Nancy Keir

Objective and subjective responses in patients refitted to daily-wear silicone hydrogel contact lenses.

Purpose. Silicone hydrogel (SiH) lenses offer many physiological advantages for daily wear (DW) in addition to the continuous-wear modality for which they were originally developed. The purpose of this study was to investigate the clinical performance and physiological responses in a group of successful long-term wearers of conventional hydrogel lenses when refitted with DW SiH contact lenses. Methods. Eighty-seven successful soft lens wearers (8.4 ± 4.7 years of prior lens wear) participated in this study. Bulbar and limbal hyperemia were subjectively graded and digitally photographed for subsequent masked objective evaluation. Subjective symptoms were scored using visual analog scales. In addition, refractive error, corneal curvature, and corneal thickness were measured. All subjects were refitted with Focus Night & Day (lotrafilcon A) SiH lenses; however, to reduce the potential for bias, they were informed that they were being randomly assigned to wear either low oxygen permeability (Dk) lenses or high Dk SiH lenses and were “masked” as to their lens assignment. Subjects returned after 1 week, 1 month, and 2 months of DW, at which time all gradings, photographs, and measurements were repeated. End-of-day subjective symptoms were also graded periodically during the study. Results. Ninety-three percent of subjects were successfully refitted. Both objective and subjective evaluations showed that bulbar and limbal hyperemia decreased significantly in all quadrants during the study (p < 0.001), particularly for those subjects with greater baseline hyperemia (p < 0.001). Subjects reported a concurrent reduction in end-of-day dryness and improved end-of-day comfort compared with their habitual lenses (p < 0.001). No significant changes in refractive error, tarsal papillary response, corneal curvature, or corneal thickness were found during the study. Conclusions. Hyperemia in contact lens wearers may be attributed to a number of factors, including hypoxia. Refitting existing low Dk lens wearers with SiH lenses on a DW basis can result in a decrease in hyperemia, which may be significant for some subjects and also results in improvements in symptoms of dryness and discomfort.

Psychometric properties and validation of the Standard Patient Evaluation of Eye Dryness questionnaire.

Purpose: To characterize the psychometric properties of the standard patient evaluation of eye dryness (SPEED) questionnaire and to validate and compare its performance with 4 existing dry eye questionnaires. Methods: A total of 50 subjects (40 female and 10 male) were enrolled; of these, 30 were symptomatic and 20 asymptomatic, as determined using the ocular surface disease index (OSDI). This study consisted of 2 visits in which all subjects completed 5 different dry eye questionnaires (SPEED, OSDI, dry eye questionnaire, McMonnies dry eye questionnaire, and subjective evaluation of symptom of dryness) in random order at each visit. Clinical measurements were obtained on the first visit. Repeatability was determined using concordance correlation coefficient; dimensionality was determined using principal component, factor, and Rasch analyses; and validity was determined by comparing SPEED scores with dry eye diagnosis based on OSDI (primarily using receiver–operator curve analysis). Results: The SPEED questionnaire data were found to be unidimensional and repeatable. Three principal components (dryness, burning, and soreness/fatigue) were identified and SPEED between visit concordance correlation coefficient was 0.923 (95% confidence interval, 0.868–0.955). The area under the receiver–operator curves was 0.928. The only clinical measures that correlated “well” with SPEED questionnaire scores were corneal staining (P < 0.05), meibomian gland score (P < 0.05), and meibomian glands yielding liquid secretion score (P < 0.05). Conclusions: The SPEED questionnaire was shown to be a repeatable and valid instrument for measurement of dry eye symptoms. The SPEED score also correlated significantly with ocular surface staining and clinical measures of meibomian gland function.

Clinical performance of different care systems with silicone hydrogel contact lenses

PURPOSE To assess the clinical and subjective performance of a one-step hydrogen peroxide (H2O2) lens care system compared to a multi-purpose disinfecting system (MPDS) when used with silicone hydrogel (SiH) lenses. METHODS This was an eight-week, contralateral (lens type) clinical trial with a randomized, cross-over (care system) design. The H2O2 system was Clear Care ((AO Sept Plus) CIBA VISION) and the MPDS was OPTI-FREE RepleniSH (Alcon) and the SiH materials were lotrafilcon B (Air Optix; CIBA VISION) and senofilcon A (Acuvue OASYS, Johnson & Johnson Vision Care). Investigators and subjects were masked to lens care and lens type, respectively. Clinical variables and ocular health assessments were conducted at a baseline, two-week and four-week visit for each cross-over phase. Comfort, dryness and vision were rated on 0-100 scales. Wearing times and comfortable wearing times were also recorded. RESULTS Twenty-six subjects were enrolled: nine male, 17 female, mean age (+/-standard deviation) 31+/-12 years (range 17-59 years) and 24 subjects completed the study. Clinical variables showed no difference between solutions (all p > 0.05), however one subject exhibited solution-induced corneal staining with both lens materials and the MPDS. There was no difference between solutions in subjective overall ratings of comfort, dryness or vision (p > 0.05). The H2O2 resulted in longer reported comfortable wearing times than the MPDS (10.93 +/- 1.71 vs 9.84 +/- 1.47 h; repeated measures ANOVA, p < 0.01). CONCLUSIONS While both lens care systems performed well with the SiH lenses used, the H2O2 resulted in a longer reported comfortable wearing time then the MPDS.

Clinical Evaluation of Long-Term Users of Two Contact Lens Care Preservative Systems

Purpose: To clinically evaluate long-term users of two different contact lens care preservative systems and to investigate whether prolonged use is associated with an increase in the prevalence of dry eye. Methods: Eighty-nine wearers of group IV hydrogel or silicone hydrogel lenses participated in this one-visit, investigator-masked study. Subjects were required to have consistently used a polyhexamethylene biguanide (PHMB) or polyquaternium-1 (PQT) based solution for 2 years. Consistent use was defined as 80% for the past 2 years and 100% for the past year. Clinical assessments included: average and comfortable wear time; overall and end-of-day comfort; signs of dryness, discomfort, burning or stinging, grittiness or scratchiness and visual changes; non-invasive and fluorescein break-up-time; pre-ocular tear film lipids, tear meniscus height, Schirmer and fluorescein clearance tests; limbal and bulbar hyperemia; palpebral roughness; corneal and conjunctival staining; lens front surface wetting; and lens film deposits. Results: Significantly more grittiness or scratchiness was reported by subjects using a PHMB-containing system (67% vs. 44%; P = 0.02). Palpebral roughness and hyperemia were significantly greater in the PHMB group wearing group IV lenses (P = 0.01 and P = 0.05, respectively). Corneal staining was significantly higher in the PHMB users in all four peripheral sectors (P < 0.01). Nasal and temporal conjunctival staining was also significantly higher for users of PHMB-containing systems (P < 0.05). Front surface lens wettability was significantly better for group IV PQT users compared to PHMB users (P = 0.008), with 84% vs. 72%, respectively, with lenses graded by the investigator as having “good” or “excellent” wettability. Significantly higher levels of lens front surface film deposits were noted with PHMB users (P = 0.007), with 58% of group IV lenses treated with PHMB compared with 38% of group IV lenses treated with PQT showing some lens front surface film deposition. No significant differences between the two preservative system groups were noted for the range of dry eye evaluations nor the remaining clinical assessments. Conclusions: Differences in both ocular and lens characteristic were observed between long-term users of two preservative systems used in many contact lens multi-purpose solutions. The findings from this study did not support the hypothesis that prolonged use of PHMB-containing solutions leads to dry eye. Additional studies including a larger sample size and perhaps longer use of the systems could help to further elucidate differences in clinical performance between systems.

Wavefront-guided LASIK for myopia: effect on visual acuity, contrast sensitivity, and higher order aberrations.

PURPOSE To determine the impact of wavefront-guided LASIK for myopia with or without astigmatism on high and low contrast best spectacle-corrected visual acuity (BSCVA), photopic and mesopic contrast sensitivity, and higher order aberrations. METHODS Bilateral wavefront-guided LASIK (LADAR-Vision4000; Hansatome microkeratome) was performed on 324 eyes (162 patients) with a mean spherical manifest refraction of -2.84 +/- 1.35 diopters (D) (range: -0.25 to -6.50 D) and astigmatism of -0.81 +/- 0.74 D (range: 0 to -4.00 D). Mean age was 37.7 +/- 9.3 years (range: 20 to 60 years). Best spectacle-corrected visual acuity and contrast sensitivity were assessed using ETDRS charts and vertical sinusoidal gratings, respectively. Higher order aberrations were measured using a Shack-Hartmann wavefront sensor, analyzed across a 5-mm pupil. Repeated measures and post hoc analyses determined statistical significance (P < .0025). Only right eyes were analyzed. RESULTS One hundred thirty-six eyes (84%) had uncorrected visual acuity of 20/20 or better 6 months postoperative; 80.9% (131 eyes) were within +/- 0.50 D of attempted correction. Statistically significant postoperative improvements were noted in high and low contrast BSCVA (both P < or = .001); in photopic contrast sensitivity at 3, 6, and 12 cycles per degree (cpd); and in mesopic contrast sensitivity at 12 and 18 cpd (all P < .001). With respect to higher order aberrations, a statistically significant change was seen in Zernike coefficients Z3(-1), Z3(1), Z3(-3), Z3(3), and Z4(4) following surgery (range of mean absolute change: 0.042 to 0.142 microm; all P < or = .001). All increased in magnitude except for Z3(-3), which decreased. CONCLUSIONS Despite an increase in higher order aberrations, wavefront-guided LASIK yields excellent visual acuity and contrast sensitivity. Spherical aberration, which increases the most following non-wavefront-guided LASIK, showed no significant change.

Wettability and silicone hydrogel lenses: a review.

Abstract: One of the major breakthroughs in the development of silicone hydrogel contact lenses has related to the ability of manufacturers to overcome the surface hydrophobicity that occurred with silicone elastomer lenses. However, the wettability of silicone hydrogel lenses continues to be of interest as a potential link between in vivo lens performance and contact lens–related comfort. This article will review some of the knowledge we have gained in the area of contact lens wettability over the past decade and will discuss some of the challenges related to its measurement.

Outcomes of wavefront-guided laser in situ keratomileusis for hyperopia.

PURPOSE: To determine the impact of wavefront‐guided laser in situ keratomileusis (LASIK) for hyperopia on corrected distance visual acuity (CDVA), contrast sensitivity, and higher‐order aberrations (HOAs). SETTING: Centre for Contact Lens Research, University of Waterloo, Waterloo, Ontario, Canada. DESIGN: Case series. METHODS: This study comprised patients who had LASIK for hyperopia. The HOAs up to the 4th order (5.0 mm pupil) in right eyes were analyzed. RESULTS: The study enrolled 31 patients. The preoperative mean values were sphere, +2.60 diopters (D) ± 1.15 (SD) (range +1.00 to +5.00 D); astigmatism, −0.87 ± 0.74 D (range 0.00 to −3.75 D); and spherical equivalent (SE), +2.16 ± 1.00 D (range +0.63 to +4.50 D). The postoperative refractive SE was within ±0.50 D in 71.0% of eyes. The uncorrected distance visual acuity was 20/20 or better in 87.2% of eyes. There was no significant change in CDVA or contrast sensitivity (all P>.05). There was a significant change in Zernike coefficients Z(0,4), Z(−1,3), Z(−3,3), and Z(3,3) (range of mean absolute change ± SEM: 0.092 ± 0.013 μm to 0.208 ± 0.018 μm; all P<.001). Coefficients Z(−1,3) and Z(3,3) increased and Z(0,4) and Z(−3,3) decreased in magnitude; each had a reversal of sign. The only significant postoperative association was between low‐contrast CDVA and Z(0,4) (r = 0.617, P<.001). CONCLUSIONS: Low‐contrast CDVA after LASIK surgery for hyperopia was correlated with Z(0,4). There were no significant changes in CDVA or contrast sensitivity. The relative risk for losing low‐contrast CDVA increased if more than 1 Zernike term had a sign change. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

The TFOS international workshop on contact lens discomfort : report of the subcommittee on clinical trial design and outcomes

The goal of this report is to review previously published clinical trials addressing contact lens discomfort (CLD) to identify appropriate trial design and outcome parameters to guide future clinical research that will characterize and investigate possible causes of CLD. A further goal is to identify possible confounding features of clinical trial design and performance in order to reduce bias in conduct of future trials or analysis of data from those trials.

Clinical performance of three silicone hydrogel daily disposable lenses.

Purpose To determine the clinical performance of DAILIES TOTAL1 (DT1), Clariti 1Day (C1D), and 1-DAY ACUVUE TruEye (AVTE) silicone hydrogel daily disposable contact lenses (SiHy DDCLs). Methods Eligible participants, subdivided into asymptomatic and symptomatic groups, wore each SiHy DDCLs for three consecutive days. Each participant attended three visits (on day 1 at 0 hours; on days 1 and 3 after 8 hours of wear) per lens type. The order of lens wear was randomized, with at least 1 day washout between lenses. Lens-related performance was evaluated by assessing lens surface deposits, wettability, pre-lens noninvasive tear breakup time, lens movement, and centration; ocular response assessments included conjunctival redness, corneal staining, and conjunctival staining and indentation. Results Fifty-one asymptomatic and 53 symptomatic participants completed the study. For all visits, the mean noninvasive tear breakup time was about 1 second longer with DT1 than with C1D and AVTE (p < 0.01). Overall, the wettability of all three lenses was good; however, DT1 was graded marginally better than the other lenses (both p < 0.01). On day 3, eyes wearing AVTE had significantly more dehydration-induced corneal staining compared with DT1 (AVTE, 24%; DT1, 11%; p < 0.01). After 8 hours, conjunctival staining was different between lenses (greatest with C1D and least with DT1; all p < 0.01). Conjunctival indentation was more prevalent with the C1D lenses (n = 70) compared with DT1 (n = 1; p < 0.01) and AVTE (n = 11; p < 0.01). There were no differences between asymptomatic and symptomatic lens wearers for any of the clinical parameters (all p > 0.05). Conclusions Each of the three SiHy DDCLs performed well. Noninvasive tear breakup time was longest and wettability was greater with DT1. C1D had the most conjunctival staining conjunctival indentation. There was no difference between asymptomatic and symptomatic wearers with regard to ocular response and contact lens–related parameters. These results suggest that SiHy DDCLs may be an excellent contact lens modality for the symptomatic patient.

Comfort Response of Three Silicone Hydrogel Daily Disposable Contact Lenses

Purpose To evaluate subjective ocular comfort across the day with three silicone hydrogel daily disposables (SHDDs) in a group of adapted lens wearers. Methods Masked subjects (asymptomatic or symptomatic of end-of-day (EOD) dryness with habitual lenses) wore three SHDDs: DAILIES TOTAL1 (DT1), Clariti 1day (C1D), or 1-DAY ACUVUE TRUEYE (AVTE), each for 3 days. On day 2, wearing time (WT) and comfort ratings after insertion, at 4, 8, and 12 hours, and at EOD were recorded. Because not all subjects wore lenses for 12 hours, comfort was analyzed across the day (up to 8 hours, 8 to 12 hours), and a new variable (“cumulative comfort” [CC]) was calculated for EOD. Results One hundred four subjects completed the study (51 asymptomatic, 53 symptomatic). The two groups had different WTs (mean WT, 14.0 and 12.7 hours, respectively; p < 0.001). Ocular comfort was rated higher in the asymptomatic group throughout the day (p < 0.001). One hundred four subjects wore all three SHDDs for at least 8 hours, whereas 74 (45 asymptomatic, 29 symptomatic) subjects wore them for 12 hours or longer. Comfort ratings were higher with DT1 (least square means [LSM] = 91.0) than with C1D (LSM = 86.5; p < 0.001) and AVTE (LSM = 87.7; p = 0.011) for the first 8 hours and lower with C1D compared with DT1 (p = 0.012) from 8 to 12 hours. Mean EOD (± SD) comfort with the C1D lens was 72 ± 21, lower than both DT1 (mean, 79 ± 17; p = 0.001) and AVTE (mean, 78 ± 21; p = 0.010). Mean CC was higher in the asymptomatic group (mean, 1261 ± 59) compared with that in the symptomatic group (mean, 1009 ± 58; p < 0.001) and higher for DT1 (mean, 1184 ± 258) than C1D (mean, 1094 ± 318; p = 0.002) and AVTE (mean, 1122 ± 297; p = 0.046). Conclusions All three SHDDs had average WTs of 12 hours or longer for 1 day. Comfort during the first 12 hours was highest with DT1 (similar to AVTE between 8 and 12 hours) and lowest with C1D. End-of-day comfort was lowest with C1D, and CC was highest for DT1. Cumulative comfort may be a valuable new metric to assess ocular comfort during the day.