When weighing therapeutic options to address dry eye symptoms, practitioners rarely consider contact lenses. Yet, specialty lenses may alleviate dryness symptoms and, in some cases, may address and treat some of the underlying etiologies of dry eye disease. Specialty soft lenses, overnight orthokeratology (ortho-k), and scleral lenses may not only improve contact lens comfort but may also rehabilitate the ocular surface.

DRY EYE VERSUS CONTACT LENS DISCOMFORT

Dry eye symptoms can range from dryness, grittiness or scratchiness, burning, or watering to more vague complaints of soreness, discomfort, irritation, ocular fatigue, or blur.¹ These symptoms overlap with those reported by contact lens wearers who may have contact lens-induced irritation that is not associated with dry eye or ocular surface disease. These “pseudo-dryness” symptoms are not uncommon, particularly in patients who wear soft toric lenses. Rotational blur and discomfort can easily be incorrectly attributed to dry eye. Furthermore, many other conditions mimic or have significant comorbidity with dry eye and need to be ruled out or addressed before initiating dry eye treatment. These conditions include ocular allergies; viral, bacterial, and parasitic conjunctivitis; eyelid, corneal, and conjunctival tissue abnormalities; digital eye strain; and systemic disease.¹

Symptoms caused by a poorly fitting contact lens can lead a troubleshooting practitioner to the incorrect assumption and treatment of dry eye disease or to multiple, ineffective, and time-consuming refits. Not only do poorly fitting lenses feel uncomfortable, but the resulting blur often causes patients to repeatedly rub their eyes and touch their lenses, leading to inflammation and irritation. These patients often benefit from a specialty contact lens, as described in the case on p. 28.

Numerous specialty soft lenses are widely available and can be designed to fit nearly any unusual but regular cornea as well as many irregular corneas. When blurred vision is the primary concern, hybrid lenses, corneal GPs, and scleral lenses are good options to consider, as the optics of GP lenses often outperform those of soft lenses.

If a contact lens patient describes symptoms that sound like dry eye disease, a thorough examination for signs of ocular surface disease should be completed. While signs and symptoms of dry eye do not always correlate, the absence of clinical signs may indicate that the cause of the patient’s discomfort is something other than dry eye disease. This is particularly true if a patient is in a lower-risk demographic group; for example, if a patient is male, a younger age, and/or has no environmental contributing factors.

CORNEAL GP LENSES AND ORTHOKERATOLOGY

Ortho-k is a good option for patients who meet the refractive and corneal health criteria for this modality. Switching from daytime to overnight lens wear is useful in many ways for patients who experience dry eye symptoms. Ortho-k lenses are not as exposed to environmental debris, allergens, or chemicals as daily wear soft lenses are, and GP lenses in general are less likely to absorb these irritants. Ortho-k lenses are worn in the more controlled environment of the home and are not likely to dehydrate as much as soft lenses worn on an open eye are. Dry eye treatments, such as hot compresses, artificial tears, gels, and other topical therapies, are more easily applied to the eye during the day when no contact lenses are being worn. A bedroom humidifier may further improve comfort for patients wearing ortho-k lenses.

Research has shown additional benefits of overnight ortho-k when compared with daily wear of silicone hydrogel lenses; responses to dry eye symptom questionnaires have demonstrated improvement, as have the objective measurements of bulbar and limbal redness and conjunctival staining.^2,3 Of particular note, Carracedo et al found significantly increased goblet cell density in patients who switched from daily wear soft lenses to ortho-k.²

Findings that support improved goblet cell health are of particular interest in dry eye disease, not only because the conjunctival goblet cells are responsible for mucin production but also because they are likely linked to ocular surface immune tolerance.⁴ If damage to goblet cells leads to less tolerance and to greater immune response (i.e., excessive inflammation), a contact lens that interacts less with the bulbar conjunctiva should be more beneficial to a patient who has dry eye. Corneal GPs have limited interaction with the bulbar conjunctiva and, therefore, with goblet cell structure and function. In addition, corneal GPs are significantly less likely than soft lenses are to be linked to giant papillary conjunctivitis (GPC).⁵ The inflammatory nature of GPC can induce or mimic dry eye symptoms in contact lens wearers.

It is understood that corneal GP lens wear requires an initial adaptation period. Be aware, however, that symptoms of discomfort or discontinuation of lens wear during a neophyte GP lens trial are likely related to individual pain tolerance and not to the chronic, inflammatory symptoms of dry eye disease. If a soft lens wearer agrees to try GP lenses to alleviate dry eye symptoms, a reasonable next step is to administer a pain sensitivity questionnaire to determine whether the patient is able to adapt to the initial sensation of GP lenses.⁶ Patients who have poor pain tolerance will need considerable dedication and extended adaptation time. Those who have high pain tolerance but significant recalcitrant dry eye symptoms may be open to trying corneal GP lenses or ortho-k if they want to continue wearing contact lenses.

Newer plasma treatments and surface coatings for GP lenses can help with adaptation and ongoing comfort. Mickles et al demonstrated that polyethylene glycol-treated scleral GP lenses can significantly improve many common dry eye signs and symptoms.⁷ Clinical signs of corneal and conjunctival staining, lid wiper epitheliopathy, and papillae improved in patients wearing the treated lenses compared to untreated lenses. Patients wearing the treated lenses reported improvements in comfort and in symptoms of dryness and foggy vision.

With advances in materials and surface treatments, as well as flexibility in daytime or nighttime wear, corneal GP lenses may be a valid and beneficial option for many patients who have dry eye disease.

SCLERAL LENSES

When dry eye and ocular surface disease reach a moderate-to-severe level, many therapies fail to provide adequate symptom relief, and traditional contact lens wear can become intolerable. Scleral lenses are increasingly becoming a contact lens-based treatment for these patients. Not only does this modality correct refractive error and irregular astigmatism, it also shields and protects the ocular surface. This results in reduced inflammation, a more stable layer of moisture over the cornea, and restored homeostasis of the ocular surface.⁸

A scleral lens and its fluid reservoir can provide direct protection from the mechanical interaction and/or irritation of trichiasis (Figure 1), environmental debris, and arid conditions; in addition, the constant lubrication is supportive of corneal healing in the presence of epithelial defects (Figure 2) and inflammation.

Numerous ocular conditions may benefit from scleral contact lens wear, including Stevens-Johnson syndrome, graft-versus-host disease, ocular cicatricial pemphigoid (Figure 3), exposure keratopathy, filamentary keratitis, limbal stem cell deficiency, and Sjögren’s, to name a few.⁹ The true potential of the fluid reservoir of scleral lenses is only beginning to be understood.

While the thickness of the fluid reservoir must be strictly controlled and minimized to avoid hypoxia, there is space to add supplemental medication or lubrication for dry eye disease treatment and management.¹⁰ Many patients currently use simple, nonpreserved saline to fill the bowl of their scleral lenses; however, upgraded and potentially more beneficial filling solutions are now available.

Buffered saline solutions that better match the pH of human tears may be more comfortable.¹¹ A new solution that includes mineral electrolytes plus tear-mimicking osmolality and pH has been developed in an effort to offer even more “natural” support to the tear film and cornea.¹²

Further analysis of the components of the reservoir environment may be facilitated using sensors embedded in scleral lenses to better determine the needs of patients who have dry eye disease.¹³

Patients who have dry eye can supplement their saline filling solution with nonpreserved artificial tears or with other over-the-counter ocular lubricants; other ingredients also may be worth adding to the mix. For example, topical antibiotics may be incorporated into the bowl prophylactically to treat persistent epithelial defects or neurotrophic ulcers. If neovascularization is threatening the cornea and vision, research has shown that the vascular endothelial growth factor inhibitor bevacizumab is safe and effective in reducing neovascularization.¹⁴ A small case series by Donaldson suggests that simultaneous use of autologous serum and scleral lenses may be useful in certain situations.¹⁵

It’s exciting to think about how topical dry eye therapies and scleral lenses may be used synergistically to enhance or improve treatment success. Further research in this area will surely provide more opportunities to take advantage of the scleral lens tear reservoir to help patients who have severe ocular surface and dry eye disease.

Preventing aggressive surgical procedures for patients who have ocular surface disease is another reason to consider scleral contact lenses. Just as scleral lenses may be prescribed for a patient who has keratoconus to avoid corneal transplantation, they also may be used for patients who have severe exposure keratopathy, nonhealing ulcers, or other persistent epithelial defects to prevent tarsorrhaphy, a Gunderson conjunctival flap procedure, or amniotic membrane graft.⁹

Patients who have dry eye symptoms without clinically observable signs of ocular surface disease may be experiencing neuropathic pain. This valid but difficult-to-diagnose condition often does not respond to traditional dry eye therapies, and practitioners can feel helpless when they have no obvious clinical signs to address. Scleral lenses may reduce hypersensitive responses of the ocular somatosensory nerves and give these patients relief.^16,17 In such cases, the scleral lens is not directly treating aqueous deficiency or evaporative/meibomian gland dysfunction (MGD) but is acting more as a pain therapy for hyperalgesia. More research is needed in this area to better define and understand this disease, and comanagement with other members of a patient’s healthcare team, often including a pain management specialist, is critical for success.

While scleral lenses are valuable for treating many types of ocular surface disease, they do not directly treat MGD, which is a driving factor in many cases of dry eye disease. Failing to address MGD with targeted treatment may result in GP lens depositing, midday fogging, blurred vision, and poor lens comfort. As a result, both patient and practitioner will be disappointed that the scleral lens trial did not improve the dryness symptoms. In addition, uncontrolled conjunctival inflammation, injection, and chemosis can make scleral lenses difficult to fit and assess and can make scleral lens wear uncomfortable for patients. This is true for patients who have ocular allergies, particularly those who report a significant amount of eye rubbing or mucus fishing. While scleral lenses may protect and heal the cornea, “uncovered” ocular structures still require attention, and pre- or coexisting conditions must be addressed concomitantly.

Scleral lenses are generally reserved as a therapeutic option for patients who have moderate-to-severe dry eye; however, they could be considered for patients who have milder symptoms and are struggling in other modalities but want to continue wearing contact lenses for cosmetic reasons. These patients should be advised of the increased costs and fitting time as well as the considerable expertise and experience required to fit these more complicated lenses.

CASE EXAMPLE

A 29-year-old white male reported blurred vision, ocular irritation, and dryness with multiple brands of soft toric contact lenses. Despite frequent attempts at refitting, he hasn’t had a comfortable contact lens in more than 10 years.

Preliminary assessment revealed a healthy ocular surface without staining, a tear breakup time of more than 10 seconds, and thin, clear meibomian gland secretions without notable capping, lid notching, or inspissation. His spectacle refraction was plano –4.00 x 003 (20/20) OD and plano –2.75 x 168 (20/20) OS.

Corneal topographies revealed larger-than-average corneal diameters of approximately 12.5mm OD and OS and relatively flat keratometry values, with mild inferior steepening (see figure at right). Because of the size and shape of the patient’s corneas, a specialty soft lens was ordered with the following parameters:

• OD: 8.6mm base curve (BC), 15.0mm overall diameter (OAD), plano –3.75 x 003 power
• OS: 8.9mm BC, 15.0mm OAD, plano –2.75 x 168 power.

Upon dispensing, both lenses showed good centration and movement with no rotation, and the patient’s visual acuity was 20/20 for each eye.

After two weeks of lens wear, the patient called to order his annual supply of lenses. He said that these were the best lenses that he’s had in more than a decade, and he was experiencing no symptoms of irritation.

DRUG-ELUTING LENSES

The concept of drug-eluting contact lenses has been discussed over the last decade, but these lenses have yet to reach the market, leading many people to believe that drug-eluting lenses are a sort of contact lens “urban myth.” Developing these lenses is understandably difficult and presents many challenges, including the impact on lens properties (i.e., transparency, water content, permeability, comfort), drug stability during fabrication and storage, drug release rate and sustainability on the eye, and commercial need and cost/benefit to manufacturers.¹⁸ Nonetheless, technological advancements continue in this area, and numerous types of drug-eluting lenses designed to help patients who have dry eye will be available in the near future.

Cyclosporine A-eluting lenses tested on rabbit eyes have demonstrated the ability to release and sustain the concentration of the drug on the eye for at least 48 hours. In addition, these lenses improved many clinical markers of dry eye (tear volume, tear breakup time, and corneal staining) as well as increasing goblet cell density and decreasing matrix metalloproteinase and inflammatory cytokines.^19,20 As cyclosporine A is generally accepted as an effective treatment for dry eye disease, and most practitioners are familiar with its use, a lens that delivers this medication should be a welcome addition to the specialty lens armamentarium.²¹

Treating ocular allergies can also help alleviate dry eye symptoms in many patients. As these conditions tend to overlap in their responsibility for ocular discomfort,²² a drug-eluting contact lens that delivers antihistamine into the tear film could indirectly treat dry eye symptoms in patients who have both conditions. A recent study reported that an etafilcon A lens drug delivery system designed to deliver therapeutic levels of the antihistamine ketotifen during contact lens wear was effective in reducing ocular itching compared to controls while simultaneously providing vision correction.²³ This lens has cleared phase 3 trials and may move to market within the next year.

IN CONCLUSION

Searching for effective therapies for persistent dry eye and ocular surface disease can be exhausting for patients and practitioners. As you focus on your patients’ ocular well being and vision, remember the following:

• Take care to properly diagnose dry eye.
• Consider less common treatment options and new ideas.
• Consider combining dry eye therapy with vision treatment goals.

Many patients who are struggling with mild-to-moderate dry eye disease and poor comfort with one contact lens modality may find relief and the ability to continue contact lens wear with another modality. Patients who have more severe ocular surface disease can look to scleral lenses as a possible therapeutic option. For the right patients, specialty contact lenses can provide relief from symptoms and sometimes can even treat dry eye and ocular surface disease. CLS

REFERENCES

1. Wolffsohn JS, Arita R, Chalmers R, et al. TFOS DEWS II Diagnostic Methodology report. Ocul Surf. 2017 Jul;15:539-574.
2. Carracedo G, Martin-Gil A, Fonseca B, Pintor J. Effect of overnight orthokeratology on conjunctival goblet cells. Cont Lens Anterior Eye. 2016 Aug;39:266-269.
3. García-Porta N, Rico-Del-Viejo L, Martin-Gil A, Carracedo G, Pintor J, González-Méijome JM. Differences in Dry Eye Questionnaire Symptoms in Two Different Modalities of Contact Lens Wear: Silicone-Hydrogel Daily Wear Basis and Overnight Orthokeratology. Biomed Res Int. 2016;2016:1242845.
4. Barbosa FL, Xiao Y, Bian F, et al. Goblet Cells Contribute to Ocular Surface Immune Tolerance-Implications for Dry Eye Disease. Int J Mol Sci. 2017 May;18:978.
5. Alipour F, Khaheshi S, Soleimanzadeh M, Heidarzadeh S, Heydarzadeh S. Contact Lens-related Complications: A Review. J Ophthalmic Vis Res. 2017 Apr-Jun;12:193-204.
6. Nosch DS, Joos RE, Müller D, Matt SM. General pain perception sensitivity, lid margin sensitivity and gas permeable contact lens comfort. Clin Exp Optom. 2020 Nov;103:766-771.
7. Mickles CV, Harthan JS, Barnett M. Assessment of a Novel Lens Surface Treatment for Scleral Lens Wearers With Dry Eye. Eye Contact Lens. 2020 Nov 3. [Online ahead of print]
8. McClure KA. Scleral Lenses for Dry Eye and Ocular Surface Disease. Contact Lens Spectrum. 2020 July;35:39-46.
9. Schornack MM, Pyle J, Patel SV. Scleral lenses in the management of ocular surface disease. Ophthalmology. 2014 Jul;121:1398-1405.
10. Michaud L, Vincent S. Scleral Lenses and Hypoxia: a Balanced Approach. Contact Lens Spectrum. 2019 Oct;34:38,40-42.
11. Caroline PJ, André MP. Contact Lens Case Reports: The Effect of pH When Filling Scleral Lenses for Dry Eye. Contact Lens Spectrum. 2019 May;34:52.
12. https://nutrifill.com . Accessed Dec. 22, 2020.
13. Yetisen AK, Jiang N, Castaneda Gonzalez CM, et al. Scleral Lens Sensor for Ocular Electrolyte Analysis. Adv Mater. 2020 Feb;32:e1906762.
14. Yin J, Jacobs DS. Long-term outcome of using Prosthetic Replacement of Ocular Surface Ecosystem (PROSE) as a drug delivery system for bevacizumab in the treatment of corneal neovascularization. Ocul Surf. 2019 Jan;17:134-141.
15. Donaldson KE. The combined use of scleral lenses and autologous tears in the treatment of non-healing epithelial defects. Presented at: Hawaiian Eye 2018; Jan. 13-19, 2018; Wailea, HI.
16. Harthan JS, Shorter E. Therapeutic uses of scleral contact lenses for ocular surface disease: patient selection and special considerations. Clin Optom (Auckl). 2018 Jul;10:65-74.
17. Parminder A, Jacobs DS. Advances in scleral lenses for refractive surgery complications. Curr Opin Ophthalmol. 2015 Jul;26:243-248.
18. Maulvi FA, Soni TG, Shah DO. A review on therapeutic contact lenses for ocular drug delivery. Drug Deliv. 2016 Oct;23:3017-3026.
19. Choi JH, Li Y, Jin R, et al. The Efficiency of Cyclosporine A-Eluting Contact Lenses for the Treatment of Dry Eye. Curr Eye Res. 2019 May;44:486-496.
20. Mun J, won Mok J, Jeong S, Cho S, Joo CK, Hahn SK. Drug-eluting contact lens containing cyclosporine-loaded cholesterol-hyaluronate micelles for dry eye syndrome. RSC Adv. 2019;9:16578-16585.
21. Tuan HI, Chi SC, Kang YN. An Updated Systematic Review With Meta-Analysis of Randomized Trials on Topical Cyclosporin A for Dry-Eye Disease. Drug Des Devel Ther. 2020 Jan;14:265-274.
22. Villani E, Rabbiolo G, Nucci P. Ocular allergy as a risk factor for dry eye in adults and children. Curr Opin Allergy Clin Immunol. 2018 Oct;18:398-403.
23. Pall B, Gomes P, Yi F, Torkildsen G. Management of Ocular Allergy Itch With an Antihistamine-Releasing Contact Lens. Cornea. 2019 Jun;38:713-717.