Barry A. Weissman

Microbial Contamination of Contact Lens Care Systems

We examined the contact lens care systems of 100 asymptomatic patients who used hard or soft contact lenses for correction of refractive errors for the presence of bacteria, fungi, Acanthamoeba, and endotoxin. Of 100 patients, 52 had contaminated contact lens care systems. Sixteen of 126 bottles (13%) of commercial contact lens care solutions were contaminated. Contaminated commercial solutions were opened and used for a longer period of time than uncontaminated solutions. Contamination was not found in bottles of preserved commercial solutions that were opened and used for less than 21 days. All 12 bottles of homemade saline were contaminated with bacteria, and Acanthamoeba was isolated from two of these bottles. Pseudomonas was found in the care systems of 12 patients. Bacillus species, which form spores resistant to heat, were found in the care systems of seven patients. Endotoxin, which is also resistant to heat, was detected in nine of 35 care systems (26%) tested. Potential pathogens were isolated from the conjunctiva of six patients.

Corneal Ulcers Associated with Daily-Wear and Extended-Wear Contact Lenses

Over a 21-month period, we treated corneal ulcers in 11 patients using daily-wear contact lenses and 29 patients using extended-wear contact lenses. Since more patients use daily-wear than extended-wear lenses, this suggests that patients using extended-wear lenses are at greater risk for the development of corneal ulcers. Positive bacterial cultures were obtained from the corneal scrapings of nine of 11 patients using daily-wear lenses and 20 of 29 patients using extended-wear lenses. In the daily-wear group, all 11 patients failed to exercise satisfactory care in using and disinfecting their contact lenses: three did not wash their hands before manipulating the contact lenses, eight wore them overnight, two did not use any disinfecting system, and four had contaminated contact lens cases, solutions, or drops. In the extended-wear group, 17 patients failed to exercise satisfactory care in using and disinfecting their contact lenses: 12 had contaminated contact lens care systems, two did not use any disinfection system, five reported not washing their hands before contact lens manipulation, and two disinfected their contact lenses at intervals of more than a month. We were unable to identify any defect in the way 12 patients took care of their extended-wear lenses, suggesting that there may be a problem with these contact lenses even when care is satisfactory.

Corneal Ulcers Associated with Extended-Wear Soft Contact Lenses

We treated nine myopic and nine aphakic eyes in patients who developed corneal ulcers while wearing extended-wear soft contact lenses. Bacteria were recovered from the corneal ulcers of 13 of 18 patients with Pseudomonas aeruginosa being the pathogen most frequently isolated. Chemical disinfection was used by seven of the nine patients with myopia and eight of the nine with aphakia. Two of nine patients in the myopic group had visual loss to 20/200 and hand movements; five of nine patients in the aphakic group had visual loss to 20/50 or worse. Invasion of the corneal stroma by bacteria may occur after breakdown of the epithelial barrier by contact lens manipulation or after chronic overnight anoxic stress. Thus, the use of soft contact lenses on an extended-wear basis may be complicated by the development of corneal ulcers. Both aphakic and myopic eyes are at risk.

Compliance in contact lens care

Fifty patients who were originally fitted or refitted with daily-wear contact lenses at the UCLA contact lens service were interviewed on the nature of their care system compliance and hygiene. Good compliance was defined as meeting three preset, standardized criteria (hand washing before lens manipulation, correct use of a FDA-approved care system, and adherence to a daily-wear schedule). Twenty of our patients, or 40%, were found to be noncompliant. Noncompliance occurred more frequently in the 10 to 30 year age group and in those over 50 years of age and after lenses had been worn for more than 2 years. We also noted that patients with contact lens experience predating our contact lens care were more noncompliant as a group than those who only obtained contact lenses and care through our practice.

Factors Associated with Corneal Scarring in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study

Purpose. The multicenter Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study is a prospective, observational study of 1,209 keratoconus patients. We report on the factors associated with corneal scarring at baseline. Methods. We defined corneal scarring as scars that had been detected both by the clinician examining the patient with the slit-lamp biomicroscope and by masked readers of corneal photographs at the CLEK Photography Reading Center. We investigated associations between corneal scarring and patient variables including gender, ethnicity, a family history of keratoconus, a history of ocular trauma, eye rubbing, contact lens wear, rigid contact lens fitting relationships, and corneal findings (such as curvature, Vogts striae, Fleischers ring, and central/apical staining). Multiple logistic regression analysis using generalized estimating equations to adjust for the correlation between eyes was used for analysis. Results. The following factors were found to increase the odds of corneal scarring at baseline in the CLEK Study: corneal staining (odds ratios (OR) = 3.40, 95% confidence interval 2.53–4.59), contact lens wear (OR = 3.51, 95% confidence interval 2.27–5.45), Fleischers ring (OR = 1.63, 95% confidence interval 1.11–2.40), steeper first definite apical clearance lens base curve radius (per diopter, OR = 1.29, 95% confidence interval 1.25–1.33), and age (per decade, OR = 1.54, 95% confidence interval 1.35–1.75). Conclusions. These baseline data suggest that corneal scarring in keratoconus is associated with corneal staining, contact lens wear, Fleischers ring, a steeper cornea, and increasing age. The factors that imply added risk for corneal scarring that may be affected by practitioner intervention are staining of the cornea, contact lens wear, and the contact lens fitting relationship.

Prevalence of contact lens-related complications: UCLA contact lens study.

Purpose: This study is a cross-sectional analysis of the types and prevalence of contact lens (CL)-related complications among CL wearing patients seen in a university clinic setting. Methods: Data on CL material and design, care system, and ocular complications were recorded and statistically analyzed for CL wearers. Results: Of the 572 patients (846 eyes) recruited during the study, approximately 50% of the eyes had at least one CL-related complication. Rigid gas permeable (GP) CLs had a statistically lower (P<0.01) average number of complications (0.54 ± 0.68) than soft contact lenses (SCLs) (0.85 ± 0.82). Papillae and giant papillary conjunctivitis were the most prevalent complications in both GP and SCL wearers. Silicone SCLs (0.79 ± 0.76) had a slightly lower, although not statistically different (P=0.23), rate of complication than nonsilicone SCLs (0.90 ± 0.87). Although not statistically significant (P=0.29), extended wear CL use had a higher complication rate (0.93 ± 0.84) compared with daily wear (0.73 ± 0.79). Use of “other” solution, including generic and private label solutions, had the highest rate of complications for both SCLs (1.11 ± 1.27) and GPs (0.96 ± 0.93) compared with name brand solutions. Conclusions: The prevalence of CL-related complications, regardless of lens design, material, and wear modality, highlights the importance of early detection with appropriate professional management and treatment.

Microbial Analysis of Contact Lens Care Systems Contaminated With Acanthamoeba

We analyzed bacterial and fungal contamination within the contact lens care systems of ten patients who had Acanthamoeba detected within their care systems. Seven patients had Acanthamoeba keratitis, one had Pseudomonas keratitis, and the remaining two were asymptomatic. Gram-negative bacteria were found in all ten care systems, and Pseudomonas was found in six. Bacillus species, the only gram-positive bacteria isolated, were found in five systems. Fungi were isolated in six care systems. The use of homemade saline and the two-cup method of peroxide disinfection were associated with microbial contamination. Acanthamoeba organisms were found only in contact lens cases or solutions that also had bacterial and in many cases fungal contamination, suggesting that the presence of bacterial and fungal contamination within the contact lens care system may be an important element for the survival and growth of Acanthamoeba.

Risk factors for contact lens associated microbial keratitis

Although the risk of developing contact lens associated microbial keratitis is small, the potential consequences of this condition, such as vision loss, are serious. This paper presents an analysis of the risk factors that have been identified for contact lens induced microbial keratitis, which include extended wear, hypoxia, non-compliance, blepharitis, diabetes mellitus, epithelial trauma, steroid use, therapeutic lens use, tobacco use, and possibly travel to warm climates. By remaining mindful of these risk factors, practitioners can take action and offer advice to patients so as to optimize the safety of contact lens wear.

Four Cases of Keratoconus and Posterior Polymorphous Corneal Dystrophy

We examined four young men with keratoconus and posterior polymorphous corneal dystrophy. All four patients showed central corneal steepening and irregularity, and large areas of irregular polymorphous opacification at the level of Descemets membrane (in at least one cornea of each patient), which are consistent with posterior polymorphous dystrophy.

Corneal ulcers associated with disposable hydrogel contact lenses

Four patients developed corneal ulcers associated with the use of disposable extended-wear hydrogel contact lenses. Bacteria were recovered from corneal ulcers in three of the patients. Three patients discarded their contact lenses after ten or more days of extended wear; the corneal ulcers in these patients developed toward the end of the wearing cycle. The fourth patient removed her contact lenses every two days for cleaning and disinfection and discarded them for a new pair on a weekly basis. Improper lens hygiene was noted in only one patient. All corneal ulcers responded to antibiotic treatment. In three patients visual acuity returned to normal, but scarring of one patients cornea resulted in a visual acuity of 20/60.