While many dry eye patients can be successfully treated with first-line remedies such as artificial tears (Pucker et al, 2016), others fail with multiple approaches. Kok and Visser (1992) described the treatment of dry eye with GP scleral lenses. This seminal study reported that 10 out of 11 patients experienced symptomatic improvement, increased lens wearing time, and better visual acuity while wearing scleral lenses. The authors also found minimal corneal changes associated with scleral lenses. Scleral lenses likely benefit dry eye patients by creating a fluid cushion over the cornea, hydrating it, and protecting it from the eyelids during blinking; this may subsequently create a shield that allows the cornea to heal and break the inflammatory stimuli cycle (Alipour et al. 2012).
The purpose of this review is to highlight a sampling of key studies that describe the treatment of dry eye and ocular discomfort with scleral lenses.
Key Studies
Severe Ocular Surface Disease Romero-Rangel et al (2000) performed an early retrospective chart review of 49 consecutive patients who were fit in scleral lenses for the purpose of treating severe ocular surface disease. Their study collected general health information along with visual acuity, slit lamp biomicroscopy findings, and changes in quality of life (mean follow-up time period was 33.6 months).
The subjects included in Romero-Rangel et al’s study had a variety of ocular surface disease-promoting conditions such as Stevens-Johnson syndrome and exposure keratitis. The mean scleral lens wear time was 13.7 hours (range was four to 18 hours). The authors found that best-corrected visual acuity improved by at least two lines in 53% of subjects, though this finding was confounded by including subjects who had procedures such as cataract surgery. This study also reported that 82% of the subjects had marked improvements in their ocular surface symptoms, with the remainder of the subjects having only mild symptoms that were resolved by lens cleaning, and 75% of the subjects experienced improvements in photophobia. Romero-Rangel et al lastly found that 92% of the included subjects had an improvement in visual function and quality of life.
Failure in Other Contact Lens Modalities Segal et al (2003) likewise performed a retrospective chart review to determine whether scleral lenses were able to help when other contact lens modalities failed. They specifically reviewed 48 consecutive charts of patients who had conditions such as corneal irregularities and refractory dry eye (n = 4) (mean follow-up time period was 17 months).
This study reported that 10.4% of the subjects failed with scleral lenses, primarily because of difficulties with application and removal or because they were intimidated by the lenses. Nevertheless, Segal et al found that all subjects who were treated with scleral lenses for dry eye were successful, and 81% of the total sample noticed an improvement in ocular symptoms. The remaining subjects noticed only mild discomfort while wearing scleral lenses. The authors lastly found that 37% of the included subjects noticed an improvement in their ability to perform daily activities.
Chronic Graft-Versus-Host Disease Jacobs and Rosenthal (2007) analyzed 33 consecutive charts from subjects who were prescribed scleral lenses for the treatment of severe dry eye associated with chronic graft-versus-host disease. All included subjects were contacted to complete a survey that asked about dry eye symptoms and quality of life while wearing scleral lenses.
The authors found that 97% of the included subjects experienced a reduction in ocular pain, with 52% of these subjects indicating that they were ocular pain free. Jacobs and Rosenthal likewise found that 94% of the subjects experienced an improvement in photophobia and that 97% experienced an improvement in quality of life. Only 6% (2 out of 33) of the included subjects were not wearing scleral lenses at the time of the study; however, one of these subjects discontinued lenses because systemic health had improved to the point that scleral lenses were no longer needed.
Performance of Scleral Lenses in Established Wearers Visser et al (2007) evaluated the indications for scleral lenses and their performance by conducting a cross-sectional survey of current lens wearers (n = 178). All included subjects had been wearing scleral lenses for at least three months; subjects who reported for an ocular emergency were excluded.
The authors found that subjects were wearing scleral lenses for the following reasons: keratoconus (n = 56), post-penetrating keratoplasty (n = 56), primary or secondary irregular astigmatism (n = 36), keratitis sicca (n = 15; mixed causes included dry eye, Sjögren’s syndrome, and neurotrophic keratitis), corneal dystrophy (n = 10), and multiple diagnoses (n = 24). Scleral lenses were most commonly fit because of visual correction alone (87.7%) or because of visual correction plus ocular protection (6.7%).
Visser et al found that the overall study group had a median increase of 0.45 logMAR units over their best-corrected visual acuity, while the subgroup of subjects who had dry eye had a median visual acuity increase of 0.20 logMAR units. The authors lastly found that all included subjects were able to successfully wear scleral lenses.
Nguyen et al (2018) likewise studied a diverse group of subjects (n = 10) and found that 93% had visual blur resolution and that all experienced ocular symptom relief.
Moderate-to-Severe Dry Eye Alipour et al (2012) conducted a prospective interventional case series by fitting patients (n = 13) who had moderate-to-severe dry eye from a variety of origins (e.g., Sjögren’s syndrome, Stevens-Johnson syndrome) and who had failed with first-line treatments such as artificial tears. Only seven of the 13 subjects in this study ordered lenses; the subjects who discontinued primarily did so because of cost or handling issues. The subjects who ordered lenses had a mean follow-up period of 18.25 months.
The authors found that four out of the seven subjects who purchased lenses experienced an improvement in comfort and visual acuity and decreased their artificial tear use; the other three subjects either dropped out or got better without lenses.
Central Clearance and Wearing Success Sonsino and Mathe (2013) performed a retrospective chart review (n = 12) to determine how central corneal lens clearance affects scleral lens success in dry eye subjects. Successful scleral lens patients who were 18 years old or older and did not have an irregular cornea were included in the study.
The authors found that the subjects had a mean central corneal clearance of 380µm, and they failed to find a relationship between central vault and visual acuity or corneal curvature; these findings could have potentially been skewed by including only successful subjects.
Dry Eye Biomarkers Carracedo et al (2016) studied the short-term effects of scleral lens wear on dry eye biomarkers in subjects who had keratoconus (n = 26, with 11 established wearers). They specifically studied how six to nine hours of scleral lens wear affected factors such as symptoms, tear osmolarity, and inflammatory markers (matrix metalloproteinase-9 [MMP-9] and diadenosine tetraphosphates [Ap4A]).
They found that short-term scleral lens use improved symptoms, tear osmolarity, and Ap4A concentration, while MMP-9 levels worsened. The authors hypothesized that Ap4A levels may have improved because of decreased shearing force on the cornea, while MMP-9 may have increased because of the tear stagnation associated with scleral lens use or because they had instructed their subjects to fill their lenses with preserved saline.
Conclusion
The literature overall suggests that many patients, even those who have severe dry eye, can be successfully treated with scleral lenses (e.g., significant improvements in comfort, vision, and ocular signs) (Bavinger et al, 2015). Nevertheless, patients who have dexterity issues or who have progressing disease may be more challenging to fit (Alipour et al, 2012). CLS
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