Purpose: To compare subjective comfort across three different contact lens multipurpose solutions (MPS) to comfort with a peroxide-based solution with three different soft contact lenses. Methods: Habitual soft contact lens wearers were enrolled at three sites and completed a washout period with no contact lens solution by wearing daily disposable lenses (etafilcon A) and spectacles for at least four days. Subjects were then randomly assigned to a 2-week disposable lens type worn on a daily wear basis: etafilcon A, galyfilcon A, or senofilcon A. Subjects wore a new lens of their assigned type for 10-14 days each while using one of four contact lens care solutions, in random order (A - polyaminopropyl biguanide + polyquaternium, B - POLYQUAD + Aldox, C - alexidine + polyquaternium-1, and D - hydrogen peroxide) with a washout period of at least four days using daily disposable lenses and spectacles between each new solution. The Contact Lens User Experience (CLUE) questionnaire was used to assess comfort after use of each care solution. Using a linear mixed model that controlled for factors including age, comfort score at baseline, and lens type, the CLUE comfort score after using each solution was analyzed, and comfort with each MPS was compared to comfort with the peroxide solution. Non-inferiority of the MPS compared to the peroxide solution was set a priori as the lower limit of the adjusted 95% confidence interval (CI) being greater than -5. Results: Of 237 subjects randomized, 208 (88%) completed all follow-up visits. Mean age (±SD) of the subjects was 31±10 years and 68% were female. Comparing across all lens types, subjective CLUE comfort score with each MPS was not significantly different than with the peroxide solution (F = 0.04; p = 0.99). The adjusted mean ± SE difference in comfort and 95% CI for each MPS compared to solution D (the peroxide solution) were: solution A (0.0 ± 1.9; 95% CI: -4.5,4.4), solution B (-0.4 ± 1.9; 95% CI: -4.7,4.0), and solution C (-0.5 ± 1.9; 95% CI: -4.9,3.9). Conclusions: CLUE comfort using the four solutions tested was similar. The three MPSs tested provided subjective comfort that was the same as (non-inferior to) the peroxide system. These data demonstrate that MPSs provide subjective comfort that is comparable with peroxide disinfection.

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  • R. J. Wirth R. J. Wirth
  • Michael C. Edwards
  • Michael Henderson
  • Carrie R. Houts

Purpose: The field of optometry has become increasingly interested in patient-reported outcomes, reflecting a common trend occurring across the spectrum of healthcare. This article reviews the development of the Contact Lens User Experience: CLUE system designed to assess patient evaluations of contact lenses. CLUE was built using modern psychometric methods such as factor analysis and item response theory. Methods: The qualitative process through which relevant domains were identified is outlined as well as the process of creating initial item banks. Psychometric analyses were conducted on the initial item banks and refinements were made to the domains and items. Following this data-driven refinement phase, a second round of data was collected to further refine the items and obtain final item response theory item parameters estimates. Results: Extensive qualitative work identified three key areas patients consider important when describing their experience with contact lenses. Based on item content and psychometric dimensionality assessments, the developing CLUE instruments were ultimately focused around four domains: comfort, vision, handling, and packaging. Item response theory parameters were estimated for the CLUE item banks (377 items), and the resulting scales were found to provide precise and reliable assignment of scores detailing users' subjective experiences with contact lenses. Conclusions: The CLUE family of instruments, as it currently exists, exhibits excellent psychometric properties.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially.

Articles published in several prominent educational journals were examined to investigate the use of data analysis tools by researchers in four research paradigms: between-subjects univariate designs, between-subjects multivariate designs, repeated measures designs, and covariance designs. In addition to examining specific details pertaining to the research design (e.g., sample size, group size equality/inequality) and methods employed for data analysis, the authors also catalogued whether (a) validity assumptions were examined, (b) effect size indices were reported, (c) sample sizes were selected on the basis of power considerations, and (d) appropriate textbooks and/or articles were cited to communicate the nature of the analyses that were performed. The present analyses imply that researchers rarely verify that validity assumptions are satisfied and that, accordingly, they typically use analyses that are nonrobust to assumption violations. In addition, researchers rarely report effect size statistics, nor do they routinely perform power analyses to determine sample size requirements. Recommendations are offered to rectify these shortcomings.

Purpose: To report on the development and validation of a short form of the Contact Lens Dry Eye Questionnaire (the CLDEQ-8) to enable it to reflect status of and change in overall opinion ("opinion") of soft contact lenses (SCLs). Methods: Item reduction for the CLDEQ was achieved by correlation with overall opinion of SCLs at follow-up visits in a sample of 38 SCL wearers at one academic clinical site. The CLDEQ-8 score (frequency plus late day intensity of dryness, discomfort, and "blurry vision"; frequency of "closing eyes to rest them" and "removing CLs to relieve discomfort") was then tested in 379 SCL wearers in a multicenter study with analysis stratified by opinion ratings at baseline and 2 weeks postrandomization to new silicone hydrogel SCLs. The sum of CLDEQ-8 scores (maximum 37) was correlated with opinion by Spearman's rank correlation coefficient and analyzed for change in opinion by analysis of variance (ANOVA). Results: The CLDEQ-8 scores in the validation sample were highly correlated with habitual baseline opinion (-0.44, p < 0.0001) and responsive to change in opinion postrandomization (-0.58, p < 0.0001). Baseline CLDEQ-8 scores by opinion status were as follows: Fair: 17.4 ± 8.7, Good 13.7 ± 6.4, Very Good 9.1 ± 4.7, and Excellent 6.4 ± 3.7 (ANOVA, F = 291.1, p < 0.0001). After 2 weeks, change in CLDEQ-8 scores by improvement status was as follows: Much Improved: -16.7 ± 10.0, Unchanged: -2.3 ± 5.0, to Much Worse +8.5 ± 5.8 (ANOVA, F = 16.5, p < 0.001). Conclusions: The CLDEQ-8 score significantly reflected baseline status and change in overall opinion after refitting with two types of silicone hydrogels. The CLDEQ-8 score is a valid outcome measure in SCL clinical trials to reflect opinion of SCLs.

Purpose. To investigate the short-term physiologic response to three soft lens materials with different oxygen permeability characteristics. Methods. Forty-three neophytes were randomly prescribed Acuvue 2, Acuvue Advance (Johnson & Johnson Vision Care), or Focus Night & Day (CIBA Vision) for 4 weeks on a daily-wear basis. A further 19 subjects did not wear lenses (control). Experimental and control subjects were examined 2 and 4 weeks after dispensing. Ocular physiologic response was measured with a slitlamp biomicroscope in a strictly masked fashion. Results. Limbal redness increased in the Acuvue 2 group compared with the other two groups. Conjunctival redness increased more in the Acuvue 2 group than in the Acuvue Advance group. More conjunctival staining was seen with the Acuvue Advance and Focus Night & Day groups compared with the Acuvue 2 group. Increased scores for papillary conjunctivitis were seen in the Focus Night & Day group compared with the Acuvue Advance group. Conclusions. The reduced level of limbal redness seen with the Acuvue Advance and Focus Night & Day groups suggests that these lenses provide more oxygen to the ocular surface than the Acuvue 2 lens to a degree that can be observed clinically. The conjunctival staining response was similar for the Acuvue Advance and Focus Night & Day groups. The results for the Acuvue Advance and Focus Night & Day groups for papillary conjunctivitis may reflect differences in their material and surface properties.

Contact lens discomfort (CLD) is a frequently experienced problem, with most estimates suggesting that up to half of contact lens wearers experience this problem with some frequency or magnitude. This condition impacts millions of contact lens wearers worldwide. Yet, there is a paucity of consensus and standardization in the scientific and clinical communities on the characterization of the condition, including the definition, classification, epidemiology, pathophysiology, diagnosis, management, influence of contact lens materials, designs and care, and the proper design of clinical trials. The Tear Film & Ocular Surface Society (TFOS), which is a nonprofit organization, has conducted two prior international, consensus building workshops, including the Dry Eye WorkShop (DEWS; available in the public domain at http://www.tearfilm.org/tearfilm-reports-dews-report.php) and the Meibomian Gland Dysfunction Workshop (MGD; available in the public domain at http://www.tearfilm.org/tearfilm-reports-mgdreport.php). To that end, TFOS initiated the process of conducting a similar workshop in January 2012—a process that took approximately 18 months to complete and included 79 experts in the field. These experts participated in one or more topical subcommittees, and were assigned with taking an evidence-based approach at evaluating CLD. Eight topical subcommittees were formed, with each generating a related report, all of which were circulated for presentation, review, and input of the entire workshop membership. The entire workshop originally is being published in this issue of IOVS, in English, with subsequent translations into numerous other languages. All of this information is intended to be available and accessible online, free of charge. This article is intended to serve as an Executive Summary of the eight subcommittee reports, and all information contained here was abstracted from the full reports.

  • Carolyn G. Begley
  • Timothy B. Edrington
  • Robin Chalmers Robin Chalmers

This randomized, single-masked, crossover design study measured the degree and frequency of corneal fluorescein staining in 85 hydrogel lens wearers following sequential usage of both a chemical (ReNu®) and a hydrogen peroxide (AOSept®) lens disinfection system for 1 month each. The study was conducted in late 1992 in three School of Optometry contact lens clinics, using standard fluorescein staining and observation techniques. Subjects presented with greater corneal fluorescein staining after the ReNu system compared with the AOSept system, with mean staining grades of 0. 61 and 0.40, respectively, on a 0–4 grading scale (p = 0.0012, paired t-test). Analyzed for individual changes in lens staining, 37 subjects showed at least Grade greater staining following use of the ReNu system, whereas 13 subjects showed greater staining after using the AOSept system (p = 0.0001, chi-square). This pattern remained the same when a change of Grade 1 was used as the criterion for a significant clinical change, with 12 subjects presenting with greater staining by Grade 1 or greater when using ReNu and six subjects had Grade 1 greater staining using AOSept (p = 0.0001, chi-squared). Overall patient comfort and lens comfort in the evening were also significantly better while subjects used the AOSept system (p = 0.0243 and p = 0.0219, respectively, paired t-test). However, symptoms of discomfort were not significantly correlated with signs of corneal fluorescein staining (rho = 0.0134, p = 0.87, Spearman's rank correlation). While 83.5% of the subjects exhibited staining during at least one visit in the study, the severity of corneal fluorescein staining was in no case severe enough to curtail contact lens wear. The staining may or may not be a significant factor in successful hydrogel lens wear.

Purpose: To determine if the ocular comfort of symptomatic contact lens (CL) wearers can be substantially influenced by choosing a better or worse performing CL-lens care product (LCP) combination. Methods: Twenty-four symptomatic and 13 nonsymptomatic CL wearers were enrolled into a prospective, crossover, randomized clinical trial. Two CL-LCP combinations were chosen from studies previously conducted at the Brien Holden Vision Institute that were found to provide the best (galyfilcon A/polyhexanide, combination 1) and worst performance (balafilcon A/polyquaternium-1 and myristamidopropyl dimethylamine + TearGlyde, combination 2) in terms of end-of-day comfort. Subjects were not informed whether they were categorized as symptomatic or nonsymptomatic nor were they aware of the rankings of each CL-LCP combination. Subjects were randomly allocated to one of the CL-LCP combinations for 8 days on a daily wear basis. Contact lens fitting was assessed after insertion from the packaging solution. Take-home questionnaires assessing ocular comfort and dryness (1 to 10 numeric rating scale) were completed on insertion and after 2 and 8 hours of wear on days 2, 4, and 6. Ocular symptoms were assessed on days 2, 4, and 6 after 8 hours of wear. A 48-hour washout period during which CLs were not worn was applied, with the procedure repeated using the second combination. Results: In symptomatic subjects, combination 1 was rated significantly better than combination 2 after 8 hours of wear for ocular comfort (7.7 ± 1.3 vs. 7.1 ± 1.5, p = 0.01) and ocular dryness (7.5 ± 1.6 vs. 7.0 ± 1.6, p = 0.045), with less frequent symptoms of ocular dryness (p < 0.01) and lens awareness (p < 0.01) reported. No significant differences were found in nonsymptomatic subjects. Conclusions: Ocular comfort and symptoms in symptomatic CL wearers can be perceptibly improved by switching to an alternative CL-LCP combination. This finding provides justification for the efforts of both eye care practitioners and researchers to improve the comfort of CL wearers.

Purpose: To evaluate subjective responses, rates of solution-induced corneal staining (SICS), and corneal infiltrative events (CIEs) associated with a silicone hydrogel when worn under a daily disposable (DD) or daily wear (DW) modality. Methods: Data were obtained from seven prospective clinical trials, involving 283 subjects wearing Senofilcon A contact lenses (Johnson and Johnson Vision Care, Jacksonville, FL). Four groups wore the contact lens on a DW basis using multipurpose solutions (DW-MPS, n = 160), two groups using hydrogen peroxide (DW-H2O2, n = 83), and one group as a DD (n = 40). Participants were followed for 3 months using the same protocol. Subjective ratings were compared between DD and DW groups using a linear mixed model. Rates of SICS and CIE were calculated as the percent frequency of first events within the 3-month study. Association of SICS and CIE with subjective responses was analyzed using a linear mixed model. Results: End-of-day comfort and dryness ratings were significantly better for DD (8.5 ± 1.7 and 8.6 ± 1.7, respectively) compared with DW-H2O2 (7.7 ± 1.8, p = 0.01; 7.6 ± 1.9, p = 0.006, respectively) and DW-MPS (7.7 ± 1.7, p = 0.004; 7.6 ± 2.0, p = 0.003, respectively). Compared with DD, a higher incidence of CIE and SICS was found for DW-MPS (0.0 vs. 3.9%, p = 0.021; 0.9 vs. 8.6%, p = 0.002, respectively). Comfort at insertion and end of day and end-of-day dryness scores were significantly lower for participants who experienced SICS (8.2 ± 1.6, 7.0 ± 1.9, and 7.0 ± 2.2) than those who did not (8.8 ± 1.2, p = 0.004; 7.9 ± 1.7, p = 0.002; and 7.9 ± 1.8, p = 0.003, respectively). Comfort at insertion scores were significantly lower for participants who experienced CIEs than those who did not (8.2 ± 1.5 vs. 8.8 ± 1.4, p = 0.032). Conclusions: Senofilcon A clinical response is modulated by the lens care products. All lens care products tested reduced subjective responses relative to DD modality, whereas MPS increased the incidence of CIEs and SICS. Senofilcon A performs best when used on a DD basis.

The aim was to determine the extent of daily disposable contact lens prescribing worldwide and to characterise the associated demographics and fitting patterns. Up to 1,000 survey forms were sent to contact lens fitters in up to 40 countries between January and March every year for five consecutive years (2007 to 2011). Practitioners were asked to record data relating to the first 10 contact lens fits or refits performed after receiving the survey form. Survey data collected since 1996 were also analysed for seven nations to assess daily disposable lens fitting trends since that time. Data were collected in relation to 97,289 soft lens fits, of which 23,445 (24.1 per cent) were with daily disposable lenses and 73,170 (75.9 per cent) were with reusable lenses. Daily disposable lens prescribing ranged from 0.6 per cent of all soft lenses in Nepal to 66.2 per cent in Qatar. Compared with reusable lens fittings, daily disposable lens fittings can be characterised as follows: older age (30.0 ± 12.5 versus 29.3 ± 12.3 years for reusable lenses); males are over-represented; a greater proportion of new fits versus refits; 85.9 per cent hydrogel; lower proportion of toric and presbyopia designs and a higher proportion of part-time wear. There has been a continuous increase in daily disposable lens prescribing between 1996 and 2011. The proportion of daily disposable lens fits (as a function of all soft lens fits) is positively related to the gross domestic product at purchasing power parity per capita (r2 = 0.55, F = 46.8, p < 0.0001). The greater convenience and other benefits of daily disposable lenses have resulted in this modality capturing significant market share. The contact lens field appears to be heading toward a true single-use-only, disposable lens market.

To evaluate the association of symptomatic soft contact lens (SCL)-related corneal infiltrative events (CIEs) with SCL material, lens care products (LCPs), and other risk factors. Cases with symptomatic CIEs were identified in a retrospective, multicenter case-control study at five academic eye care centers. Each case was matched to three controls each who had received eye care near the time of the case's last full examination at that center but were not matched for demographic or other factors. Infiltrate status was established by an expert panel who were masked to sponsor, SCL, and LCP brand. Stratified analyses were conducted removing all daily disposable (DD) and all extended wear (EW) cases. Clinical records from 166 patients with symptomatic CIEs and known EW status were included. Cases used >50 SCL brands and >10 LCP brands. Increased risk in univariate analysis for LCP was not significant after adjustment for other factors. In the multivariate analysis of all cases, use of reusable SCLs (4.03×; 95% C.I. 1.12 to 14.67) and EW (3.98×; 2.32 to 6.84) increased risk and patient age (per year older) was protective (0.96×; 0.94 to 0.98). Among daily wear cases (n = 102 cases), use of reusable SCLs (12.46×; 1.54 to 100.62) and silicone hydrogel (SiHy) (1.99×; 1.06 to 3.75) and age (0.95×: 0.92 to 0.97) were associated. Without DD cases (n = 162), EW (4.42×; 2.53 to 7.70), SiHy use (1.84×; 1.03 to 3.29), and patient age (0.96× 0.94 to 0.98) were significant factors. No specific SCL or LCP brands were associated with increased risk. In this community-based trial, younger patients were at increased risk of infiltrative events. DD lenses were protective relative to reusable lenses. Overnight use increased risk in all analyses and silicone hydrogels increased risk in daily wearers, regardless of LCP brand. Improvements in lens storage case hygiene and environment may be a mechanism for reducing risk of CIEs related to SCL use.

The purpose of this study was to investigate the effect of lens care products on short-term subjective and physiological performance silicone hydrogel lenses. Ten subjects wore either lotrafilcon B or galyfilcon A silicone hydrogel contact lenses soaked in a lens care product containing either Polyquad/Aldox or PHMB or control lenses inserted directly from the pack. Subjects wore the lenses for 6 h. Ocular comfort (graded on a 1 to 10 scale) and ocular physiology were assessed. Unworn but soaked lenses were analyzed for metrological changes, release of excipients into phosphate buffered saline, and changes to their surface chemical composition. None of the lens metrology measures or clinically observed conjunctival or limbal redness changed. Corneal staining was significantly (p < 0.008) raised, albeit to low levels, after 6 h wear for either lens type when soaked in the PHMB solution compared with the control lens (lotrafilcon B 0.4 to 0.9 ± 0.7 to 0.4 vs. 0.1 to 0.4 ± 0.3 to 0.5; galyfilcon A 0.2 to 0.3 ± 0.2 to 0.4 vs. 0.0 ± 0.0). For lotrafilcon B lenses, there were decreases in comfort (p = 0.002), increases in burning/stinging (p = 0.002) after 1 h of wear, and increases in lens awareness on lens insertion (p = 0.0001) when soaked in PHMB. However, lotrafilcon B lenses soaked in Polyquad/Aldox showed increases in burning/stinging after 1 and 6 h (p < 0.008) of lens wear. For galyfilcon A lenses, most significant (p ≤ 0.002) changes to symptomatology occurred after soaking in Polyquad/Aldox solution. More PHMB was released from lotrafilcon B lenses, and more MPDS material was released from galyfilcon A lenses. The surface of galyfilcon A lenses changed but irrespective of lens solution type, whereas the changes to the lens surface was dependent on solution type for lotrafilcon B lenses. Lens care products can change corneal staining and comfort responses during wear. These changes may be associated with release of material soaked into lenses or changes to the lens surface composition.

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. 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. 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). 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.

  • Padmapriya Ramamoorthy Padmapriya Ramamoorthy
  • Loraine T Sinnott
  • Jason J Nichols

To examine the effect of general contact lens and material characteristics, care solutions, treatment, and patient-related factors on contact lens-related dry eye. The data were derived from the Contact Lens and Dry Eye Study, designed as a cross-sectional and nested case-control study including 360 subjects. In separate statistical models, logistic regression was used to examine general contact lens characteristics, specific hydrogel lens materials, care solutions, and patient-related factors associated with dry eye status (controlled for age, gender, and current treatments). Several factors were significantly associated with dry eye, including treatment factors such as a recent contact lens refitting (odds ratios [OR] = 5.75, 95% confidence intervals [CI] = 2.14 to 15.46) and use of artificial tears/rewetting drops (OR = 1.09, 95% CI = 1.02 to 1.16), in addition, currently worn materials including Food and Drug Administration (FDA) group II (OR = 2.98, 95% CI = 1.14 to 6.19) and IV (OR = 1.87, 95% CI = 1.08 to 3.24). Significant patient-related factors included decreased overall satisfaction (OR = 3.57, 95% CI = 2.08 to 5.88,), dry eye in the absence of contact lens wear (OR = 6.54, 95% CI = 2.57 to 16.62), reduced daily lens wear duration (OR = 1.16, 95% CI = 1.06 to 1.26), and reduced ability to wear lenses as long as desired (OR = 2.44, 95% CI = 1.30 to 4.54). Care solutions were not associated with contact lens-related dry eye. The strong association of common treatment factors with dry eye status in contact lens wearers suggests that these treatments are not entirely effective. The use of high water content materials was strongly related to dry eye in lens wearers, whereas care solutions were not. Contact lens-related dry eye was also associated with several patient-related factors such as greater ocular discomfort (without lenses), dissatisfaction, and inability to wear lenses for desired durations.

Success in contact lens wear is often judged on the basis of patient "survival" rather than the achievement of satisfactory performance based on specific criteria. In 1971, Sarver and Harris defined a series of standards for successful polymethyl methacrylate (PMMA) lens wear which incorporated criteria for wearing time, comfort, vision, ocular tissue changes, and patient appearance. In this paper we propose a revision of these criteria based on current understanding of the ocular response to contact lens wear. These revised CCLRU (Cornea and Contact Lens Research Unit) standards for success are intended as realistic performance objectives, and can be applied in clinical trials to evaluate and compare the clinical performance of present and future rigid and soft contact lenses, worn for daily and extended wear.

  • Nathan Efron
  • Philip Morgan Philip Morgan
  • Smaragda S. Katsara

The validity of use of two artist-rendered and two photographic sets of grading scales (grading 'systems') designed for gauging the severity of contact lens-related ocular pathology was assessed in terms of precision and reliability. Thirteen observers each graded 30 images--by interpolation or extrapolation to the nearest 0.1 increment--of each of the three contact lens complications (corneal staining, conjunctival redness and papillary conjunctivitis) that were common to all four grading systems. This entire procedure was repeated approximately two weeks later, yielding a total data base comprising of 9360 individual grading estimates. Analysis of variance revealed statistically significant differences in both precision and reliability between systems, observers and conditions (p < 0.03 for system reliability; p = 0.0001 for all other combinations). The artist-rendered systems generally afforded lower grading estimates and better grading reliability than the photographic systems. Corneal staining could be graded less reliably than conjunctival redness and papillary conjunctivitis. Grading reliability was generally unaffected by the severity of the condition being assessed. Notwithstanding the above differences, all four grading systems are validated for clinical use and practitioners can initially expect to use these systems with average 95% confidence limits of +/- 1.2 grading scale units (observer range +/- 0.7 to +/- 2.5 grading scale units). In view of the significant between-system differences revealed in this study, it is advisable to consistently use the same grading system. It may be possible to reduce between-observer differences by applying personalised correction factors to normalise grading estimates.

  • Lyndon W Jones Lyndon W Jones
  • Nancy MacDougall
  • L Gina Sorbara

To compare subjective symptoms and signs in a group of individuals who wear silicone-hydrogel lenses on a daily wear basis while they sequentially used two differing care regimens. Fifty adapted soft-lens wearers were fitted with a silicone-hydrogel lens material (PureVision, Bausch & Lomb). The lenses were worn on a daily wear basis for two consecutive 1-month periods, during which the subjects used either a Polyquad (polyquaternium-1) -based system or a polyaminopropyl biguanide (PHMB) -based system, using a double-masked, randomized, crossover experimental design. Significant levels of relatively asymptomatic corneal staining were observed when subjects used the PHMB-based system, with 37% of subjects demonstrating a level of staining consistent with a classical solution-based toxicity reaction. Only 2% of the subjects exhibited such staining when using the Polyquad-based system. These results were significantly different (p < 0.001). Significant symptoms were not correlated with the degree of staining, with no differences in lens comfort or overall preference being reported between the regimens (p = NS). The only statistically significant difference in symptoms related to minor differences in stinging after lens insertion being reported, with the Polyquad-based system demonstrating less stinging (p < 0.008). Practitioners who fit silicone-hydrogel contact lenses on a daily wear basis should be wary of the potential for certain PHMB-containing multipurpose care systems to invoke corneal staining. Switching to non-PHMB based regimens will eliminate this complication in most instances.

  • Kathryn A Dumbleton Kathryn A Dumbleton

High Dk silicone hydrogel lenses have overcome many of the hypoxic problems associated with traditional extended wear and the popularity of continuous wear (up to 30 nights) with these lens types is increasing. Results from clinical trials indicate that the typical physiological changes associated with edema from conventional extended wear of low Dk/t lenses do not occur with continuous wear of silicone hydrogel lenses. These changes include neovascularization, striae, microcysts and an increase in bulbar and limbal hyperemia. It is perhaps not surprising though that a number of adverse events do still occur with silicone hydrogel lenses when they are worn on a continuous wear basis. These include inflammatory conditions such as contact lens-induced peripheral ulcers (CLPU), contact lens-induced acute red eye (CLARE), infiltrative keratitis (IK) and contact lens papillary conjunctivitis (CLPC). Other events such as superior epithelial arcuate lesions (SEAL) and localised CLPC may be due to mechanical influences. While these conditions are not sight threatening, they may be painful and are certainly inconvenient to both the patient and the practitioner. It is therefore very important that the signs and symptoms associated with these events be recognised in order that they may be accurately identified and appropriately managed. The purpose of this review article is to describe the pathophysiology, etiology, and clinical presentation of these adverse events when observed with continuous wear contact lenses and to discuss their associated risk factors and incidence. Clear management and treatment strategies are also presented and a number of approaches to minimize adverse events with continuous wear of silicone hydrogel contact lenses are suggested.

Increased use of silicone hydrogel contact lenses for daily wear has necessitated a parallel rise in the use of multipurpose care solutions (MPS). This in turn has been accompanied by substantially more reports of solution related complications, in particular corneal staining and low grade infiltrates. Management of these problems involves reducing the impact of care system components on the ocular surface. Options for achieving this include use of low impact lens/MPS combinations, daily disposable lenses or hydrogen peroxide based disinfection systems.

The impact of contemporary contact lenses on contact lens discontinuation

  • K Dumbleton
  • C A Woods
  • L W Jones
  • D Fonn

Dumbleton K, Woods CA, Jones LW, Fonn D. The impact of contemporary contact lenses on contact lens discontinuation. Eye Contact Lens 2013;39:93Y8.

Center for Biologics Evaluation and Research (CBER) Guidance for Industry. E9 Statistical Principles for Clinical Trials. Washington: U.S. Department of Health and Human Services

U.S. Department of Health and Human Services, Food and Drug Administration, Center for Drug Evaluation and Research (CDER), Center for Biologics Evaluation and Research (CBER). Guidance for Industry. E9 Statistical Principles for Clinical Trials. Washington: U.S. Department of Health and Human Services; 1998. Available at: http://www.fda. gov/downloads/drugs/guidancecomplianceregulatoryinformation/ guidances/ucm073137.pdf. Accessed October 16, 2015.

Guideline on the Choice of the Noninferiority Margin. London: European Medicines Agency

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European Medicines Agency. Guideline on the Choice of the Noninferiority Margin. London: European Medicines Agency; 2006. Available at: http://www.ema.europa.eu/docs/en_GB/document_ library/Scientific_guideline/2009/09/WC500003636.pdf. Accessed October 16, 2015.

Center for Biologics Evaluation and Research (CBER) Guidance for Industry: Non-Inferiority Clinical Trials. Washington: U.S. Department of Health and Human Services Available at: http://www

U.S. Department of Health and Human Services, Food and Drug Administration, Center for Drug Evaluation and Research (CDER), Center for Biologics Evaluation and Research (CBER). Guidance for Industry: Non-Inferiority Clinical Trials. Washington: U.S. Department of Health and Human Services; 2010. Available at: http://www.fda.gov/downloads/Drugs/I/Guidances/UCM202140.pdf.