CONTACT LENS DISCOMFORT (CLD) is defined as “a condition characterized by episodic or persistent adverse ocular sensations related to lens wear” (Nichols KK et al, 2013). CLD is likely related to a reduction in the compatibility of the lens being worn with the ocular surface and is likely a contributing factor in contact lens discontinuation. Of the collection of symptoms associated with CLD, the feeling of the lenses being dry is reported as one of the most frequent (Markoulli, 2017).

For practitioners, improving the symptoms and signs of CLD are of concern to ensure continued comfortable contact lens wear, as up to 31% of contact lens wearers may discontinue due to discomfort-related issues (Rumpakis, 2010). This article will discuss some of the recent evidence identifying the factors associated with CLD as well the effectiveness of some proposed treatment options.

THE IMPACT OF HUMIDITY IN THE ENVIRONMENT ON CLD

A recent study in Japan examined the tear film thickness and stability, the temperature of the ocular surface, and blink patterns, in addition to symptom intensity associated with 15 words related to eye discomfort in contact lens-wearing and non-contact lens-wearing participants placed in rooms with two levels of humidity (Ito and Takada, 2022). Patients wearing contact lenses were reported to have a thinner and more destabilized tear film and a decreased ocular surface temperature when they were in a low (10%) humidity room condition compared to non-CL-wearing participants in the same room. It is thought that this was due to greater tear evaporation from the ocular surface from an already thinner tear film overlaying the contact lens (Ito and Takada, 2022).

Interestingly, differences in blink rates were only seen in non-CL-wearing participants when placed in a 10% humidity environment compared to a 45% humidity environment. The authors suggested that the physiological response to a thinning or evaporating tear film by blinking may be lessened or impaired when wearing a contact lens.

This has implications for the overall lens performance when worn in a low humidity environment, as the lens itself may be subject to more drying out over time with an inadequate stimulus to blink, ultimately leading to the lens becoming more uncomfortable (Ito and Takada, 2022).

The impact of humidity demonstrated by this study contributes to some of the other environmental factors that have been previously identified as being potentially contributory to CLD, including the presence of dust, pollution, or smoke (Papas et al, 2013).

THE IMPACT OF LID HYGIENE, LENS REFITTING, AND ARTIFICIAL TEARS IN PATIENTS WITH CLD

The quality of the tear film, including the lipid layer, is thought to have an important impact on the development of CLD. Thus, patients who have meibomian gland dysfunction (MGD) need to be proactively managed for the best chance of contact lens-wearing success (Nichols JJ et al, 2013). The material of the contact lens also likely plays an important role, although a particular “best” lens in terms of compatibility likely varies between patients.

A study examined patients diagnosed with CLD and non-severe grades of MGD and the combined impact of lid hygiene, refitting with a daily disposable lens made of delefilcon A, and use of an artificial tear containing povidone iodine (Arroyo-Del Arroyo, 2021). These interventions were done in sequence on smaller and smaller subsets of the study cohort, so that the impact of each could be better defined. It found that lid hygiene and refitting with the daily disposable lens were both able to significantly improve symptoms (Arroyo-Del Arroyo, 2021).

The group that received an artificial tear after both lid hygiene and lens refit did not experience any additional improvement in symptoms, suggesting that in this population, the health of the meibomian glands, the lens material, or the wearing modality may have been greater contributors to the CLD. While there was improvement in the symptoms, measurements of clinical signs—including conjunctival redness, noninvasive tear breakup time (TBUT), and corneal and conjunctival staining—were not significantly impacted by these interventions in the author’s analysis for this particular study, which is unfortunately not unheard of among CLD studies trying to correlate signs and symptoms (Arroyo-Del Arroyo, 2021).

Other recent studies have attempted to investigate the impact of artificial tears alone in the management of CLD. A prospective study investigated the efficacy of using a hypotonic artificial tear containing trehalose and hyaluronic acid that is preservative-free four times a day for 84 days, in patients who had CLD (Fernández-Jimenez, 2022). It also looked at whether this regimen could improve measures of anterior segment staining, tear film stability, and symptoms as measured by several questionnaires.

The combination of trehalose and hyaluronic acid has been demonstrated in some studies to protect proteins on the ocular surface and may have a role in decreasing inflammation (Fariselli et al, 2018; Li et al, 2012). The eye drop was effective in reducing symptoms, as well as individual dry eye symptoms such as pain, photophobia, and foreign body sensation when using a visual analogue scale (Fernández-Jimenez, 2022). Corneal fluorescein staining also improved with the use of the drops over 84 days, but other measures, such as tear meniscus height and TBUT, did not see a statistically significant change (Fernández-Jimenez, 2022).

INTENSE PULSED LIGHT IN CLD MANAGEMENT

Several devices have been used to stimulate, clean, clear, or otherwise target the lids and meibomian glands as part of general dry eye management, and these technologies, including intense pulsed light (IPL), are increasingly also being applied to manage CLD patients. IPL in eye care applies a broad wavelength of light between 500nm and 1,200nm to the skin surrounding the eye in high-intensity pulses.

It is thought that these light pulses destroy abnormal vasculature associated with meibomian glands through a thermal effect, as the energy is absorbed by melanin, water, and hemoglobin and raises the temperature (Yang et al, 2022). This stimulates the meibomian glands, decreases inflammation, and is thought to be able to help with CLD overall through improvements in the tear film (Yang et al, 2022).

In a study of patients who had contact lens-induced dry eye treated with two IPL sessions three weeks apart, the treatment yielded improvement in noninvasive TBUT as well as symptoms OSDI by three weeks after the second treatment (Yang et al, 2022). In comparison, participants who had received a sham IPL treatment did not benefit in tear film stability measures or symptoms throughout the entire study. Participants receiving IPL also saw a significant decrease in the frequency of using artificial tears within the three weeks of the first treatment, while those without treatment did not see any change in their eye drop usage frequency (Yang et al, 2022).

LIFITEGRAST IN CLD MANAGEMENT

Lifitegrast works by blocking the interaction between intercellular adhesion molecular 1 (ICAM-1), which is overexpressed on cells of the ocular surface during dry eye disease, and the lymphocyte function-associated antigen 1 (LFA-1), which is used by immune cells to target ICAM-1 expressing cells (Gonzalez, 2018). Blocking this interaction results in less activation and migration of T-cells and thus decreases inflammation on the ocular surface when the drop is used (Gonzalez, 2018).

In 2016, commercial release of a 5% solution of this agent to be used twice a day was heralded as an additional agent approved specifically for the therapeutic management of dry eye disease after cyclosporine. Reports of the use of lifitegrast in the management of CLD have begun to emerge, with one study reporting that eight weeks of use of the agent led to significant improvements in patient symptoms (Gonzalez, 2018).

SUMMARY AND CONCLUSIONS

Proactive management of CLD is essential to ensure that patients remain comfortable, long-term contact lens wearers. The recent evidence of the factors associated with CLD and the efficacy of strategies to manage it, including modifying environmental conditions, lens materials, and pharmaceutical agents, provide insight into the tools and treatments that can be used to manage this condition. The more demonstrably effective treatments that can be found, the more flexibility clinicians and patients will have in ensuring contact lens-wearing success. CLS

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