Working With The Dry Eye Patient
By Linda Conlin, ABOC, NCLEC
Release Date: May 1, 2013
Expiration Date: April 16, 2018
Upon completion of this program, the participant should be able to:
- Gain knowledge of ocular anatomy and physiology through an understanding of dry eye syndrome and its causes and symptoms.
- Understand how to manage dry eye syndrome using a range of options from over-the-counter treatments to surgical intervention.
- Learn about contact lens fitting considerations for patients with dry eye syndrome to increase comfort and wearing time.
Linda Conlin, ABOC, NCLEC
This course is approved for both ABO and NCLE credit.
This course is approved for one (1) hour of CE credit by the American Board of Opticianry (ABO). Course SWJMI518.
This course is approved for one (1) hour of CE credit by the National Contact lens Examiners (NCLE). Course # CWJHI301.
How is it that drying can affect an organ that has its own irrigation system? The eye is such an organ, and almost half of adult Americans are dealing with dry eye syndrome. Knowing the causes, symptoms and treatments for dry eye provides the tools for increased patient comfort and contact lens wear success.
Dry eye syndrome is the lack of sufficient lubrication and moisture on the surface of the eye because of decreased quality or quantity of tears. As a result, patients suffer constant discomfort from eye irritation, and longer healing time if they have had refractive surgery. Symptoms include persistent dryness, scratchiness, burning, foreign body sensation, and blurred vision, light sensitivity and, surprisingly, tear overproduction. (Figure 1)
Accessed March 3, 2013.
Fifty percent of contact lens dropouts are associated with discomfort from dry eye1. The syndrome is more common in smokers and women, especially following blepharoplasty that resulted in incomplete lid closure.2 According to the Allergan Dry Eye Survey in March 2011, 48% of adult Americans regularly experience symptoms of dry eye. The incidence of dry eye symptoms was 42% in women ages 45 to 54. In adult's age 55 and older, 30% of men and 19% of women had symptoms for more than 10 years. In spite of the high incidence of the problem, however, 69% of survey respondents reported that they did not seek treatment from an eye care professional.3
With the prevalence of the syndrome an acronym developed, but unlike most acronyms, this one- CLIDE-describes describes two issues. The first is for the condition known as Contact Lens-Induced Dry Eye, and the second is for the causes of dry eye: Climate, Drugs, Environment.1 The acronym becomes a handy tool when we understand the causes of dry eye.
The incidence of dry eye increases in dry, dusty, windy and cold climates. Of the top 20 U.S. cities for dry eye, Las Vegas ranks first and five Texas cities are included in the group as one might expect, but so were Boston and Newark, NJ.3 Dry eye is so prevalent in Texas that a vision center specializing in dry eye treatment sponsors a Dry Eye Index on the local news in Amarillo, much the way other cities report heat indices or wind chill factors. The Dry Eye Index indicates grades of environmental conditions that result in dry eye symptoms progressing from "clear" to "comfortable" to "uncomfortable" to "miserable".4
In these cities, the effects of drying can take dramatic turns, especially for individuals working outside. Denver, also on the top 20 list, had a windstorm during a baseball game that affected Atlanta Braves first baseman, Freddie Freeman. Dust and dirt blew everywhere. Freeman changed his contact lenses six times during the game and wore sunglasses. At some point during the lens changes, he scratched his cornea, forcing him to wear glasses until the lesion healed. During that time, Freeman's batting average dropped 50 points. He finished the 2012 season with an average of .259 versus .282 in 2011.5
Drugs-such as antihistamines, antidepressants, anti-hypertensives which are frequently diuretics, Parkinson's medications and oral contraceptives-can result in dry eye as a side effect. Aside from climate, environments with dry heat or air conditioning can contribute to dry eye. Other factors that produce dry eye include insufficient blinking as can occur with computer use, long term contact lens wear, eyelid disease, tear gland deficiency, aging, menopause and diseases such as lupus, rheumatoid arthritis, ocular rosacea and Sjӧgren's syndrome.2 (Figure 2)
Causes of dry eye
Accessed March 3, 2013.
Sjӧgren's syndrome is a disorder of the immune system characterized by dry eyes, dry mouth and fatigue. It is commonly associated with rheumatoid arthritis and lupus, and results in a decreased production of tears, saliva and sweat. It occurs more often in women over age 40, and is treated with increased water intake, eye drops and drugs.6 Sjӧgren's syndrome gained national attention in the late summer of 2011 when tennis pro Venus Williams, then 31, announced she suffered from the syndrome and its symptoms. Williams cited fatigue as the reason she withdrew from her 13th U.S. Open.7
The quality and quantity of tears are the critical factors in dry eye syndrome, so let's look at the source and composition of tears. The tear film consists of three layers: lipid, aqueous and mucin. The outer, lipid layer is oily and prevents the evaporation of tears. The oily layer is manufactured by the meibomean glands located on the lid margins. The middle, aqueous layer is the largest portion of the tear film, contains dissolved sticky proteins or mucins, and supplies oxygen to the cornea. The lacrimal glands above the outer canthus secrete this layer of the tear film. The inner, mucin layer-which is produced by the goblet cells in the conjunctiva- keeps the highest concentration of mucins at the surface of the eye. Mucins help stabilize and spread tear film, which prolongs break up time.8 It's easy to see how poor composition or inadequate production of any layer of the tears could lead to insufficient lubrication and moisture on the surface of the eye. (Figure 3)
Layers of tear film
Accessed March 3, 2013.
Dry Eye Classification
The National Eye Institute has identified two classifications of dry eye syndrome based on the type of tear deficiency: aqueous tear deficiency (ATD) and evaporative tear deficiency (ETD). Aqueous tear deficiency, also called keratitis sicca, is an insufficiency in the aqueous or watery layer of tears and is the most common type of dry eye. Causes include lacrimal deficiency, lacrimal gland duct obstruction, reflex block and systemic drugs. Evaporative tear deficiency is an insufficiency of the lipid or oily tear layer which functions to slow tear evaporation. Causes include meibomian oil deficiency, disorders of the lids, low blink rate, drug side effects, vitamin A deficiency, and contact lens wear and ocular surface disease such as occurs from allergies.9 In addition, patients can suffer from a combination of both ATD and ETD.
Eye care practitioners (ECPs) commonly use two tests to classify dry eye syndrome: the Schirmer test and the Break Up Time test. The Schirmer test evaluates the quantity of tears. The practitioner places the folded end of a thin strip of filter paper inside the lower lids of both eyes. One can perform the test without an anesthetic. However, the test is more accurate with an anesthetic because irritation from the paper may temporarily increase tear production. After five minutes, the practitioner evaluates the moisture of the eye by observing how much of the filter paper became wet through capillary action. Fifteen millimeters or more is considered normal, nine to 14 millimeters indicates mild insufficiency, four to eight millimeters indicates moderate insufficiency and less than four millimeters indicates a severe condition.10 In conjunction with the Schirmer test, applying fluorescein drops will indicate whether tears can drain through the lacrimal duct into the nose.11 A similar procedure is the cotton thread test. The practitioner uses a chemically treated cotton thread instead of filter paper. The thread changes color as it moistens. The practitioner then measures the length of the color change on the thread. Lengths of less than 10 millimeters indicate dryness. The advantages of the cotton thread test are that it indicates results in 15 seconds as opposed to five minutes, and it does not require anesthetic drops.12
The B.U.T. (Break Up Time) test evaluates tear quality by measuring how long it takes for dry spots to appear on the cornea after a blink. The ECP applies fluorescein to the patient's eye and then observes the tear film after a blink while the patient tries to avoid the next blink. The practitioner counts by seconds until a dry spot appears. A break up time of more than 10 seconds is normal, from five to 10 seconds is marginal, and less than five seconds is low.13
A 2012 study by Isabelle Jabert, OD, and colleagues at the University of New South Wales, Sydney, found that increased lower lid margin sensitivity was related to more concentrated tears and meibomian gland dysfunction, both of which contribute to dry eye symptoms. 14 ECPs can conduct the sensitivity test, called esthesiometry, in the office using an esthesiometer or cotton tipped applicator applied to the lower lid margin. The patient's reaction to the least amount of pressure indicates sensitivity that is normal, reduced or absent.15 Interestingly, the study's finding of a higher concentration of tears indicates an aqueous deficiency, while the additional finding of meibomian gland dysfunction indicates an evaporative deficiency. Patients with reduced lower lid margin sensitivity, therefore, are likely to have a combination of the two classifications of dry eye syndrome.
While no cure for dry eye syndrome presently exists, ECPs can help patients manage the symptoms. For mild cases, this can be as simple as encouraging the patient to drink more water. Adult women should have 91 ounces or about 12 glasses of water a day, while men should have 125 ounces or 16 glasses. Studies have shown that increasing omega-3 and vitamin A intake is beneficial.1 Both of those nutrients are found in some fish oils and maintain mucous membranes. Severe or prolonged vitamin A deficiency is characterized by dry eye and changes to the cornea that can result in corneal ulcers, scarring and blindness.16 (This is why Mom told you to eat your carrots!) Patients should also avoid caffeine because it is a diuretic.
Other things patients can do to alleviate dry eye symptoms include wraparound sunglasses with side shields, indoor air filters and humidifiers, checking with their doctors to change medications that have dry eye as a side effect, and resting their eyes during visually demanding tasks.9 Remind patients of the 20/20/20 rule. After 20 minutes of a visually demanding task such as reading or computer work, rest the eyes for 20 seconds by gazing at a point 20 feet away.
Blinking is an important part of keeping the eye moist and lubricated. Blinking facilitates tear drainage, eliminates debris, spreads lipids across the tear film and nourishes the cornea. Research indicates that patients with dry eye have a higher blink rate, and a higher blink rate is associated with a shorter tear break up time. The chicken-or-the-egg question remains, however. Does a higher blink rate result in a shorter break up time or the irritation from the dry eye itself? When medications are used to treat dry eye, the blink rate usually slows.1
Artificial tears or contact lens rewetting drops may be all that is needed to alleviate the symptoms of mild dry eye. However, drops containing preservatives may cause irritation and patients shouldn't use them more than four times a day. Patients can use non-preserved drops in single use vials more often. When contact lens wearers use artificial tears, they should remove their lenses and wait 15 minutes before reinserting them. Patients can also use ointments applied before sleeping.17 Instruct patients that drops to "get the red out" are vasoconstrictors and may not lubricate the eye. What's more, a tolerance to the drops can build up and result in more redness.
For some dry eye patients, such home and OTC remedies will mask the problem for a short time, and other measures need to be taken. For instance, blepharitis, an inflammation of the lid follicles, blocks production of the oily component of tears. One way to reduce the inflammation is to gently rub the lids with a warm washcloth, then massage the lids near the base of the lashes with baby shampoo or lid scrubs.22 Taking a different aim at inflammation, Allergan introduced Restasis® cyclosporine emulsion in 2003 to treat dry eye symptoms. It is an immunosuppressant that reduces inflammation, and in this way, it helps increase natural tear production. Patients need to administer the drops only twice a day, and it can be used in conjunction with artificial tears. A study in 2005 reported that 67% of patients felt symptoms abate after 30 days of use.18
A 1998 study at the University of Iowa found that androgen levels in patients with meibomian gland dysfunction were abnormally low. Then, in 2002, Charles Connor, OD, and Charles Haine, OD, of the Southern College of Optometry presented research showing that transdermal testosterone cream applied to the upper eye lids improved tear production and meibomian gland secretion in subjects after three weeks. Post-menopausal women showed the greatest improvement while men showed the least improvement. Although those results are encouraging, no large scientific studies have been conducted, long-term effects of this treatment are not known, and this off-label use of testosterone cream is not yet FDA approved.1
Punctal plugs are another common in-office treatment for dry eye. Biocompatible plugs are inserted into the upper, lower or both puncta of the tear ducts to block drainage, and thereby increase tear film and surface moisture on the eye. There are two types of plugs. Semi-permanent plugs are durable and made from soft plastic materials such as silicone. Dissolvable plugs, made from materials that the body can absorb such as collagen, last anywhere from a few days to several months. Frequently they are used to prevent dry eye after refractive surgery. Both types of plugs can be removed by flushing with saline.19 Other punctal occlusion methods are more invasive. Those include punctal patching in which a tiny patch from the sclera is sutured over the punctum, cauterization of the punctum and ligation, adhesion or excision of the tear duct.20
Contact Lens Options
As you recall, CLIDE also is an acronym for Contact Lens-Induced Dry Eye. In this condition, the presence of the contact lens, as well as decreased corneal sensitivity from long term contact lens wear, disrupts normal tear film, resulting in a shorter break up time.1 While the practitioner must have special consideration for these patients, there are a variety of contact lens options within the categories of rigid and soft lenses.
Rigid lenses are less susceptible to dehydration on the eye, but dry eye patients may have a longer adjustment time due to edge awareness. These lenses may not work well in dry environments if the tear film is compromised. Consider corneal refractive therapy for dry eye patients, especially those who have worn rigid lenses. With CRT, the patient wears rigid lenses overnight to reshape the cornea and eliminate the need for corrective lenses. Wearing the lenses only overnight reduces tear evaporation and the risk of drying during the day.2 For severe dry eye cases, rigid scleral lenses can become a prosthetic ocular surface. The lens is designed with computer-assisted lathe cut back curves to vault the cornea. Saline in the dome continually bathes the cornea to provide relief.21
High water content soft lenses can be problematic for dry eye patients. The lenses themselves may draw moisture from tears to maintain hydration. Silicone hydrogel lenses are a better choice because they have high oxygen transmission but low water content. Some silicone hydrogel lenses have on-eye wettability. It is a surface treatment that accommodates tear film behind the lens and reduces the friction between the lids and the lens for better comfort.2 One day disposable lenses are another good option. Some of the new lenses have a water and oxygen content similar to that of the cornea, and a surface treatment designed to mimic the lipid layer of the tear film.22 What's more, contact lenses with molecular imprinting are on the horizon. For example, researchers are developing daily disposable and silicone hydrogel lenses imprinted with an adjustable release comfort agent.23
Contact lens solutions also are an important consideration for dry eye patients. Some solutions work better with certain contact lens materials than others. Check with the lens manufacturer for solution recommendations. Advise patients against using generic solutions, which can vary from purchase to purchase. Because proteins build up more quickly on lenses for dry eye patients, recommend rub and rinse types of solutions to provide better cleaning. Intolerance to preservatives in solutions can result in dry eye. Peroxide disinfection systems eliminate preservative intolerance problems as well as the variations in generics, but make sure the patient knows how to use them.2
Fit dry eye patients for contact lenses only after symptoms subside. Any treatment with topical steroids must be completed before the fit. Be sure that the base curve, diameter and lens material allow for appropriate tear exchange. Patients should avoid overnight wear, and patients who wear their lenses more than 10 hours per day should make time to remove, clean and reinsert the lenses at some point. Recommend a frequent lens replacement schedule to reduce the risk of irritation from protein buildup, as well as more frequent follow up visits.1
Dry eye is already a prevalent condition but in all probability more Americans will suffer from the condition than ever before, as Baby Boomers get older. As a result, ECPs will hear more patients complain about dry eyes. Baby Boomers grew up wearing contact lenses and ECPs should anticipate helping them deal with dry eye effectively so they can continue enjoying the advantages of contact lenses. Lens materials are improving. There are solutions and artificial tears in the research pipeline to help dry eye patients achieve the comfort and convenience other contact lens wearers have come to expect.
1 Review of Cornea and Contact Lenses, The Dry Eye Dilemma. Available at: http://www.reviewofcontactlenses.com/content/d/dry_eye/c/36183/. Accessed October 14, 2012.
2 AllAboutVision.com, Dry Eye Syndrome. Available at: www.allaboutvision.com/conditions/dryeye.htm. Accessed June 23, 2012.
3 American Optometric Association. New Allergan survey shows 48% have dry eye symptoms. Available at: http://newsfromaoa.org/2011/11/06/new-allergan-survey-shows-48-have-dry-eye-symptoms/. Accessed January 27, 2013.
4 Connect Amarillo website, Weather. Available at: http://www.connectamarillo.com/weather/#.UFYzGlFrLLk. Accessed September 16, 2012.
5 The New York Times website, Sports. Vision Problem Subsides, but Hitting Problem Lingers for Freeman. Available at: http://www.nytimes.com/2012/06/14/sports/baseball/freddie-freemans-vision-problem-subsides-but-hitting-problem-lingers.html?_r=2&. Accessed October 14, 2012.
6 Mayo Clinic website, Sjogrens syndrome. Available at: http://www.mayoclinic.com/health/sjogrens-syndrome/DS00147. Accessed October 7, 2012.
7 The New York Times website, Health and Science, Well. Venus Williams Brings Attention to Sjogren's Syndrome. Available at: http://well.blogs.nytimes.com/2011/09/02/venus-williams-brings-attention-to-sjogrens-syndrome/. Accessed October 19, 2012.
8 Innovative Eye Care website, Dry Eye. Available at: http://innovativeeyecare.net/services/dry-eye/. Accessed September 16, 2012.
9 National Institutes of Health, National Eye Institute, Facts About Dry Eye. Available at: http://www.nei.nih.gov/health/dryeye/dryeye.asp#2. Accessed January 28, 2013.
10 YGOY Health Community website, Understanding Schirmer's Test. Available at: http://eyecare.ygoy.com/2010/09/06/understanding-schirmers-test/ . Accessed February 23, 2013.
11 National Library of Medicine, National Institutes of Health, Medline Plus website, Schirmer's Test. Available at: http://www.nlm.nih.gov/medlineplus/ency/imagepages/9888.htm. Accessed September 15, 2012.
12 FCI Ophthalmics website, Zone Quick from FCI Ophthalmics pdf. Available at: http://www.fci-ophthalmics.com/files/pdf/zone_quick_web.pdf. Accessed February 23, 2013.
13 Dry Eye Zone website, Tear Break Up Time. Available at: http://www.dryeyezone.com/encyclopedia/tbut.html. Accessed October 7, 2012.
14 ScienceDaily website, October 3, 2012, Science News, Got Dry Eyes? Measuring Eyelid Sensitivity May Reflect the Causes. Available at: http://www.sciencedaily.com/releases/2012/10/121003111129.htm?utm_source=feedburner&utm_mediu m=feed&utm_campaign=Feed:+sciencedaily/health. Accessed February 23, 2013.
15 External Disease and Cornea, Section 8. Basic and Clinical Science Course, AAO, 2010.
16 Oregon State University website, Linus Pauling Institute, Micronutrient Information Center, Vitamin A. Available at: http://lpi.oregonstate.edu/infocenter/vitamins/vitaminA/. Accessed October 19, 2012.
17 Mayo Clinic website, Health Information, Dry Eyes. Available at: http://www.mayoclinic.com/health/dry-eyes/DS00463/DSECTION=lifestyle-and-home-remedies. Accessed October 7, 2012.
18 Invest Ophthalmol Vis Sci 2005;46: E-Abstract 2026. © 2005 ARVO Viewed 2/23/13.
19 AllAboutVision.com website, Punctal Plugs. Available at: http://www.allaboutvision.com/conditions/punctal-plugs.htm. Accessed October 14, 2012.
20 Mishra, Atul, Dry Eye Following Cataract and Refractive Surgery. Available at: http://www.jdosmp.org/lectures/dryeye_am.htm. Accessed October 14, 2012.
21 Science Daily website, Science News, March 22, 2012, Big Contact Lenses Provide Instant Relief for Dry Eyes, Experts Say. Available at: http://www.sciencedaily.com/releases/2012/03/120322113354.htm. Accessed October 14, 2012.
22 PRNewswire website, Bausch & Lomb Launches BiotrueTM ONEDay Contact Lenses Made from Breakthrough HypergelTM Material. Available at: http://www.prnewswire.com/news-releases/bausch--lomb-launches-biotrue-oneday-contact-lenses-made-from-breakthrough-hypergel-material-154024875.html. Accessed October 20, 2012.
23 Academy for Eye Care Excellence website, Front Row, Controlled Release of Eye Drops via Contact Lenses. Available at: http://image.exct.net/lib/fefa1576776202/m/1/BCLA1-ComfortMolecules.pdf. Accessed October 14, 2012.