A retrospective study of disposable extended wear lenses in 100 patients: year 2.

We present the results of the second year of follow-up of 100 patients wearing disposable contact lenses on an extended wear basis. Thirty-seven males and 63 females participated in the study (mean age: 41.1 years +/- 13.88 (mean +/- 1 standard deviation); and the mean patient follow-up time was 26 months +/- 4.9). A total of 13 patients were lost to follow-up. Seventeen patients discontinued extended wear yet continued to wear soft lenses on a daily wear basis--the reasons for this finding are discussed. A significant decrease in the number of events defined as complications (32 events) was noted when compared to the first year of follow-up (136 events). Seven corneal infiltrates occurred during the second year, compared to 6 such events during the first year of the study. Additional complications included: giant papillary conjunctivitis (6 cases), corneal staining (5 cases), and corneal abrasions (4 cases). Disposable extended wear soft contact lenses offer a reasonable means of vision correction in the properly selected patient. At the same time, caution should be exercised in the fitting and wear of these lenses.     

Complications of disposable extended-wear contact lenses. Apropos of 6 cases]

We report six cases of corneal complications observed in disposable extended-wear contact lens users: two corneal ulcers, one superficial infiltrate, two punctate keratitis with subepithelial infiltrates and one superficial punctate keratitis. In four cases a bacterial etiology was confirmed. Disposable contact lenses are not complication-free. In our series, complications were favoured or provoked by incorrect use in most cases. Other possible risk factors include poor hygiene during lens manipulation, damage to the corneal epithelium during lens exchange or lens wear, use of contaminated lubricant eyedrops, relative corneal hypoxia during overnight wear or in the case of improper fitting. Correct and adequate patient information is therefore essential to ensure that these lenses constitute a safe choice.     

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.     

The risk of microbial keratitis with daily-wear and extended-wear use of disposable lenses

A pilot case-control study indicated an excess risk of microbial keratitis (MK) with disposable soft contact lenses (DSCL). A larger case-control study was conducted to separate the risks associated with daily-wear (DW) and extended-wear (EW) use of DSCL, and to determine whether there is an excess risk associated with the lenses after controlling for other variables.
Contact lens (CL) wearers presenting as new patients to Moorfields Eye Hospital Casualty over 12 months completed a questionnaire detailing CL use and hygiene practices. Cases were patients with presumed MK, according to established clinical criteria. Controls were patients attending with disorders unrelated to CL wear. Relative risks were calculated using conventional soft lenses (SCL) as the referent, and multivariable analysis was performed. DW and EW patients were analysed separately.
Among SCL wearers there were 89 cases, and 566 controls. Multivariable analysis confirmed a statistically significant increased risk with DSCL among both DW (×3.5) and EW patients (×4.8).
This study shows that, despite the proven reduction in less serious complications with the disposable regimen, there is an increased risk of MK with both DW and EW DSCL, even after controlling for other variables. Although patient and practitioner factors may contribute to these risks, it is likely that properties of some DSCL are partly responsible and require further investigation.     

Immunologic effects of extended-wear contact lenses

All worn contact lenses are coated with materials from the tear film and the environment. Antigens are included in this complex and ever-present coating on the front and back surfaces of the worn contact lens. These deposited materials lead to insult of the conjunctival surface that influences mucus production and conjunctival-related comfort in the wearing of contact lenses.     

Association of Pseudomonas aeruginosa and Serratia marcescens with extended-wear soft contact lenses in asymptomatic patients.

PURPOSE: To isolate and identify aerobic bacteria, particularly gram-negative species associated with the use of extended-wear (EW) soft contact lenses. METHODS: Extended-wear contact lenses were collected, using aseptic technique, from the eyes of individuals after 30 days of extended wear (5-7 day intermittent periods) and were examined for adhered aerobic bacteria. RESULT: Coagulase-negative staphylococci (CoNS) were isolated from 74% of the lenses. Serratia marcescens was found at an incidence of 10% and Pseudomonas aeruginosa at an incidence of 6%. CONCLUSION: The presence of species of bacteria, including P. aeruginosa and S. marcescens, that have been associated with daily wear soft contact lenses, solutions, and cases also appear to be associated with EW lenses.     

Microbiological study of disposable soft contact lenses after photorefractive keratectomy.

PURPOSE: To evaluate the bacterial contamination of bandage disposable soft contact lenses used in patients following photorefractive keratectomy (PRK) and to correlate our findings with clinical data. METHODS: Forty-six patients (81 eyes) underwent PRK. Immediately after each procedure, disposable soft contact lenses were positioned with sterile forceps. After 3 days, the lenses were removed in a sterile manner, placed in sterile Eppendorf pipettes containing 8 mL of enriched brain heart infusion broth, and analyzed for microbial contamination. RESULTS: Seven positive cultures were found: six gram positive cocci (7.4%) and one gram negative bacillus (1.2%). There was no clinical correlation with these findings. CONCLUSION: Isolated microorganisms were similar to those described in the literature as agents of bacterial keratitis and are components of the normal ocular flora. Klebsiela pneumoniae--considered an occasional or transient flora--was the exception. All isolated microorganisms but K. pneumoniae were sensitive to most of the antibiotics tested. Our findings suggest that the risk of infectious keratitis after PRK related to soft contact lens wear for 3 days seems to be low, which may be because lenses were not manipulated by the patient during the wearing period, and the postoperative antibiotic regimen was strictly followed by patients. However, care should be taken to instruct patients in proper lens care practices to reduce the risk of bacterial keratitis in contact lens wear following PRK.