Stephanie M. Cox

Agreement between Automated and Traditional Measures of Tear Film Breakup.

Purpose To determine the repeatability and agreement between the noninvasive Keratograph tear break-up time (NIK-BUT) as measured by the Oculus Keratograph 4 and fluorescein tear break-up time (FBUT). Methods Sixty subjects were recruited for two study visits separated by 7 (±2) days. At each visit, three NIK-BUT measures and FBUT measures were obtained. Each NIK-BUT measure from the Keratograph included a first and an average NIK-BUT. The means of the measures obtained, first NIK-BUT, and average NIK-BUT and FBUT were calculated for each visit. Between- and within-visit agreement was assessed using intraclass correlation coefficients (ICCs) and Bland-Altman 95% limits of agreement (LoA) analyses of log-transformed data. Results Between-visit ICCs were 0.53 [95% confidence interval (CI), 0.32 to 0.69] for first NIK-BUT, 0.59 (95% CI, 0.40 to 0.73) for average NIK-BUT, and 0.66 (95% CI, 0.49 to 0.78) for FBUT, whereas 95% LoA were −0.65 to 0.67, −0.44 to 0.48, and −1.14 to 1.10 [back transformed: (visit 1 + 0.01)/(visit 2 + 0.01) = 0.22 to 4.68, 0.36 to 3.02, and 0.07 to 12.59] for the aforementioned methods, respectively. The visit 1 within-visit ICC between first NIK-BUT and FBUT was 0.44 (95% CI, 0.21 to 0.62), whereas the 95% LoA was −0.84 to 1.18 [back transformed: (first NIK-BUT + 0.01)/(FBUT + 0.01) = 0.14 to 15.14]. Likewise, the visit 1 within-visit ICC between average NIK-BUT and FBUT was 0.41 (95% CI, 0.18 to 0.60), whereas the 95% LoA was −0.58 to 1.44 [back transformed: (average NIK-BUT + 0.01)/(FBUT + 0.01) = 0.26 to 27.54]. Conclusions The 95% LoA suggest that the average NIK-BUT has better between-visit agreement compared with the first NIK-BUT or FBUT. The first NIK-BUT showed better within-visit agreement with the FBUT than the average NIK-BUT. In addition, there is better between- and within-visit agreement for all measures at lower values.

Eyelid Margin and Meibomian Gland Characteristics and Symptoms in Lens Wearers.

Purpose To describe the lid margin characteristics of contact lens wearers and relate them to comfort during lens wear. Methods Three study sites enrolled habitual contact lens wearers. Subjects completed the Comfort domain of the Contact Lens User Experience (CLUE) questionnaire, and each eye was graded for the presence of mucocutaneous junction (MCJ) displacement, lid margin irregularity, and lid margin vascularity. Examiners counted the number of meibomian gland (MG) orifices in the central centimeter of the lower eyelid and the number of those that showed pouting/plugging and vascular invasion. MG expressibility was graded according to the Shimazaki schema. Subjects were grouped based on presence/absence of each characteristic, total number of orifices (≥5 vs. <5), and expressibility (grade 0 vs. >0). Descriptive statistics are reported. A linear model was used to assess the fixed effect of each characteristic on combined CLUE score and each CLUE statement, if the effect on combined CLUE score showed p < 0.10. Results The study included 203 subjects (67.5% female) with mean age (±SD) of 30.3 ± 9.6 years. The most commonly observed characteristics were orifice pouting/plugging, compromised MG expressibility, and lid margin vascularity (35.0, 30.3, and 20.4%, respectively). MCJ displacement and MG expressibility had an effect on the combined CLUE score such that individual CLUE statements were analyzed (p = 0.01 and p = 0.06, respectively). MCJ displacement had an effect on comfort upon insertion (p = 0.01), comfort after 5 minutes (p = 0.03), end-of-day comfort (p = 0.01), and ability to maintain ocular moisture (p = 0.030). MG expressibility had a significant effect on general comfort (p = 0.01), comfort throughout the day (p = 0.02), and the ability to maintain ocular moisture (p = 0.02). Conclusions MCJ displacement and MG expressibility have an effect on contact lens comfort.

Association Between Meibomian Gland Testing and Ocular Surface Sensitivity.

Purpose: To assess whether corneal sensitivity is associated with clinical tests assessing the tear film and meibomian glands. Methods: Subjects were recruited based on the history of contact lens wear and the extent of meibomian gland dropout. Clinical examination included assessment of symptoms, redness of the lower eyelid margin, lipid layer thickness, esthesiometry of the inferior cornea and palpebral conjunctiva, noninvasive tear breakup time, Schirmer test assessment, and meibomian gland assessment through orifice count and expressed meibum quality grade. Subjects were grouped into a high corneal sensitivity (HS) group or low corneal sensitivity (LS) group, based on the median sensitivity measure. Groups for palpebral conjunctival sensitivity were created in the same manner. Mann–Whitney U tests were used for comparisons of sensitivity groups, and a Spearman rho correlation coefficient was used to study the associations between each tear film characteristic and the sensitivities. Results: Fifty-seven subjects with an average age of 34.7 years (SD = 15.1) were included in the analysis, of which 63.2% were female. The median corneal and conjunctival thresholds for sensation were 0.5 and 1.4 g/mm2, respectively. The average noninvasive tear breakup time [HS: 7.8 seconds [interquartile range (IQR) = 5.7]; LS: 11.6 seconds (IQR = 8.4); P = 0.05] and Schirmer test assessments [HS: 16.0 mm (IQR = 15.0); LS: 25.0 mm (IQR = 19.0); P = 0.04] were significantly different between the palpebral conjunctival HS and LS groups. All other group comparisons and correlations were not statistically significant. Conclusions: The palpebral conjunctival sensitivity may be more critical than the corneal sensitivity when assessing dry eye.

Impact of lens care solutions on protein deposition on soft contact lenses

Purpose To evaluate the effect of four contemporary lens care solutions on total protein, total lysozyme, and active lysozyme extracted from three contact lens materials. Methods Adapted contact lens wearers were recruited at three sites, and all subjects were randomly assigned to daily wear of either etafilcon A, galyfilcon A, or senofilcon A for 2 weeks. Four lens care solutions (Biotrue, OPTI-FREE PureMoist, RevitaLens OcuTec, and ClearCare) were used by each subject in random order with a new pair of lenses after a washout period between solutions of at least 4 days. After 2 weeks of daily wear, contact lenses were collected for analysis. Proteins were extracted from a subset of contact lenses (n = 568) and total protein, total lysozyme, and lysozyme activity were quantified using a modified Bradford assay, an enzyme-linked immunosorbent assay, and a micrococcal assay, respectively. Results Higher levels of total protein were extracted from etafilcon A when used with Biotrue compared to other solutions (p = 0.0001). There were higher levels of total lysozyme extracted from galyfilcon A lenses when used with PureMoist than with Biotrue or ClearCare (p < 0.006). Higher total lysozyme was extracted from senofilcon A when used with RevitaLens OcuTec compared to Biotrue (p = 0.002). Lower lysozyme activity was recovered from senofilcon A lenses with RevitaLens OcuTec when compared to all other care solutions (all p < 0.004). When Biotrue, PureMoist, or RevitaLens OcuTec were used, higher total lysozyme was extracted from galyfilcon A compared to senofilcon A (p < 0.01). When RevitaLens OcuTec was used, higher levels of active lysozyme were extracted from galyfilcon A compared to senofilcon A (p = 0.02). Conclusions The ability of lens care solutions to remove protein from lenses varies depending upon the care solution composition and also the polymeric make-up of the contact lens material.

Microbial Contamination of Contact Lens Storage Cases During Daily Wear Use.

Purpose To evaluate contact lens (CL) storage case contamination when used with four different CL care solutions during daily wear of three different CL materials. Methods A parallel, prospective, bilateral, randomized clinical trial (n = 38) was conducted. Subjects were randomly assigned to use one of three CL materials (etafilcon A, senofilcon A, or galyfilcon A) on a daily wear basis. Subsequently, each subject randomly used one of four different CL care solutions (Biotrue, OPTI-FREE PureMoist, RevitaLens OcuTec, and CLEAR CARE) for 2 weeks, along with their respective storage cases. After every 2-week period, their storage cases were collected and the right and left wells of each storage case were randomized for two procedures: (1) microbial enumeration by swabbing the storage case surface and (2) evaluation of biofilm formation (multipurpose solution cases only) using a crystal violet staining assay. Results More than 80% of storage cases were contaminated when used in conjunction with the four CL care solutions, irrespective of the CL material worn. Storage cases maintained with CLEAR CARE (mean Log colony forming units (CFU)/well ± SD, 2.0 ± 1.0) revealed significantly (p < 0.001) greater levels of contamination, compared to those maintained with Biotrue (1.3 ± 0.8) and RevitaLens OcuTec (1.2 ± 0.8). Predominantly, storage cases were contaminated with Gram-positive bacteria (≥80%). There were significant differences (p = 0.013) for the levels of Gram-negative bacteria recovered from the storage cases maintained with different CL care solutions. Storage cases maintained with OPTI-FREE PureMoist (0.526 ± 0.629) showed significantly higher biofilm formation (p = 0.028) compared to those maintained with Biotrue (0.263 ± 0.197). Conclusions Levels of contamination ranged from 0 to 6.4 Log CFU/storage case well, which varied significantly (p < 0.001) between different CL care solutions, and storage case contamination was not modulated by CL materials.