A Lens Fit for Dry Eye

Here are some clinical pearls to help treat and fit contact lens patients who present with dry eye.

By Lakshman N. Subbaraman, PhD, BSOptom, MSc, and Sruthi Srinivasan, PhD, BSOptom

Goal Statement:

This article offers some clinical pearls to help treat and fit contact lens patients who present with dry eye.

Faculty/Editorial Board:

Lakshman N. Subbaraman, PhD, BSOptom, MSc, and Sruthi Srinivasan, PhD, BSOptom

Dr. Srinivasan is a research assistant professor at the Centre for Contact Lens Research, School of Optometry and Vision Science, University of Waterloo, Canada. She is a fellow of the American Academy of Optometry, member of the Association for Research in Vision & Ophthalmology and the Tear Film & Ocular Surface Society.

Dr. Subbaraman is the head of Biological Sciences at the Centre for Contact Lens Research, School of Optometry and Vision Science, University of Waterloo. He is a two-time recipient of the American Optometric Foundation’s prestigious William Ezell Fellowship, a fellow of the American Academy of Optometry and a member of the Association for Research in Vision & Ophthalmology.

Credit Statement:

This course is COPE approved for 1 hours of CE credit. COPE ID 37163-CL. Check with your local state licensing board to see if this counts toward your CE requirements for relicensure.

Joint-Sponsorship Statement:

This continuing education course is joint-sponsored by the Pennsylvania College of Optometry.

Disclosure Statement:

The authors have no financial relationships to disclose.

Almost 50% to 80% of contact lens wearers experience symptoms of dry eye.¹ Contact lens-related dry eye (CLDE) may be reported as dryness, discomfort, gritty sensation, irritation, stinging, burning or foreign body sensation.^2,3 Discontinuations and dropouts from lens wear are primarily due to symptoms of discomfort and dryness.

CLDE is complex and multifac-torial. Increased tear evaporation, altered tear osmolarity, poor or low tear film quality and quantity, oxygen deprivation, lens deposits, reactions to lens care solutions and non-wetting surfaces are some of the factors that exacerbate dry eye in contact lens wearers. Environmental components, allergies and lid disease can also influence this condition.

This article provides an overview of the factors that influence CLDE and outlines some strategies for effective treatment.

Materials

Clinicians should start by determining which time of day is most problematic for the patient who complains of CLDE. Symptoms that develop two to three hours into lens wear are normally indicative of solution toxicity. On the other hand, end-of-day dryness may be due to lack of lens surface wetting or other material-related factors.

The FDA classifies commercially available hydrogel contact lens materials into four groups, depending upon their charge and water content: non-ionic, low water content (Group I); non-ionic, high water content (Group II); ionic, low water content (Group III); and ionic, high water content (Group IV). This material classification seems to be a very strong predictor of CLDE.

• Deposition. Hydrogel contact lenses absorb components from the tear film, particularly proteins, lipids and mucins.^4-7 Deposits are associated with diminished visual acuity, dryness and discomfort, and lid-related inflammatory changes.^8-13

High water content materials have been associated with significant tear film deposition.^9,14-16 In particular, Group II lenses are prone to lipid deposition whereas Group IV lenses have been shown to attract more protein than lipids.^6,17 Further, once tear proteins (such as lysozyme) firmly adsorb onto contact lens materials, the protein undergoes conformational changes and dena-turation.^7,15,18,19 Protein denaturation is closely linked to inflammatory conditions, such as papillary conjunctivitis, and can also impact subjective comfort.^11-13,20,21

Practitioners should advise their patients to maintain a clean and deposit-free lens surface, as well as review appropriate lens replacement schedules. Practitioners should also recommend that their patients rehydrate the lenses with rewetting drops since proteins exposed to hydrophobic surfaces are more likely to denature, which could potentially result in reduced comfort. Heavy lipid depositors should be advised to use a separate surfactant cleaner.

• Wettability. Deposition of tear film-derived material reduces wettability due to denatured protein and increased lipid deposition.^17,22,23 This produces areas of hydrophobicity, resulting in further deposition and comfort problems. If patients do exhibit reductions in wettability, changing to another lens material will likely have a minimal impact. Such patients are best managed by switching to lenses that are replaced more frequently, such as daily disposable lenses, or by prescribing rewetting drops that contain surfactants.²⁴
  
  
• Water content and ionicity. Non-ionic, high water content (Group II) and ionic, high water content (Group IV) contact lens wearers have a two to three times greater likelihood of experiencing dry eye than individuals wearing Group I lenses.²⁵ Further, Group II lens materials are more commonly associated with dry eye than the Group IV lens materials.²⁵ This could be because the polar head groups associated with the tear film lipid molecules may be attracted to higher water content lens materials, which would leave their non-polar tails away from the surface of the lens and potentially lead to evaporation and/or dewetting. Patients who wore low water content lenses and maintained their hydration generally reported that their eyes "never felt dry" during lens wear.²⁶ Thus, evidence to date suggests that patients wearing lower water content contact lenses are less likely to complain of CLDE.
  
  
• Dehydration. Dehydration is influenced by several factors, including the surrounding environment, water content, water binding properties, thickness and wearing period.^30-38 Dryness symptoms occur more frequently in soft lens wearers during open-eye wear, when conditions are favorable for greater dehydration.²⁷ Previous studies have shown that wearing thin, high water content lenses can result in increased epithelial staining due to pervaporation. Pervaporation is a process in which a permeate passes through a membrane and subsequent evaporation in the vapor phase.^28,30 Factors that explain dehydration-induced discomfort include increased lid to lens interaction, changes in lens surface wettability or lens fit, and the development of epithelial staining due to pervaporation and subsequent desiccation.^28-30

Conventional hydrogel material dehydrates more than silicone hydrogel lens materials.^33,34 Remember, dehydration can affect the fit of a hydrogel lens by both altering the lens parameters and lowering the oxygen transmissibility.³⁹

Clinicians must examine the patient for corneal staining after lens removal. The dye of choice in most clinical practices globally is sodium fluorescein. This dye aids in highlighting the extent of cellular damage/exposure of epithelial cells by staining in the form of punctate or coalescent areas. The use of a yellow barrier filter, in addition to cobalt blue excitation filter, is essential to visualize subtle changes. Examine the location of staining (i.e., mid-inferior smile staining patterns), advise proper blinking habits for patients with incomplete blinks and prescribe artificial tear supplements if necessary.

• Silicone hydrogel. Several studies have shown that silicone hydro-gel lens wearers reported reduced dryness and end-of-day discomfort compared to hydrogel contact lens patients.^40-42 Silicone hydrogel lens wearers also reported better comfort after napping or sleeping, and in dry air or smoky environments because silicone hydrogel lens materials are less prone to evaporation (possibly due to their lower water content) and absorb fewer airborne pollutants than lenses with higher water content.^40,43-46

Clinicians should consider refitting the patient with a high-Dk lens if oxygen deficiency is suspected. Practitioners should be careful when using lenses with an increased modulus of elasticity or poor surface wettability as they may cause other conditions, including contact lens-associated papillary conjunctivitis.

Environment

In dry and low-humidity environments, such as artificially heated rooms or during the winter months, quicker and greater lens dehydration likely exacerbate dryness in existing patients or induce symptoms in otherwise asymptomatic patients. Those who complain of CLDE due to such environmental conditions would benefit by rehydrating their lenses with rewetting drops.

Lens Care

• Solutions. Hydrogen peroxide solutions are considered the gold standard for disinfecting contact lenses. However, when residual peroxide is present on the lenses in sufficiently high concentrations, it can be toxic to the cornea and can cause discomfort. When peroxide-based systems are used at the right concentration, they can provide improved comfort in contact lens wearers.^47,48

Over the last few years, several novel components have been added to multipurpose solutions, such as surfactants or ocular demulcents, to improve comfort, enhance water retention and improve surface wetting properties of contact lenses.

Clinicians should examine the lens and corneal surface carefully, ensure the appropriate cleaning solution is being used and check for patient compliance. Examine corneal staining to check if solution induced-corneal staining (SICS) is present. If SICS exists, advise appropriate lens-solution combinations or switch to daily disposables.

• Rewetting drops. Rewetting (or comfort) drops can be used to alleviate discomfort that is caused by dryness. Although they provide temporary relief from these symptoms, there is currently no rewetting drop that can provide sustained comfort and relief from dry eye symptoms for the length of an entire wearing day. The drops drain through the patient's nasolacrimal duct quickly after instillation, with the remainder absorbed by the cornea, conjunctiva and nasal mucosa. With at least 90% loss in each application, rewet-ting drops have to be re-instilled frequently throughout the day to provide effective comfort.⁴⁹

Instilling rewetting drops in the eye prior to lens wear may increase the hours of comfortable wear time. Remember, methylcellulose-containing drops instilled upon lens insertion will neutralize the effects of the preservative on the ocular surface.⁵⁰ Preservative-free rewetting drops will be beneficial for patients with sensitive eyes. The use of lubricant drops prior to lens wear and after lens removal may increase the hours of comfortable wear time.⁵⁰

Lid Disease

Meibomian gland dysfunction (MGD) is one of the major causes of evaporative dry eye and often is under-diagnosed by clinicians. Evaluation of the eyelids, meibomian gland orifices, the ocular surface and tear film (tear break-up time, tear meniscus height, debris in tears and Schirmer test) are necessary to administer appropriate treatment.

The novel LipiFlow device (TearScience) is a thermal pulsation system believed to effectively relieve the meibomian gland blockage. This tool applies a controlled amount of heat and massage to the eyelids, treating the upper and lower lids simultaneously. LipiView (TearScience) is an interferometer to evaluate lipid layer thickness. It is valuable to obtain the lipid layer thickness using LipiView before and after the treatment of MGD with the LipiFlow.

Based on the evaluation, interventions such as lid hygiene techniques (lid scrubs and warm compresses), nutraceuticals (omega-3 fatty acids), rewetting drops/ artificial tears, and topical cyclospo-rine or doxycycline for dry eye and severe MGD may be required.

Because CLDE cannot easily be traced to one cause, preventing contact lens dropouts can be quite a challenge with patients suffering from this condition. Several factors, such as lens material and solutions, can play a role in exacerbating or improving dry eye symptoms. Clinicians should stay abreast of the latest research and developments to identify underlying causes of this condition and, ultimately, better treat their patients.

Disclosure: Over the past three years, CCLR has received research support or honoraria from the following companies: Alcon, Allergan, AMO, Bausch + Lomb, CIBA Vision, CooperVision, Essilor, Inspire, Johnson & Johnson, Menicon, OcuSense and Visioneering. Drs. Subbaraman and Srinivasan are not paid consultants, do not serve on an advisory board or own shares in any optometric company.

References

1. Nichols JJ, Ziegler C, Mitchell GL, Nichols KK. Self-reported dry eye disease across refractive modalities. Invest Ophthalmol Vis Sci. 2005 Jun;46(6):1911-4.
2. Begley CG, Caffrey B, Nichols KK, Chalmers R. Responses of contact lens wearers to a dry eye survey. Optom Vis Sci. 2000 Jan:77(1):40-6.
3. Fonn D, Situ P, Simpson T. Hydrogel lens dehydration and subjective comfort and dryness ratings in symptomatic and asymptomatic contact lens wearers. Optom Vis Sci. 1999 Oct;76(10):700-4.
4. Bontempo AR, Rapp J. Protein and lipid deposition onto hydrophilic contact lenses in vivo. CLAO J. 2001 Apr;27(2):75-80.
5. Castillo EJ, Koenig JL, Anderson JM, Jentoft N. Protein adsorption on soft contact lenses. III. Mucin. Biomaterials. 1986 Jan;7(1): 9-16. 6.
6. Jones L, Evans K, Sariri R, et al. Lipid and protein deposition of N-vinyl pyrrolidone-containing group II and group IV frequent replacement contact lenses. CLAO J. 1997 Apr;23(2):122-6.
7. Sack RA, Jones B, Antignani A, et al. Specificity and biological activity of the protein deposited on the hydrogel surface. Relationship of polymer structure to biofilm formation. Invest Ophthalmol Vis Sci. 1987 May;28(5):842-9.
8. Gellatly KW, Brennan NA, Efron N. Visual decrement with deposit accumulation of HEMA contact lenses. Am J Optom Physiol Opt. 1988 Dec;65(12):937-41.
9. Jones L, Franklin V, Evans K, et al. Spoilation and clinical performance of monthly vs three monthly group II disposable contact lenses. Optom Vis Sci. 1996 Jan;73(1):16-21.
10. Fonn D, Dumbleton K. Dryness and discomfort with silicone hydro-gel contact lenses. Eye Contact Lens. 2003 Jan;29(1 Suppl):S101-4; discussion S115-8, S192-4.
11. Allansmith MR, Korb DR, Greiner JV, et al. Giant papillary conjunctivitis in contact lens wearers. Am J Ophthalmol. 1977 May;83(5):697-708.
12. Porazinski AD, Donshik PC. Giant papillary conjunctivitis in frequent replacement contact lens wearers: a retrospective study. CLAO J. 1999 Jul;25(3):142-7.
13. Skotnitsky CC, Naduvilath TJ, Sweeney DF, Sankaridurg PR. Two presentations of contact lens-induced papillary conjunctivitis (CLPC) in hydrogel lens wear: Local and general. Optom Vis Sci. 2006 Jan;83(1):27-36.
14. Subbaraman LN, Glasier MA, Senchyna M, et al. Kinetics of in vitro lysozyme deposition on silicone hydrogel, PMMA, and FDA groups I, II, and IV contact lens materials. Curr Eye Res. 2006 Oct;31(10):787-96.
15. Suwala M, Glasier MA, Subbaraman LN, Jones L. Quantity and conformation of lysozyme deposited on conventional and silicone hydrogel contact lens materials using an in vitro model. Eye Contact Lens. 2007 May;33(3):138-43.
16. Jones L, Fcoptom, Mann A, et al. An in vivo comparison of the kinetics of protein and lipid deposition on group II and group IV frequent-replacement contact lenses. Optom Vis Sci. 2000 Oct;77(10):503-10.
17. Lorentz H, Jones L. Lipid deposition on hydrogel contact lenses: how history can help us today. Optom Vis Sci. 2007 Apr;84(4):286- 95.
18. Jones L, Senchyna M, Glasier MA, et al. Lysozyme and lipid deposition on silicone hydrogel contact lens materials. Eye Contact Lens. 2003 Jan;29(1 Suppl):S75-9; discussion S83-4, S192-4.
19. Senchyna M, Jones L, Louie D, et al. Quantitative and conformational characterization of lysozyme deposited on balafilcon and etafil-con contact lens materials. Curr Eye Res. 2004 Jan;28(1):25-36.
20. Skotnitsky C, Sankaridrug PR, Sweeney DF, Holden BA. General and local contact lens induced papillary conjunctivitis (CLPC). Clin Exp Optom. 2002 May;85(3):193-7.
21. Subbaraman LN, Glasier MA, Varikooty J, et al. Protein deposition and clinical symptoms in daily wear of etafilcon lenses. Optom Vis Sci. 2012 Oct;89(10):1450-9.
22. Patel S, Thomson A, Raj S. Tear film stability with planned replacement soft lenses. Optician. 1996;212(5558):28-30.
23. Lorentz H, Rogers R, Jones L. The impact of lipid on contact angle wettability. Optom Vis Sci. 2007 Oct;84(10):946-53.
24. Subbaraman LN, Bayer S, Glasier MA, et al. Rewetting drops containing surface active agents improve the clinical performance of silicone hydrogel contact lenses. Optom Vis Sci. 2006 Mar;83(3):143- 51.
25. Ramamoorthy P, Sinnott LT, Nichols JJ. Treatment, material, care, and patient-related factors in contact lens-related dry eye. Optom Vis Sci. 2008 Aug;85(8):764-72.
26. Efron N, Brennan N. A survey of wearers of low water content hydrogel contact lenses. Clin Exp Optom. 1988 May;71(3):86-90.
27. Efron N, Young G. Dehydration of hydrogel contact lenses in vitro and in vivo. Ophthal Physiol Opt. 1988;8(3):253-6.
28. Holden B, Sweeney D, Seger R. Epithelial erosions caused by thin high water content lenses. Clin Exp Optom. 1986;69(3):103-7.
29. Pritchard N, Fonn D. Dehydration, lens movement and dryness ratings of hydrogel contact lenses. Ophthal Physiol Opt. 1995 Jul;15(4):281-6.
30. Orsborn GN, Zantos SG. Corneal desiccation staining with thin high water content contact lenses. CLAO J. 1988 Apr-Jun;14(2):81-5.
31. Andrasko G, Schoessler J. The effect of humidity on the dehydration of soft contact lenses on the eye. Int Contact Lens Clin. 1980;7(9/10):30-3.
32. Brennan N, Efron N, Bruce AS, et al. Dehydration of hydrogel lenses: Environmental influences during normal wear. Am J Optom Physiol Opt. 1988 Apr;65(4):277-81.
33. Jones L, May C, Nazar L, Simpson T. In vitro evaluation of the dehydration characteristics of silicone hydrogel and conventional hydrogel contact lens materials. Cont Lens Anterior Eye, 2002 Sep;25(3):147-56.
34. González-Méijome JM, López-Alemany A, Alemida JB, et al. Qualitative and quantitative characterization of the in vitro dehydration process of hydrogel contact lenses. J Biomed Mater Res B Appl Bio-mater, 2007 Nov;83(2):512-26.
35. Larsen DW, Huff JW, Holden BA. Proton NMR relaxation in hydro-gel contact lenses: Correlation with in vivo lens dehydration data. Curr Eye Res. 1990 Jul;9(7):697-706.
36. Benz P, Ors J. New materials demand more accurate measurements of performance. CL Spectrum. 1997 Jul;7:40-6.
37. Andrasko G. Hydrogel dehydration in various environments. Int Contact Lens Clin. 1983;10(1):22-8.
38. Wechsler S, Prather D, Sosnowski J. In vivo hydration of gel lenses. Int Contact Lens Clin. 1982;9(3):154-8.
39. Efron N, Morgan PB. Hydrogel contact lens dehydration and oxygen transmissibility. CLAO J. 1999 Jul;25(3):148-51.
40. Chalmers RL, Hunt C, Hickson-Curran S, Young G. Struggle with hydrogel CL wear increases with age in young adults. Cont Lens Anterior Eye. 2009 Jun;32(3):113-9.
41. Chalmers RL, Dillehay S, Long B, et al. Impact of previous extended and daily wear schedules on signs and symptoms with high Dk lotrafilcon A lenses. Optom Vis Sci. 2005 Jun;82(6):549-54.
42. Brennan NA, Coles ML, Ang JH. An evaluation of silicone hydrogel lenses worn on a daily wear basis. Clin Exp Optom. 2006 Jan;89(1):18-25.
43. Quesnel NM, Giasson CJ. On-eye dehydration of proclear, resolution 55G and Acuvue contact lenses. Cont Lens Anterior Eye. 2001;24(3):88-93.
44. King-Smith PE, Nichols JJ, Nichols KK, et al. Contributions of evaporation and other mechanisms to tear film thinning and break-up. Optom Vis Sci. 2008 Aug;85(8):623-30.
45. Morgan PB, Efron N. In vivo dehydration of silicone hydrogel contact lenses. Eye Contact Lens. 2003 Jul;29(3):173-6.
46. Morgan PB, Efron N. Hydrogel contact lens ageing. CLAO J. 2000 Apr;26(2):85-90.
47. Dillehay S, McCarter H, T.A.C.C.S. Group. A comparison of multipurpose care systems. CL Spectrum. 2002 Apr;17:30-6.
48. Begley C, Edrington T, Chalmers R. Effect of lens care systems on corneal fluorescein staining and subjective comfort in hydrogel lens wearers. Int Contact Lens Clin. 1994 Jan/Feb;21(1-2):7-12.
49. Tonge S, Tighe B, Franklin V, Bright A. Contact lens care, part 6: comfort drops, artificial tears and dry-eye therapies. Optician. 2001;222(5817):27-32.
50. Sindt CW, Longmuir RA. Contact lens strategies for the patient with dry eye. Ocul Surf. 2007 Oct;5(4):294-307.

Back to top