Article

RESEARCH REVIEW

MEIBOMIAN GLAND ATROPHY IN CONTACT LENS WEARERS

One of the biggest advances in ocular surface disease management in the past decade has been the development of patient-friendly, non-contact meibography (meibomian gland imaging) (Wise et al, 2012). Meibography has historically been conducted by everting the eyelids, transilluminating the meibomian glands, and imaging them with an infrared camera (Wise et al, 2012). This method was only able to visualize the glands in segments, which required serial imaging to document the entire eyelid (Wise et al, 2012). This method was also uncomfortable for the patients and time consuming for the clinicians, limitations that subsequently prevented its widespread clinical use. (Wise et al, 2012). This all changed in 2008 when Arita et al published a method for non-contact meibography. Arita et al’s (2008) meibography device consisted of a slit lamp biomicroscope with an “infrared transmitting filter and an infrared charge-coupled device (CCD) video camera”; it was able to quickly and easily image the meibomian glands while at the same time minimally disturbing patients. Industry has since introduced commercially available meibomian gland imaging devices that can be easily run by trained technicians, and meibography is now subsequently emerging as a standard procedure in ocular surface disease management (Pucker et al, 2015; Machalińska et al, 2015).

Meibography is clinically useful for judging the severity of meibomian gland dysfunction (fewer, more tortuous glands may be a sign of worse meibomian gland function), determining treatment options (e.g., few or no meibomian glands may be a contraindication for thermal pulsation), and informing patients about their condition (e.g., patients can visualize a potential source of the condition), which could subsequently improve patient compliance through better understanding (McMonnies, 2011; Qiao and Yim, 2013; Arita et al, 2012). Meibography is typically subjectively graded with Arita and colleagues’ (2008) meiboscore scale. A higher score is considered to be a worse grade (Table 1 and Figure 1), and a grade of 0 or 1 is likely a normal amount of atrophy (Arita et al, 2008). Other subjective and semi-objective grading methods have been proposed (Pult et al, 2012; Alghamdi et al, 2016).

TABLE 1 SUBJECTIVE MEIBOMIAN GLAND ATROPHY (MEIBOSCORE) GRADING SCALE (ARITA ET AL, 2008)
MEIBOSCORE DESCRIPTION
SCALE 0 1 2 3
PERCENTAGE OF GLAND LOSS None 1 to < 33 33 to 67 > 67

Figure 1. Meibography images. Left: Upper eyelid presents with a grade 1 meiboscore and gland tortuosity (gland deviation). Right: Lower eye presents with a grade 3 meiboscore.

Meibography can also be useful for determining factors associated with meibomian gland dysfunction and/or atrophy, knowledge that could result in better treatment and prevention strategies. Likewise, meibography can be used for determining the impact of medical treatments on the eye (e.g., contact lenses [CLs]), which is a longstanding concern of CL patients and practitioners.

Over the past few years, there has been a wealth of information gained about the effect of CLs on the ocular surface or, more specifically, the impact of CLs on the meibomian glands.

A Look at the Studies

Arita et al (2009) conducted a cross-sectional study of mostly Asian subjects that analyzed 121 (39 rigid and 82 soft) CL wearers and 137 non-CL wearers. They noted that meiboscores were significantly worse in the upper and lower eyelids in the CL wearers compared to the non-CL wearers, though meiboscores did not statistically differ between rigid and soft CL wearers. They also found that a greater number of CL wearing years was associated with worse meiboscores.

Alghamdi et al (2016) likewise sought to determine whether there was an association between CL use and increased meibomian gland atrophy. They specifically compared subjects (20 per group) who had short (~2 years), moderate (~5 years), and long-term (~10 years) exposure to CLs; past CL wearers; and healthy, non-CL wearers. The researchers found that CLs induced meibomian gland atrophy and promoted decreased meibomian gland function during the first two years of CL wear; however, meibomian gland changes were stable after the first two years of CL use. Interestingly, the researchers found that there was no improvement in meibomian gland function after ceasing CL wear, which suggests that the induced meibomian gland changes were permanent.

Pucker et al (2015) also evaluated how CL use was associated with meibomian gland atrophy, though they used a different approach by recruiting a sample of age- and sex-matched CL wearers (n = 71) who were compared to healthy, non-CL wearers (n = 71). The researchers found minimal differences between subjects who do and do not wear CLs; overall, however, they failed to find an association between soft CL use and meibomian gland atrophy. Machalińska et al (2015) likewise studied a group of age- and sex-matched CL wearers (n = 41) who were compared to healthy, non-CL wearers (n = 31). They also failed to find an association between soft CL use and meibomian gland atrophy, though they did find CL use to be a predictor of abnormal meibum production.

Pucker et al (2018) attempted to determine whether the past lack of associations between CL use and meibomian gland atrophy could be attributed to a survivor bias (e.g., subjects who have high degrees of meibomian gland atrophy may have been excluded by restricting inclusion to healthy CL wearers). The study compared 56 age- and sex-matched comfortable CL wearers to 56 subjects who had dropped out of CLs because of discomfort. Nevertheless, the investigators failed to find an association between meibomian gland atrophy and being able to successfully wear CLs.

Arita et al (2012) alternatively studied how CL-related allergic conjunctivitis (CLAC) impacted meibomian gland health by recruiting 64 CL wearers who had CLAC, 77 CL wearers who did not have CLAC, 55 subjects who had perennial allergic conjunctivitis, and 47 healthy, non-CL wearers. They found that meibum scores and meiboscores did not significantly differ among groups, though they did find that meibomian gland tortuosity (gland deviation) was worse in the CL wearers who had CLAC compared to the CL wearers who did not have CLAC. Meibomian gland tortuosity was significantly worse in non-CL wearers who had perennial allergic conjunctivitis compared to healthy non-CL wearers. Meibomian gland tortuosity was not associated with CL use. This finding is corroborated by Marx et al (2018), who found that meibomian gland tortuosity did not significantly differ between healthy CL wearers (n = 56) and CL dropouts (n = 56); nevertheless, they did find meibomian gland tortuosity to be associated with dry eye signs.

Conclusion

Overall, the literature suggests that it is unclear whether CL use induces meibomian gland atrophy; however, the predominance of evidence does suggest that meibomian gland atrophy does promote meibomian gland dysfunction and dryness symptoms, which together have the potential to lead to decreased CL wear time and/or CL dropout. Therefore, early meibomian gland health screening may be warranted in CL wearers so that preventative measures can be taken to avoid meibomian gland atrophy, ocular discomfort, and subsequent CL dropout. CLS

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