Effect of Short Recovery Periods on Ocular Comfort During Daily Lens Wear.

PURPOSE: To assess the impact of lens-free intervals of varying lengths on end-of-day comfort with soft contact lenses. METHODS: Twenty-five symptomatic lens wearers participated in this randomized, cross-over study involving nine individual 12-hour days: one spectacle (no lens) and eight lens wear days. On each lens wear day, lenses were worn bilaterally in 2-hour intervals, separated by lens-free (recovery) periods of 0, 30, 60, or 80 minutes (repeated throughout the day). For each 2-hour lens wear interval, new lenses were worn. Ocular comfort was rated on a 0 to 100 visual analogue scale (0 = extremely uncomfortable); tear film and ocular parameters were assessed at the beginning and end of each study day. This study involved two different types of silicone hydrogel lenses, and the order of lens type and length of recovery period was randomized. Participants were unaware of the true study purpose and that a new lens pair was used for each lens wear interval. RESULTS: End-of-day comfort on lens wear days was significantly worse than on the spectacle day (p < 0.002). There was no significant effect of the recovery periods on end-of-day comfort (p > 0.05). Although lens wear affected noninvasive tear film break-up time and conjunctival staining, there were no effects of recovery period length on noninvasive tear film break-up time (p > 0.05), tear meniscus height (p > 0.05), corneal staining (p > 0.05), conjunctival staining (p > 0.05), bulbar conjunctival redness (p > 0.05), or limbal redness (p > 0.05). There was no consistent effect of recovery period length on lid margin staining. CONCLUSIONS: Lens-free recovery periods during a 12-hour lens wear day did not positively impact end-of-day comfort in this study. Cumulative lens wear times ranged from 8 to 12 hours, and the results suggest that once the length of lens wear exceeds the usual comfortable wear time, there is no benefit of short recovery periods.

Effect of Masking on Subjective Responses to Daily Disposable Contact Lenses.

PURPOSE: To explore the effect of masking on subjective responses when wearing daily disposable (DD) contact lenses. METHODS: In an adaptation phase, habitual wearers of Manufacturer-A (MFA) (n = 43) and Manufacturer-B (MFB) (n = 53) wore MFA-brand 1 or MFB-brand 1 DDs, respectively, for 30 days, open-label. Subjects were then randomly assigned to one of two experiments. Each experiment included two, 3-day crossover phases. An enhanced version of MFA and MFB lenses (MFA-brand 2 and MFB-brand 2) were worn contralaterally to evaluate potential differences in masking result between manufacturers. Experiment 1: subjects were fully masked to lens and packaging (FM) then unmasked (UM). Experiment 2: subjects were FM then partially masked using an over-label (PM). Comfort ratings (0-100) were recorded for each lens daily and preference between lenses was recorded on day 3 for each crossover phase. The mean difference between 0-100 ratings or preference when FM or PM versus UM for the same lens was considered a measurement of the effect associated with masking. The purpose of the study was withheld from subjects to minimize bias. RESULTS: The effect associated with masking for habitual wearers of MFA and MFB lenses was less than 1 out of 100 (0 ± 2.5) in both experiments. Fifty-eight subjects (60%) expressed no preference when FM. This decreased to 29 (30%) when UM or PM (proportion test, p < 0.001). Approximately half the subjects had a change in lens preference when they were UM or PM, primarily in favor of their habitual lens manufacturer. CONCLUSIONS: Masking did not have a measurable impact on 0-100 ratings with the DD lenses used in this study but did have an impact on lens preference. Subjects were more likely to express a preference when they handled the lenses and were exposed to the lens packaging and, in some cases, able to read the lens brand and lens manufacturer.

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.

Impact of silicone hydrogel lenses and solutions on corneal epithelial permeability.

PURPOSE: The primary purpose of this pilot study was to compare epithelial barrier function (EBF) and staining in a small group of participants using a silicone hydrogel (SH) lens worn on a daily basis with two different care regimens. Secondarily, the aim was to see if there was any correlation between corneal staining and EBF. METHODS: The corneal EBF of 10 non-lens wearers (control) and 15 age-matched asymptomatic SH contact lens wearers (test) were assessed using fluorophotometry. Biomicroscopy was performed to assess corneal staining after the EBF was measured. The lens wearers wore PureVision (FDA group V) SH lenses for two consecutive 1-month periods while using either Alcon Opti-Free Express or Renu Fresh using a randomized, investigator-masked, crossover design. Control subjects were assessed on one occasion, and lens wearers were examined before fitting with lenses and after 7, 14, and 28 days of lens wear, with each combination. RESULTS: Compared with the control group, both study groups had an increase in epithelial permeability at baseline (p ≤ 0.04). There were no changes in EBF during the treatment period for either solution (p = 0.87). A significant difference in EBF was found between the test groups during the treatment period (p = 0.02), with greater permeability in the Renu Fresh-disinfected lenses. There was poor correlation between corneal staining and EBF (r = 0.35, p > 0.05) because of large individual variations. CONCLUSIONS: Daily wear of highly oxygen-permeable SH lenses increases corneal epithelial permeability to fluorescein probably because of increased mechanical effects. In addition, certain lens-solution interactions can add to this effect, as seen in this study. Despite having a low amount of central corneal staining in the Renu Fresh group, staining and EBF did not prove to be well correlated. The presence of central corneal staining is a confounding factor when measuring EBF.

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.

Wettability and silicone hydrogel lenses: a review.

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.

Estimating tear film spread and stability through tear hydrodynamics.

PURPOSE: The stability and ease of spread of the tear-film over the contact lens surface may be an indicator of contact lens surface dewetting. The present in vivo methods of determining lens dewetting are complex. This study introduces a novel and objective way of determining the upward spread and stability of the tear-film through measurement of tear-film particle dynamics. METHODS: Ten adapted contact lens wearers wore the same type of contact lens. Using a video camera mounted to a slit-lamp, the tear-film spread over the lens surface was recorded after a blink, at 8× magnification and capture rate of 30 frames per second, at morning after lens insertion, and after 8 h of lens wear. Images from 20 videos, without blinks and without an observable change in fixation were analyzed without any further postprocessing of the images. Using a customized calibrated ImageJ macro for particle tracking, the velocity of naturally occurring reflective particles was determined. The results were analyzed using the R program and ProFit. RESULTS: The results established that the upward particle velocity was highest immediately after a blink and declined with time. The spread of the tear film measured through upward particle velocity was different on lens insertion than after 8 h of lens wear (p = 0.001). The exponential time constants ± SE were 346.02 ± 29.0 for lens insertion at morning and 1413.13 ± 419.6 after 8 h of lens wear. CONCLUSIONS: A novel and non-invasive way to measure in vivo spread and stability of the prelens tear-film has been developed. Additional studies are needed to understand whether this simple measure is able to differentiate the performance of different soft contact lenses and how this method may help in the understanding other aspects of lens performance such as non-invasive tear breakup time, surface deposition, and lens comfort.

CLEAR - Contact lens wettability, cleaning, disinfection and interactions with tears.

Contact lens materials have undergone significant changes over the past 20 years, particularly with respect to the introduction of silicone hydrogel materials. Whilst this development addressed hypoxic issues, other important areas relating to contact lens success, notably comfort, require further research. Contact lens wettability remains a crucially important part of biocompatibility. Contact lenses can be made more wettable by incorporation of surfactants into blister packs, internal wetting agents, surface treatments or care solutions. However, there remains no clear association between contact lens wettability and comfort, making it challenging to determine the potential for these approaches to be of significant clinical benefit. Most contact lenses are used on a daily wear, reusable basis, which requires them to be disinfected when not worn. The ideal disinfecting solution would also improve comfort during wear. However, balancing these requirements with other factors, including biocompatibility, remains a challenge. Soft lens materials invariably take up and subsequently release certain components of disinfecting solutions onto the ocular surface. This may affect tear film stability and the normal ocular microbiome, and further research is needed in this area to determine whether this has any affect on comfort. Finally, contact lens materials sorb components of the tear film, and these interactions are complex and may change the biochemistry of the tear film, which in turn may affect their comfort. In conclusion, the interaction between lens materials, tear film and disinfection solution plays an important role in the biocompatibility of lenses. However, the exact role and whether this can be altered to improve biocompatibility and comfort during wear remains debatable. This report summarises the best available evidence to examine this complex relationship and the opportunities for practitioners to enhance in-eye comfort of contemporary lenses, along with providing suggestions for areas of study that may provide further information on this topic.

Measurement of the refractive index of soft contact lenses during wear.

PURPOSE: To determine whether the refractive index (RI) of a soft contact lens can be evaluated using refractometry while the lens remains on the eye and to compare this with more traditional ex vivo RI measurements. METHODS: A slitlamp apparatus was modified to incorporate a customized Atago hand refractometer. With a double-masked study design, nine adapted symptomatic soft contact lens wearers wore a contact lens in each eye (lotrafilcon B and etafilcon A) in a randomized order. In vivo RI was determined from the relative Brix scale measurements immediately after lens insertion and after 1 and 10 hr of lens wear. Ex vivo refractometry was performed after 10 hr of lens wear for comparison. Means +/- standard errors of the means are reported. RESULTS: In vivo RI values at baseline were 1.422 +/- 0.0004 (lotrafilcon B) and 1.405 +/- 0.0021 (etafilcon A); after 1 hr of lens wear, values were 1.423 +/- 0.0006 and 1.408 +/- 0.0007, respectively; and after 10 hr of lens wear, values were 1.424 +/- 0.0004 and 1.411 +/- 0.0010, respectively. Ex vivo RI values at the end of the 10 hr wearing period were 1.424 +/- 0.0003 (lotrafilcon B) and 1.412 +/- 0.0017 (etafilcon A). The change in in vivo RI across the day was statistically significant for the etafilcon A lens (repeated-measures analysis of variance, P<0.01) but not for the lotrafilcon B lens (P>0.05). CONCLUSIONS: This novel adaptation of refractometry was able to measure the RI of soft contact lenses during wear (without lens removal). End of day RI measurements using in vivo and ex vivo refractometry were comparable with each other. Future work is required to determine whether this in vivo method can improve our understanding of the relationships between soft contact lens RI, hydration, on-eye lens performance, and symptomology.

Role of diurnal variation of corneal sensory processing in contact lens discomfort.

PURPOSE: To examine the diurnal variation of corneal threshold and suprathreshold sensory processing, symptoms, and tear secretion in symptomatic and asymptomatic contact lens (CL) wearers and controls. METHODS: 26 symptomatic and 25 asymptomatic CL wearers and 15 asymptomatic non-CL wearing controls participated. Cooling thresholds, symptoms and tear meniscus height (TMH) were measured on each of 3 measurement days (random order) on the following schedules; Day-1 within 1 h of awakening (Baseline) and 3, 6 and 9 h later, Day-2 baseline and 9 h later (CLs worn in CL group) and Day-3 baseline and 9 h later. Magnitudes estimates for threshold-scaled suprathreshold stimuli were also estimated on Day-3. Data were analyzed using mixed models and repeated measures ANOVA. RESULTS: Cooling thresholds for the symptomatic group were lower and decreased over Day-1 (p < 0.008) and after 8 h of CL wear on Day-2 (p < 0.001) and were paralleled by increased symptoms (all p < 0.001), whereas minimal variations were found in the asymptomatic and control groups. Magnitude estimates for suprathreshold stimuli were higher (p ≤ 0.002) in the symptomatic group but did not differ significantly over the day. TMH varied little over time and was lower in the symptomatic group, but the difference was not statistically significant. CONCLUSION: Corneal sensitivity and symptoms, but not TMH, increased diurnally irrespective of CL wear in symptomatic CL wearers. These results reveal the essential role of neurosensory abnormalities in CL discomfort and suggest involvement of a central mechanism in the diurnally increased symptoms of these patients.

Monitoring ocular discomfort using a wrist-mounted electronic logger.

PURPOSE: To investigate ocular discomfort during contact lens wear using a wrist-mounted electronic 'lens awareness logger' (LAL). METHODS: Thirty symptomatic contact lens wearers wore study contact lenses for three days. On the first two days, two lens types which are known to differ in end-of-day comfort (lens A: senofilcon A and lens B: balafilcon A), were worn as a matching pair (randomised order). On day three, a pair of lens B was worn. On each day, the participant used a LAL. On day one and two, the participant pressed a button on the LAL whenever they became aware of their lenses due to discomfort. On day three, the participant used a multiple click protocol (1 = mild awareness to 3 = severe awareness) to report discomfort. RESULTS: LAL events were similar on days one and two (17.3 vs. 15.8 events per day). There were significantly more LAL events for lens B (21.6 events per day) in comparison with lens A (11.6 events per day) (p = 0.006). The LAL event profile highlighted peaks in awareness following lens application and towards the end of the wearing cycle. Comparison of the LAL event profile for the two lens types showed significant differences in lens awareness, particularly in the first half of the wearing cycle. LAL events on day 3, showed a uniform distribution of single and double clicks through the day, but a marked peak in triple clicks in the last two hours of lens wear. CONCLUSION: The LAL was able to differentiate between the study lenses and demonstrated differences in their LAL event profiles. Lens awareness associated with discomfort appeared to increase not only in frequency, but also in intensity towards the end of the wearing cycle. The ability of the LAL to track lens awareness suggests it is likely to be a useful tool in furthering understanding of ocular discomfort.

The impact of contact lens wear on ocular surface mucins using a novel clinical fluorescence imaging system.

PURPOSE: Fluorescein-labelled wheat germ agglutinin (F-WGA) acts as a marker for ocular surface mucins. This clinical study sought to investigate whether the degree of F-WGA fluorescence observed at the ocular surface differed between symptomatic contact lens wearers, asymptomatic contact lens wearers and non-contact lens wearers, using a novel imaging system. METHODS: Twenty-five participants (10 symptomatic contact lens wearers, 10 asymptomatic contact lens wearers and 5 non-contact lens wearers) attended a single study visit. Photographs of the cornea, bulbar and tarsal conjunctiva were captured following application of F-WGA solution. RESULTS: The imaging system captured high-resolution images of F-WGA fluorescence at the ocular surface. The degree of fluorescence differed between the ocular surface regions (p < 0.001). A significant difference in fluorescence was observed between participant groups for the cornea (p = 0.01), with both the symptomatic and asymptomatic contact lens wearers showing lower fluorescence than the non-lens wearers. F-WGA associated fluorescence appeared diminished in the lid wiper region of the symptomatic lens wearers, compared to the asymptomatic group (p = 0.025). CONCLUSION: The use of F-WGA as a clinical marker for ocular surface mucins allows an improved understanding of their distribution across the ocular surface. Contact lens wear appears to negatively impact mucin density across the ocular surface, with the most marked effect on the cornea. F-WGA fluorescence appeared diminished in the lid wiper region for the symptomatic contact lens wearing group, indicating that mechanical interaction in this region may play a role in the aetiology of contact lens discomfort. Given the ability of F-WGA to disclose mucin distribution across the ocular surface it is likely to be a key clinical tool in furthering our understanding of (i) the aetiology of contact lens related discomfort, (ii) contact lens designs/materials to minimise interaction with the ocular surface and (iii) dry eye disease and other ocular surface diseases.

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.

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.

Self versus examiner administration of the Ocular Surface Disease Index©.

PURPOSE: To compare the difference in Ocular Surface Disease Index© (OSDI) scores when participants were given the OSDI to complete on their own (self-guided, SG), versus under the guidance of the examiner (examiner-guided, EG). METHODS: 100 participants enrolled in this prospective two-visit study (fifty under-45 years old, 38F/12M; and fifty 45 years-and-older, 42F/8M). Participants who scored ≥1 on the Subjective Evaluation of Symptoms of Dryness (SESoD) were included in this study. Participants completed the OSDI SG during the first visit. Participants returned the next day and repeated the OSDI, but with EG (with standardized instructions). Participants were under deception and believed that they were comparing the OSDI to the SESoD. RESULTS: The mean OSDI score of the SG and EG administration was 32.0±17.3 and 33.8±19.6 respectively (p>0.05) with 95% limits of agreement between -20.6 and +24.2. The correlation between SG and EG administration was Spearman's r=0.81, p<0.01. The mean difference between SG and EG was not significant (p>0.05) for both the under-45 group, and 45-and-older group. The 95% limits of agreement for the under-45 group were smaller than the 45-and-older group (under-45: [-15.5, +13.1,], 45-and-older: [-23.3, +32.2]). A significant difference was found between 8 of the 12 questions items (all p≤0.01). However, the mean difference for each was <0.6 and was not considered to be clinically significant. CONCLUSION: There was no clinically significant difference in OSDI score between SG and EG administration, however having instructions provided with EG administration affected variability of scores in the older group more than the younger group.

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.

Inhibition of defocus-induced myopia in chickens.

PURPOSE: To determine the effect of wearing a lens with a unique peripheral optical design on the development and progression of defocus-induced myopia in newly hatched chickens. METHODS: Eighty-five newly hatched chickens underwent bilateral retinoscopy and A-scan ultrasound to determine their refractive error and axial length. They were randomly divided into Control and two Test groups, in which each chicken was fitted with a goggle-lens over the right eye, with the left eye remaining untreated. The Control group wore a lens of power -10.00 diopters (D) of standard spherical optical design. The two Test lenses both had a central optical power -10.00 D, but used different peripheral myopia progression control (MPC) designs. For all groups, retinoscopy was repeated on days 3, 7, 10, and 14; ultrasound was repeated on day 14. RESULTS: On day 0 there was no statistical difference in refractive error (mean +6.92 D) or axial length (mean 8.06 mm) between Test and Control groups or treated and untreated eyes (all P 0.05). At day 14, 37 (43.5%) of 85 chickens had not experienced goggle detachment and were included in the final analyses. in this cohort there was a significant refractive difference between the treated eyes of the control group (n = 17) and those of test 1 (n = 14) and Test 2 (N = 6) groups (both P <0.01): Control -4.65 ± 2.11 D, Test 1 +4.57 ± 3.11 D, Test 2 +1.08 ± 1.24 D (mean ± SEM). There was also a significant axial length difference (both P < 0.01): Control 10.55 ± 0.36 mm, Test 1 9.99 ± 0.14 mm, Test 2 10.17 ± 0.18 mm. CONCLUSIONS: Use of these unique MPC lens designs over 14 days caused a significant reduction in the development of defocus-induced myopia in chickens; the degree of reduction appeared to be design specific.

3. Ocular surface health with contact lens wear.

Eye care practitioners (ECPs) would tend to agree that wearing contact lenses increases the risk for infection, but millions of patients are still fitted with lenses every year because ECPs feel that the risk is manageable and that their patients' eye health can be protected. The Fusarium and Acanthamoeba keratitis outbreaks of years past were a wake-up call to manufacturers, ECPs, and regulatory agencies that risk cannot be managed without diligence, and that the complex relationship between contact lens materials, contact lens solutions, and compliance needs to be better understood in order to optimize the efficacy of contact lens care and improve care guidelines.

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.

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.