Article

RESEARCH REVIEW

UNDERSTANDING CONTACT LENS DROPOUT

The Tear Film & Ocular Surface Society (TFOS) described the progression of a struggling contact lens (CL) wearer in its 2013 report on the International Workshop on Contact Lens Discomfort (Nichols et al, 2013). After being fit, a neophyte CL wearer typically performs well with CLs; however, the majority of CL wearers experience occasional symptoms such as irritation and discomfort (Nichols et al, 2013; Begley et al, 2001). These symptoms can become more bothersome, leading to a reduction in CL wear time (Nichols et al, 2013).

Eventually, many patients begin to wear their CLs only for special occasions, and they soon stop wearing CLs altogether. While some patients are able to resume wearing CLs after being refit into an alternative CL or after an intervention is prescribed, there remains a portion of patients who permanently drop out of CLs (Young et al, 2002). The following is a summary of key studies that have evaluated CL dropout.

CL Dropout Frequency

After reviewing the literature, it became clear that CL dropout differs for neophyte and established wearers. The neophyte CL-wearing experience was first well evaluated by Sulley et al (2017) with a one-year retrospective chart review of 524 subjects who were mostly soft CL wearers in the United Kingdom. This study reported that poor vision was the top reason for dropping out of CLs. The authors likewise determined that if patients dropped out of CLs, 25% dropped out within one month, and 75% dropped out within six months.

Sulley et al (2018) have since performed a prospective study in which 250 subjects completed the one-year survey. The authors again determined that poor vision was the top reason for dropping out of CLs. These studies determined that the frequency of CL dropout among neophyte soft CL wearers was 22.4% to 26.0%.

Macedo-de-Ara├║jo et al (2019) evaluated dropout in scleral lens wearers. They similarly found a frequency of CL dropout in neophyte scleral lens wearers of 27%. Nevertheless, neophyte scleral lens wearers most frequently dropped out of CLs because of handling issues.

These data strongly suggest that neophyte CL wearers should be monitored closely during the initial adaptation period via in-person visits or, at a minimum, by phone or email surveys that ask about their wearing experience. These data furthermore suggest that patients’ visual needs should be fully addressed early on by prescribing for low amounts of astigmatism when present and by offering multifocal CLs for emerging presbyopic patients.

Once a patient becomes an established wearer, the literature suggests that patients are at risk of dropping out of CLs for alternate reasons. Weed et al (1993) provided the first study on CL dropout in established wearers. They specifically performed a Canadian-based survey of 568 subjects and found that the top reason for CL dropout in established wearers was ocular discomfort. Pritchard et al (1999) completed a much more comprehensive survey (n = 1,444) of Canadian CL wearers and determined again that CL discomfort was the top reason why established wearers dropped out of CLs. The authors more specifically found that 49% of subjects dropped out of CLs because of ocular discomfort, with other top reasons being dry eye (9%) and red eyes (5%). Given the time frame, Weed et al (1993) and Pritchard et al (1999) primarily evaluated patients who were wearing hydrogel CLs.

With the advent of silicone hydrogel CLs, there were great hopes that this new material would alleviate the discomfort and hypoxia complications associated with the low-oxygen-transmissibility hydrogel materials. While hypoxia issues such as corneal edema have been greatly reduced with the introduction of silicone hydrogel CLs (Sweeney, 2013), other contact lens complications such as microbial keratitis and CL discomfort have remained unchanged (Guillon, 2013; Szczotka-Flynn and Diaz, 2007).

This latter point was highlighted by Richdale et al (2007) who performed a U.S.-based survey of 730 subjects and found that 24.1% of their study population had dropped out of CLs primarily because of ocular discomfort. This point is likewise highlighted by Dumbleton et al (2013) who surveyed 4,207 subjects in Canada, with the authors finding that 23% of their subjects dropped out of CLs primarily because of discomfort.

An international survey by Rumpakis (2010) additionally reported that the frequency of CL dropout is relatively consistent across the CL prescribing world (15.9% in the United States; 17.0% in the Americas including the United States; 31.0% in the Asia/Pacific Rim; 30.4% in Europe/Middle East/Africa). These data overall suggest that there is no noticeable difference between the dropout frequencies for silicone hydrogel and hydrogel CLs.

Resuming CL Wear

The above data suggest that patients frequently drop out of CLs for a variety of reasons, though it does not fully comment on whether struggling patients are able to resume CL wear. This issue was first evaluated by Schlanger in 1993. The author specifically refit 199 self-identified CL dropouts in an alternative CL option and found that 82% of these subjects could at least occasionally wear CLs again during this one-week study.

Young et al (2002) later performed a prospective study that recruited 236 subjects who had previously dropped out of CLs. The authors refit these patients in an appropriate alternative lens option and found that 73% of subjects were still wearing their new CLs at the six-month visit. Therefore, while not everyone is able to resume CL wear, if given the chance, many patients are able to become successful wearers again. These data overall suggest that CL wearers should be regularly monitored to determine whether they are struggling, and if they do report issues, simply offering patients a new CL option may alleviate their problems.

Factors Promoting Dropout

Several studies have attempted to determine the factors that promote CL dropout with the hope that these issues could be avoided or treated in a manner that would allow patients to maintain comfortable CL wear. Unfortunately, studies have produced conflicting results. The literature specifically indicates that subject sex and age may or may not be risk factors for CL dropout (Pritchard et al, 1999; Young et al, 2002; Richdale et al, 2007). Likewise, soft CL material (hydrogel versus silicone hydrogel) may or may not be a precipitating factor for CL dropout (Dumbleton et al, 2013; Sulley et al, 2018; Pucker et al, 2019).

It is unclear whether wear schedule is a risk factor for CL dropout (daily disposable versus two-week versus monthly) (Dumbleton et al, 2013; Sulley et al, 2018), and it is unclear whether commonly evaluated tear film metrics such as tear breakup time, Schirmer’s test, or corneal staining are associated with being more likely to cause CL dropout (Giannaccare et al, 2016; Pucker et al, 2019). Nevertheless, a recent case-control study by Pucker et al (2019) determined—by comparing 56 CL dropouts who dropped out of CLs because of discomfort within the previous six-to-12 months to 56 asymptomatic CL wearers—that meibomian gland plugging was a significant risk factor for dropping out of CLs. These data suggest that if ocular surface disease is present (e.g., meibomian gland dysfunction), treating it may promote additional years of CL use.

More Work to Be Done

The literature overall indicates that while there have been vast improvements in CL materials, CL dropout is still a major issue in modern practice. The literature likewise suggests that aggressive patient monitoring, offering patients alternative CL options, and treating underlying ocular surface disease may allow patients additional years of comfortable CL wear. It furthermore suggests that more research and better treatments are needed to help curtail the CL dropout epidemic. CLS

For references, please visit www.clspectrum.com/references and click on document #297.