Defining Daily Disposable Contact Lens Wear in a Clinical Study.

SIGNIFICANCE: The U.S. Food and Drug Administration regulates contact lenses as prescription medical devices and defines daily disposable lenses for single use; however, safety comparisons between daily disposable and reusable lenses rely on the lens-wearing regimen. When inappropriately discerned, studies may erroneously report replacement regimen, resulting in inaccurate risk rates. PURPOSE: This study aimed to explore different measures for defining daily disposable wearers in the context of a clinical study. METHODS: A secondary analysis of data from five multisite fieldings (n = 1059) from the Contact Lens Risk Survey was performed. Descriptive statistics were used to examine self-reported lens replacement, use of lens case, and manufacturer's recommended replacement frequency as defined by the participants' selection of their habitual lenses using a photographic aide. Daily disposable wearers were identified as reporting daily replacement (by self-report and lens identification) and not using a lens case. If there was a discrepancy among these three factors, the lens assignment was assessed as a majority response (two of three) or as missing if conflicting information was reported. RESULTS: The cohort was approximately two-thirds (68.7%) female and ranged from 12 to 33 years of age. A total of 154 participants (14.5%) were classified as daily disposable wearers and 896 (84.6%) as reusable wearers. Congruence was observed among all three daily disposable assignment factors for only 106 wearers (68.8%). The greatest discrepancy among daily disposable wearers was the report of using a lens case (n = 32 [20.8%]). In contrast, reusable lens wearers were more likely to report agreement across all three factors (n = 798 [89.1%], P < .001). CONCLUSIONS: This analysis suggests that the report of not using a lens case is a more conservative surrogate for true single-use lens wear, as one in five may be storing and reusing their daily disposable lenses.

Examining daily disposable soft contact lens wearers' attitudes and beliefs using the Health Belief Model.

PURPOSE: To use the Health Belief Model (HBM) to understand daily disposable (DD) soft contact lens (SCL) wearers' attitudes and beliefs. METHODS: A convenience sample of DD SCL wearers (18-33 years) was enrolled at two sites. Participants were queried about demographics, SCL wear and HBM constructs. Rasch analysis was used to assess the psychometric properties of the survey instrument and generate scores for each HBM subscale. ANOVA was used to determine relationships among HBM constructs, subject demographics and DD SCL-related health behaviours. RESULTS: One hundred people participated (mean ± SD), age = 24.2 ± 3.9 years, 76% female. Thirty-seven percent reported sleeping in DD SCLs and 25% reported reusing DD SCLs. Self-report of reusing DD SCLs was associated with scores on the benefits: reuse (p = 0.02) and barriers (p = 0.007) subscales, and sleeping in lenses was associated with scores on the susceptibility (p = 0.05), benefits: wear behaviours (p = 0.006) and barriers (p = 0.01) subscales. Rasch analysis showed some subscales demonstrated multidimensionality. CONCLUSIONS: Selected health belief constructs were associated with DD SCL-related behaviours including reusing and overnight wear. Increased understanding of SCL attitudes and beliefs could inform patient education and interventions to decrease risks associated with improper SCL wear.

Change in Risk Score and Behaviors of Soft Contact Lens Wearers After Targeted Patient Education.

OBJECTIVES: To determine if targeted education can influence the behaviors and scores of soft contact lens (SCL) wearers via the Contact Lens Risk Survey (CLRS). METHODS: This was a multicenter, prospective, case-control study. Cases were symptomatic red eye SCL wearers (age, 18-39 years), and controls were age , sex, and site matched. Participants completed the CLRS and were provided targeted patient education at three time points: baseline, one, and six months. Change in scores and behaviors were analyzed using the Wilcoxon signed rank test. RESULTS: Forty-one cases and 71 controls were analyzed. The mean risk score (mean±SE) from baseline to follow-up improved (reduced) for all participants (-1.96±0.73; P =0.01), mostly driven by the improvement among cases (-2.55±1.32; P =0.05). Case subjects reported a decrease in frequency of wearing lenses while showering (-0.32±0.07; P <0.0001), discarding lens solution (-0.13±0.06; P =0.03), and rinsing lenses with tap water (-0.19±0.08; P =0.02) after targeted education. CONCLUSIONS: Targeted patient education can influence some behaviors of SCL wearers, especially those who experienced a red eye event. Further study is needed to determine how to improve other risk behaviors and whether these changes are sustained long term.

Gas-Permeable Contact Lenses and Water Exposure: Practices and Perceptions.

SIGNIFICANCE: This study provides insight into the current recommendations, clinical behaviors, and risk assessments of eye care professionals on the topic of rigid contact lens exposure to tap water. This knowledge may motivate professional organizations to develop initiatives to educate eye care professionals on the dangers of contact lens exposure to water. PURPOSE: The purpose of this study was to investigate the practice patterns and risk perceptions of eye care professionals regarding gas-permeable contact lens exposure to tap water. METHODS: A branched-logic survey was started by 320 clinicians, vision scientists, and industry personnel and was fully completed by 272 participants. The survey queried participants about their current practices, recommendations, and perceptions of risk regarding exposure of gas-permeable contact lenses to tap water. RESULTS: Of those who prescribe gas-permeable contact lenses, 57.4% reported rinsing lenses with tap water, whereas only 32.7% reported engaging in this same behavior in front of patients. Of those who reported never rinsing lenses with tap water, 85.6% indicated that rinsing lenses with water increases infection risk, whereas 52.1% of those who rinse lenses with water reported the same perceived risk (P < .001). Of all participants, 60% indicated that wearing contact lenses while showering increases infection risk, and 50.2% of all participants advised patients to avoid this behavior. CONCLUSIONS: A discrepancy exists between perceptions of risk concerning exposure of contact lenses to water and both clinical practices and patient education provided by professionals.

The contact Lens risk survey to assess risk of soft contact lens-related inflammatory events.

PURPOSE: To test the Contact Lens Assessment in Youth Contact Lens Risk Survey (CLRS) scoring algorithm in soft contact lens (SCL) wearers presenting with SCL-related adverse events and healthy matched controls. METHODS: This prospective case-control study compared CLRS responses in SCL wearers presenting with symptomatic red eyes (Cases) with age-, sex- and site-matched healthy SCL wearers (Controls) at six locations across North America. Responses to individual questions from Cases and Controls were analyzed using either the Pearson, Mantel-Haenszel chi-square, or Fisher's exact test. Differences in the CLRS scores were compared using t-tests. RESULTS: A total of 171 SCL wearers were enrolled (n = 57 Cases, 114 Controls). Cases were adjudicated to consensus and classified as contact lens-related serious and significant (S&S) or non-serious events. S&S Cases scored significantly higher on the CLRS (56.1 ±â€¯11.1) than either their matched Controls (44.3 ±â€¯11.1) (P <  0.001) or the non-Serious Cases (44.8± 12.8 P =  0.002). Scores of non-serious Cases were not significantly different than scores of their Controls (43.4 ± 10.7, P = 0.33) CONCLUSIONS: The CLRS scoring algorithm discriminated between SCL wearers presenting with S&S CL-related adverse events from healthy SCL wearers and those with non-serious events. This survey and scoring system could help practitioners identify patients at greatest risk for CL-related adverse events and support targeted interventions aimed at reducing risk behaviors.

Development of a contact Lens risk survey.

PURPOSE: To describe the development and report psychometric properties of the Contact Lens Risk Survey (CLRS) to identify patients at risk for soft contact lens-related complications. METHODS: Psychometric properties of the CLRS, a web-based survey with branching logic, were determined using data from 5 multi-site fieldings (n = 1059), including re-fielding to sub groups. Responses from participants with and without an active red eye were used to identify risk factors of a red eye event and calculate an overall risk score. A 6th fielding of the CLRS (n = 171) was used to assess discriminate validity. RESULTS: Participants needed 11-12 min to complete the survey with a negligible difference by age. Internal consistency was excellent (Cronbach's α ≥ 0.70) for 3 of the 5 constructs identified by factor analysis. Twelve of the 17 survey items exhibited excellent within-subject repeatability (Kappa ≥ 0.61). Between-subject agreement, assessed in 18-25 year olds, was high for the majority of items, suggesting good generalizability across different populations of SCL wearers. The ability of the model using individual items of the CLRS to discriminate Controls and participants with a red eye was good with an area under the curve of 0.779. CONCLUSION: The CLRS tool is a repeatable and valid instrument to standardize documentation of demographic, behavior, and exposure factors which appear to drive the greatest risk of a contact lens related red eye event.

Multicenter Testing of a Risk Assessment Survey for Soft Contact Lens Wearers With Adverse Events: A Contact Lens Assessment in Youth Study.

PURPOSE: To test the ability of responses to the Contact Lens Assessment in Youth (CLAY) Contact Lens Risk Survey (CLRS) to differentiate behaviors among participants with serious and significant (S&S) contact lens-related corneal inflammatory events, those with other events (non-S&S), and healthy controls matched for age, gender, and soft contact lens (SCL) wear frequency. METHODS: The CLRS was self-administered electronically to SCL wearers presenting for acute clinical care at 11 clinical sites. Each participant completed the CLRS before their examination. The clinician, masked to CLRS responses, submitted a diagnosis for each participant that was used to classify the event as S&S or non-S&S. Multivariate logistic regression analyses were used to compare responses. RESULTS: Comparison of responses from 96 participants with S&S, 68 with non-S&S, and 207 controls showed that patients with S&S were more likely (always or fairly often) to report overnight wear versus patients with non-S&S (adjusted odds ratio [aOR], 5.2; 95% confidence interval [CI], 1.4-18.7) and versus controls (aOR, 5.8; CI, 2.2-15.2). Patients with S&S were more likely to purchase SCLs on the internet versus non-S&S (aOR, 4.9; CI, 1.6-15.1) and versus controls (aOR, 2.8; CI, 1.4-5.9). The use of two-week replacement lenses compared with daily disposables was significantly higher among patients with S&S than those with non-S&S (aOR, 4.3; CI, 1.5-12.0). Patients with S&S were less likely to regularly discard leftover solution compared with controls (aOR, 2.5; CI, 1.1-5.6). CONCLUSIONS: The CLRS is a clinical survey tool that can be used to identify risky behaviors and exposures directly associated with an increased risk of S&S events.

Water Exposure is a Common Risk Behavior Among Soft and Gas-Permeable Contact Lens Wearers.

PURPOSE: To understand soft contact lens (SCL) and gas-permeable (GP) lens wearers' behaviors and knowledge regarding exposure of lenses to water. METHODS: The Contact Lens Risk Survey (CLRS) and health behavior questions were completed online by a convenience sample of 1056 SCL and 85 GP lens wearers aged 20 to 76 years. Participants were asked about exposing their lenses to water and their understanding of risks associated with these behaviors. Chi-square analyses examined relationships between patient behaviors and perceptions. RESULTS: GP lens wearers were more likely than SCL wearers to ever rinse or store lenses in water (rinsing: 91% GP, 31% SCL, P < 0.001; storing: 33% GP, 15% SCL P < 0.001). Among SCL wearers, men were more likely to store (24% vs. 13%, P = 0.003) or rinse (41% vs. 29%, P = 0.012) their lenses in water. Showering while wearing lenses was more common in SCL wearers (86%) than GP lens wearers (67%) (P < 0.0001). Swimming while wearing lenses was reported by 62% of SCL wearers and 48% of GP lens wearers (P = 0.027). Wearers who rinsed (SCL; P < 0.0001, GP; P = 0.11) or stored lenses in water (SCL; P < 0.0001, GP P = 0.007) reported that this behavior had little or no effect on their infection risk, compared with those who did not. Both SCL (P < 0.0001) and GP lens wearers (P < 0.0001) perceived that distilled water was safer than tap water for storing or rinsing lenses. CONCLUSIONS: Despite previously published evidence of Acanthamoeba keratitis' association with water exposure, most SCL, and nearly all GP lens wearers, regularly expose their lenses to water, with many unaware of the risk.

Case-Control Pilot Study of Soft Contact Lens Wearers With Corneal Infiltrative Events and Healthy Controls.

PURPOSE: The purpose of this study was to assess risk factors associated with soft contact lens (SCL)-related corneal infiltrative events (CIEs). METHODS: This was a single-visit, case-control study conducted at five academic centers in North America. Cases were defined as current SCL wearers with a symptomatic CIE. For each case, three age- and sex-matched controls were enrolled. Subjects completed the Contact Lens Risk Survey (CLRS), a standardized scripted medical interview, supplied a recent health history, and underwent an ocular examination. Microbial culturing of the ocular surface, SCL, and lens storage case was conducted for all cases and one of the three matched controls. Univariate and multivariate logistic regression modeling were used to assess the risk of developing a CIE. RESULTS: Thirty cases and 90 controls 13 to 31 years of age completed the study. Corneal infiltrative event diagnosis included contact lens-associated red eye, infiltrative keratitis, and contact lens peripheral ulcer. Subjects with symptomatic CIEs were more likely to harbor substantial levels of gram-negative bioburden on the ocular surface and contact lens. Significant risk factors for developing a CIE were overnight wear of SCLs, use of multipurpose solution, rinsing SCLs with water, lens storage case older than 6 months, previous "red eye" event, use of ocular drops in the past week, and illness during the past week. CONCLUSIONS: This pilot study demonstrated feasibility of enrolling a representative pool of SCL wearers with an untreated, symptomatic CIE and assessing CIE risk factors by using standardized methods. A larger sample size is needed to determine relationships between patient-reported behaviors and exposures, microbial bioburden, and CIE development.

Contact Lens Corneal Inflammatory Events in a University Population.

PURPOSE: To identify the contact lens-related modifiable and nonmodifiable factors associated with corneal inflammatory events (CIEs) in a university eye care center. METHODS: Contact lens-wearing undergraduate and graduate/professional students (age range, 18 to 36 years) with CIEs and contact lens wearers without complications (non-CIEs) were surveyed about their age, education level, overnight wear, brand of lens, brand of care solution, storage case age, topping-off, and lens replacement. Logistic regression was used to assess the impact of participant characteristics (demographic and behavior) and contact lens factors on the risk of a CIE. RESULTS: There were 160 participants enrolled, with 76 presenting with a CIE. Age was significant in the multivariate model (p < 0.001) as was an interaction between disinfectant and wearing schedule (p = 0.027). When daily wear (DW) and disinfectant were compared, polyquaternium-1/myristamidopropyl dimethylamine (PQ-1/MAPD) was associated with a greater risk of CIE versus peroxide (adjusted odds ratio [aOR], 18.4; 95% confidence interval [95% CI], 1.9-173.9) and versus polyhexamethylene biguanide or polyaminopropyl biguanide (PHMB) (aOR, 15.0; 95% CI, 4.5-50.0). For PHMB users only, extended wear (EW) compared with DW increased CIE risk (aOR, 10.0; 95% CI, 2.0-51.2). There was no difference in risk between EW and DW for PQ-1/MAPD (aOR, 0.8; 95% CI, 0.2, 2.6). CONCLUSIONS: The multivariate analysis suggests that younger age and the use of PQ-1/MAPD, particularly in DW, increase the risk of acquiring a CIE with soft contact lens wear in college-aged students. For PHMB users, EW compared with DW increases the risk of a CIE; but for PQ-1/MAPD users, there is no difference between EW and DW.

Contact lens associated microbial keratitis: practical considerations for the optometrist.

Microbial keratitis (MK) is a corneal condition that encompasses several different pathogens and etiologies. While contact lens associated MK is most often associated with bacterial infections, other pathogens (fungi, Acanthamoeba species, etc) may be responsible. This review summarizes the risk factors, microbiology, diagnostic characteristics, and treatment options for all forms of contact lens-related MK.

A method to monitor eye and head tracking movements in college baseball players.

PURPOSE: This study had two purposes. The first was to develop a method to measure horizontal gaze tracking errors (based on synchronized eye and head tracking recordings) as subjects viewed many pitched balls. The second was to assess horizontal eye, head, and gaze tracking strategies of a group of Division 1 college baseball players. METHODS: Subjects viewed, but did not swing a bat at, tennis balls projected by a pneumatic pitching machine. Subjects were to call out numbers and the color of these numbers (black or red) on the balls. The trajectory of each pitch was very predictable. Eye and head movements were monitored with a video eye tracker and an inertial sensor, respectively, and these movements were synchronized with ball position using an analog recording device. Data were analyzed for 15 subjects. RESULTS: Eye rotation, head rotation, gaze errors (GEs), and unsigned gaze errors (UGEs) were calculated at various elapsed times. On average, subjects tracked the pitched ball with the head throughout the pitch trajectory, while the eye was moved very little until late in the pitch trajectory. On average, gaze position matched the target position throughout the pitch trajectory. There was some variability in the mean amplitudes of head and eye movement between subjects. However, the eye and head were related by a common rule (partial rotational vestibulo-ocular reflex suppression) for all subjects. Although the mean amplitudes of the GE and UGE varied between subjects, these means were not consistent with anticipatory saccades for any subject. CONCLUSIONS: On average, Division 1 college players tracked the pitched ball primarily with the head and maintained gaze close to the ball throughout much of the pitch trajectory. There was variability between subjects regarding the head and eye movement amplitudes and GEs, but, overall, all subjects maintained gaze close to the ball throughout the pitch trajectory despite the fact that these individuals were not batting.

Microbial keratitis secondary to unintended poor compliance with scleral gas-permeable contact lenses.

PURPOSE: To report a case of neurotrophic keratitis in which scleral contact lenses improved vision from 20/100 to 20/20, however, due to poor lens care, an incident of microbial keratitis developed. METHODS: A 64-year-old man with an ocular history of neurotrophic keratitis secondary to herpes simplex in each eye was successfully fit with scleral lenses. He subsequently developed microbial keratitis due to a number of risk factors. RESULTS: The lesion was culture negative, yet was very responsive to treatment with moxifloxacin. The lesion fully healed, and the patient did not suffer additional vision loss. CONCLUSIONS: This case demonstrates the ability of scleral lenses to correct visual impairments secondary to poor epithelial integrity and illustrates the importance of the practitioner providing detailed lens care instruction.

Intercollegiate usage schedule and the impact resistance of used football helmet faceshields.

PURPOSE: Although new polycarbonate helmet faceshields can withstand impacts exceeding forces of 2,400 N, repeated impacts and ultraviolet radiation degrade the structural integrity. In this study, the impact resistances of unused, solar-radiated, and of game-used faceshields were analyzed. Also, Division 1 National Collegiate Athletic Association football programs were surveyed concerning their faceshield practices. METHODS: Impact resistance was tested by impacting faceshields with baseballs at velocities exceeding 67.1 m/s. Twenty-four new faceshields were exposed to southern daylight, 3 hours per day for 3 months before testing. Subsequent testing was performed on 60 game-used faceshields. Additionally, a faceshield utilization survey was distributed to 117 college programs. RESULTS: Solar-irradiated shields did not fail at maximum test velocity. The survivability of nonimpacted shields was greater than game-worn shields (P = 0.0003). Fifty-nine surveys were returned with 58 programs reporting faceshield use. Approximately 21 players per program use a faceshield. The main reason reported for use was aesthetic. Only 21% of reporting programs require a faceshield for players with reduced visual acuity in 1 eye. CONCLUSION: Faceshields lose impact resistance with typical use. Programs should incorporate a policy for replacement and require that players with reduced vision in at least 1 eye wear a faceshield.

Visual acuity and contrast sensitivity testing for sports vision.

UNLABELLED: : The building blocks of effective sports vision are visual acuity and contrast sensitivity. Proper measurement of these spatial vision attributes is necessary for repeatability in the clinic or in the laboratory. The most repeatable method of testing visual acuity is with logMAR charts-either the Bailey-Lovie chart or the Early Treatment Diabetic Retinopathy Study chart. The Pelli-Robson and the Mars are the most repeatable contrast sensitivity tests. Athletes may or may not demonstrate superior visual acuity and contrast sensitivity compared with age-matched nonathlete populations, and the optical quality of their eyes may be similar. Dynamic visual acuity in athletes and their performance are typically superior to those of nonathletes. How these differences relate to on-field performance is not known. Other changes to the visual system because of refractive surgery or contact lens wear may increase higher order aberrations and reduce low-contrast visual acuity. The ability to improve already-normal visual acuity is unclear although contrast sensitivity can improve with fast-paced video games. Tinted contact lenses help reduce discomfort glare and speed up adaptation but do not have an appreciable effect on visual acuity and contrast sensitivity. CONCLUSION: The use of valid and repeatable visual acuity and contrast sensitivity tests is essential for measuring the differences in visual performance among athletes and nonathletes. The development of a standardized dynamic visual acuity test is needed as are well-controlled scientific studies to evaluate the benefits of sports vision training.

Text legibility and the letter superiority effect.

Effects of font design and electronic display parameters upon text legibility were determined using a threshold size method. Participants' visual acuity (inverse of the minimum detection size, representing the threshold legibility for each condition) was measured using upper- and lowercase letters and lowercase words in combinations of 6 fonts, 3 font-smoothing modes, 4 font sizes, 10 pixel heights, and 4 stroke widths. Individual lowercase letters were 10% to 20% more legible than lowercase words (i.e., lowercase words must be 10%-20% larger to have the same threshold legibility). This letter superiority effect suggests that individual letters play a large role and word shape plays a smaller role, if any, in word identification at threshold. Pixel height, font, stroke width, and font smoothing had significant main effects on threshold legibility. Optimal legibility was attained at 9 pixels (10 points). Verdana and Arial were the most legible fonts; Times New Roman and Franklin were least legible. Subpixel rendering (ClearType) improved threshold legibility for some fonts and, in combination with Verdana, was the most legible condition. Increased stroke width (bold) improved threshold legibility but only at the thinnest width tested. Potential applications of this research include optimization of font design for legibility and readability.