Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “CONTACT LENSES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMedDate not supplied

Therapeutic uses of contact lenses.

Therapeutic use of contact lenses is an essential element in ophthalmic care. Materials currently in use include polymethyl methacrylate (PMMA), cellulose acetate butyrate, siloxane-containing polymethacrylates, silicones, and hydrogels. Suitability of a material for therapeutic contact lens use is determined by the physical, chemical, and mechanical properties (notably gas permeability and hydrophilicity, but also lipid absorption and lens movement, among others) and the condition to be treated; fabrication techniques are likewise important, affecting lens diameter and base curve. Selection and fitting of therapeutic contact lenses requires knowledge of how different contact lenses affect corneal physiology, as well as an understanding of the mechanisms whereby a contact lens can be therapeutic. In addition to these topics, general fitting guidelines are discussed, and results of therapeutic lens use in selected clinical situations (including recurrent erosion, metaherpetic ulcers and other epithelial defects, and keratitis sicca, and other dry eye states). Common therapeutic contact lens complications and their treatment are also discussed.

Contact Lenses↗
PubMed1991

Contact lenses following keratoplasty.

Bandage contact lenses can be used following keratoplasty to protect the ocular surface and promote epithelial healing. Rigid gas permeable contact lenses are indicated to correct irregular astigmatism and anisometropia. The Rotterdam Eye Hospital fit 77 keratoplasty patients with contact lenses following their surgery. The methods of fitting contact lenses over the irregular or highly astigmatic surface of a graft are discussed.

Anisometropia↗
PubMed1976

Tissue culture studies of contact lenses.

Standard methylmethacrylate hard contact lenses and several available soft (HEMA) contact lenses were studied in tissue culture using secondary rabbit kidney cells. No toxic constituents were found but the cells were readily destroyed by a keratoprosthesis which was found to be toxic in culture. The tissue culture technique should assist in determining which plastics are most suitable for in vivo use and make conclusions concerning mechanical or metabolic effects of lenses more meaningful.

Animals↗
PubMed2004

The influence of lens conditioning on signs and symptoms with new hydrogel contact lenses.

BACKGROUND: Daily disposable contact lenses are considered to be the pinnacle of safe contact lens wear, yet it has been suggested that it takes some period of wear for the lens surface to reach optimal compatibility with the ocular surface. This study assesses the influence of brief treatment with a conditioning drop on the ocular response to new contact lenses over a single day of wear. METHODS: The study was a single-masked, paired (contralateral) comparison of the signs and symptoms with wear of new Acuvue 2 contact lenses pretreated with a conditioning agent containing carboxymethylcellulose (carmellose, CMC) against new lenses inserted directly from the blister pack. Sixty-one subjects participated in the study, of whom 59 were considered eligible for data analysis. Subjects were also divided into symptomatic and asymptomatic lens wearers based on their overall comfort level in lens wear. Symptoms and signs were recorded at lens delivery and following eight hours of wear. RESULTS: A set of slitlamp signs, comprising corneal staining (p <0.05), limbal redness (p <0.05), bulbar conjunctival hyperaemia (p <0.05), bulbar conjunctival staining (p <0.01) and palpebral conjunctival redness (p <0.05) showed small but statistically significant (p <0.05) end-of-day mean values in favour of the lens that was conditioned with the rewetting agent. These data were supported by the proportion of subjects showing lower gradings with conditioned lenses versus unconditioned lenses, as follows: corneal staining (35 per cent versus 12 per cent, p <0.05), limbal redness (43 per cent versus 22 per cent, p <0.05), bulbar conjunctival hyperaemia (50 per cent versus 15 per cent, p <0.05), bulbar conjunctival staining (46 per cent versus 30 per cent, p <0.1) and palpebral conjunctival hyperaemia (28 per cent versus 17 per cent, NS). For those subjects reporting symptoms with lens wear (n=12), there was a statistically significant (p <0.05) preference in terms of comfort as a result of preconditioning. CONCLUSIONS: The results of the investigation suggest that use of a conditioning agent can provide a more physiologically suitable environment for a new lens, thereby reducing the clinical signs associated with lens discomfort. The protocol used here, which is based on a statistical paradigm using standard pictorial grading scales, allows high sensitivity in detecting small changes in ocular parameters.

Adult↗
PubMed1992

Contact lenses and corneal shields.

Contact lenses are widely used all over the world. If fitted and handled properly, contact lenses can be good cosmetic and therapeutic tools. In this review, the different indications for contact lens wear are discussed. Contact lenses can also lead to serious problems. Tear film and morphologic alterations of the cornea, as well as corneal infections of microbial origin, are reviewed. Collagen bandage lenses have been used for some time in the treatment of corneal epithelial defects. Currently, these lenses are being tested as drug delivery systems, especially for use with poorly penetrating drugs, in serious infections of the cornea.

Collagen↗
PubMed1993

Contact lenses and corneal shields.

Contact lens wear has been associated with a wide spectrum of corneal complications. Disposable contact lenses have not eliminated the problem of corneal ulcers associated with extended-wear contact lenses. Rigid, gas-permeable extended-wear lenses may be considered as an acceptable alternative to extended wear of soft contact lenses. Collagen corneal shields are a clinical indicator of collagenase activity on the ocular surface and serve as a collagenase inhibitor.

Collagen↗
PubMed1983

Intraocular lenses versus extended-wear contact lenses in aphakic rehabilitation. A controlled clinical study.

A controlled clinical study with random allocation of method of rehabilitation (lens implant or contact lenses) was designed for comparative outcome assessments. Sixty-one patients were included in the study: 31 patients randomized to lens implantation and 30 patients to extended-wear contact lens rehabilitation with early post-operative fitting. Complication rates were low in both groups with slight accumulation of intraocular complications in the implant group and of external complications in the contact lens group. We found no significant differences between the groups in final visual acuity, in vision dependent practical functioning, or in patients' contentment. Two main points summarize our results and impressions from this study: At the expense of a slightly higher risk the lens implant patients get the most convenient and comfortable rehabilitation and at the expense of frequent visits for follow-up and lens cleaning the contact lens patients get the safest rehabilitation. The patient offered contact lens rehabilitation should be capable of alert cooperation, fairly mobile and living within easy access to ophthalmic service, while the patient offered lens implant does not need to fulfill these criteria.

Aged↗
PubMed2004

[Bringing back scleral contact lenses].

PURPOSE: Although old generations of scleral contact lenses were totally replaced by soft and hard contact lenses, new designs and materials have recently allowed the successful use of nonfenestrated scleral contact lenses in patients who are intolerant to regular contact lenses. These new scleral contact lenses form a bridge over the cornea, which is thus permanently bathed in a saline reservoir. METHODS: Retrospective study in patients suffering from corneal diseases altering the vision and/or responsible for ocular discomfort, and who are intolerant to conventional contact lenses. RESULTS: Fifteen eyes (10 patients) were fitted with specially designed scleral contact lenses. The mean follow-up was 16 months (range, 1-31 months). The scleral lenses were indicated for optical and/or therapeutic reasons: keratoconus (3 eyes), corneal grafts (7 eyes), refractive surgery (2 eyes), corneal dysplasia (2 eyes), and Stevens-Johnson syndrome (1 eye). Optical results and tolerance were excellent except for one eye. CONCLUSION: New nonfenestrated scleral contact lenses provide a good alternative for patients who are intolerant to conventional contact lenses.

Adult↗
PubMedDate not supplied

[Use of rigid gas permeable contact lenses].

By application of contact lenses destined for a extended wearing, for preservation of a normal structure and metabolism of the cornea a considerable permeability of the contact lens for oxygen is necessary (Dk/L 75-80). The actually most popular in the world soft contact lenses have no such parameters. The application of rigid lenses produced from materials of high permeability for oxygen enables the extended wearing without substantial disturbances of the corneal metabolism. The paper presents a new generation of fluoro-silicone acrylates used for the production of contact lenses permeable for oxygen. Discussed are the problems connected with the adjusting of these lenses, their tolerance and influence on the corneal metabolism.

Acrylates↗
PubMed1991

Contact lenses after corneal lacerations.

Contact lenses were fit after traumatic corneal lacerations in 30 eyes (28 patients). Twenty-eight of the eyes (93%) were aphakic. Twenty-two of the 30 eyes (73%) wore the contact lens successfully (average follow-up 22 months). The visual acuity with the contact lens was 20/40 or better in 25 eyes (83%). In 13 eyes (43%) the final contact lens fit was a rigid gas permeable lens, with a daily wear soft contact lens as the final lens in 17 eyes (57%). The eight failures included four patients who were contact lens intolerant, two who had binocular diplopia, and two who lacked motivation. All but one of 12 (92%) small corneal lacerations (less than 3 mm) were successfully fit with contact lenses. Eleven out of the 13 (85%) central large lacerations, but none of the five large peripheral lacerations could be successfully fit with a contact lens. Three of the 30 eyes (10%) developed late retinal detachments. Contact lenses are successful in the majority of patients referred after corneal lacerations, but fitting these patients is challenging and time consuming.

Adolescent↗
PubMed1979

Oxygen-transmitting hard contact lenses.

Nine PMMA contact lens wearers with persistent corneal edema were refitted with CAB contact lenses. All of the patients showed less corneal swelling with CAB lenses than with PMMA lenses.

Acetates↗
PubMed2003

The correction of astigmatism with soft contact lenses.

Soft contact lens correction for astigmatism has made significant advances over the last 20 years. Soft toric tinted lenses, disposables lenses, and bifocal lenses are now available at lower costs with greater reproducibility, enhanced parameters, and better comfort. Because of these innovations and significant design changes, a greater percentage of astigmatic patients are being treated with soft toric lenses than before.

Astigmatism↗
PubMed1995

Aberrations associated with rigid contact lenses.

A rigid contact lens on an eye can produce levels of spherical aberration very different from those produced by a spectacle lens in front of the eye. These levels are considerably affected by contact lens surface asphericity. Change in longitudinal spherical aberration associated with aspherizing a contact lens surface is well predicted by a simple equation for change in sagittal power of the surface. Displacing an aspheric contact lens on the eye can produce considerable defocus, which is well predicted by simple equations for change in sagittal and tangential surface powers. The best refractive correction with contact lenses can be determined only by overrefraction with a patient wearing a contact lens of power and characteristics similar to that which will be prescribed. An aspheric contact lens that moves to a considerable extent on the eye will cause more unstable vision than will a spherical lens that moves to the same extent.

Contact Lenses↗
PubMed2003

Disposable and frequent replacement contact lenses.

Disposable and frequent replacement contact lenses dominate the marketplace. They are available in a wide variety of parameters for use in refractive errors, including myopia, hyperopia, astigmatism, and presbyopia. They are convenient and affordable and lend themselves to most wearing modalities, including daily wear, flexible wear, and extended wear for up to 30 days. In addition, they have been shown to be the most trouble-free contact lens wear modality for daily wear or extended wear. They are an appropriate choice for patients who desire occasional contact lens wear and have gained wide acceptance as therapeutic bandage contact lenses. Disposable and frequent replacement lenses will remain important modalities for some time to come as the variety of contact lenses and contact lens parameters that are offered continue to expand. New contact lens varieties, such as the high-Dk silicone hydrogel lenses, will further expand the role of these contact lenses in vision correction.

Contact Lenses↗
PubMed1978

[Complications due to soft hydrophilic contact lenses].

Soft hydrophilic contact lenses are widely favored thanks to their minimal ocular irritation. They may, however, also cause severe eye disease. In this report, allergies, hypoxia, tear film alterations, toxic effects and infections, as caused by soft lenses, are described, and their diagnosis, differential diagnosis and prophylaxis discussed. Moreover, it is pointed out that a misdiagnosis of "contact lens intolerance" may have serious consequences.

Bacteria↗