Contact Lens ◽  
Potential Energy Method

A soft contact lens, because of its elasticity, can re-center itself over the cornea after it has been displaced by a blink. In this paper, a potential energy method is used to simulate the centering mechanism. Specifications for commercially available soft contact lenses and realistic eye shapes are used for the examples. With this technique we can compare the centering attributes of different lens and eye geometries.

scholarly journals STUDY OF THE OPTICAL POWER OF NANOPHOTONIC SOFT CONTACT LENSES BASED ON POLY (2- HYDROXYETHYL METHACRYLATE) AND FULLERENE

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Aleksandra Debeljković Mitrović ◽  
Dragomir Stamenković ◽  
Manuel Conte ◽  
Božica Bojović ◽  
Spomenko Mihajlović
Keyword(s):  
Contact Lens ◽  
Contact Lenses ◽  
Measurement Techniques ◽  
Optical Power ◽  
Soft Contact ◽  
Standard Material ◽  
Soft Contact Lenses ◽  
Soft Contact Lens ◽  
Power Cylinder

In this paper results of comparative study of the optical power of soft contact lenses (SCL) made of standard material for SCL and nanophotonic materials with different measurement techniques used for the final contact lens controllers are presented. Three types of nanophotonic soft contact lenses were made of standard polymacon material (Soleko SP38TM) incorporated with fullerene C60, fullerol C60(OH)24 and fullerene metformin hydroxylate C60(OH)12(OC4N5H10)12. For the purposes of material characterization for potential application as soft contact lenses, the optical properties of the soft contact lenses were measured by Rotlex and Nidek device. With Rotlex device the following optical results were obtained: optical power and map of defects, while with the Nidek device: optical power, cylinder power and cylinder axis. The obtained values of optical power and map of defects showed that the optical power of synthesized nanophotonic soft contact lens is same to the nominal value, while this was not the case for the standard soft contact lens. Also, the quality of the nanophotonic soft contact lens is better than the standard one. Hence, it is possible to synthesize new nanophotonic soft contact lenses of desired optical characteristics, implying possibilities for their application in this field.

scholarly journals Characterization of nanophotonic soft contact lenses based on poly (2-hydroxyethyl methacrylate) and fullerene

2013 ◽  
Vol 67 (6) ◽  
pp. 861-870 ◽  
Author(s):  
Aleksandra Debeljkovic ◽  
Lidija Matija ◽  
Djuro Koruga
Keyword(s):  
Contact Lens ◽  
Near Infrared ◽  
Contact Lenses ◽  
Base Material ◽  
Optical Power ◽  
Sem Analysis ◽  
Hydroxyethyl Methacrylate ◽  
Soft Contact ◽  
Soft Contact Lenses ◽  
Soft Contact Lens

This work presents comparative research of characteristics of a basic and new nanophotonic material, the latter of which was obtained by incorporation fullerene, C60, in the base material for soft contact lenses. The basic (SL38) and nanophotonic materials (SL38-A) for soft contact lenses were obtained by radical polymerization of 2-hydroxyethyl methacrylate and 2-hydroxyethyl methacrylate and fullerene, which were derived by the technology in the production lab of the company Soleko (Milan, Italy). The materials were used for production of soft contact lenses in the company Optix (Belgrade, Serbia) for the purposes of this research. Fullerene was used due to its apsorption transmission characteristics in ultraviolet, visible and near infrared spectrum. For the purposes of material characterization for potential application as soft contact lenses, network parameters were calculated and SEM analysis of the materials was performed while the optical properties of the soft contact lenses were measured by a Rotlex device. The values of the diffusion exponent, n, close to 0.5 indicated Fick's kinetics corresponding to diffusion. The investigated hydrogels could be classified as nonporous hydrogels. With Rotlex device, values of optical power and map of defects were showed. The obtained values of optical power and map of defects showed that the optical power of synthesized nanophotonic soft contact lens is identical to the nominal value while this was not the case for the basic lens. Also, the quality of the nanophotonic soft contact lens is better than the basic soft contact lens. Hence, it is possible to synthesize new nanophotonic soft contact lenses of desired optical characteristics, implying possibilities for their application in this field.

The effect of soft contact lenses with L-Menthol to enhance soft contact lens end of the day comfort

2021 ◽  
Vol 44 (1) ◽  
pp. 18
Author(s):  
Ruby Chiang ◽  
Rebecca Gao ◽  
Terry Chang ◽  
Jerry Chen ◽  
George Hsu
Keyword(s):  
Contact Lens ◽  
Contact Lenses ◽  
Soft Contact ◽  
Soft Contact Lenses ◽  
Soft Contact Lens

Keratitis induced by soft contact lens

2021 ◽  
pp. 111-114
Author(s):  
Е.L. Usubov ◽  
◽  
I.A. Rusakova ◽  
E.M. Rakhimova ◽  
◽  
...  
Keyword(s):  
Contact Lens ◽  
Contact Lenses ◽  
Antimicrobial Effect ◽  
Term Treatment ◽  
Soft Contact ◽  
Soft Contact Lenses ◽  
Uv Crosslinking ◽  
Soft Contact Lens ◽  
Long Term Treatment ◽  
Improper Use

A clinical case demonstrates that improper use of soft contact lenses can induce serious changes in the cornea, followed by long-term treatment, which in turn may be ineffective due to the developed antibiotic resistance. In similar cases, the use of UV crosslinking provides an additional antimicrobial effect, which ultimately allows the inflammatory process to be resolved. Key words: keratitis, soft contact lens, crosslinking.

The Conformity of a Soft Contact Lens on the Eye

1996 ◽  
Vol 118 (3) ◽  
pp. 341-348 ◽  
Author(s):  
GuoMing T. Funkenbusch ◽  
Richard C. Benson
Keyword(s):  
Contact Lens ◽  
Transverse Shear ◽  
Contact Lenses ◽  
Elastic Shell ◽  
Deformation Model ◽  
Soft Contact ◽  
Reaction Pressure ◽  
Soft Contact Lenses ◽  
Soft Contact Lens ◽  
Shear Loads

An axisymmetric elastic shell deformation model has been created to predict the conformity of a soft contact lens when pressed against the eye. Regions of contact and gap may be predicted, and the nonuniform reaction pressure between the lens and eye may also be found. This is important for issues like abrasion and comfort. Bending, membrane and transverse shear loads within the lens are also computed. Commercial soft contact lenses and a representative eye shape are used for the examples. We find that the uniformity of loading against the eye is strongly affected by the degree to which the lens is shaped to fit the eye, and relatively unaffected by the thickness of the lens.

scholarly journals Characterization of Soft Contact Lens Fitting Using Ultra-Long Scan Depth Optical Coherence Tomography

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Lele Cui ◽  
Ming Li ◽  
Meixiao Shen ◽  
Fan Lu ◽  
Jianhua Wang
Keyword(s):  
Optical Coherence Tomography ◽  
Contact Lens ◽  
Contact Lenses ◽  
Repeated Measurements ◽  
Optical Coherence ◽  
Soft Contact ◽  
Soft Contact Lenses ◽  
Soft Contact Lens ◽  
Good Repeatability ◽  
The Right

Objectives. To evaluate the centration and movement of soft contact lenses and to verify the repeatability of two repeated measurements of the lens centration and movement using ultra-long scan depth optical coherence tomography (UL-OCT). Methods. A 1-day Acuvue® Define™ lens was tested on both eyes of 10 subjects (5 males and 5 females; mean age, 31.6 years). The centration and blink-induced movement of the contact lens were measured using UL-OCT at 5 min and 30 min after insertion. The measurements were repeated once at each checkpoint. Results. Good repeatability was found in the lens centration and movement between the two repeated measurements at either checkpoint. The values of the lens movement were 0.457 ± 0.248 mm and 0.402 ± 0.229 mm at 5 min and decreased to 0.197 ± 0.065 mm and 0.211 ± 0.110 mm at 30 min after insertion for the right and left eyes, respectively (P<0.05). Conclusions. The custom-built UL-OCT presented good repeatability of centration and movement in Define lenses at 5 min and 30 min after insertion. Most of the lenses were centered temporal and inferior to the cornea during the first 30 min wearing period. Compared with 5 min after insertion, the lens was centered better and exhibited less movement at 30 min.

scholarly journals Soft-contact-lenses-induced complications

2008 ◽  
Vol 65 (1) ◽  
pp. 15-20 ◽  
Author(s):  
Gordana Suvajac
Keyword(s):  
Contact Lens ◽  
Vision Loss ◽  
Contact Lenses ◽  
Tear Film ◽  
Video Camera ◽  
Conjunctival Hyperemia ◽  
Soft Contact ◽  
Soft Contact Lenses ◽  
Soft Contact Lens ◽  
Number Of Patients

Background/Aim. Soft contact lenses occupy significant place in ophthalmology, both in the correction of refraction anomalies and in the treatment of many eye diseases. The number of patients that wear soft contact lenses for the purpose of correcting ametropia is constantly increasing. Due to the increasing number of wearers, the percentage of complications that can lead to serious eye damage and serious vision loss is also increasing. The aim of this study was to point out the most common complications related to soft contact lens use. Methods. In the period from 1995?2004 this prospective study included 510 patients wearing soft contact lenses for correcting ametropia. None of the patients wore contact lenses before and none suffered from any system or local diseases that could affected the development of eventual complications. The study took seven years with the patients who wore conventional lenses and three years with those who wore replacement contact lenses. All the necessary ophthalmologic examinations were done (visual acuity, refractokeratometry, the quantity of tear film, biomicroscopic examination of anterior eye segment). All the complications were filmed by video camera. Results. Of all the patients, 19 had blepharitis, 73 suffered from ?dry eye?, 57 had conjunctival hyperemia, 12 had conjunctivitis, 34 had gigantopapillary conjunctivitis (GPC), 93 had punctiform epitheliopathy, 20 had corneal infiltration, one patient had keratitis, 91 had corneal vascularisation, and 95 patients had corneal deposits. Conclusion. Both the type and frequency of complications related to soft contact lens use in our group of patients, proved to be significant. Some of this complications (keratitis) can significantly damage vision and lead to loss of vision and sometimes can require operative treatment.

scholarly journals The Relationship of Knowledge Level of Installation and Maintenance with the Successful Use of Soft Contact Lens in Myopia patients

2021 ◽  
Vol 15 (6) ◽  
pp. 1562-1564
Author(s):  
Didik Wahyudi ◽  
J Dahjono ◽  
Untung Suparman
Keyword(s):  
Contact Lens ◽  
Contact Lenses ◽  
Refractive Errors ◽  
Soft Contact ◽  
Cross Sectional ◽  
Soft Contact Lenses ◽  
Soft Contact Lens ◽  
Level Of Knowledge ◽  
The Right ◽  
The Relationship

Background: Refractive errors have occurred in many parts of the world, including in Indonesia, with different types of abnormalities, one of which is myopia which can be corrected with glasses and spherical contact lenses. Aim: To determine the relationship between the level of knowledge of the installation and care of soft contact lenses in myopic patients. Methods: This research method is Cross Sectional at Optik Metro, the number of samples is the total population, the research instrument is a questionnaire, the independent variable of this research is the level of knowledge while the dependent variable is the attitude and behavior of Care and Installation with Successful Use of Contact Lenses. This research has been approved by the Widya Husada STIKES Ethics Commission. Results: The results of the study based on the number of sufferers and the distribution of refractive errors at Optik Metro from March 15-20, 2021, showed that the number of myopia patients who came was 13.0% with the type of treatment using soft contact lenses as much as 2.2%. There is a relationship between knowledge and attitudes of respondents with maintenance and installation behavior with successful use of LK with a significance value of 0.000 (p < 0.05). Conclusion: It was concluded that the toric soft contact lens installation procedure was carried out in the right way by taking into account a good fitting assessment. It is necessary to provide education to increase knowledge and education on Care and Installation of Contact Lenses for all customers. Keywords: Knowledge, Attitude, Soft LK, Myopia

scholarly journals Characterization of Soft Contact Lens Edge Fitting during Daily Wear Using Ultrahigh-Resolution Optical Coherence Tomography

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Lele Cui ◽  
Sisi Chen ◽  
Weihe Zhou ◽  
Kaixuan Sheng ◽  
Lei Zhang ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Contact Lens ◽  
Contact Lenses ◽  
Optical Coherence ◽  
Soft Contact ◽  
Ultrahigh Resolution ◽  
Soft Contact Lenses ◽  
Soft Contact Lens ◽  
Lens Wear ◽  
Peripheral Cornea

Purpose. To determine conjunctival overlap over the edge of soft contact lens and to visualize the peripheral postlens tear film (PoLTF) underneath soft contact lenses using ultrahigh-resolution optical coherence tomography (UHR-OCT). Methods. Twenty participants (4 males and 16 females, 23.0 ± 3.7 years) were fitted with two different types of soft contact lenses randomly. The limbus with lens was imaged with the UHR-OCT at the horizontal meridian every two hours up to 6 hours during lens wear. The conjunctival overlap was ranked as the percentage of the edge covered by the conjunctiva. The frequency of occurrence for visualized peripheral PoLTF was determined. Results. The average conjunctival overlaps at insertion were 49% and 73% for galyfilcon A and balafilcon A lenses and increased significantly to 84% and 90% by 6 hours of lens wear (P<0.001). Lenses with rounded edges had more conjunctival overlap than the lenses with angled edges (P=0.014). There were significant decreases for PoLTF on the conjunctiva (P=0.014) and peripheral cornea (P=0.004) over the study period compared to insertion. The percentage of subjects with PoLTF on the conjunctiva (32.5%) and peripheral cornea (36%) were greater in subjects wearing balafilcon A lenses (P=0.017). Conclusions. Increased conjunctival overlap over the lens edges and reduced PoLTF underneath the peripheral region of soft contact lenses were shown during lens daily wear. The lens edge configuration may play a role in conjunctival response and peripheral PoLTF.

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