Publications

Showing 25 results out of 431 in total.

Dumbleton,K., Caffery,B., Dogru,M., Hickson-Curran,S., Kern,J., Kojima,T., Morgan,P. B., Purslow,C., Robertson,D. M., Nelson,J. D. The TFOS International Workshop on Contact Lens Discomfort: Report of the subcommittee on epidemiology Investigative Ophthalmology and Visual Science 2013;54(11):TFOS20-TFOS36

Dumbleton,K., Jones,L., Chalmers,R., Williams-Lyn,D., Fonn,D. Clinical characterization of spherical post-lens debris associated with lotrafilcon high-DK silicone lenses CLAO Journal 2000;26(4):186-192 [ Show Abstract ]

Purpose: Experience with high Dk silicone hydrogel lenses has revealed post-lens debris, which is characterized by the appearance of spherical, translucent particles referred to as 'mucin balls.' The objectives of this analysis were to characterize the presence of mucin balls, determine whether any ocular characteristic predicts the development of mucin ball debris, and determine whether there is any association between mucin balls and the ocular response to contact lens wear. Methods: Ninety-two subjects wore lotrafilcon A lenses on an extended wear basis for up to 30 nights and were followed for 6 months. Mucin balls were graded on a 0 to 4 scale at three visits. Subjective ratings and biomicroscopic appearance were recorded at all visits. Results: Mucin balls were observed in 70% of subjects at one or more visits, and 29% of subjects at all three visits. There was no change in the mean grade of mucin balls over time. Mucin balls were graded > 1 in 20% of eyes, > 2 in 6% of eyes, and > 3 in 2% of eyes. Subjects who exhibited mucin balls at each clinical visit had significantly steeper keratometry readings along the flatter meridian (44.3 D) than those who never exhibited mucin balls (42.9 D, P<0.0001). The percentage of subjects who 'never' use lubricating drops was higher in the subjects with mucin balls (P=0.0014). No association was found between mucin ball observation and biomicroscopic appearance, inflammatory responses, or subjective responses. Conclusions: The presence of mucin balls does not appear to be detrimental to contact lens wear. Eyes with steeper corneal curvature were significantly more likely to present with mucin ball debris, indicating they may be a function of lens fit. Clinical factors that may be modified in order to menage the more severe presentation of mucin balls are the use of lubricating drops and the number of nights extended wear schedule.

Dumbleton,K., Keir,N., Moezzi,A., Feng,Y., Jones,L., Fonn,D. Objective and subjective responses in patients refitted to daily-wear silicone hydrogel contact lenses Optometry and Vision Science 2006;83(10):758-768 [ Show Abstract ]

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. © 2006 American Academy of Optometry.

Dumbleton,K., Richter,D., Bergenske,P., Jones,L. W. Compliance with lens replacement and the interval between eye examinations Optometry and Vision Science 2013;90(4):351-358 [ Show Abstract ]

PURPOSE: Eye care practitioners (ECPs) acknowledge that their patients do not always follow recommendations for lens replacement, but many may not realize the possible implications for their offices. The study was conducted to investigate whether there is a relationship between contact lens compliance and the interval between full eye examinations (IEE). METHODS: The study was conducted in ECP offices in the United States. Eye care practitioners and patients independently completed linked questionnaires, evaluating their contact lens wear and care. Patients were required to be current wearers of daily disposable (DD) lenses or reusable silicone hydrogel lenses with a manufacturer-recommended replacement frequency (MRRF) of 2 weeks (2WR) or 1 month (1MR). RESULTS: A total of 2147 questionnaires from 141 offices were eligible. Fifty-four percent of patients were wearing 2WR, 37% 1MR, and 9% DD lenses. Wearers of 2WR lenses were significantly less compliant with replacement than wearers of both DD and 1MR lenses (34% vs. 74% and 67%, both p < 0.001); patients purchasing an annual supply were more compliant (55% vs. 45%, p < 0.001). The mean IEE was 16 months and was longer for wearers who were noncompliant with the MRRF (17.4 months vs. 14.5 months, p < 0.001). Other factors affecting IEE were household income (p = 0.030), insurance (p < 0.001), purchase source (p < 0.001), and sex (p = 0.007). CONCLUSIONS: Patients who were not compliant with the MRRF had longer IEEs and were less likely to purchase an annual supply of lenses. Patients who purchased lenses from their ECP, had a higher household income, had eye examination insurance, and were female had shorter IEEs. Patients failing to replace their lenses when scheduled were also found to be less compliant with lens care procedures. Eye care practitioners should reinforce the importance of all aspects of lens wear and care with their patients, with the overall aim of reducing possible complications and retaining successful contact lens wearers in their offices. Copyright © 2013 American Academy of Optometry.

Dumbleton,K., Richter,D., Woods,C., Jones,L., Fonn,D. Compliance with contact lens replacement in Canada and the United States Optometry and Vision Science 2010;87(2):131-139 [ Show Abstract ]

PURPOSE.: To assess eye care practitioners (ECPs) recommendations for replacement frequency (RF) of silicone hydrogel (SH) and daily disposable (DD) lenses in Canada and the U.S. and to compare noncompliance (NC) with manufacturer recommended RF by the ECP and patient, and the reasons given for NC. METHODS.: Invitations to participate were sent by e-mail to ECPs in Canada and the U.S. Twenty patient surveys were sent to 420 ECPs, and 2232 eligible surveys were received from 216 ECPs (26% Canada, 74% U.S.). Questions related to patient demographics, lens type, wearing patterns, ECP instructions for RF, and actual patient RF. ECPs provided lens information and their recommendation for RF after the surveys were completed and sealed in envelopes. Responses were anonymous. RESULTS.: DD accounted for 18% (Canada) vs. 16% (U.S.) of wearers (p > 0.05); 35% (Canada) vs. 45% (U.S.) wore 2-week replacement SH (2WR; p = 0.011); and 47% (Canada) vs. 39% (U.S.) wore 1-month replacement SH (1MR) lenses (p = 0.025). Thirty-four percent (Canada) vs. 18% (U.S.) of ECPs recommended longer RFs than the manufacturer recommended RF for 2WR lens wearers (p 0.05) and were lowest for DD (13% Canada, 12% U.S.), followed by 1MR (33% Canada, 28% U.S.). The highest NC rates were with 2WR (50% Canada, 52% U.S.). The most frequent reason for NC with 2WR and 1MR was 'forgetting which day to replace lenses' (54% Canada, 53% U.S.) and in DD wearers 'to save money' (56% Canada, 29% U.S., p < 0.001). CONCLUSIONS.: 1MR lenses are more frequently prescribed in Canada. ECPs in Canada were NC with 2WR lenses more frequently than U.S. ECPs, but patient NC rates were the same in both countries for all lens types. ECP and patient NC rates were highest for 2WR lens wearers. Copyright © 2010 American Academy of Optometry.

Dumbleton,K., Woods,C., Fonn,D. An investigation of the efficacy of a novel ocular lubricant Eye and Contact Lens 2009;35(3):149-155 [ Show Abstract ]

OBJECTIVE: To investigate the efficacy of a novel ocular lubricant compared with a commercially marketed ocular lubricant in a group of noncontact lens wearers currently using over-the-counter products for the management of symptoms of moderate to severe dry eye. METHODS: This was a prospective, double-masked study that randomized 110 subjects in a ratio of 1:1 to receive a novel ocular lubricant (test group) or a marketed ocular lubricant (control group). Subjects were instructed to instill the lubricant eye drops at least three times daily. After enrollment, subjects were evaluated at baseline and at 7 and 30 days. They were also required to complete a series of home-based subjective questionnaires after 15 days. Main outcomes were subjective symptoms and objective clinical assessment at 7 and 30 days. RESULTS: The test group had higher overall comfort ratings than the control group (P = 0.012). Seventy-one percent of the test group and 57% of the control group said the drops used "somewhat" or "definitely" improved ocular comfort; 62% of the test group had greater end-of-day comfort compared with 45% of the control group (P = 0.015). There were no between-group differences in visual acuity, tear quality or quantity, corneal staining, conjunctival staining, or bulbar and limbal conjunctival hyperemia. CONCLUSIONS: The novel ocular lubricant offers equivalent or superior comfort compared with a marketed lubricant eye drop. Objective clinical outcomes were not statistically significantly different between the two groups. © 2009 Lippincott Williams & Wilkins.

Dumbleton,K., Woods,C., Jones,L., Fonn,D., Sarwer,D. B. Patient and practitioner compliance with silicone hydrogel and daily disposable lens replacement in the United States Eye and Contact Lens 2009;35(4):164-171 [ Show Abstract ]

OBJECTIVE: The objectives of this study were to assess current recommendations for replacement frequency (RF) of silicone hydrogel (SH) and daily disposable (DD) lenses, to determine compliance with these recommendations, and to investigate the reasons given for noncompliance. METHODS: A package containing 20 patient surveys was sent to 309 eye care practitioners (ECPs) in the United States who had agreed to participate in the study. One thousand eight hundred fifty-nine completed surveys were received from 158 ECPs and 1,654 surveys were eligible for analysis. Questions related to patient demographics, lens type, lens wearing patterns, the ECP instructions for RF, and the actual patient reported RF. ECPs were asked to provide lens information and their recommendation for RF after the surveys had been completed and sealed in envelopes. All responses were anonymous. RESULTS: Sixty-six percent of patients were women and their mean age was 34 ± 12 years. Eighty-eight percent of lenses were worn for daily wear, 12.8 ± 3.2 hours a day, 6.2 ± 1.5 days a week. Lens type distribution was 16% DD, 45% 2 week (2W) SH, and 39% 1 month (1M) SH. ECP recommendations for RF varied according to the lens type; 1% of 1M (95% CI 0.2-1.7), 4% of DD (95% CI 2.1-7.2), and 18% of 2W (95% CI 15.1-20.7) patients were given instructions that did not conform to the manufacturers' recommended RF (MRRF). When considering only those patients who were given the correct instructions for RF, 38% were not compliant with the MRRF; noncompliance rates varied according to the lens type and were 12% for DD (95% CI 8.6-17.2), 28% for 1M (95% CI 24.9-32.1), and 52% for 2W (95% CI 47.8-55.8). The most frequent reasons for over wearing lenses were "forgetting which day to replace lenses" (51%) and "to save money" (26%). Fifty-three percent believed that a reminder system would aid compliance; the most popular methods being a cell phone reminder or text message (29%) and a nominated day each week or month (26%). Discussions between the ECPs and the patients were more extensive for patients who were compliant with the MRRF. CONCLUSIONS: ECPs recommended RFs more frequently with DD and 1M SH lenses than with 2W SH lenses, consistent with manufacturers' recommendations. Patients were less compliant with RF than ECPs for all lens types investigated. Patients were most compliant with RF when wearing DD lenses and least compliant when wearing 2W SH lenses. Better communication facilitated greater compliance with RF. More than half of those not replacing lenses, when recommended, reported that this was because they forgot which day to replace their lenses. © 2009 Lippincott Williams & Wilkins, Inc.

Dumbleton,K., Woods,C., Jones,L., Richter,D., Fonn,D. Comfort and vision with silicone hydrogel lenses: Effect of compliance Optometry and Vision Science 2010;87(6):421-425 [ Show Abstract ]

PURPOSE. Silicone hydrogel (SH) lenses are usually replaced after 2 weeks (2W) or 1 month (1M); however, many patients do not comply with the manufacturers' recommended replacement frequency (MRRF). The purpose of this analysis was to investigate the effect of compliance with MRRF on comfort and vision in SH wearers. METHODS. As a part of a larger study investigating compliance with MRRF, patients were asked to rate their subjective comfort and vision from 0 (very poor) to 10 (excellent) in the morning, at the end of the day (EVE), when lenses were new, and needed replacing (NR). RESULTS. One thousand three hundred forty-four patients wore 2W replacement modality (2WR) (n = 717) or 1M replacement modality (1MR) (n = 617) SH lenses. Comfort and vision in the morning and when lenses are new were significantly higher than for EVE and NR (p < 0.001). Twenty-nine percent (95% confidence interval 25.3-32.4) of 1MR and 59% (95% confidence interval 55.5-62.7) of 2WR wearers were non-compliant with the MRRF. Compliance had a significant effect on EVE (p = 0.002, p = 0.008) and NR (p < 0.001, p < 0.001) comfort and vision. After accounting for compliance, EVE and NR comfort and EVE vision were higher for 1MR than 2WR (p = 0.015, p = 0.044, p = 0.019). CONCLUSIONS. Compliant patients had better EVE and NR comfort and vision than non-compliant patients, regardless of replacement modality. Optimal subjective performance with SH lenses seems to be facilitated by replacing lenses as recommended. Copyright © 2010 American Academy of Optometry.

Dumbleton,K., Woods,C. A., Jones,L. W., Fonn,D. The impact of contemporary contact lenses on contact lens discontinuation Eye and Contact Lens 2012 [ Show Abstract ]

OBJECTIVES: Discontinuation or "dropout" from contact lens (CL) wear continues to afflict the CL industry. This study was conducted to determine whether the advent of new CL materials and designs has impacted the dropout rate and the reasons for discontinuation. METHODS: Current and lapsed CL wearers residing in Canada were recruited using Facebook to take part in an on line survey investigating CL wearing experiences during 2008 to 2010 and to establish the percentage of participants who temporarily and permanently discontinued CL wear during the period surveyed. RESULTS: Four thousand two hundred seven eligible surveys were received (64% female; median age 27 years). Forty percent had lapsed from lens wear for at least 4 months; however, 62% of the lapsed wearers (LWs) resumed wear. There were no differences between LWs and nonlapsed wearers (NLWs) with respect to gender; however, LWs were older, started lens wear when older, and had not worn lenses for as long as NLWs (all P<0.001). More NLWs than LWs wore silicone hydrogel CLs (49% vs. 38%, P<0.001) and more LWs than NLWs wore daily disposable lenses and hydrogel CLs (24% vs. 19% and 22% vs. 18%, respectively, P≤0.001). Primary reasons for discontinuation were discomfort (24%), dryness (20%), red eyes (7%), and expense (7%). Compliance with lens replacement was no different between LWs and NLWs (48% vs. 45%). CONCLUSIONS: About 23% of those surveyed had discontinued CL wear permanently. The primary reasons for dropping out continue to be discomfort and dryness. Dropout rates were lower in silicone hydrogel wearers.

Dumbleton,K., Woods,C. A., Jones,L. W., Fonn,D. The impact of contemporary contact lenses on contact lens discontinuation Eye and Contact Lens 2013;39(1):93-99 [ Show Abstract ]

OBJECTIVES: Discontinuation or "dropout" from contact lens (CL) wear continues to afflict the CL industry. This study was conducted to determine whether the advent of new CL materials and designs has impacted the dropout rate and the reasons for discontinuation. METHODS: Current and lapsed CL wearers residing in Canada were recruited using Facebook to take part in an on line survey investigating CL wearing experiences during 2008 to 2010 and to establish the percentage of participants who temporarily and permanently discontinued CL wear during the period surveyed. RESULTS: Four thousand two hundred seven eligible surveys were received (64% female; median age 27 years). Forty percent had lapsed from lens wear for at least 4 months; however, 62% of the lapsed wearers (LWs) resumed wear. There were no differences between LWs and nonlapsed wearers (NLWs) with respect to gender; however, LWs were older, started lens wear when older, and had not worn lenses for as long as NLWs (all P<0.001). More NLWs than LWs wore silicone hydrogel CLs (49% vs. 38%, P<0.001) and more LWs than NLWs wore daily disposable lenses and hydrogel CLs (24% vs. 19% and 22% vs. 18%, respectively, P=0.001). Primary reasons for discontinuation were discomfort (24%), dryness (20%), red eyes (7%), and expense (7%). Compliance with lens replacement was no different between LWs and NLWs (48% vs. 45%). CONCLUSIONS: About 23% of those surveyed had discontinued CL wear permanently. The primary reasons for dropping out continue to be discomfort and dryness. Dropout rates were lower in silicone hydrogel wearers. © 2013 Lippincott Williams & Wilkins.

Dumbleton,K. A., Chalmers,R. L., McNally,J., Bayer,S., Fonn,D. Effect of lens base curve on subjective comfort and assessment of fit with silicone hydrogel continuous wear contact lenses Optometry and Vision Science 2002;79(10):633-637 [ Show Abstract ]

Purpose. To study the effect of base curve on subjective comfort of silicone hydrogel extended wear lenses. Methods. Ninety-five subjects were first trial fitted with 8.6-mm base curve lotrafilcon A (Focus Night & Day) lenses and then with 8.4-mm lenses only if poor subjective comfort or poor fit was present. Comfort and fit were assessed after 15 min. Subjects with discomfort or signs of poor fit were then trial fitted with 8.4-mm lenses. Results. Of 190 eyes, 74.2% were fitted with 8.6-mm lenses, and 23.7% required 8.4-mm lenses. Two (2.1%) subjects could not be fitted with either base curve. Mean steep keratometry (K) reading for eyes dispensed with 8.6-mm lenses was 43.88 D and 45.56 D for eyes dispensed in the 8.4-mm lenses (p < 0.001). Conclusions. A clinically useful criterion showing the need for 8.4-mm lenses was steep K of ≥45.50 D; 77% of these eyes required the steeper lens for good comfort and fit. Subjective discomfort with 8.6-mm lenses was also a useful signal for the need of a steeper lens; mean comfort scores for those subjects rose from 6.33 with 8.6-mm lenses to 9.44 with the 8.4-mm lenses for eyes requiring the steeper lens (p < 0.001).

Dumbleton,K. A., Chalmers,R. L., Richter,D. B., Fonn,D. Changes in myopic refractive error with nine months' extended wear of hydrogel lenses with high and low oxygen permeability Optometry and Vision Science 1999;76(12):845-849 [ Show Abstract ]

Background: A small but significant increase in myopia after extended wear of low oxygen permeability (Dk) hydrogel lenses has been previously reported; however, the specific impact of hypoxia on refractive status and corneal curvature with extended wear are not well documented. The purpose of this study was to compare the refractive changes induced over a period of 9 months' extended wear with high-Dk fluorosiloxane hydrogel lenses and low-Dk hydrogel lenses. Methods: Adapted daily wear contact lens wearers were randomly assigned to one of two groups. The low-Dk group wore etafilcon A (Dk = 28) for up to 7 days and 6 nights and the high-Dk group wore Iotrafilcon A (Dk = 140) for up to 30 days and nights. Refractive error and corneal curvature were measured at 3-month intervals over 9 months of extended wear. Results: The etafilcon A group demonstrated an average increase in myopia of 0.30 D over the 9-month period; however, no change in spherical myopic correction was measured in the Iotrafilcon A group. The cylindrical component did not change in either group. A stratified analysis revealed a greater increase in myopia for low myopes than moderate myopes in the etafilcon A group but no difference in the Iotrafilcon A group. Keratometric analysis revealed no change in the etafilcon A group and a small degree of central corneal flattening in both major meridians of 0.35 D in the Iotrafilcon A group. Conclusions: Nine months of extended wear of low-Dk lenses is associated with a small degree of myopic progression in adult myopes that appears to be reversible. Wearing fluorosiloxane-hydrogel lenses of high-Dk had no impact on refractive error and may be associated with a small degree of central corneal flattening.

Dumbleton,K. A., Chalmers,R. L., Richter,D. B., Fonn,D. Vascular response to extended wear of hydrogel lenses with high and low oxygen permeability Optometry and Vision Science 2001;78(3):147-151 [ Show Abstract ]

Purpose. The purpose of this study was to determine the impact of extended wear of high and low oxygen permeability (Dk) lenses on the development or resolution of limbal hyperemia and corneal neovascularization in a randomized prospective clinical trial. Methods. Adapted daily-wear contact lens wearers were randomly assigned to one of two groups. The low-Dk group (N = 23) wore etafilcon A lenses (Dk/t = 40) for up to 7 days and 6 nights, and the high-Dk group (N = 39) wore lotrafilcon A lenses (Dk/t = 175) for up to 30 days and nights. Limbal hyperemia and neovascularization were assessed and graded during 9 months of extended wear. A stratified analysis to determine how change in ocular redness depended on initial presentation was also conducted. Results. On a 0 to 100 scale, extended wear of low-Dk lenses resulted in a 16-point increase in limbal hyperemia (p < 0.0001); no significant change occurred with the high-Dk lenses. The difference was greatest for low-Dk participants who initially presented with lower levels of hyperemia (N = 18). There was a slight resolution of redness in participants who initially presented with higher levels of hyperemia (N = 10) after wearing the high-Dk lenses. Neovascularization increased by an average of 0.5 on a scale of 0 to 4 in low-Dk lens wearers (p < 0.0001) but remained unchanged in the high-Dk lens wearers. The increase was most marked for the low-Dk group with lower levels of neovascularization at baseline. Conclusions. Subjects who wore lenses with higher oxygen permeability for 9 months of extended wear exhibited a lower vascular response of the ocular surface compared with subjects who wore lenses of lower oxygen permeability for the same period. This result was found both for the surface limbal vessels and in the deeper neovascular stromal vessels. Moderate neovascularization also developed after 3 months of extended wear of low-Dk hydrogels, whereas high-Dk lenses caused no neovascularization.

Dumbleton,K. A., Richter,D., Woods,C. A., Aakre,B. M., Plowright,A., Morgan,P. B., Jones,L. W. A multi-country assessment of compliance with daily disposable contact lens wear Contact Lens and Anterior Eye 2013;36(6):304-312 [ Show Abstract ]

Purpose: To investigate compliance with daily disposable contact lens (DDCL) wear and investigate re-use of lenses according to country and DDCL material worn. Methods: Optometrists invited eligible DDCL patients from their practices to participate in a survey on DDCL wear in Australia, Norway, the United Kingdom (UK) and the United States (US). Eligible participants completed an online or paper version of the survey. Results: 805 participants completed the survey (96% online): Australia 13%, Norway 32%, UK 17%, US 38%. The median age was 38 years; 66% were female. Silicone hydrogel (SiHy) DDCLs were worn by 14%. Overall, 9% were non-compliant with DDCL replacement; Australia 18%, US 12%, UK 7% and Norway 4%. There were no differences with respect to sex, years of contact lens wear experience or DDCL material (SiHy versus hydrogels). The primary reason for re-use was "to save money" (60%). Re-use of DDCLs resulted in inferior comfort at insertion and prior to lens removal (p= 0.001). 75% reported occasional napping and 28% reported sleeping overnight for at least one night in the preceding month, while wearing their DDCLs. Conclusion: Non-compliance with replacement of DDCLs occurred in all countries investigated; the rate was highest in Australia and lowest in Norway. Re-use of DDCLs was associated with reduced comfort. DDCL wearers often reported wearing lenses overnight. It is important for optometrists to counsel their patients on the importance of appropriate lens wear and replacement for DDCLs. © 2013 British Contact Lens Association.

Dumbleton,K. A., Spafford,M. M., Sivak,A., Jones,L. W. Exploring compliance: A mixed-methods study of contact lens wearer perspectives Optometry and Vision Science 2013;90(8):898-908 [ Show Abstract ]

PURPOSE: Using both quantitative and qualitative research methods, this article explores in detail the lens wear and care habits of adapted contact lens wearers and seeks a better understanding of what enables and constrains patient compliance with appropriate lens wear and lens care. METHODS: The study was conducted in two phases: a preliminary online questionnaire (quantitative phase), identifying types of noncompliance, and a series of sequentially conducted focus groups (qualitative phase), exploring constraints to, and enablers of, compliance. RESULTS: One hundred participants completed the online questionnaire; 12 of them also participated in one of four focus groups. The most frequently reported aspects of noncompliance revealed were failure to replace lenses when scheduled, inappropriate lens purchase and supply, sleeping while wearing lenses, use of tap water with lenses and failure to wash hands, failure to clean and replace cases regularly, and inappropriate use of care systems. Using an iterative process, a number of "themes" associated with noncompliance were identified in the focus group discussions. The most frequently occurring themes related to the consequences that may occur if patients were noncompliant with one or more aspects of their contact lens wear and the importance of receiving instructions regarding the most appropriate way to wear and care for their lenses. Most of the themes that emerged during the analysis were both constraints to, and enablers of, compliance. CONCLUSIONS: This study confirms the frequent types of noncompliance with contact lens wear and care while offering a greater understanding of what may constrain and enables contact lens wear and care compliance. Future qualitative studies may help eye care practitioners and the contact lens industry to develop strategies and tools to aid compliance and success in contact lens wear. © 2013 American Academy of Optometry.

Dumbleton,K. A., Woods,C. A., Jones,L. W., Fonn,D. Comfort and adaptation to silicone hydrogel lenses for daily wear Eye and Contact Lens 2008;34(4):215-223 [ Show Abstract ]

Objectives. To investigate initial comfort and adaptation of currently successful low oxygen transmissibility soft lens wearers refitted with silicone hydrogel (SH) lenses for daily wear. Methods. Fifty-five subjects were enrolled in a subject-masked 5-month clinical trial in which they wore 5 SH lenses in a randomized, crossover design. Comfort, burning, and dryness were rated on scales of 0 to 100 immediately on insertion and the time for lens settling was recorded. Symptoms were then rated at various times, using BlackBerry wireless communication devices (Research in Motion, Waterloo, Canada), during the day for 2 cycles of 2 weeks wear for each lens type. Results. Comfort immediately on insertion varied between lens types (P=0.002). All lens types were reported by the subjects to have settled within 30 to 45 sec of insertion (P=0.14) and "settled" comfort was greater than comfort immediately on insertion (P<0.001). Comfort within the first hour of wear also varied between lens types (P=0.02). Comfort during the day decreased significantly for all lenses (P=0.001), but there was no difference between lenses (P=0.19) and no effect of lens age (P=0.15). The wearing times were greater with the SH lenses than the habitual lenses worn before study commencement (P=0.001). Overall performance of the lenses after 4 weeks was high, with no difference between lenses (P=0.45). Conclusions. Initial comfort and adaptation to all SH lenses were good and no differences in the overall ratings were found between the 5 SH lenses investigated. Decreased comfort was noted later in the day with all lens types, but longer wearing times were reported with the SH lenses than previous hydroxyethyl methacrylate-based lenses. © 2008 Contact Lens Association of Ophthalmologists, Inc.

Dumbleton,K. A., Woods,C. A., Jones,L. W., Fonn,D. The relationship between compliance with lens replacement and contact lens-related problems in silicone hydrogel wearers Contact Lens and Anterior Eye 2011;34(5):216-222 [ Show Abstract ]

To evaluate the relationship between compliance with replacement frequency (RF) and contact lens (CL)-related problems in silicone hydrogel (SiHy) wearers. Methods: 501 SiHy wearers from seven optometry offices completed surveys regarding their lens wear and any CL related problems which they may have experienced in the preceding 12 months. File review was subsequently conducted at their optometry offices to confirm the information provided. Results: 49% of respondents were wearing 2-week replacement (2WR) and 51% 1-month replacement (1MR) SiHy lenses. 67% wore their lenses for longer than the manufacturers' recommended RF (MRRF) and 60% for longer than their optometrist's recommended RF (ORRF). The mean RF was 2.6× the MRRF for 2WR and 1.5× for 1MR wearers (p< 0.001) with median values of 31 and 37 days, respectively. Twenty-three percent reported signs or symptoms consistent with potential complications relating to CL wear. This rate was significantly higher for wearers who were non-compliant with the ORRF than compliant wearers (26% versus 18%, p= 0.028). It was also higher for those multipurpose solution users who reported never/almost never rubbing and rinsing their lenses when compared with those who did this every night (29% versus 17%, p= 0.007). Conclusions: Two thirds of the SiHy wearers did not comply with the MRRF and 2WR wearers stretched the replacement interval of their lenses to a greater degree than 1MR wearers. Failing to replace lenses when recommended and failing to rub and rinse lenses were associated with a higher rate of patient-reported CL problems. © 2011 British Contact Lens Association.

Dumbleton,K. A., Woods,M., Woods,C. A., Jones,L. W., Fonn,D. Ability of patients to recall habitual contact lens products and enhancement of recall using photographic aids Contact Lens and Anterior Eye 2011;34(5):236-240 [ Show Abstract ]

To determine the proportion of soft contact lens (CL) wearers who are able to recall their habitual products (lenses and care system) correctly from memory, and to evaluate the value of using photographic aids (PAs) to improve recall. Methods: 103 soft lens wearers attended 2 visits to investigate their habitual CL product use. At the first visit they were asked to recall which products they were using and then to identify their products from PAs. They returned for a second visit with their products for confirmation. Results: 51% correctly reported their lens brands from memory alone, which improved to 87% with the use of the PAs (p< 0.001). 41% correctly reported their habitual care system from memory alone, which improved to 80% with the use of PAs (p< 0.001). Females were better at recalling care system brand names than males (49% versus 27% correct, p= 0.040) and wearers with more than 1 year experience with their habitual CLs had better recall than those with up to 1 year experience (63% versus 27%, p= 0.014). Conclusion: Less than 50% of contact lens wearers were able to recall the names of their habitual lens and lens care products correctly from memory. PAs improved this recall significantly for both contact lenses and contact lens care systems. © 2011 British Contact Lens Association.

Du Toit,R., Pritchard,N., Heffernan,S., Simpson,T., Fonn,D. A comparison of three different scales for rating contact lens handling Optometry and Vision Science 2002;79(5):313-320 [ Show Abstract ]

Purpose. To compare the validity, responsiveness, and reliability of three subjective rating scales applied to soft contact lens (SCL) handling. Methods. Fifty-four adapted SCL wearers handled three different types of lenses on two occasions and rated the handling with each scale: visual analogue scales (VAS), 20-interval visual analogue scales with descriptors (VAD) and Likert rating scales with five intervals (LRS). Results. There were significant differences between the scales (p < 0.01) and between the subjective ratings of lens handling (p < 0.001). VAS showed the least variability, exhibited the highest construct validity, were the most responsive, and were the most reliable: interclass correlations (0.63), coefficient of repeatability (27.5), and correlation between test and retest (Spearman r = 0.65, [all p < 0.05]). Higher repeatability, because of the fewer intervals of LRS, was not demonstrated and, generally, LRS was the least satisfactory scale. Handling was rated as easiest using VAD and most difficult using LRS. Conclusions. Although all three scales can be used to provide measures of lens handling, VAS may provide a simple and repeatable tool for measuring subjective responses.

Du Toit,R., Simpson,T. L., Fonn,D., Chalmers,R. L. Recovery from hyperemia after overnight wear of low and high transmissibility hydrogel lenses Current eye research 2001;22(1):68-73 [ Show Abstract ]

Purpose. To measure the limbal vascular response after 8 hours of eye closure while wearing high and low permeability lenses compared to control eyes without lenses. Method. Twenty neophyte participants wore lotrafilcon A silicone hydrogel lenses (HDk; Dk = 140) or etafilcon A hydrogel lenses (LDk; Dk = 18). On two different nights the lenses were randomly worn for 8 hours during sleep in the right eyes only. Left eyes were non-lens wearing controls. Biomicroscopic images of the temporal limbal area were videotaped at baseline, on eye opening and every 20 minutes for 3 hours. A masked observer graded digitized images of the limbal area. Results. On waking and after lens removal there were no differences in hyperemia between the HDk and LDk lens wearing eyes. There were also no differences at any time between the HDk lens wearing eyes and their control eyes (p > 0.05). On waking the eyes wearing the LDk lens were more hyperemic compared to baseline (p < 0.001) and compared to their control eyes at 20 (p < 0.001) and 180 minutes (p = 0.01), indicating slower recovery from hyperemia. The HDk lens wearing eyes recovered to their baseline levels by 180 minutes (p = 0.99), compared to the LDk lens wearing eyes, which had not recovered to baseline levels by 180 minutes (p = 0.04). Conclusion. The reduction in hyperemia over time of the HDk lens wearing eyes was the same as the controls. The LDk lens wearing eyes were more hyperemic than the controls on waking and the reduction in hyperemia over time was slower. This suggests that the slower recovery from hyperemia may be affected by the lower oxygen transmissibility of the LDk lens.

Du Toit,R., Situ,P., Simpson,T., Fonn,D. The effects of six months of contact lens wear on the tear film, ocular surfaces, and symptoms of presbyopes Optometry and Vision Science 2001;78(6):455-462 [ Show Abstract ]

Purpose. To assess the tear film, ocular surfaces, and symptoms of ocular discomfort in a presbyopic population before and after contact lens wear. Methods. A total of 150 presbyopes (49% were previous soft contact lens wearers) participated in a clinical trial in which they wore either monovision (single vision Acuvue lenses) or Acuvue Bifocal contact lenses. Clinical measurements of tear film, biomicroscopy, and corneal sensitivity as well as subjective ratings using the Dry Eye Questionnaire were collected at the initial visit and repeated after 6 months. Comparisons were made between age groups (40 to 51 years and 52 to 71 years) and genders before and after contact lens wear. Associations between objective and subjective tests were sought. Results. After 6 months of contact lens wear, clinical signs had worsened by less than one-half of a grade, and tear break up time (TBUT) worsened by 3 s. Only TBUT was lower for the older age group. Females had less bulbar hyperemia, more sensitive eyes, more lissamine green staining, and lower TBUT and phenol red thread measurements (all p lt; 0.04). Twenty-eight percent experienced dryness before contact lens wear, but this figure increased to 68% when wearing contact lenses. There were no age differences, but almost twice as many females as males reported dryness. Reporting symptoms of dryness was associated with gender, corneal sensitivity, and type of corneal staining. Conclusions. These results provide a representation of the ocular surface condition and symptoms of ocular discomfort in the middle-aged population and seem similar to reports of younger populations. Wearing contact lenses seems to influence dry eye symptoms more than age or gender. Therefore, presbyopes should not be excluded from consideration for contact lens fitting.

Du Toit,R., Vega,J. A., Fonn,D., Simpson,T. Diurnal variation of corneal sensitivity and thickness Cornea 2003;22(3):205-209 [ Show Abstract ]

Purpose. To measure the diurnal variation of central corneal sensitivity and thickness over 24 hours. Methods. A noncontact pneumatic esthesiometer to measure central corneal sensitivity and an optical pachymeter to measure central corneal thickness were used on 20 noncontact lens wearers. These measurements were performed at 22:00 before 8 hours of sleep and on the following day on eye opening and at hourly intervals between 7:00 and 22:00. Results. Central corneal sensitivity varied by 35% over the 24 hours. Sensitivity was significantly lower by 17.1 ± 2.1% on eye opening and recovered to the level of the previous night after 4 hours. Corneal sensitivity continued to increase throughout the day but was not significantly higher. Central corneal thickness varied by 3.9% over the 24 hours. The mean overnight corneal swelling was 2.9 ± 0.31%, and 2 hours after eye opening, the cornea had deswelled to the same thickness as the previous night. The cornea thinned further throughout the day, but there were no statistically significant differences between the values after 14:00. There was a high correlation between corneal sensitivity and thickness over time (r = 0.8; p < 0.05). Discussion. Corneal sensitivity correlated with corneal thickness: both were higher on awakening and then decreased and remained below the levels measured the previous night. This may be due to physiological and/or environmental factors. The lack of significant differences between the values after 14:00 suggests that baseline may be measured at any time from 7 hours after eye opening.

Efron,N., Brennan,N. A., Bright,F. V., Glasgow,B. J., Jones,L. W., Sullivan,D. A., Tomlinson,A., Zhang,J. Contact lens care and ocular surface homeostasis Contact Lens and Anterior Eye 2013;36(SUPPL.):S9-S13 [ Show Abstract ]

The early focus of contact lens wear and ocular health was on oxygen delivery. However, as we learn more about how the eye works, and investigate how the contact lens interacts with the cornea, the role of the tear film has risen in prominence. A healthy tear film is critical for normal ocular homeostasis, and abnormalities of the tear film are the primary cause of dry eye. In order to improve patient eye health and comfort during lens wear, we need to further elucidate the relationship among contact lenses, contact lens solutions, the tear film, and the corneal epithelium, and find ways to maintain homeostasis of the ocular surface. In this section, we review the latest data and opinions on this complex relationship between contact lenses and lens care solutions. © 2013 British Contact Lens Association.

Efron,N., Brennan,N. A., Chalmers,R. L., Jones,L. W., Lau,C., Morgan,P. B., Nichols,J. J., Szczotka-Flynn,L. B., Willcox,M. D. Thirty years of ‘quiet eye’ with etafilcon A contact lenses Contact Lens Anterior Eye 2020;43(3):285-297 [ Show Abstract ]

Frequent replacement contact lenses made from the etafilcon A hydrogel lens material were introduced onto the market over 30 years ago, and etafilcon A remains the most widely used hydrogel lens material today. Although the prescribing of silicone hydrogel lenses is increasing, millions of lens wearers globally have been wearing hydrogel lenses for many years and exhibit a physiologically-stable ‘quiet eye’, with a low profile of adverse events. Hydrogel lenses are demonstrated to maintain a low inflammatory response and infection risk profile during daily wear, which in the case of etafilcon A, may be related to its low modulus, and the naturally-protective, anti-microbial, non-denatured lysozyme absorbed into the lens from the tear fluid. Although improved corneal physiology from decreased hypoxia with silicone hydrogel lenses is well accepted, equivalent levels of corneal oxygenation are maintained during daily wear of low to medium powered hydrogel lenses, which do not impede the daily corneal de-swelling process, and do not induce clinically significant changes in ocular health. Therefore, hydrogel lenses remain an important alternative for daily wear in modern contact lens practice.

Efron,N., Jones,L., Bron,A. J., Knop,E., Arita,R., Barabino,S., McDermott,A. M., Villani,E., Willcox,M. D. P., Markoulli,M. The TFOS International Workshop on Contact Lens Discomfort: Report of the contact lens interactions with the ocular surface and adnexa subcommittee Investigative Ophthalmology and Visual Science 2013;54(11):TFOS98-TFOS122