Scientific Presentations


Guthrie S, Woods J, Vega J, Orsborn G, Ng AY, Jones L.. Exploring the factors which impact overall satisfaction with contact lenses Optometry & Vision Science 2020 [ Show Abstract ]

Purpose: To evaluate the performance of two spherical lenses, one silicone hydrogel (SiHy) (somofilcon A) and one hydrogel (Hy) (etafilcon A), using subjective evaluations after 1-week and to correlate the relationships between specific subjective evaluations of lens performance and subjective overall satisfaction.
Methods: Fifty-five subjects participated in a prospective, double-masked, bilateral crossover dispensing study, wearing each lens for 1 week in a randomized order. Subjective ratings (0-10 scale) were completed after 1 week based on a typical day experience and a 4-point Likert scale (Strong/slight preference for each lens) was used to determine lens preference.
Results: Data for both lenses were combined and correlation analyses were conducted. Overall satisfaction was found to be significantly correlated (p<0.01) with handling for insertion (r=0.64), overall satisfaction with vision (r=0.64), handling for removal (r=0.50), comfort at insertion (r=0.59), comfort at end of day (r=0.61) and overall satisfaction with comfort (r=0.88). In addition, insertion comfort was significantly correlated with overall satisfaction with comfort (r=0.66). Considering the lenses separately, SiHy was rated significantly higher for handling for lens insertion compared to Hy (9.4 vs 8.1, p<0.01) and correlation strength with overall satisfaction varied greatly with lens material (SiHy: r=0.26, p=0.05 vs Hy: r=0.72, p<0.01). Overall lens preference based on lens handing for insertion also strongly favoured SiHy (37 subjects vs 18, p<0.01). Comfort at insertion was rated significantly higher at insertion with SiHy (9.0 vs 8.1, p<0.01) and similarly at end of day (8.1 vs 7.9, p=0.80). Correlation strength of comfort at insertion/end of day with overall satisfaction again varied with lens material (Insertion: SiHy: r=0.40 vs Hy: r=0.61; End of day: SiHy: r=0.76 vs Hy: r=0.58; all p≤ 0.01). There were no other statistically significant differences in subjective results for SiHy and Hy.
Conclusions: Significant correlations were found between overall satisfaction and the specific subjective evaluations of handling, vision and comfort. Interestingly, handling for insertion had a similar correlation (r) value as vision, suggesting that handling for insertion should not be underestimated when considering overall patient satisfaction. And while insertion and end of day comfort correlated moderately with overall satisfaction, overall satisfaction with comfort highly correlated with overall satisfaction. Separate analysis of SiHy and Hy also indicate that lower handling and comfort scores for Hy at insertion drove a higher correlation, suggesting that dissatisfaction with both handling for lens insertion and comfort upon lens insertion can play major roles in overall dissatisfaction with a lens.

Luensmann D, Schulze M, Ng AY, Woods J, Jones L.. Refitting symptomatic daily disposable contact lens wearers with dry eye disease with delefilcon A lenses Optometry & Vision Science 2020 [ Show Abstract ]

Purpose: To refit symptomatic wearers of daily disposable (DD) contact lenses with a confirmed dry eye diagnosis with Dailies Total1 (delefilcon A, Alcon) to evaluate the performance of the new lenses after one month of wear.
Methods: In this prospective, participant-masked study (over-labelled lenses), symptomatic DD lens wearers were recruited who demonstrated symptoms and signs of dry eye disease according to the TFOS DEWS II criteria. The performance of the lenses after one month was evaluated using subjective ratings and comfort scores, and by determining average wear time and comfortable wear time. Lens wear times as well as subjective symptom scores for comfort, dryness and vision (0-100 scale, with 100 being best) with habitual DD were collected at the screening visit and these results were then compared to delefilcon A after 1 month of wear. The data were not normally distributed, therefore non-parametric analysis (Wilcoxon Matched Pairs Test) was conducted. Data are reported as median (range), with delefilcon A data reported first.
Results: In total, 27 symptomatic DD lens wearers (19 female, 8 male) completed the study. Comfort ratings across all participants were significantly higher (p=0.014) for delefilcon A (80 (40-100)) compared to habitual DD lenses (80 (25-90)). Participants reported less dryness (p=0.007) with delefilcon A compared to their own lenses (80 (40-100) vs 70 (20-95)), and no difference in vision (p>0.05, 90 (50-100) vs (85 (60-100)). There were no statistically significant differences in total hours of lens wear per day (p>0.05, 12.5 hours (6.5-17) vs 11 hours (2.5-16)) or for comfortable wearing time (p>0.05, 8 hours (1-17) vs 6 hours (1-14.8). There were no lens-related ocular findings after one month of delefilcon A wear.
Conclusion: In general, participants had a positive lens wear experience with delefilcon A and rated this lens more comfortable and less dry compared to their habitual DD lenses. This suggests that symptomatic DD lens wearers with dry eye disease may benefit when refit into delefilcon A lenses.

Luensmann D, Woods J, McParland M.. Toric lens fitting success supported by an online fitting App Contact Lens Anterior Eye 2020 [ Show Abstract ][ PDF ]

Purpose: To provide eye care professionals quick access to lens parameter availability and to make soft toric lens fitting easier, online tools are now available to calculate and suggest a first choice prescription based on the patient’s subjective refraction. How close the recommended prescription matches the dispensed lens has been investigated in this study.

Method: In clinical studies, two daily disposable toric lenses, stenfilcon A and somofilcon A, and one monthly replacement toric lens, comfilcon A (all CooperVision, Inc.), were fitted and dispensed to 54, 37 and 47 habitual lens wearers respectively, following the manufacturer’s fitting guides. The final lens prescriptions were determined by the clinician based on over-refraction and lens rotation (Final-Rx). In a secondary analysis the subjective refraction data and back vertex distance were entered in the OptiExpert™ app to determine the recommended initial trial lens (App-Rx). The prescription results from both approaches were compared by calculating the mean differences (Bland-Altman) and the percentages of matching prescriptions following predetermined allowances for sphere, cylinder and axis.

Results: The mean differences between OptiExpert™ and the clinician final prescriptions for sphere, cylinder and axis were within ±0.13DS, ±0.01DC and ±1.38 degrees, respectively. For allowance combination sphere ±0.25D, cylinder ±0.00DC, axis ±10 degrees, the lens prescriptions from both methods matched in 75-82% of eyes (82% stenfilcon A, 75% somofilcon A, 79% comfilcon A). For allowance combination of sph ±0.50D, cyl ±0.00DC, axis ±20 degrees the Final-Rx and the App-Rx matched in 86-92% of eyes (91% stenfilcon A, 92% somofilcon A, 86% comfilcon A).

Conclusions: All three toric lens types showed a predictable on-eye performance, resulting in a close agreement between the initial OptiExpert recommended prescription and the lens prescription dispensed by the clinician. The OptiExpert™ app can therefore confidently be used to assist CooperVision toric lens fitting in order to help optimize patient chair time.

Luensmann D, Woods J, McParland M.. The use of a modern web-application to assist reusable toric lens fitting success Contact Lens Anterior Eye 2020 [ Show Abstract ][ PDF ]

Purpose: Increasing numbers of online tools are available to assist ECPs in fitting contact lenses. In this study, the contact lens prescription of a reusable toric silicone hydrogel lens was determined using a traditional fitting guide and the results were compared to the prescription recommended by the lens fitting app OptiExpert™.

Method: Forty-seven habitual lens wearers were fit with monthly replacement toric silicone hydrogel contact lenses (comfilcon A; CooperVision, Inc.).The manufacturer’s fitting guide was followed and the final lens prescription was determined based on the subjective refraction, the over-refraction and lens rotation (Final-Rx). Following this clinical study, the participant’s subjective refraction data and back vertex distance were entered in the OptiExpert online app to determine the recommended initial trial lens prescription (App-Rx). In this secondary analysis, the fitting results from both approaches were compared using Pearson correlation analysis. Different allowances for sph (±0.25, ±0.50D), cyl (±0.00DC) and axis (±10, ±20degrees) were combined to calculate the percentage of matching fitting results between both methods. Additionally, Bland-Altman graphs were plotted.

Results: A high correlation was found in respect to sphere, cylinder and axis between the Final-Rx and the App-Rx (all r ≥0.88). For the allowance combination of sphere ±0.25D / cylinder ±0.00DC / axis ±10, the lens prescriptions from both methods matched in 79% of eyes. For the allowance combination of sphere ±0.50D / cylinder ±0.00DC / axis ±20, the Final-Rx and the App-Rx matched in 86% of eyes. Bland-Altman comparisons between methods determined a mean difference of +0.06D for sph, +0.01D for cyl and 1.38 degrees for axis.

Conclusions: For most participants, the initial trial lens power recommended by the OptiExpert app was in close agreement to the final power dispensed in the clinical setting. The OptiExpert app can confidently be used as a clinical tool to aid comfilcon A toric lens fitting success.

Phan CM, Shukla M, Heynen M, Walther H, Jones L.. Development of an In Vitro Blink Model for Measuring Drug and Comfort Agent Elutes from Soft Contact Lens Polymers Optometry & Vision Science 2020 [ Show Abstract ]

Purpose: To develop an advanced in vitro blink model that could be used to examine release of a wide variety of components (topical drugs; comfort agents etc) from soft contact lenses.
Methods: The model was designed using CAD software and 3D printed using an SLA printer. A UV-curable resin polymer was used to fabricate the main components of the eye model to ensure water-sealed parts. The eyelid and eyeball were synthesized from a polyvinyl alcohol and a silicone material respectively. Simulated tear fluid is delivered through tubing attached to the eyelid. With each blink cycle (1 blink/10s), the eyelid slides and flexes across the eyeball to create an artificial tear film. The flow-through fluid is collected in a specialized trough. Two contact lenses, etafilcon A and senofilcon A, were incubated in 2 mL of a water-soluble red dye for 24 hours and then placed on the eye model. The release of the dye was measured at t= 0.5, 1, 2, 4, 8, 12, and 24 hours (n=3) in phosphate buffered saline (flow rate = 5 µL/min). The dye release from the lenses was also evaluated in a vial containing 2 mL of PBS over 24 hours (n=3). The amount of dye in the samples was determined using a UV/Vis spectrophotometer at 520 nm.
Results: All of the contact lenses were visibly red after the incubation with the dye. After the release studies, the etafilcon A lenses became transparent with a slight red tint, whereas the senofilcon A lenses retained a moderate red colour. For the vial study, the release of the dye from the contact lenses was rapid within the first 4 hours, which was then followed by a slower release phase. In contrast, dye release from the lenses on the eye model was significantly slower and was sustained over the 24-hour period. The total amounts of dye released in the eye model were also significantly lower compared to the vial (p<0.05), which could be attributed to the absorption of the dye into the eyelid. From the total amount of tear fluid (7.2 mL) that was infused into the eye model, approximately 5.2 ± 0.6 mL of flow-through was collected. The loss of fluid can be attributed to fluid absorption into the eyelid and contact lenses, as well as evaporation.
Conclusion: The blink model developed in this study could be used to measure the release of topical ophthalmic drugs or comfort agents from contact lenses. The results showed that the release kinetics of a dye from contact lenses on the eye model was significantly different than that of a vial. The model also simulated non-specific absorption of the dye into the eyelid. Future work will focus on developing polymers to simulate the absorption of drugs on the eye.

Schulze M, Ng AY, Luensmann D, Guthrie S, Woods J, Jones L.. The subjective response to verofilcon A daily disposable contact lenses during extensive digital device use Optometry & Vision Science 2020 [ Show Abstract ]

Purpose: To evaluate the subjective response of habitual lens wearers during extensive digital device use when switched to Precision1 (verofilcon A) daily disposable (DD) contact lenses (CLs).
Methods: Volunteers between 18-40 years of age who used digital devices for at least 6 hours/day while wearing their habitual CLs were recruited for the study. Eligible participants were dispensed with verofilcon A DD CLs for a period of 2 weeks, during which they were required to wear the study CLs for at least 5 days/week and at least 10 hours/day. Participants returned after 142 days for their final visit, where they reported their CL wear time and time spent using digital devices, and rated their typical experience on a 0 to 100 scale, with 100 being best. Comfort, dryness and clarity of vision with verofilcon A were rated directly after insertion, after 6 hours of digital device use, and just before removal, as well as by rating their overall performance. Participants also completed a 4-point (strongly agree, slightly agree, slightly disagree, strongly disagree) Likert scale-based questionnaire. Subjective ratings were not normally distributed, therefore non-parametric analysis was conducted and data are reported as median (range). The Likert scale responses were analyzed using binomial testing.
Results: Twenty participants completed the study (18F:2M), mean age of 25.1 ± 6.0 years (range 19-40). They reported their typical day to include median CL wear time of 13.8 hours (10.5-17), comfortable CL wear time of 12.1 hours (8-16.5) and digital device use of 9 hours (6-12). After 2 weeks of verofilcon A DD CL wear, subjective ratings after 6 hours of digital device use were high, with ratings for a typical day of 93 (68-100) for comfort, 93 (52-100) for dryness and 96 (70-100) for clarity of vision. After 2 weeks of wear, the majority of participants agreed that the study lenses provided good comfort (16/20 subjects; p=0.01) and good vision (18/20; p<0.01) all day long. Similarly, the majority of participants were satisfied with the comfort (16/20; p=0.01), vision (18/20; p<0.01) and overall performance (16/20; p=0.01) they experienced with the study lenses while using digital devices for 6 hours. Additionally, most reported they did not experience any eye strain while using verofilcon A lenses (n=16/20; p=0.01). No significant lens-related ocular findings were observed after 2 weeks of wear.
Conclusions: After 2 weeks of wear, participants rated the performance of verofilcon A DD CLs very highly, with median overall performance ratings for comfort, dryness and vision all 93 on the 0 to 100 scale (with 100 being best). Verofilcon A DD CLs may be a viable alternative for those struggling with their habitual lens performance when spending long hours using digital devices.

Woods J, Guthrie S, Varikooty J, Jones L.. Satisfaction of habitual wearers of reusable multifocal lenses when refitted with a daily disposable, silicone hydrogel multifocal lens Contact Lens Anterior Eye 2020 [ Show Abstract ][ PDF ]

Purpose: Visual performance with multifocal contact lenses (MFCL) can vary with lens design. This study simulated a real-world refit of habitual wearers of reusable MFCL with a silicone hydrogel (somofilcon A), daily disposable multifocal (DDMF) lens to assess visual and overall experience with the new design and modality.

Method: Subjects rated the DDMF and compared it with their habitual reusable MFCL. The habitual MFCL prescription was not reviewed or confirmed as optimal, though all reported having an eye-examination within 2-years. Subjects were masked to the DDMF brand. After 2 weeks of daily wear with the new lens, subjects reported their experience using 0-10 ratings and Likert scales.

Results: Twenty-eight subjects, spanning 14 habitual lens brands, completed the study. Visual acuity with DDMF was statistically better than with habitual MFCL for all four distances measured (all p<0.05); distance (≥6m): -0.040.09, long intermediate (1.5m): -0.110.11, short intermediate (0.75m): -0.100.09, and near (0.4m): 0.020.09. Subjective vision clarity was statistically better with the DDMF for distance tasks in the dark, long intermediate tasks, and when considering all visual needs (all p<0.05). There were no statistical differences (all p>0.05) for vision clarity performing tasks at distance, short intermediate and near. When asked for a preference, the DDMF was significantly preferred over habitual for long intermediate tasks (p=0.03), but not different for tasks at other distances. Ease of insertion was statistically better with the DDMF (p=0.03); ease of removal was not different. End of day comfort was not different from the habitual lenses (p=0.10), however the DDMF was rated better for end-of-day dryness (p=0.01) and overall satisfaction with lenses (p=0.04).

Conclusions: This daily disposable, silicone hydrogel (somofilcon A), multifocal lens provided good vision and overall performance. Many ratings showed it to provide statistically better performance than their habitual reusable MFCL, supporting the benefits of a trial wear period.