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Purpose To evaluate silicone-hydrogel balafilcon A (PureVision, Bausch & Lomb Inc., Rochester, NY) contact lenses worn on a 30-day continuous wear basis when compared with a traditional hydrogel (Acuvue, Vistakon, Johnson and Johnson Vision Products, Inc., Jacksonville, FL) worn on a 7-day extended wear schedule. Design Prospective, comparative, paired-eye, interventional, multicenter clinical trial. Participants Two hundred twelve ametropes with no significant ocular pathology. Methods Subjects with normal ocular health who conformed to a set of standard criteria were monitored at seven different sites around the globe. Subjects wore both study lenses simultaneously, one on each eye. Lenses were assigned to right and left eyes according to a randomized schedule. The silicone hydrogel was removed and replaced every month and the traditional hydrogel was removed every 7 days and replaced at 14-day intervals. Subjects were followed for up to 1 year with discontinuation on indication divided between lens-related causes, unrelated factors, and loss to follow-up. Main outcome measures Discontinuations, symptoms, vision, lens fit, lens surface assessment, slit-lamp assessment, and patient preferences. Results One hundred twenty three subjects completed the 12-month wearing period. There were no vision-threatening events with either lens type. The silicone-hydrogel lenses showed statistically superior performance in physiologic terms with regard to epithelial microcysts, striae, corneal staining, limbal injection, and bulbar injection. Inflammatory reactions, such as corneal infiltrates and tarsal conjunctival abnormalities occurred at similar rates between the lens types. Visible deposition and postlens debris with associated transient corneal indentation were significantly lower with the traditional hydrogel material at specific time points in the study. Visual acuity was comparable with the two lens types. Subjects rated the silicone-hydrogel material as preferable on subjective scales of dryness, comfort, and lens handling. Overall subjective performance was rated superior with the silicone-hydrogel material. Conclusions The high oxygen performance of the silicone-hydrogel lenses provides a superior physiologic environment compared with a traditional hydrogel material during continuous wear. Despite the slightly higher levels of visible deposit on the silicone-hydrogels, superior subjective responses suggest that the plasma coating technology on these lenses is effective in providing comfortable lens wear. The results look promising for the success of silicone-hydrogels as the material of choice for continuous wear contact lenses.

Objective To determine effects of lens type and oxygen transmissibility on human corneal epithelium during extended wear (EW). Design Prospective, randomized, double-masked, single-center, parallel treatment groups, 1-year clinical trial. Participants One hundred seventy-eight patients completed the study: (1) high-O 2 soft lens (6-night [N] EW) (n = 27); (2) hyper-O 2 soft lens (6N-EW, n=33) or (30N-EW, n=66); and (3) hyper-O 2 rigid gas-permeable lens (RGP) (30N-EW, n=52). Intervention Irrigation chamber to collect exfoliated corneal surface cells, confocal microscopy, and tear collection at baseline, 1, 3, 6, 9, 12 months of EW. Main outcome measures (1) Pseudomonas aeruginosa (PA) binding to exfoliated corneal surface cells; (2) central epithelial thickness; (3) superficial epithelial cell area; (4) epithelial surface cell exfoliation; and (5) tear lactate dehydrogenase. Results Quantitative evidence demonstrated increased binding of PA to human exfoliated corneal epithelial cells during the first 3 months of soft lens EW; the control high-O 2 test lens showed significantly higher bacterial binding ( P P 2 soft lens for all outcome measures. Importantly, hyper-O 2 RGP lens wear did not show significantly increased PA binding during 1 year. Conclusions This study establishes three important new findings: (1) hyper-O 2 soft lens EW produces significantly less PA binding than the lower O 2 soft lens with no significant difference in PA binding with 6N versus 30N EW of the hyper-O 2 soft lens; (2) there is a remarkable adaptive recovery after 6 months with all soft lens wear with gradual return to prelens PA binding levels and partial recovery of other outcome measures for all test lenses EW except surface cell size; (3) 30N EW of the hyper-O 2 RGP lens produced no significant increases in PA binding over 1 year. Taken together, these results suggest that introduction of new hyper-O 2 transmissible lens materials into clinical use may offer safer EW, and future epidemiologic studies of ulcerative infectious keratitis should consider both lens type and time in lens EW in any incidence/risk analysis.

Objective To explore the impact of eye closure and soft contact lens extended wear (SCLEW) on epithelial permeability to fluorescein (P dc ). Design A prospective cohort study. Participants Thirty-one noncontact lens (CL) wearers participated. Intervention The effects of eye closure on P dc were evaluated by comparing morning (am) and afternoon (pm) measurements on non-CL subjects. The effects of SCLEW on P dc were determined by measuring P dc before beginning SCLEW and then after 2, 4, and 12 weeks of SCLEW. Main outcome measures P dc measured in the morning versus the afternoon and before versus after SCLEW was examined. Results Analyses of P dc were done using the natural logarithm (In). The mean ± standard error (SE) In(P dc ) measured in the am versus pm on 16 non-CL wearers did not differ significantly (−2.56 ± 0.16 vs. −2.69 ± 0.15, respectively; P = 0.46). In contrast, the mean ± SE ln(P dc ) in 15 subjects after 2 (−1.73 ± 0.183, P P P = 0.02) of SCLEW was substantially greater than that measured before lens wear (−2.42 ± 0.159 ln(nm/sec)). Interestingly, the mean ± SE In(P dc ) measured in the afternoon on seven subjects after 13 weeks of SCLEW was similar to their average baseline In(P dc ) (−2.62 ± 0.27 vs. −2.52 ± 0.243, respectively; P = 0.54). Further analysis showed that P dc was highest in the morning and decreased approximately 12.5%/hour ( P Conclusions Sleeping without CLs does not appear to alter P dc ; however, 2 weeks of SCLEW caused a 99% increase in permeability without observable changes by slit-lamp examination. Increases in P dc appear greatest in the morning after SCLEW and then decrease exponentially during the day. Whether changes in P dc will predict CL-associated keratopathy needs further study.

A retrospective evaluation of 100 patients who wore disposable extended-wear contact lenses is presented. The patients were selected at random and were fitted with one of three lens brands approved for extended wear. There were 37 males and 63 females in the study. The mean age was 40.1 years (range, 14 to 76 years). Sixty-seven of the patients wore nondisposable extended-wear soft contact lenses before being fitted with disposable lenses. Complications were noted and included two instances of infectious ulcerative keratitis and six cases of peripheral corneal infiltrates. It is believed that the rate of complications is due to the ongoing hypoxic effect of prolonged use of extended-wear or other contact lenses and may be improved by providing a greater variety of lens fitting parameters. Disposable extended-wear lenses may be a reasonable means of vision correction in the appropriately selected patient and with proper follow-up. At the same time, caution should be exercised in the fitting and wear of disposable extended-wear lenses.

The authors studied the adherence of Pseudomonas aeruginosa and Staphylococcus aureus to extended wear soft contact lenses (EWSCLs) with and without focal deposits using both a radiolabeling technique and electron microscopy. P. aeruginosa showed significant adherence to contact lenses in vitro. In contrast, S. aureus failed to show significant adherence to contact lenses in vitro (i.e., the radioactive uptake was not significantly above background). The extent of adherence of Pseudomonas was proportional to the number of focal deposits on the lenses. Results of electron microscopic examination showed the bacteria to be adherent primarily to large focal deposits (greater than or equal to 150 microns). There was no pseudomonal adherence to the small focal deposits (less than or equal to 50 microns) and little adherence to the areas in between the focal deposits. The authors hypothesize that worn lenses, especially those with large focal deposits, serve as a vehicle for the transport of P. aeruginosa to the cornea. This hypothesis could be a partial explanation for the high incidence of keratitis caused by P. aeruginosa in EWSCL patients.

While prolonged wear of contact lenses is possible for the aphakic patient, careful consideration must be given to patient selection and to the potential complications of such use. Currently available lenses are far from ideal and, if used at all, must be carefully monitored. The newer lenses, specifically designed for extended wear, more closely fit our needs. Several manufacturers are testing their devices under strict FDA supervision. FDA guidelines dictate a minimum of two years follow-up before a determination will be made as to which lenses are safe and effective enough for prolonged wear in aphakic eyes.

During the period 1976-79, 1,201 of 1,552 aphakic patients were successfully fitted with third generation extended wear hydrogen lenses of thin-membrane design (CSI? lens) and highly hydrated polymer design (Permalens,?Sauflon?) without significant or permanent visula loss. Between 79% and 82% of the patients who failed did so in the first 90 days, and thereafter failure rates declined with time. Replacement rates for lenses approximated one lens per eye per year. Rates of required removal for cleaning varied. Ten to 13% of patients required cleaning at less than three-month intervals, and 5-6% at less than one month. For average patients with unilateral devices and no complication, extended wear lenses in Georgia are estimated to cost approximately three times as much as an intraocular lens over a 20-year follow-up period. General advantages ofextended wear third generation lenses include: (1) an acceptably savce and visually effective way to correct aphakia when patients are carefully selected, fitted, educated, and followed; (2) can be easily removeed, refitted or updated as technology advances; and (3) will not replace intraocular lenses, but can be used when implantation is contraindicated and should prevent the need for secondary or bilateral implantation or keratophakia in most cases.

In order to assess the applicability and safety of cellulose acetate buterate (CAB) contact lenses for extended wear in aphakia, 139 lenses were fitted in 102 aphakic patients. These lenses were removed periodically for cleaning only. There has been an average follow-up of 24.75 months on 99 patients (135 lenses), with a success rate of 80%. No serious complications or corneal vascularization have occurred. The major problems encountered were due to lack of tint, increased tendency to accumulate mucus, and the need for periodic insertion and removal.

Our study of a random series of more than 300 spoiled soft contact lenses reveals that virtually all lenses currently in use for daily or extended wear are subject to deterioration due to extraneous deposits, physical and chemical changes in the lens material, and microbial invasion. Common causes include ocular secretions, finger dirt and cosmetics, disinfecting and cleansing techniques, environmental factors, manufacturing defects and polymer impurities, mechanical stress and breakage, as well as aging and decay of the lens material. Mucoprotein-lipid deposits, with or without calcium, and calcareous deposits constitute the major forms of lens spoilage. Removal of encrusted deposits leaves surface irregularities and matrix defects which facilitate secondary spoilage including microbial invasion, and such lenses should be discarded. As virtually no soft lens material currently in use is "safe" for extended wear, the practitioner must carefully evaluated and follow his patients to identify those at risk of lens failure and spoilage complications. To eliminate spoilage, new lens materials and improved manufacturing techniques are needed. In the interim, for many patients, an inexpensive disposable soft lens which can be easily replaced, perhaps weekly or bi-weekly, may be the answer.

Although both the extended-wear contact lens and the intraocular lens are under intense clinical investigation, years will be required to collect sufficient data for valid comparisons of their risk factors. Meanwhile, a rational appraisal of risks associated with both therapeutic alternatives should be considered, with decisions based on risks or benefits for each patient. The factors to be considered in comparing these alternatives for the correction of aphakia are discussed.

In 52 patients with a history of using cosmetic extended wear soft contact lenses, corneal ulcers developed requiring admission to Wills Eye Hospital between January 1, 1982, and June 30, 1986. A retrospective study was conducted to determine the contact lens history, clinical presentation, culture and sensitivity results, and final visual acuity of these patients. Pseudomonas organisms were isolated in 75% of culture-positive cases. The final visual acuity was 6/60 or less in 12% of all cases and 25% of the Pseudomonas ulcers. Patients and practitioners must be aware of this vision-threatening problem in patients wearing cosmetic extended wear lenses. The pathogenesis of corneal ulcers in contact lens patients has not been established. There may be an inherent increased risk in the use of extended wear, compared to daily wear, soft contact lenses for cosmetic purposes.

One thousand ninety-nine patients were fitted by 42 investigators with a Hydrocurve II®-55% contact lens for myopia extended wear. Five hundred thirty-three patients (48%) have successfully worn the lenses for 3 1/2 years. The major reasons for discontinuing extended wear were due to lack of interest or discontinuance of follow-up visits. Ninety-eight percent of all patients achieved a corrected acuity of better or equal to 20/30; 84% achieved an acuity better than or equal to 20/20. There was no permanent change in visual acuity in any patient during the study. Ocular complications forced 6.4% of patients to discontinue the study. It is clear from the results of this study that myopic extended wear is highly successful.

To date, a number of specific materials have been used for extended wear lenses in aphakia. While none of the materials are ideal, reasonable results have been achieved with three types of materials: thin hydrophilics, silicone, and high water content hydrophilics. The various available lenses are described, and their physicial properties are related to the process of extended wear. The authors' techniques for fitting, follow-up, evaluation, and prevention of complications are presented.

We report 13 cases of corneal ulcers caused by gram-negative bacteria. These cases occurred in aphakic eyes wearing hydrophilic contact lenses on an extended-wear basis. The risks for infection in the elderly aphakic eye with extended-wear hydrophilic lenses are increased by delay in removal of the lens. Caution in the use of these lenses is urged. The ability of either the patient or an attendant to remove the lens as soon as redness, diminished vision, or pain presents itself is essential in minimizing the risks for serious infection.

Fifty pediatric aphakic patients, ranging in age from 7 days to 11 years, were fitted with the Silsoft extended wear contact lens. Compared to other extended wear lenses, the Silsoft lens has several advantages. These include easier handling, a less traumatic fitting procedure for the child, the use of fluorescein for evaluation of the lens-cornea relationship and a low loss rate. This lens appears to be safe, with no permanent adverse effects on the cornea.

Summary A contact lens made from silicone rubber has been fitted successfully for extended wear in children. The lens has been used primarily with aphakic children, but it has also been tolerated by children with anisometropia, high myopia, and keratoconus. The lens can be handled like a hard contact lens and can be fitted by a variety of methods. The eye shows excellent tolerance of the lens and complications or failures to wear the lens have been due primarily to discomfort. After about a year of wear the lens surface can no longer be cleaned.

We studied 41 aphakic eyes in 30 patients who had been wearing CAB (cellulose acetate butyrate) contact lenses on an extended basis. Patients were 51 to. 81 years old and averaged 14.3 months of wearing time. Visual acuity was very good. Pachometry measurements ranged from 0.42 mm to 0.66 mm and averaged 0.550 mm. This compares favorably with data in the literature on corneal thickness seen with routine use of PMMA or hydrogel lenses or with extended wear of hydrogel lenses. Corneal thickness was also compared with unoperated fellow eyes and eyes using CAB lenses on a daily basis only.