Many eyecare practitioners already use contact lenses for purposes other than simple refractive error correction. They can provide pain relief when used as bandage lenses (Lim and Lim, 2020; Jacobs et al, 2021; Mohammadpour et al, 2021). However, the opportunities to use contact lenses to manage ocular disease may be further expanded with exciting future advancements in technology (Jones et al, 2021).

Various options are available for managing dry eye, and novel contact lenses may offer additional alternatives. Dehydration-resistant materials may promote fluid retention and reduce fluid evaporation (Kusama et al, 2019). Special ionic materials that can conduct fluid through the lens to replenish the post-lens tear film (Kusama et al, 2019). Graphene may be applied to the anterior lens surface to reduce fluid loss and a variety of technologies may be incorporated into lenses to increase tear production (Lee et al, 2017).

Existing technology involving intranasal stimulation has been used to activate the tear production pathway (Farhangi et al, 2020; Yu et al, 2021). Controlling the level of reactive oxygen species and matrix metalloproteinases (MMPs) on the ocular surface is another strategy to tackle dry eye (Stoddard et al, 2013). Delivery of MMP inhibitors via an eye drop may be suboptimal because the eye drops evaporate quickly from the ocular surface. Contact lens delivery may offer more consistency. The potential future role of contact lenses in dry eye management is exciting; however, current clinical evidence is nominal, and more clinical data is required.

Managing limbal stem cell deficiency involves replenishing the dysfunctional limbal stem cells with healthy ones. Healthy limbal stem cells can be sourced from donor tissue via corneal transplant. However, if the donor tissue is an autograft, retrieving the tissue from the donor eye may damage its own limbus. If the graft derives from another individual, graft rejection may occur. Limbal stem cells can be cultured from human amniotic membrane, but the process is difficult and expensive. Being non-immunogenic, less invasive, and more accessible, contact lenses can overcome the aforementioned limitations. As a vehicle for stem cell delivery, contact lenses have had clinical success (Bobba and Di Girolamo, 2016), with a 100% success rate being reported in three patients at a 12-month follow-up (Di Girolamo et al, 2009).

Patients who have pupil or iris defects (such as aniridia, coloboma, and transillumination iris defects) may benefit from devices that enhance their iris functionality. One study incorporated an active electronic artificial iris on a scleral lens and evaluated its optical performance (Vásquez Quintero et al, 2020). Using visual simulations, this smart contact lens demonstrated an optical benefit to a patient who had aniridia (Vásquez Quintero et al, 2020).

Diabetic retinopathy is a disease of ischemia and can be aggravated by hypoxia. Hypoxia can occur during dark adaptation when the rod photoreceptors have the highest oxygen consumption. It is anticipated that delivering light to the retina during sleep may “dampen” rod activities and reduce their oxygen consumption, thus minimizing hypoxia. This concept sparked the development of phosphorescent lenses that can deliver light to the retina in closed-eye situations (Cook et al, 2018). However, to date, their therapeutic benefit remains controversial, with conflicting results between an animal model and a multicentered randomized clinical trial (Sivaprasad et al, 2018).

A goal in managing patients who have color vision deficiency is improving their color perception. Conventionally, this is achieved using color filters and tints, and tinted contact lenses have been available for many years to serve such a purpose (Kassar et al, 1984). Unfortunately, evaluation of current commercial filters showed little or no performance enhancement. More recently, a novel plasmonic metasurface was embedded in a rigid contact lens (Karepov and Ellenbogen, 2020). The metasurface has the capability of fine-tuning the color filter that it elicits, and it is hoped that this feature would allow enhanced color perception. Promising evidence was observed in patients who have deuteranomaly and who showed not only improved color perception but also contrast sensitivity while wearing the metasurface-based contact lenses (Karepov and Ellenbogen, 2020).

In the future, novel technologies will offer promising opportunities for contact lenses to manage ocular disease that, for now, remain almost impossible to conceive. CLS

References

1. Lim L, Lim EWL. Therapeutic Contact Lenses in the Treatment of Corneal and Ocular Surface Diseases-A Review. Asia Pac J Ophthalmol (Phila). 2020 Dec;9:524-532.
2. Jacobs DS, Carrasquillo KG, Cottrell PD, et al. CLEAR - Medical use of contact lenses. Cont Lens Anterior Eye. 2021 Apr;44:289-329.
3. Mohammadpour M, Heirani M, Khorrami-Nejad M, Ambrósio Jr R. Update on Pain Management After Advanced Surface Ablation. J Refract Surg. 2021 Nov37:782-790.
4. Jones L, Hui A, Phan CM, et al. CLEAR - Contact lens technologies of the future. Cont Lens Anterior Eye. 2021 Apr;44:398-430.
5. Kusama S, Sato K, Yoshida S, Nishizawa M. Self-Moisturizing Smart Contact Lens Employing Electroosmosis. Adv Mater Technol. 2019 Nov 28;5:1900889.
6. Lee S, Jo I, Kang S, et al. Smart contact lenses with graphene coating for electromagnetic interference shielding and dehydration protection. ACS Nano. 2017 Jun 27;11:5318-5324.
7. Farhangi M, Cheng AM, Baksh B, et al. Effect of non-invasive intranasal neurostimulation on tear volume, dryness and ocular pain. Br J Ophthalmol. 2020 Sep;104:1310-1316.
8. Stoddard AR, Koetje LR, Mitchell AK, Schotanus MP, Ubels JL. Bioavailability of antioxidants applied to stratified human corneal epithelial cells. J Ocul Pharmacol Ther. 2013 Sep;29:681-687.
9. Yu MD, Park JK, Kossler AL. Stimulating Tear Production: Spotlight on Neurostimulation. Clin Ophthalmol. 2021 Oct;15:4219-4226.
10. Bobba S, Di Girolamo N. Contact Lenses: A Delivery Device for Stem Cells to Treat Corneal Blindness. Optom Vis Sci. 2016 Apr;93:412-418.
11. Di Girolamo N, Bosch M, Zamora K, Coroneo MT, Wakefield D, Watson SL. A contact lens-based technique for expansion and transplantation of autologous epithelial progenitors for ocular surface reconstruction. Transplantation. 2009 May;87:1571-1578.
12. Vásquez Quintero A, Pérez-Merino P, De Smet H. Artificial iris performance for smart contact lens vision correction applications. Sci Rep. 2020 Sep;10:14641.
13. Cook CA, Martinez-Camarillo JC, Yang Q, Scianmarello NE, Humayun MS, Tai YC. Phototherapeutic contact lens for diabetic retinopathy. Presented at the 2018 IEEE Conference on Micro Electro Mechanical Systems, Belfast, UK. Jan. 21-25, 2018
14. Sivaprasad S, Vasconcelos JC, Prevost AT, et al. Clinical efficacy and safety of a light mask for prevention of dark adaptation in treating and preventing progression of early diabetic macular oedema at 24 months (CLEOPATRA): a multicentre, phase 3, randomised controlled trial. Lancet Diabetes Endocrinol 2018 May;6:382-391.
15. Kassar BS, Dresner SC, May JG, Marx MS, Safir A. Evaluation of the X-chrom lens and color deficiency. CLAO J. 1984 Jan-Mar;10:100-103.
16. Karepov S, Ellenbogen T. Metasurface-based contact lenses for color vision deficiency. Opt Lett. 2020 Mar 15;45:1379-1382.