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At least 217 records · Page 12Linked to original sources
PubMed1998

[Treatment of corneal complications after cataract surgery with soft contact lenses].

PURPOSE: To evaluate results of therapeutic soft contact lenses in treatment of corneal complication after cataract surgery. MATERIAL NAD METHODS: We examined 25 patients (25 eyes) with cataract operated on in the years 1990-1994, who developed corneal complications. All patients were treated with use of soft contact lenses and the effect on healing a cornea was evaluated. We used Bausch & Lomb and Cooper Vision lenses. We qualified for treatment such cases as: bullous keratopathy, marginal infiltration erosion, central ulceration, complicated with perforation and protracted ulceration with no result after pharmacological therapy. Contact lenses were applied for period from 10 days to 6 months. During follow up examinations we evaluated time of healing a cornea, its anatomical condition and function. RESULTS: The best therapeutic result was achieved in 12 cases such as erosions, central ulceration, marginal infiltration, in 7 cases temporary improvement appeared, in 6 no result was observed. Two last groups applied patients with bullous keratopathy. CONCLUSION: Soft contact lenses are valuable methods of treating some corneal disorders, in other cases they may be used during a preparation period before corneal transplantation. The main function of lenses is to protect diseased tissue and help it return to its anatomical and physiological functional state. At the same time they are meant to be the best therapeutic repository for medications.

Aged↗
PubMed2006

Comparison of corneal thickness of long-term contact lens wearers for different types of contact lenses.

PURPOSE: To compare the central corneal thickness (CCT) values of long-term wearers of different types of contact lenses with those of each other and a normal control group. METHODS: Twenty-three healthy eyes with no history of contact lens wear were used for the control group. Forty-eight eyes were evaluated in four different groups according to the type of contact lens worn; each group comprised 12 eyes. Group 1 (SofLens 38) and group 2 (Contact Day 30) had worn daily-wear frequent-replacement soft contact lenses with a 38% and 55% water content, respectively, and they had worn their lenses for an average of 4.28 +/- 1.70 years and 3.71 +/- 1.11 years, respectively. Group 3 (Wöhlk A90) and group 4 (Conflex-air) had worn daily-wear rigid gas-permeable (RGP) contact lenses with a Dk/t value of 68 and 22, respectively, and they had worn their lenses for an average of 3.00 +/- 0.63 years and 3.25 +/- 1.17 years, respectively. CCT values in micrometers were measured by optical coherence tomography. RESULTS: When comparing the CCT between the control group and the contact lens groups, the CCT was significantly thinner in the group wearing Conflex-air RGP contact lenses with a low Dk/t value (P = 0.010). In comparing the CCT among the four contact lens groups, the CCT was significantly thinner in the group wearing SofLens 38 contact lenses with a water content of 38% than in the group wearing Contact Day 30 contact lenses with a water content of 55% (P = 0.004). There was also significant thinning in the group wearing Conflex-air RGP contact lenses versus the group wearing Contact Day 30 soft contact lenses (P = 0.0005). CONCLUSIONS: CCT was significantly thinner in patients wearing long-term low-Dk/t RGP contact lenses compared to no contact lens wear and soft contact lenses with a water content of 55%. CCT was also decreased significantly in long-term soft contact lens wear with a water content of 38% compared to 55%.

Adult↗
PubMed1981

Part II. Clinical evaluation of toric hydrophilic contact lenses.

Five toric hydrogel contact lenses have been approved for marketing by the FDA and several more await final approval in the near future. Clinical use of these special design lenses for correction of astigmatism has increased during the past year, improvements in lens design and fabrication are taking place, but problems remain. Analysis of the reasons for fitting failures show that lens quality and axis mislocation are the primary causes of lens performance failures.

Astigmatism↗
PubMed1998

Masking of irregular corneal topography with contact lenses.

PURPOSE: We examined the effectiveness of various types of contact lenses in masking irregular corneal topography using videokeratoscopy, residual aberrations, and measurement of visual acuity. METHODS: Thirteen subjects with differing degrees of keratoconus were recruited. Four types of soft lenses were used that varied in both thickness and water content, along with a rigid gas permeable (RGP) and a flexible gas permeable contact lens. RESULTS: RGP contact lenses provided the best visual acuity and the least residual aberrations. Flexible gas permeable lenses showed a reasonable masking of corneal distortion but did not provide the expected improvement in visual acuity. Soft contact lenses provided marginally better visual acuity than spectacle correction, but the level of residual aberrations was still high, even for relatively thick soft lenses (up to 0.2 mm). A significant correlation existed between the regularity of the front surface of the contact lenses on the eye and visual acuity in low illumination. CONCLUSIONS: Among the currently available contact lens materials, RGP lenses provide the best visual performance for subjects with keratoconus.

Adult↗
PubMed1986

Release of therapeutic agents from contact lenses.

Drug release from contact lenses was studied by a technological approach. Different parameters such as introduction of drug into the lenses, release, hydration level, molecular weight of drugs, kinetics of release, and clinical tests were reviewed. Therapeutical benefits of this kind of dispensation was taken up. The actual inadequacies from the techniques used must be palliated by publication of new performance technologies that are studied today.

Adrenergic beta-Antagonists↗
PubMed1992

A pig model of Acanthamoeba keratitis: transmission via contaminated contact lenses.

A model of contact lens-induced Acanthamoeba keratitis was developed in Yucatan micropigs. Pigs fitted with parasite-laden soft contact lenses developed corneal infections that clinically and histopathologically mimicked the human counterpart. Three distinct stages of disease became apparent and were categorized as: acute, condensed infiltrate, and resolution stages. Viable parasites were isolated from corneal scrapings and smears were taken during the acute and condensed infiltrate stages. In addition, cysts could be identified deep within the stroma of histological specimens taken during the resolution stages. The characteristic dense, white ring-like infiltrates, stroma edema, keratic precipitates, and the chronic nature of the infections were similar to those observed in human Acanthamoeba keratitis. Histopathological examination of infected corneas revealed extensive neutrophilic infiltrates, stromal necrosis, and disorganization of the collagen lamellae. The strong correlation between the clinical and histopathologic features of contact lens-induced Acanthamoeba keratitis in the pig as well as the anatomical similarity of the pig eye with the human eye make the porcine model a valuable tool for investigations of the immunology, cell biology, and therapy for Acanthamoeba keratitis.

Acanthamoeba↗
PubMed1998

Surface deposits on frequent replacement and conventional daily wear soft contact lenses: a scanning electron microscopic study.

PURPOSE: We performed a prospective study to compare the surface deposits on frequent replacement soft contact lenses with deposits on conventional daily wear soft contact lenses. METHODS: We fit two groups of young myopic patients with either conventional daily wear or frequent replacement soft contact lenses. Subjects in both groups wore their lenses on a daily wear basis and used a hydrogen peroxide/catalytic disk based care system. Contact lenses were obtained from patients in the frequent replacement group after 1 month of wear and from the conventional contact lens group after 12 months. Contact lenses from each group were examined with scanning electron microscopy and surface deposits were compared. RESULTS: Frequent replacement lenses were covered with significantly fewer deposits than conventional daily wear soft contact lenses (P = 0.0003). No microorganisms were seen on frequent replacement contact lenses. Bacteria in the form of coccus on two contact lenses were seen in the other group. CONCLUSIONS: Surface deposits occur less often on frequent replacement lenses but they cannot be totally prevented. Surface deposit related contact lens complications may be expected to occur less frequently with the use of frequent replacement lenses.

Adolescent↗
PubMed1990

Hazards of contact lenses used by workers.

The hazards of contact lenses used by workers have been addressed by many articles and warnings from safety experts for the past twenty years. An "accident" which occurred in Baltimore, MD, USA in 1967 with a welder set off a worldwide epidemic of rumours, coming in waves from the USA, spreading throughout Europe and most notably in France since 1982. The thorough study of the "Baltimore Case" and other similar incidents by the authors, along with the recent experimental studies permit the elimination of the possible appearance of severe consequences for workers, such as arc welders, who wear contact lenses in the workplace. However the consequences of wearing contact lenses in some jobs are not yet well enough known, and a French study group looking into this problem would be ready to communicate with concerned individuals who wish to share their experience.

Accidents, Occupational↗
PubMed1997

Microbial contamination of hydrogel contact lenses.

Bacterial contamination of contact lenses (CLs) may contribute to CL-related corneal infection and inflammation. This study reports CL biota over time during daily and extended wear. Microbial contamination of a 58% water, ionic hydrogel CL and a 38% water, non-ionic hydrogel CL was evaluated in an Australian and an Indian population. Fifty wearers were repeatedly sampled over 18 months. Overnight CL use did not alter the frequency of positive cultures, nor the spectrum of organisms compared with daily CL wear. There were no differences in type and frequency of CL contamination between the CL types. Positive cultures were more frequently recovered from the Indian population compared with the Australian population. Streptococcus spp. and Propionibacterium spp. were more frequently isolated from the Australian population. Fungi and Bacillus spp. were more frequently isolated from the Indian population. Normal CL biota alone cannot explain the increased rate of infection and inflammation in extended wear.

Bacillus↗
PubMed1989

[Use of soft contact lenses after scleroplasty surgery for myopia].

Authors refer their favourable experiences with the application of soft contact lenses used after the performed scleroplastic operation described by Pivovarov. Soft contact lenses were applied in 54 patients where myopia was operated. In 90% of patients the daily use of contact lenses was more than 8 hours. These patients tolerated the contact lenses even better than the patients with myopia but without operation. Compared with the correction with spectacles, the visual acuity was significantly increased in the group using the contact lenses. The visual acuity 6/6-6/9 was achieved in the group of contact lenses wearers in 63% and in the group of patients using spectacles was present only in 29%. In all patients wearing the contact lenses their specific working activity was distinctly enhanced. The modest scarring of the conjunctive as well as presence of implants does not interfere with the contact lens wear, when the myopic operation was carefully performed.

Adolescent↗
PubMed1994

Contact lenses and collagen shields.

Contact lenses may change the topography of the eye of asymptomatic patients. Complications continue to occur requiring extreme attention to be paid to fitting techniques, care instructions, and follow-up. All physicians must be alert to complications. Early diagnosis and treatment are essential. The pediatric aphakic patient and the presbyopic contact lens wearer present a challenge. The contact lens fitter must understand the way these lenses function to fit patients more successfully. Collagen shields may be of some benefit in cataract surgery and symblepharon, but may exacerbate the effects of alkali burns on the eye.

Collagen↗
PubMed1982

Flurbiprofen in the treatment of corneal neovascularization induced by contact lenses.

Cellulose acetate butyrate extended-wear contact lenses were fitted bilaterally on ten New Zealand albino rabbits. We administered flurbiprofen 0.03% solution topically to the experimental eyes and vehicle solution to the contralateral control eyes four times a day in a random, masked fashion beginning 24 hours before the contact lens was fitted. Corneal neovascularization, which developed in all eyes by the 25th day of contact lens wear, was significantly suppressed by flurbiprofen treatment (mean vessel length was 1.5 +/- 0.4 mm for the treated eyes and 3.0 +/- 0.3 mm for the control eyes; P less than .005). Topical administration of a noncorticosteroidal anti-inflammatory agent may be an effective treatment for corneal neovascularization induced by contact lenses.

Administration, Topical↗
PubMed1985

Contact lenses in hypoxia.

Seven women with soft contact lenses were examined during a 4 h period in a decompression chamber. The atmospheric pressure was lowered from the normal value of 1000 millibars (750 mmHg) to 560 millibars (420 mmHg), which corresponds to the altitude of 4000 m above sea level. The humidity, temperature, percentage of carbon acid and illumination were attempted to be kept even. Five test subjects developed subjective, and all the 7 also developed objective eye symptoms. It was concluded that hypoxia itself may cause eye discomfort for aircraft passengers with contact lenses. The most serious objective findings were corneal erosions in 3 and opacities of corneal stroma in 5 test persons. The control group without contact lenses did not develop any symptoms during the test.

Adult↗
PubMed2001

Microbiological profile of a shipboard environment and the flora on contact lenses of seamen.

PURPOSE: The purpose of this study was to culture and identify the spectrum of organisms (and their sensitivities) that contaminate the extended wear contact lenses of seamen in their working environment. A secondary aim was to identify the most appropriate first-line antibiotic regimen to be used on seamen who sustain contact lens-related corneal keratitis on board ship. METHODS: Twenty pairs of contact lenses of 20 seamen in one group and 24 pairs in another group wearing contact lenses were collected at the end of 1 week of extended wear. Groups one and two differed only in the way lenses were stored prior to culturing. All contact lenses were then brought to the microbiological lab within 24 hours for culture and sensitivity testing. RESULTS: The most common contaminants on the contact lenses in this study were Staphylococcus epidermidis and Staphylococcus aureus, organisms resident on the normal eyelids. Enterobacterand Pseudomonas species, present in a shipboard environment, were also identified as contaminants on the contact lenses. The organisms cultured from the contact lenses correlated well with those of normal lid flora as well as from the ship environment and are probably derived from these sources. Storage in saline-containing preservatives yielded significantly less positive bacterial cultures from the contact lenses in our study. All bacterial isolates were sensitive to ciprofloxacin whereas several bacteria resistant to cefazolin and gentamicin were identified. CONCLUSION: The most common contaminants on the contact lenses in this study were Staphylococcus epidermidis and Staphylococcus aureus, organisms resident on the normal eyelids. Enterobacter and Pseudomonas species, which are normally present in a shipboard environment, were also identified as contaminants on the contact lenses. Ciprofloxacin is effective against all organisms identified as contaminants on the contact lenses in this study. Of all the antibiotics tested, it is probably the most suitable agent against contact lensrelated keratitis under such shipboard circumstances and is thus recommended in these situations.

Anti-Infective Agents↗
PubMed1992

Task and visual performance with contact lenses and spectacles.

Previous studies found task and vision performance differences between presbyopic contact lens corrections and distant contact lenses combined with reading spectacles. The present study was designed to compare task and vision performance with single vision contact lenses and spectacles. Eighteen soft (SCL) and seventeen rigid gas permeable (RGP) successful contact lens wearers were examined and fitted with CR-39 spectacles (SPEX) which corrected their distance vision. Their occupational task performance and visual acuity (high contrast, low contrast, low contrast with glare) were measured while they wore their contact lenses and spectacles. The tasks included putting pointers in straws, filing cards in a box, counting letters on a photograph of a VDT screen, and a distance/near fixation task. Visual acuity scores were lower with SCL than with SPEX. Low contrast visual acuity with glare was reduced by 1.36 letters on a 5-letter row (p less than 0.05) for SCL compared to SPEX. No statistically significant differences in performance times were measured between contact lenses and spectacles. None of the error performance differences were statistically significant; however, more errors were made on each occupational task with soft contact lenses compared to spectacles. The findings suggest nearly equivalent task and visual performance with properly prescribed RGP contact lenses and spectacles, and minimal performance decrements with SCL compared to spectacles.

Adult↗
PubMed2004

[Correction of refractive errors in children with contact lenses].

PURPOSE: To appreciate the indications, complications and visual outcomes in the correction of refractive errors with contact lenses at children. MATERIAL AND METHOD: We studied 15 eyes from nine kids. The times prescription included: history (motivation of wearing contact lenses), ocular refraction (with cycloplegia), best corrected visual acuity, keratometry, the corneal diameter, slit lamp examination, the selection of contact lens and follow up. RESULTS: The age of patients varied between several months to twelve years. The refractive errors in which we used contact lenses were: aphakia--6 eyes, myopia--6 eyes, hyperopia--3 eyes. The types of contact lenses were for permanent use--8 eyes and discontinuity use--7 eyes. We didn't have any major complication. The best corrected visual acuity with contact lenses was: 0.1-0.3 at 4 eyes, 0.4-0.6 at 2 eyes and one at 7 eyes. CONCLUSIONS: (1) Contact lenses represent the optimal correction of anisometropia after congenital or traumatic cataract operation in children. (2) The quality of vision obtained with contact lenses represents an important factor in the prevention and treatment of amblyopia.

Child↗
PubMed2001

Visual performance of rigid gas permeable contact lenses in patients with corneal opacity.

PURPOSE: To evaluate the visual performance of rigid gas permeable (RGP) contact lenses in patients with nebular and nebulo-macular corneal opacity and correlate the improvement in visual acuity with other visual parameters. METHODS: In a prospective study, visual performance of RGP contact lenses was evaluated in eyes with corneal opacity involving the pupillary area. The baseline visual acuity and other visual parameters with glasses were compared with those recorded with RGP contact lenses. The visual functions evaluated were visual acuity, contrast sensitivity, glare acuity, and mesopic vision. Binocular status with RGP contact lenses was assessed. All patients were followed up for 3 months. RESULTS: Twenty-eight eyes (26 patients) with nebular or nebulo-macular corneal opacity were included in this study. All eyes (100%) achieved significantly better visual performance with RGP contact lenses than with glasses (P< 0.0020). Visual acuity of 6/9 or better was achieved in 50% of patients with RGP contact lenses compared to none with glasses. RGP contact lenses improved the visual acuity by 0.27 decimals over the baseline value with glasses, butthe improvement for mesopic vision and glare acuity was significantly lower at 0.15 and 0.06 decimals respectively. Similarly, contrast sensitivity did not improve to the same extent as visual acuity. Stereopsis was present only in patients with best corrected visual acuity of 6/9 or better with RGP lenses. CONCLUSION: RGP contact lenses improved the visual acuity and other visual performance in patients with reduced vision due to nebular or nebulo-macular corneal opacity. However, contrast sensitivity, glare acuity, and mesopic vision did not improve to the same extent as visual acuity.

Adolescent↗
PubMed1999

Comparison of contrast sensitivity in different soft contact lenses and spectacles.

PURPOSE: To compare the visual performance of soft contact lenses and spectacles. METHODS: Twenty eyes of ten patients were examined. Each patient was fit with Acuvue, Cibasoft, and Biomedics contact lenses in random order. LogMar visual acuity and contrast sensitivity using the VectorVision CSV-1000 were measured. RESULTS: There was no significant difference in visual acuity between any contact lenses (P=.15). Contrast sensitivity at 12 cycles/degree was significantly lower for the Cibasoft lens compared to spectacles (P=.04). There was no significant difference between spectacles and contact lenses for remaining spatial frequencies (P=.07-.35). CONCLUSIONS: Visual acuity appears to be an insensitive method for evaluating soft contact lenses. The lathe-cut manufacturing process may be responsible for reduced visual function compared to cast-molded lenses. Further study in this area is needed.

Adult↗