Neurological Comorbidities Affect Scleral Lens Compliance

More than half of patients in a recent study reported difficulty wearing scleral lenses. The Eye & Contact Lens report shows ocular irritation and fogging are common complaints that may lead to noncompliance. The study also shows that patients with neurologic comorbidities, such as tremor, had significant difficulty inserting and removing the lenses and may require particular clinical guidance.

Corneal ectasias, such as keratoconus, corneal transplant, and ocular surface disease, are the most common indicators for scleral contact lens use. Although these devices are widely used for these purposes, they remain a cause of patient  discomfort and can be difficult to insert and remove, which can lead patients to discontinue use.

To better understand the outcomes of scleral contact lens use, researchers conducted a study with the veteran population to evaluate the outcomes of using these lenses and what medical, as well as demographic, factors impact these outcomes, with attention to reasons for discontinuation. 

A total of 120 adult veterans — who were fitted with scleral contact lenses between August 2010 and September 2018 at Houston’s Michael E. DeBakey Veterans Affairs Medical Center eye clinic — were included in the study. Participants had a mean age of approximately 56 years. If participants had bilateral eye disease and bilateral scleral contact lens fittings, 1 eye was selected at random to be in the study.  

The investigators focused on the veteran population because of their “significant prevalence of mental illnesses, such as post-traumatic stress disorder,” the study explains. “Psychiatric disease has been found to decrease the threshold for discomfort while using contact lenses and increase lens awareness, dryness, and subjective discomfort. Veterans are also susceptible to traumatic brain injury (TBI) during combat. Patients with TBI have been found to have a higher prevalence of dry eye disease and other ocular surface diseases. Owing to these differences between veterans and the general population, it was our hypothesis that outcomes of scleral contact lens use in veterans are different from those seen in the general population.”

All participants were fitted with “semisealed lenses that do not closely contour the cornea to allow for adequate tear exchange. These lenses are fit to certain diameters, and an ideal fit is a complete vault over the cornea and limbus with resting on the sclera.”

The researchers organized the participants’ primary diagnoses into 4 categories: corneal ectasia (54.2%), ocular surface disease (31.7%), irregular astigmatism (11.7%), and multiple primary diagnoses (2.5%). 

The study shows that 55% of participants had had difficulty with wear, the most common being ocular irritation (20.0%) and mid-day fogging or bubbles (15.8%). 

Out of 120 veterans in the study, 41 (34.2%) stopped wearing the lenses approximately 5.2 months after their first fitting. The most common reason for discontinuation was cited by 53.7% of participants to be the difficulty around inserting and removing the lenses. On the other side, 76 participants (63.3%) reported subjective satisfaction with their fitting and the resultant outcome at their follow-up appointment. 

The authors also found that comorbid neurologic disease had a statistically significant association with discontinuation (P =.022). There were statistically significant differences in mean visual acuity improvement (P =.003) and daily wear time (P <.001) but not age (P =.70) between patients who continued and discontinued lens use.

The researchers say their study demonstrates that patient selection is key to success with scleral lenses and that ophthalmologists have a role in encouraging compliance. They report that clinicians should consider comorbidities when offering the devices. For the majority of the patients in this study population, scleral lenses were only offered as a last line therapy, due to comorbid neurologic disease, which this study shows has a statistically significant association with scleral lens discontinuation. 

The study’s limitations include a limited sample size and the potential for subjective recall bias. Another limitation was the lack of chart information regarding who helps the patients with their scleral lenses — whether the patients perform insertion and removal themselves or whether a family member or caregiver assists them. 

Researchers believe that patient counseling should focus on improvements in patients’ vision as a result of the lens as opposed to ocular surface protection primarily, since that appears to encourage continuation of wear. 

Reference

Kanakamedala A, Salazar H, Campagna G, et al. Outcomes of scleral contact lens use in veteran population. Eye & Contact Lens. 2020;46(6):348-352. doi:10.1097/ICL.0000000000000671.