Reducing contact lens dropout rates has always been a goal, and often a challenge, for even the best contact lens practitioners. The primary reasons why patients discontinue contact lens wear are poor vision and reduced comfort. In fact, it has been reported that approximately 25% of neophyte contact lens wearers drop out within the first year.¹

This article will discuss the impact of the tear film, lid margin health, and inflammatory processes as well as the role that moisture retention has on contact lens comfort. It will also address external factors such as allergic eye diseases.

THE IMPORTANCE OF THE TEAR FILM

Contact lenses are introduced to the ocular surface as purposeful foreign bodies to correct vision. Upon application, lenses are immediately immersed in and enveloped by the properties of the tear film. The cornea, along with the tear film, is responsible for the vast majority of the eye’s refractive power. A consistent, stable tear film is critical to visual performance and comfort, especially for contact lens wearers.²

With every blink, tears are essential for maintaining corneal moisture, integrity, and health. Dry eye disease (DED) affects approximately 30 million people in the United States and is one of the most frequent reasons why patients seek care with an eyecare professional.³ DED is a growing concern and an increasing economic burden, due not only to treatment costs to relieve symptoms but also to a loss of productivity from reduced visual performance.⁴ All told, 86% of DED is due to tear evaporation.⁵

Good science has clearly shown that a dysfunctional tear film is directly associated with ocular discomfort and contributes to contact lens-related dryness, in turn leading to reduced wear time for patients and increased chair time for practitioners. Ultimately, it can result in contact lens dropout.⁶ Contact lenses inherently disrupt the tear film; thus, they need to have properties that support tear performance. Patients who have known DED prior to initiating contact lens wear need to be managed and then appropriately fit only when a stable tear film is obtained. Stability of the pre- and post-lens tear film is essential for all types of contact lens wear including soft, GP, or hybrid lenses.

The lipid layer of the tears prevents evaporation, so improving the production and quality of the meibomian glands will increase the thickness and quality of the lipids and keep the contact lens surface hydrated.⁷ Synergistically, a healthy mucoaqueous layer supports an increased tear volume, which facilitates lens hydration and reduces friction.⁸ The physical dynamics of a contact lens interacting positively with the tear film are essential for maintaining comfort and vision, thereby reducing dropout rates.

The Importance of Comfort Addressing contact lens dropout is a serious concern for contact lens practitioners. Statistics show that somewhere between 12% and 51% of contact lens wearers discontinue annually.⁹

So why do patients stop wearing contact lenses? While we cannot rule out issues of cost or challenges with application and removal, practitioners have to acknowledge that a major indicator of a patient’s lens satisfaction is comfort.¹⁰ If patients do not like how the lenses feel, there is a greater likelihood that they will discontinue wear. To be successful, contact lens practitioners must identify as well as address any discomfort with contact lenses.

Fortunately, advancements in both materials and designs have provided practitioners with multiple options to achieve the most comfortable contact lens experience possible. Increased options in daily disposable lenses offer more patients shorter replacement schedules, which represent another method to increase lens comfort.¹¹ Advances in contact lens coating technologies have also demonstrated an increase in perceived comfort.¹² Recently, manufacturers have placed an increased emphasis on the surface friction between the contact lens and the upper lid.¹³ This effort has resulted in newer products that attempt to increase comfort.¹⁴

Despite all of these advances, some patients still experience challenges with contact lens comfort. So, when we have an unsatisfied patient, is it fair to blame only the fit parameters or the physical properties of the lens? In reality, the ocular surface plays an equal, if not a more important, role in the contact lens fitting process.

What practitioners need to understand is that patients who have these underlying conditions will not respond to treatments that involve only changing contact lens materials. Fitting success requires eyecare practitioners to differentiate between symptoms that are contact lens-related or ocular surface-related.

THE ROLE OF THE LID AND LID MARGIN

Practitioners’ understanding of the lid margin and its influence on a healthy tear film is becoming increasingly relevant. As a healthy tear film and ocular surface represent an important pillar in healthy, comfortable lens wear, it becomes increasingly important to diagnose and treat abnormalities of the lid margin appropriately.

Diagnostically, it is critical to assess the lid margin for the presence of volcano signs and collarettes at the base of the lashes, lid margin irregularity, and visible inflammation at the lid margin. The meibomian glands should be assessed for any visible capping or involution that may be present.

Additionally, an assessment of the meibum expressed through a controlled manner such as the use of a meibomian gland evaluator provides an opportunity to assess the meibomian glands yielding secretions as well as the quality of the meibum expressed from those glands. Meibomian gland assessment should be performed to obtain a better idea of the structure of the glands. This can be done through direct visualization (Figure 1A), through eyelid transillumination (Figure 1B), and through infrared imaging of meibomian glands (Figure 1C).

Appropriately establish a treatment strategy with a high level of specificity based on the diagnostic findings. Beginning at the anterior surface of the lid margin, it is important to appropriately manage any signs of blepharitis. Microblepharoexfoliation (MBE) has become an important in-office procedure that mechanically debrides the anterior lid margin, removing the excessive biofilm that is present.

Appropriate lid hygiene following microblepharoexfoliation is also critical. Several prepackaged lid hygiene wipes are available for patients to utilize. A more recent addition to lid hygiene has been the use of hypochlorous acid. It has remarkably effective antimicrobial activity. It is currently available at concentrations of 0.01%, 0.015%, and 0.02%.

Additionally, meibomian gland dysfunction should also be appropriately treated. To do this effectively, application of heat along with evacuation of the glands are required. There are three technologies that allow clinicians to perform this procedure. With one, the eyelids are heated from the posterior surface while pressure is applied to the anterior surface of the lids. Another is a handheld device that warms the meibomian glands through the posterior surface of the lid margin while pressure is placed along the anterior lid margin to evacuate the glands. With this device, practitioners can view expressed meibum during the procedure. A final product is a wearable device that provides targeted and adjustable thermal energy to the meibomian glands. After the thermal treatment, manual expression is performed to evacuate the stagnant meibum from the glands.

The Impact of Inflammation Care of the lid margin is becoming increasingly important to optimize contact lens wear. Practitioners now have both advanced diagnostics and therapeutics in their armamentarium to help them care for these individuals.

Specifically, inflammation can play a large role in contact lens success. Despite advances in materials and solutions, contact lens dropout rates have remained unchanged for more than 20 years. Many studies have looked at the various reasons why patients drop out of lens wear, and comfort has consistently topped this list. With DED being the primary driver of discomfort in contact lens wear,¹⁵ and inflammation identified as a major etiological factor in dry eye,¹⁶ practitioners can improve their patients’ lens-wearing experience and reduce dropout rates by controlling ocular surface inflammation.

Without a doubt, the inflammation component can directly influence comfort and needs to be addressed. Contact lens discomfort has been associated with the presence of degraded lipids, leukotriene B4, and phospholipase A2 in tears, all of which are byproducts of the inflammatory pathway.¹⁷ Practitioners also need to look at the role of inflammation in contact lens-associated complications. The inflammatory pathway is involved in almost every adverse event in contact lens wear.

While typically a result of other etiologies (hypoxia, infection, etc.), inflammation can also be a causative factor. For example, ocular inflammation can lead to corneal neovascularization by signaling corneal epithelial and endothelial cells, along with macrophages and other inflammatory cells, to produce angiogenic vascular endothelial growth factors (VEGFs).¹⁸

How is inflammation identified on the ocular surface? One method involves testing for the concentration of matrix metalloproteinase-9 (MMP-9) in tears via an in-office test. A normal ocular surface produces very low levels of MMP-9, which is a cytokine involved in the degradation of the extracellular matrix. Elevated MMP-9 in tears is strongly indicative of dry eye.

The Tear Film and Ocular Surface Society (TFOS) Dry Eye Workshop II (DEWS II) report concluded that the core mechanism of DED is tear hyperosmolarity induced by evaporation. In addition, hyperosmolarity can damage the ocular surface both directly and by initiating inflammation.¹⁹ This increase in tear osmolarity causes epithelial cell death, proinflammatory cytokine production, and loss of goblet cells. Therefore, another way to determine dry eye is via a tear osmolarity test. Osmolarity can be measured with an in-office device that collects tear fluid directly from the eyelid margin.

Both MMP-9 and tear hyperosmolarity can alert practitioners to inflammation at the ocular surface and should be addressed to improve outcomes with contact lens patients. In addition, practitioners have several different methods to treat inflammation at the ocular surface. The most effective option is often a corticosteroid, but because of the risk of complications such as elevated intraocular pressures and decreased resistance to infections, the use of these medications should be limited.

While these risks apply to all corticosteroids, loteprednol has a significantly lower risk due to its chemical structure. While most corticosteroids are ketones and need to be inactivated by liver metabolism, loteprednol is an ester, and the human body has esterase enzymes readily available to inactivate the drug after its use. This makes loteprednol a safer option for those patients needing a longer course of treatment or frequent pulse dosing.

Other options are currently available as well. Cyclosporine is a calcineurin inhibitor that reduces inflammation by reducing the activation of T cells.²⁰ It has been available as a cyclosporine ophthalmic emulsion 0.05% since 2003. Another recent entry into this area is a cyclosporine ophthalmic solution 0.09%, which after being approved by the U.S. Food and Drug Administration late last year became the first new prescription formulation of cyclosporine available to treat dry eye in 15 years. In addition to the increased concentration (0.09% versus 0.05%), the new product has a nanomicellar formulation.

Another alternative is lifitegrast 5%, which is designed to block the interaction of ICAM-1 (intercellular adhesion molecule-1) and LFA-1 (lymphocyte function-associated antigen-1); this reduces the inflammation mediated by T lymphocytes.²¹

To reduce contact lens dropout and associated complication rates, it is important to begin by controlling inflammation. With accurate diagnostic tools and effective treatment options, practitioners have no excuse to leave their patients spiraling in the vicious cycle of inflammation.

IMPROVING MOISTURE RETENTION

Punctal Occlusion Punctal occlusion is an obstruction of tear drainage at the level of the canaliculus, allowing tears or tear substitutes to remain on the ocular surface.²² Punctal occlusion may be temporary with collagen or silicone plugs or permanent with surgical punctal cautery.²³ There are no large-scale studies demonstrating the efficacy of plug occlusion. Several reports strongly suggest the positive impact of punctal occlusion on dry eye signs and symptoms.²⁰

One study investigated the differences between two treatments—tear substitutes compared to punctal plugs—over a three-month period in 42 patients who had primary Sjögren’s syndrome.²³ The researchers concluded that, compared to baseline scores, there were statistically significant improvements for both groups in Ocular Surface Disease Index, corneal fluorescein staining, Schirmer’s test, and tear breakup time (TBUT) scores. However, treatment of inflammation prior to punctal occlusion is essential.

Scleral Lenses The primary indications of scleral lenses are visual rehabilitation in irregular corneas and the therapeutic treatment of ocular surface disease.²⁴ The scleral’s post-lens fluid reservoir provides continuous corneal lubrication and ocular protection. Scleral lenses prevent mechanical damage, prevent tissue desiccation, promote healing, and disrupt the pain cycle. Large-diameter scleral lenses cover most of the ocular surface and protect corneal and conjunctival tissue from potential aggravation that can result from friction between the ocular surface and the palpebral surface of the lids.

When conventional treatments are insufficient, scleral lenses are a viable management option for dry eye patients²⁴ (Figure 2). Therapeutic scleral lens indications for ocular surface disease include neurotrophic keratitis, exposure keratitis, dry eye syndrome, graft-versus-host disease, Stevens-Johnson syndrome, ocular cicatricial pemphigoid, chemical burns, limbal stem cell deficiency, Sjögren’s syndrome, and persistent epithelial defects.²⁴ Additionally, scleral lenses have been indicated for the treatment of conditions that are associated with neuropathic ocular pain.²⁴

Scleral lens designs are also available for patients who have normal, healthy eyes. Scleral lenses can be used for corneas with a regular, normal, prolate shape without disease, ectasia, or irregularities and can significantly improve the lens-wearing experience for normal eyes. Scleral lenses for normal eyes are beneficial for patients who are not satisfied with their current soft, corneal GP, or hybrid contact lenses. Perhaps their vision is not sufficiently clear or consistent, or lens awareness and discomfort are present. Patients who have refractive errors such as myopia, regular astigmatism, hyperopia, and presbyopia should be considered.

Transitioning patients from other lens modalities to scleral lenses is easily attainable and can improve their contact lens experience. If vision, comfort, or both are not optimal with their current lens modality, a scleral lens option should be considered. It is still critical to discuss realistic expectations including scleral lens risks, benefits, handling, solutions, and the scleral lens fitting process.

In mild-to-moderate dry eye patients who do not have systemic co-morbidities, scleral lenses should not be the primary therapy. Other conventional treatment options should be attempted first, including environment modifications, preservative-free eye drops, prescription dry eye medications, eyelid hygiene, nighttime lubrication or goggles, and punctal occlusion. When conventional treatments are insufficient, scleral lenses are a viable management option for dry eye patients.

This sentiment is echoed by DEWS II, which says that scleral lenses are a tertiary therapy, after prescription medications and overnight treatments such as ointments or moisture goggles and before long-term use of steroids, amniotic membrane grafts, surgical punctal occlusion, or other surgical procedures such as tarsorrhaphy or salivary gland transplantation.²⁵ In addition to sclerals, other step-three therapies include oral secretagogues, autologous/allogenic serum eye drops, and soft bandage contact lenses.

Scleral lenses are ideal for presbyopic patients who often have concomitant dry eye. There are numerous multifocal scleral lens options that provide exceptional vision at all distances. As scleral lenses protect and bathe the ocular surface, they are very beneficial for patients who have dry eye. Of note, multifocal scleral lens optics may be used in patients who have corneal irregularities, which a scleral lens neutralizes.

The performance of scleral lenses for a wide range of clinical indications has been evaluated.²⁶ This prospective, cross-sectional study evaluated 38 existing contact lens patients fit with lenses based on a lens selection algorithm. The authors determined that wearing lenses significantly improved corrected distance visual acuity compared to wearing spectacles. There also was an improvement in satisfactory wearing time. Both the scleral and soft lens groups were generally effective and had high subjective scores with similar results. Overall satisfaction was high in the scleral lens group (≥ 70 for 81% of patients).²⁶

ALLERGIC EYE DISEASE

Patients who suffer from environmental allergies often experience ocular symptoms as well. In fact, the World Allergy Organization refers to this condition as allergic rhinoconjunctivitis.²⁷ According to the 2012 Gallup Well-Being Index, as many as one in four people struggle with allergies on any given day in April. In January, the number of sufferers drops to one in eight, indicating that this problem is year-round. It is also important to note that the number of sufferers continues to rise.²⁸

Keeping patients comfortably in contact lenses can be difficult when they are allergy sufferers.²⁹ Allergy sufferers have increased inflammation and a disrupted mucin layer. This leads to symptoms of redness, itchiness, dryness, and scratchiness; these symptoms are all exacerbated when a contact lens is applied to the eye, further disrupting the tear layer. For contact lens-wearing allergy sufferers, practitioners may need to take a multi-pronged approach to maintain comfortable lens wear.

Identifying the offending allergen can help direct needed education on avoidance. For example, patients who have dust mite allergies can be counseled to use dust covers on their pillows and mattresses. They can also be advised that carpets, stuffed animals, and other fuzzy items may harbor dust mites.³⁰ Patients who have pollen allergies can be advised to reduce the amount of pollen on their bodies, eyelashes, and hair by frequent face washing and hair brushing as well as showering before going to bed.³¹ Removal of shoes when indoors may also be beneficial. Patients who have more complicated allergy profiles can be referred to allergists for counseling.

Systemic allergies may require systemic medications. Unfortunately, many of these medications also dry the ocular surface, making contact lens wear even more difficult. Therefore, it’s important to educate patients about the increase in dryness and the potential impact on their contact lens wear. Alternative medication recommendations may include nasal steroids to help reduce inflammation along the nasal pathway. This may also improve inflammation in the canaliculus and up onto the ocular surface. During acute exacerbations that include significant watering or itching of the eyes, topical antihistamine/mast cell stabilizer medications and cool compresses may be helpful. Newer medications that are applied just once a day can often provide rapid and effective relief.^32,33 Unfortunately, these medications cannot be applied during active contact lens wear. It is preferable for patients to instill their drops prior to applying their contact lenses or after removing them.

Contact lens wear may also need to be adjusted during peak allergy season. Patients may find that they need to utilize a daily disposable modality during peak season. Disposing of the lens every day helps to minimize the number of allergens that may build up on the lens surface and assists in reducing the severity of the allergenic response. Those patients who are able to remain in their multiuse lenses may require enhanced cleaning regimens. Choosing a preservative-free peroxide system may be an excellent option.³⁵ Other patients may have to skip days or reduce their hours of wear to maintain ocular comfort. Rewetting drops may become consistently necessary.

For patients whose conjunctiva mounts a vigorous response in the form of either giant papillary conjunctivitis or vernal keratoconjunctivitis (VKC), a more aggressive approach may be required. These patients may actually need a break from their lenses. In the case of VKC, patients frequently require topical steroids. In rare cases, the large papillary bumps associated with VKC can erode the ocular surface, in which case a bandage lens may be needed. These patients represent a significantly high-risk group, so frequent follow up is required. Long term, these patients may benefit from the use of calcineurin inhibitors.³⁵

Allergy sufferers can still be successful contact lens wearers. They may require additional testing to determine how to best proceed with reducing their allergenic response. Counseling, systemic medication, or referral may be needed in accordance with the results of this testing. Contact lens wear success may require better cleaning, more frequent replacement, tear supplementation, cool compresses, and topical medications.

PREVENT DROPOUT AND IMPROVE RETENTION

Thus far, we have identified the role that both the ocular surface and contact lenses play in maintaining a healthy contact lens fitting relationship. Both components of the equation are important and have to be analyzed, cared for, maintained, and improved upon with time to ensure a long life of healthy contact lens wear.

We have explored the ocular surface and ocular environment. Now let us take a closer look at the contact lens itself. There are changes that practitioners can initiate to modify their patients’ contact lenses and their routines to ensure greater success with lens wear. For example, switching to a daily disposable lens results in a more comfortable, cleaner, and healthier wearing experience. Or, our clinical experience has shown that using hydrogen peroxide solutions rather than multipurpose solutions to clean lenses increases the length of comfortable wear time. And, treating lenses with enhanced surface coatings can improve lens comfort and wear time as well as reduce contact lens dropout.

Changing patients’ daily habits to improve their contact lens comfort cannot be ignored. These days, many people’s lives revolve around the use of digital devices, resulting in a constant state of accommodation. In an effort to reduce readjusting, they tend to get absorbed in their work and to not blink while concentrating. The end result is a dry ocular surface due to a lack of meibum being released from the meibomian glands. Asking patients to reduce device use is difficult; however, it is important to have them consider avoiding tasks that do not need to be performed at a close distance. For example, they can watch movies, television shows, and videos on a television screen across the room rather than on a phone or laptop.

The use of makeup is an important part of many people’s identity. Teaching patients how to appropriately wash their face, eyebrows, and eyelashes (i.e., which specific products to use, how frequently it should be done, and the negative impact of not removing makeup) is part of an eyecare provider’s job.

Lash extensions are a growing trend, and practitioners need to remind their patients of a few important tips to ensure their safety. Find a reputable salon to avoid corneal abrasions, chemical burns, and lid and lash damage. In addition, advise patients to clean lashes daily to avoid debris buildup and to seek care immediately if redness, itchiness, discharge, or pain occur. Educating patients on the importance of blinking with lash extensions is essential. Key steps to preventing dropout include educating patients on the importance of healthy practices; cleaning routines; replacement schedules for cases and lenses; proper contact lens wear, care, and handling; and of routine annual eye examinations to evaluate both parts of the fitting relationship.

Eyecare practitioners have the knowledge to ensure great comfort for their patients, and they need to remember to share this knowledge with them. The sharing of information starts on the first day that a patient begins wearing contact lenses. This is referred to as long-term planning. Patients are often excited about their first day of contact lens wear and are not thinking about the day that they may want to discontinue lens wear. Practitioners can ensure that this day doesn’t arrive anytime soon through attention to detail and care for their patients. CLS

REFERENCES

1. Sulley A, Young G, Hunt C. Retention rates in new contact lens wearers. Eye Contact Lens. 2018 Sep;44:S273-S282.
2. Craig J, Wilcox M, Argueso P, et al. The TFOS international workshop on contact lens discomfort: report of the contact lens interactions with the tear film subcommittee. Invest Ophthalmol Vis Sci. 2013 Oct;54:TFOS123-TFOS156.
3. Tear Film & Ocular Surface Society. TFOS DEWS II Report. Available at http://www.tearfilm.org/dettreports-tfos_dew_ii_report/32_30/eng . Accessed Dec. 5, 2019.
4. Yu, J, Asche CV, Fairchild CJ, The economic burden of dry eye disease in the United States: a decision tree analysis. Cornea. 2011 Apr;30:379-387.
5. Lemp MA, Crews LA, Bron AJ, Foulks GN, Sullivan BD. Distribution of Aqueous-Deficient and Evaporative Dry Eye in A Clinic-Based Patient Cohort: A Retrospective Study. Cornea. 2012 May;31:472-478.
6. Harthan J, Hom M. It’s All About the Tear Film. Rev Cornea Contact Lens. 2017 May 15. Available at https://www.reviewofcontactlenses.com/article/rccl0517-its-all-about-the-tear-film . Accessed Dec. 5, 2019.
7. Willcox MDP, Argüeso P, Georgiev GA, et al. TFOS DEWS II Tear Film Report. Ocul Surf. 2017 Jul;15:334-365.
8. Ablamowicz AF, Nichols JJ. Ocular surface membrane-associated mucins. Ocul Surf. 2016 Jul;14:331-341.
9. Nichols JJ, Willcox MD, Bron AJ, et al. The TFOS international workshop on contact lens discomfort: Executive summary. Invest Ophthalmol Vis Sci. 2013 Oct;54:TFOS7-TFOS13.
10. Diec J, Naduvilath T, Tilia D. Subjective Ratings and Satisfaction in Contact Lens Wear. Optom Vis Sci. 2018 Mar;95:256-263.
11. McConville P, Pope JM. Diffusion limited evaporation rates in hydrogel contact lenses. Eye Contact Lens. 2001 Oct;27:186-191.
12. Wolffsohn JS, Hunt OA, Chowdhury A. Objective clinical performance of ‘comfort-enhanced’ daily disposable soft contact lenses. Cont Lens Anterior Eye. 2010 Apr;33:88-92.
13. Roba M, Duncan EG, Hill GA, Spencer ND, Tosatti SGP. Friction measurements on contact lenses in their operating environment. Tribol Lett. 2011;44:378-397.
14. Jones L, Brennan NA, González-Méijome J, et al. The TFOS International Workshop on Contact Lens Discomfort: report of the contact lens materials, design, and care subcommittee. Invest Ophthalmol Vis Sci. 2013 Oct;54:TFOS37-TFOS70.
15. Richdale, K, Sinnott LT, Skadahl E, Nichols JJ. Frequency of and Factors Associated with Contact Lens Dissatisfaction and Discontinuation. Cornea. 2007 Feb;26:168-174.
16. Craig JP, Nelson JD, Azar DT, et al. TFOS DEWS II Report Executive Summary. The Ocular Surface. 2017 Oct;15:802-812.
17. Willcox MD. Is There a Role for Inflammation in Contact Lens Discomfort? Eye Contact Lens. 2017 Jan;43:5-16.
18. Chiang HH, Hemmati HD. Treatment of Corneal Neovascularization. EyeNet Magazine. 2013 Oct. Available at https://www.aao.org/eyenet/article/treatment-of-corneal-neovascularization . Accessed Dec. 2, 2019.
19. Liu H, Begley C, Chen M, et al. A link between tear instability and hyperosmolarity in dry eye. Invest Ophthalmol Vis Sci. 2009 Aug;50:3671-3679.
20. Kumar I, Abbas AK, Aster JC. Rejection of Tissue Transplants. In: Robbins & Cotran Pathologic Basis of Disease, 9th Edition. Elsevier. 2014 Jul 28.
21. Tauber J, Karpecki P, Latkany R, et al. Lifitegrast Ophthalmic Solution 5.0% versus Placebo for Treatment of Dry Eye Disease: Results of the Randomized Phase III OPUS-2 Study. Ophthalmology. 2015 Dec;122:2423-2431.
22. Ervin AM, Law A, Pucker A. Punctal occlusion for dry eye syndrome. Cochrane Database Syst Rev. 2017 Jun;2017:CD006775.
23. Qiu W, Liu Z, Ao M, Li X, Wang W. Punctal Plugs Versus Artificial Tears for Treating Primary Sjögren’s Syndrome with Keratoconjunctivitis Sicca: A Comparative Observation of Their Effects on Visual Function. Rheumatol Int. 2013 Oct;33:2543-2548.
24. Schornack M. Medical indications for scleral lens use. In Barnett M, Johns LK, eds. Contemporary Scleral Lenses: Theory and Application. Bentham Science, 2017, pp. 133-165.
25. Jones L, Downie LE, Korb D, et al. TFOS DEWS II Management and Therapy Report. Ocul Surf. 2017 Jul;15:575-628.
26. Michaud L, Bennett ES, Woo SL, et al. Clinical Evaluation of Large Diameter Rigid-Gas Permeable Versus Soft Toric Contact Lenses for the Correction of Refractive Astigmatism. A MultiCenter Study. Eye Contact Lens. 2018 May;44:164-169.
27. de Groot H, Brand PLB, Fokkens WF, Berger MY. Allergic rhinoconjunctivitis in children. BMJ. 2007 Nov 10;335:985-988.
28. Morales L. U.S. Allergy Season Worse Than Usual. Available at https://news.gallup.com/poll/153950/Allergy-Season-Worse-Usual.aspx . Accessed Sept. 30, 2019.
29. Solomon A. Allergic manifestations of contact lens wearing. Curr Opin Allergy Clin Immunol. 2016 Oct;16:492-497.
30. Portnoy J, Miller JD, Williams PB, et al; Joint Taskforce on Practice Parameters, Practice Parameter Workgroup. Environmental assessment and exposure control of dust mites: a practice parameter. Ann Allergy Asthma Immunol. 2013 Dec;111:465-507.
31. Portnoy JM, Kennedy K, Sublett JL, et al. Environmental assessment and exposure control: a practice parameter—furry animals. Ann Allergy Asthma Immunol. 2012 Dec;108:223.e1-223.e15.
32. Bielory L, Katelaris CH, Lightman S, Naclerio RM. Treating the Ocular Component of Allergic Rhinoconjunctivitis and Related Eye Disorders. MedGenMed. 2007 Aug 15;9:35.
33. Fauquert JL. Diagnosing and managing allergic conjunctivitis in childhood: The allergist’s perspective. Pediatr Allergy Immunol. 2019 Jun;30:405-414.
34. Lemp MA. Contact lenses and allergy. Curr Opin Allergy Clin Immunol. 2008 Oct;8:457-460.
35. Pleyer U, Leonardi A. [Vernal keratoconjunctivitis]. Ophthalmol Z Dtsch Ophthalmol Ges. 2015 Feb;112:177-189.
36. Nichols JJ, Chalmers RL, Dumbleton K, et al. The Case for Using Hydrogen Peroxide Contact Lens Care Solutions: A Review. Eye Contact Lens. 2019 Mar;45:69-82.