A Clinical Study Evaluating How Delefilcon A Contact Lenses Perform in Satisfied Senofilcon A Contact Lens Wearers

1. INTRODUCTION

Refitting patients into a different Contact Lens (CL) is a common practice for troubleshooting CL discomfort and dissatisfaction [1]. Several CL materials have demonstrated success in re-engaging previously unsatisfied patients in CL wear [1-3]. However, there is much less literature regarding the refitting of currently satisfied CL wearers. Many practitioners may be reluctant to refit their currently satisfied CL wearers, even when newer, more advanced technology is available or when patients can benefit from a cost perspective while having a similar wearing experience. The main reason for this stance may be fear of upsetting the patient and jeopardizing their retention [4]. Recent studies have shown potential for successfully refitting a previously satisfied CL wearer, as similar on-eye performance between CL materials has been reported [5-8].

The Dailies Total1® CL (DT1; delefilcon A; Alcon; Fort Worth, Tx, USA) is a daily disposable CL that has a core modulus of 0.76 Minimum Protection Area (MPA) and an oxygen transmissibility of 156 dk/t. The water content of the CL gradually increases, starting at 33% in the core and approaching 100% at the surface. DT1 CLs featuring this Water Gradient Technology were reported to have a reduced Thin Aqueous Layer Break (TALB) and an increased Non-Invasive Tear-Break Up Time (NIBUT) compared to the CLs when using another conventional silicone hydrogel material in CL wearers [9]. This CL also releases phosphatidylcholine during wear, which is a polar lipid that can be found in natural tears. This type of tear film lipid has been reported to help with tear film stability [10]. This CL material has been recently found to provide adequate comfort to wearers who had previously discontinued CL wear due to dryness and discomfort [1]. In Lievens et al., the subjects reported high satisfaction with their vision, comfort at the end of the day, and overall satisfaction while wearing the study CL. At the end of the 1-month study period, nearly 90% of the subjects reported that they were likely to continue wearing the study CL, and an even greater percentage was willing to recommend it to a friend [1]. Similar rates of satisfaction and a decrease in dryness have also been found in DT1 CL when compared to other CL materials [11, 12]. Acuvue® Oasys MAX (MAX; Senofilcon A; Johnson & Johnson Vision Care, Inc.; Jacksonville, FL, USA) is the newest version of the Acuvue material that has also shown good comfort [8]. MAX is a daily disposable CL that has a comparable core modulus of 0.74 MPA and oxygen transmissibility of 121 dk/t. The water content is 38% throughout the CL. It is designed with TEARSTABLE™ technology, which enhances the stability of the tear film by distributing Polyvinylpyrrolidone (PPV) throughout the CL, resulting in reduced in-vitro evaporative dehydration. This lens also features OPTIBLUE™ LIGHT FILTER (blue-violet and ultraviolet filtering) for protection throughout the day [13].

Despite these advancements in the CL field, the definition of satisfied CL wear remains ill-defined, likely because its subjective nature makes it difficult to quantify. It is often better understood once broken down into the factors that most strongly impact it. The Cornea and Contact Lens Research Unit (CCLRU) defined successful CL use based on wear time, comfort, and vision [14]. These standards require 12 hours of wear each day, for at least 6 days per week, with visual acuity within one line of correction with spectacles, and no reports of ocular discomfort. Other factors, such as ease of handling, have also been found to influence CL satisfaction [5]. However, Diec et al. agree that comfort and vision satisfaction are the most impactful, as they found that when either was unsatisfactory, only 50% of subjects would continue wearing the CL, and if both were unsatisfactory, no subjects wished to continue wearing it [12]. Therefore, the purpose of the current study was to investigate whether successful patients in one lens material (senofilcon A) could be successfully switched to another (delefilcon A). The results of the study may also provide clinical evidence to further expand the utility of DT1 for some clinicians who primarily reserve the lens as a problem-solving refit solution.

2. METHODS

3. RESULTS

This study enrolled 36 participants who were satisfied MAX CL wearers based on self-report and had a median (IQR) CLDEQ-8 score of 8.0 (8.0) units at the baseline visit (Fig. 1). The median age of the enrolled participants was 30.5 (11.0) years, and 69.4% were female participants. Regarding ethnicity and race, the total sample reported 8.3% being Hispanic, with 2.8%, 88.9%, 5.6%, and 2.8% identifying as Black or African American, White, more than one race, or unknown or not reported, respectively. Manifest refraction at the baseline visit found right eyes to have a median (IQR) sphere and cylinder power of -3.00 (1.88) D and 0.0 (0.5) D, respectively, while manifest refraction at the baseline visit found left eyes to have a median (IQR) sphere and cylinder power of -3.00 (2.25) D and 0.00 (0.25) D, respectively. Visual acuity with manifest refraction was -0.10 (0.05) logMAR for the right eye and -0.10 (0.00) logMAR for the left eye. None of the subjects reported any adverse events, and all slit-lamp examination findings remained normal throughout the study.

At baseline, subjects had their MAX fits confirmed. When evaluating the MAX CLs, all CLs had acceptable coverage, centration, and movement. The power of the MAX CLs was found to be satisfactory, with none of the subjects requiring a change in CL power. The subjects also exhibited good visual acuity while wearing the CLs (Tables 1 and 2). When subjects returned for visit 2, 1 week later, their MAX CLs were again evaluated and were found to have efficient coverage, centration, and movement, with no power changes needed, as well as good visual acuity while wearing the CLs (Table 1). Moreover, all subjects indicated that they were satisfied with the comfort of the MAX CLs. At visit 2, the evaluations of the DT1 CLs revealed that all CLs had good coverage, centration, and movement. Visual acuity while wearing the CLs was also satisfactory, and their DT1 CLs had a similar power compared to the MAX CLs (Tables 1 and 2). Subjects then returned for visit 3, 1 week later, and they were dispensed their DT1 CLs. When evaluating the dispensed DT1 CLs, all were found to have good coverage, centration, and movement. Additionally, the subjects exhibited good visual acuity while wearing the CLs (Table 1). Ultimately, subjects then returned for visit 4, one month later, and their CLs were reevaluated. The investigators determined that all subjects had good visual acuity, along with good coverage, centration, and movement while wearing DT1 CLs (Table 1).

The subject's wearing experience with the DT1 CLs was evaluated at visit 4. The subjects were found to have a median CLDEQ-8 score of 8.5 (10.5) units while wearing DT1 CLs. A Wilcoxon signed-rank test demonstrated that the CLDEQ-8 score while wearing DT1 lenses was significantly different from the baseline score with habitual MAX CLs (p = 0.004).

The absolute difference of 8.0 units (CLDEQ-8 score) for MAX CLs versus 8.5 units for DT1 was not clinically meaningful. DT1 CLs were furthermore found to have exceptionally positive IDEEL questionnaire scores, with this study finding IDEEL daily activities, feelings, and work scores of 97.8 (8.9) units, 97.9 (7.3) units, and 100 (10) units, respectively. When the subjects were asked Likert questions about their DT1 CL wearing experience (Table 3), they indicated that they strongly agreed or agreed that they would continuing wearing the CLs after the study ends (58.3%), 69.4% showed satisfaction with wearing the CLs, 80.6% were confident with their vision while wearing the CLs, 61.1% were satisfied with their end of day eye comfort while wearing the CLs, 80.6% were satisfied with their end of day vision while wearing the CLs, 69.4% were satisfied with their overall eye comfort while wearing the CLs, 80.6% were satisfied with their ability to play sports and perform fitness activities while wearing the CLs, 80.6% were satisfied with their ability to use digital devices while wearing the CLs, and 66.7% would recommend the CLs to a friend. Furthermore, the subjects were asked to rate their end of day eye comfort (35.0 [32.5] units), eye dryness (25.0 [58.0] units), and clarity of vision (44.5 [18.0] units) after wearing DT1 CLs on a ±50 visual analog scale (VAS) with the results indicating overall good/positive scores for each of these metrics.

4. DISCUSSION

Clinicians commonly refit patients into alternative CLs when they are struggling with factors such as comfort or vision, yet they might hesitate to switch patients into a different CL brand when patients are happy with their current CLs. A CL switch in a satisfied CL wearer may be driven by considerations such as the release of a newer CL material into the market, a negative clinical sign noticed by the clinician but not the patient, the discontinuation of a CL brand, or cost factors. The current study found that when switching a successful daily disposable CL wearer to an alternative daily disposable CL, most subjects were able to remain satisfied, maintain excellent visual acuity, and experience a high overall visual quality of life.

In the current study, all subjects initially started wearing MAX CLs, having done so for at least 3 months in the past year and continuing to wear them at the study's outset. These subjects were then switched to DT1 CLs. While there is limited data in the literature related to the MAX CL, Buch et al. have previously compared the MAX CL to the DT1 CLs in a prospective, parallel design study [13]. Buch et al.’s study specifically randomized habitual soft CL wearers to wear MAX CL or DT1 CLs for 2 weeks [13]. The authors then asked these subjects to rate questions related to both visual and physical comfort and found that the MAX CL wearers had a higher odds of indicating that the worn CLs had excellent or very good visual and physical comfort compared to the DT1 CL wearers. While the current study had a completely different study design, which prevents a direct comparisons between the current research and Buch et al.’s work, the current study determined that satisfied MAX CL wearers could be successfully refit into DT1 CLs while also allowing the subjects to have low/good CLDEQ-8 scores, excellent IDEEL QoL scores, and positive/comfortable VAS scores. Subjects also strongly agreed that the DT1 CLs had a positive impact on their lives.

An additional unique aspect of the current study was that it evaluated subjects who used an electronic device at least 8 hours per day. While one might hypothesize that digital devices may stress the ocular surface of CL wearers because patients who use digital devices blink far fewer times per minute than patients who are in unstimulated gaze (~16 blinks/minute vs. ~6 blinks/minute) [21], the literature suggests the typical CL wearer can use digital devices without additional issue [22-24]. This statement is supported by Meyer et al., who evaluated CL and non-CL wearers who used digital devices for at least 4 hours per day with an investigator-developed questionnaire that evaluated 10 symptoms related to eye fatigue and found both groups had similar symptomatology overall [22-24]. Nevertheless, the authors did note that the CL wearers had less severe and less frequent eye strain/pain and more severe and more frequent dry eye symptoms than non-CL wearers [22-24]. Sphere DT1 CLs used in the current study did not have blue light filtration, whereas MAX CLs filter ~60% of short-wave visible light between 380 and 450 nm. However, there is no conclusive evidence to support that blue light filtering benefits digital device users who have healthy eyes [25-27]. The present study found that the vast majority of subjects who switched CLs were satisfied with their ability to use digital devices while wearing the DT1 CLs and continued using their devices at least 8 hours per day.

While this study was strengthened by having a rigorous visit schedule that helped ensure that the subjects were truly satisfied with the MAX CLs at the start of the study, the multiple approaches used to evaluate the subjects’ wearing experience (e.g., CLDEQ-8 scores, IDEEL scores, Likert responses), and a defined washout period between CLs to help ensure that results of the study lens was truly independent, this study does have limitations that should be acknowlegded. The first key limitation is that this study only evaluated subjects who were habitually satisfied with the MAX CL. This study may have reached a different conclusion if a mix of happy and unhappy MAX CL wearers had been evaluated. This approach was taken to help ensure consistency among the subjects enrolled in this study. Nevertheless, future studies should determine whether unhappy MAX CL wearers will remain unhappy if they are switched to the DT1 CLs or if they would become satisfied CL wearers when given an alternative CL option. This study also evaluated only one CL brand at the start and offered subjects only one alternative CL brand at the switching point. Thus, the results from this study can only be applied to patients who start with MAX CLs and who are switched to DT1 CLs. Repeating this study with additional CL options that have different wear schedule options (e.g., patients who are satisfied with multiple CL brands and are willing to switch to a different brand) could provide additional data to either support or refute the practice of switching satisfied CL wearers to a different CL.

CONCLUSION

This study evaluated subjects who were happy with their habitual, premium, daily disposable CL and refitted them into an alternative premium daily disposable CL and found that these subjects remained satisfied CL wearers, as indicated by them having excellent visual acuity, a high visual quality of life, and great patient-reported outcomes. These outcomes occurred despite all the subjects being frequent digital device users. These data provide confidence for practitioners to switch satisfied senofilcon A (MAX) CL wearers to delefilcon A (DT1). While this study has provided data about satisfaction when switched to a novel CL material, additional work is needed to determine how dissatisfied CL wearers of one brand may respond to a refit with a different CL brand. Similar research should be expanded to include various brands and/or modalities of CLs, providing clinicians with more comprehensive data.

REFERENCES