SCLERAL LENSES (SLs) are an adjunct therapy for dry eye disease (DED). The lens’s fluid-filled reservoir bathes the cornea in constant lubrication, eliminating mechanical irritation to the cornea and allowing the epithelial cells to heal, while its large diameter provides protection to the ocular surface it covers. The main indication for fitting sclerals (77%) is poor vision due to corneal irregularity, while ocular surface disease (OSD) remains a distant second (15%) (Nau et al, 2023). What is the consensus on when these devices should be utilized? What is the optimal diameter for these patients? Are there any specific fitting techniques/tips that should be considered?
SLs are considered a step three intervention in the Tear Film and Ocular Surface Society Dry Eye Workshop (DEWS) II staged management hierarchy, after lid hygiene, topical lubrication, in-office meibomian gland expression, and topical medications have been prescribed (Jones et al, 2017). The Cornea, External Disease, and Refractive Society (CEDARS) group recommends that SLs be considered as a second-line treatment, again after the more common first-line treatments have failed (Milner et al, 2017).
This seems to be the consensus, as a 2020 Scleral Lenses in Current Ophthalmic Practice Evaluation (SCOPE) survey found SLs ranking sixth, seventh, or eighth as management options for OSD after in-office meibomian gland procedures, punctal occlusion, and topical therapy have been attempted but before surgical intervention (Shorter et al, 2023). Many of the available therapies for mild to moderate OSD are quite effective, thus reserving SLs for moderate to severe disease and/or when conventional options fail due to their involved custom fitting process and associated expense (Milner et al, 2017). In a review of a tertiary care clinic, patients had previously tried an average of 4.4 interventions before being referred for a SL evaluation (Scanzera et al, 2020). The exception seems to be neurotrophic or exposure keratopathies, for which SLs are prescribed earlier (Scanzera et al, 2020).
When it comes to diameter selection for fitting SLs for DED, there is no consensus in the literature on what diameter works best (Qui et al, 2024). Larger-diameter lenses may be desired for moderate/severe DED and/or those patients who have significant conjunctival staining or eyelid abnormalities, allowing a larger surface area to be protected. The downside is that more scleral asymmetry will be encountered the further from the limbus that the lens lands, making the fit more challenging (van der Worp, 2015).
Conversely, fitting smaller-diameter SLs can be more attractive to the novice practitioner and can be less daunting for patient handling (Porcar et al, 2020). Ultimately, until there’s evidence to the contrary, it might be best to choose a diameter that considers the patient’s horizontal visible iris diameter, aperture size, lid tone, and orbital anatomy to support patient success.
Ensuring proper edge alignment is critical to fitting success. A tight or loose edge may exacerbate ocular irritation in DED patients (Qiu et al, 2024). A loose edge will also facilitate midday fogging and cause an influx of debris under the lens, which can impact visual acuity (Fogt, 2021), while a tight edge may worsen ocular surface inflammation. Addition of a polyethylene glycol surface treatment can be a valuable complement to SLs and can improve the wearing experience by reducing dry eye symptoms and ocular compromise compared to untreated SLs (Mickles et al, 2021).
Although SLs don’t treat the underlying cause of DED, they can be life-changing and alleviate a patient’s symptoms and, therefore, are a valuable treatment option wherever a practitioner may choose to utilize them in their own personal treatment hierarchy.
REFERENCES
1. Nau CB, Harthan JS, Shorter ES, et al. Trends in Scleral Lens Fitting Practices: 2020 Scleral Lenses in Current Ophthalmic Practice Evaluation Survey. Eye Contact Lens. 2023 Feb 1;49:51-55.
2. Jones L, Downie LE, Korb D, et al. TFOS DEWS II Management and Therapy Report. Ocul Surf. 2017 Jul;15:575-628.
3. Milner MS, Beckman KA, Luchs JI, et al. Dysfunctional tear syndrome: dry eye disease and associated tear film disorders - new strategies for diagnosis and treatment. Curr Opin Ophthalmol. 2017 Jan;27 Suppl 1:3-47.
4. Shorter E, Fogt J, Nau C, Harthan J, Nau A, Schornack M. Prescription Habits of Scleral Lenses for the Management of Corneal Irregularity and Ocular Surface Disease Among Scleral Lens Practitioners. Eye Contact Lens. 2023 Feb 1;49:46-50.
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6. Qiu SX, Fadel D, Hui A. Scleral Lenses for Managing Dry Eye Disease in the Absence of Corneal Irregularities: What Is the Current Evidence? J Clin Med. 2024 Jun 29;13:3838.
7. van der Worp E. Pacific University CommonKnowledge. A Guide to Scleral Lens Fitting (2 ed). 2015. Available at boston.eu/downloads/scleral_lenses/A_Guide_to_Scleral_Lens_Fitting_(2ed).pdf. Accessed 2024 Sept 30.
8. Porcar E, Montalt JC, España-Gregori E, Peris-Martínez C. Fitting Scleral Lenses Less Than 15 mm in Diameter: A Review of the Literature. Eye Contact Lens. 2020 Mar;46:63-69.
9. Fogt JS. Midday Fogging of Scleral Contact Lenses: Current Perspectives. Clin Optom (Auckl). 2021 Jul 21;13:209-219.
10. Mickles CV, Harthan JS, Barnett M. Assessment of a Novel Lens Surface Treatment for Scleral Lens Wearers With Dry Eye. Eye Contact Lens. 2021 May 1;47:308-313.
