Comment on: Comfort After Refitting Symptomatic Habitual Reusable Toric Lens Wearers with a New Daily Disposable Contact Lens for Astigmatism [Letter]

Dear editor

We read with interest the recently published article titled “Comment on: Comfort After Refitting Symptomatic Habitual Reusable Toric Lens Wearers with a New Daily Disposable Contact Lens for Astigmatism” by Wan et al.¹ We want to congratulate the authors on their excellent work. The study provides valuable insights into contact lens comfort and refitting; however, there are a few drawbacks to the study which, we believe, could be considered in a similar study in the future to improve the quality of the paper.

The study did not include a direct comparison of delefilcon A toric lenses with different lens materials, including other daily disposables. A direct comparison could provide a more comprehensive understanding of how delefilcon A toric lenses compare to other options.²

Lack of masking: Subjects were not masked to their habitual toric lenses or delefilcon A toric lenses. This lack of masking could introduce bias, as the subjects were aware of the lens they were wearing. Masking would have helped to eliminate potential biases related to the subjects’ knowledge of their lens type.³ The study did not employ randomization, as subjects were dispensed their habitual lenses first and then delefilcon A toric lenses. Randomization helps to ensure that any observed differences are not due to the order of lens wear, and it would have been beneficial to include randomization in the study design.⁴

The study had a relatively short follow-up period for both the habitual toric lenses and delefilcon A toric lenses (2–4 weeks). This limited follow-up period prevents conclusions being drawn about the long-term effects of refits with these lenses. Longer-term data would be valuable to assess the sustained comfort and other factors.⁵

Limited examination of causative factors: The study did not investigate the specific factors contributing to the improved comfort after refitting. It mentioned various possibilities, such as the lens material, replacement schedule, or the absence of contact lens cleaning solutions. A more in-depth analysis could have helped to isolate the key factors responsible for the improved comfort.⁶

Small sample size for certain comparisons: While the study aimed for a sample size of 85 subjects, certain comparisons, such as the assessment of mean reported hours of comfortable wear, had lower power (65%). A larger sample size would have increased the likelihood of detecting significant differences in these aspects. The study focused on symptomatic reusable toric lens wearers, and therefore, the findings may not apply to asymptomatic wearers. The conclusions are specific to this subset of contact lens wearers and may not be generalizable to the broader population.⁷

In conclusion, the study offers important insights into refitting symptomatic reusable toric lens wearers with delefilcon A toric lenses. However, its limitations, including the lack of direct comparisons, short follow-up, and potential biases, should be considered when interpreting the findings, and further research is needed to address these limitations and provide a more comprehensive understanding of contact lens comfort and refitting.