DRY EYES. When tears do not adequately lubricate the eye, a person may experience:

Transcription

1 DRY EYES The eye depends on the flow of tears to provide constant moisture and lubrication to maintain vision and comfort. Tears are a combination of water, for moisture; oils, for lubrication; mucus, for even spreading; and antibodies and special proteins, for resistance to infection. These components are secreted by special glands located around the eye. When there is an imbalance in this tear system, a person may experience dry eyes. When tears do not adequately lubricate the eye, a person may experience: Pain Light sensitivity A gritty sensation A feeling of a foreign body or sand in the eye Itching Redness Blurring of vision Sometimes, a person with a dry eye will have excess tears running down the cheeks, which may seem confusing. This happens when the eye isn't getting enough lubrication. The eye sends a distress signal through the nervous system for more lubrication. In response, the eye is flooded with tears to try to compensate for the underlying dryness. However, these tears are mostly water and do not have the lubricating qualities or the rich composition of normal tears. They will wash debris away, but they will not coat the eye surface properly. In addition, because these emergency tears tend to arrive too late, the eye needs to regenerate and treatment is necessary. What Causes Dry Eyes? In addition to an imbalance in the tear-flow system of the eye, dry eye can be caused by the drying out of the tear film. This can be due to dry air created by air conditioning, heat, or other environmental conditions. Other conditions that may cause dry eyes are: The natural aging process, especially during menopause. Side effects of using certain medications such as antihistamines and birth control pills Diseases that affect the ability to make tears, such as Sjogren's syndrome, rheumatoid arthritis and collagen vascular diseases. Structural problems with the eyes that don't allow them to close properly or a problem with the tear ducts. Ask your doctor about steps you can take to help prevent dry eyes from occurring.

2 How Are Dry Eyes Treated? Though dry eyes cannot be cured, there are a number of steps that can be taken to treat them. You should discuss treatment options with an ophthalmologist. Treatments for dry eyes may include: Oral secretagogues Castor oil Rx Meibomian gland dysfunction Artificial Tears Warm Compresses Punctal Plugs Steroid eyedrops Moisture Chambers Punctal cautery Cyclosporine Humidifers Flaxseed oil Androgen eyedrops Mucin secretagogues Artificial tear drops and ointments. The use of artificial teardrops is the primary treatment for dry eye. Artificial teardrops are available over the counter. No one drop works for everyone, so you might have to experiment to find the drop that works for you. If you have chronic dry eye, it is important to use the drops even when your eyes feel fine, to keep them lubricated. If your eyes dry out while you sleep, you can use a thicker lubricant, such as an ointment, at night. In general, remember that if your eyes are bothersome today you didn t lubricate them enough the day before.

3 Replenish the Tears In severe dry eyes tear osmolarity increases. The tear hyperomolarity has been shown to cause ocular surface disease. Although there are some who disagree, the use of moderately hypotonic artificial tears has been shown by others to promote ocular surface disease healing in severe dry eyes. Available hypotonic tears include: Thera Tears, Hypotears and Akwa Tears. (Br J Ophthalmol Aug;86(8):879-84, Ophthalmologica Mar-Apr;215(2):124-7) Bicarbonate containing artificial tears have also been shown to promote healing in severe dry eyes. Available bicarbonate containing tears include: Bion Tears, Murine Tears. (Arch Ophthalmol Mar;113(3):371-8, Cornea Mar;12(2):115-20) Prolonging the contact time of artificial tears on the cornea also helps. This can be achieved using a gelling agent such as HP-guar (Systane), or using a viscous eye drop (Celluvisc/Liquigel).(Curr Med Res Opin Feb;21(2):255-60, Curr Eye Res Jan;28(1):55-62) Non preserved drops are the best. However if preserved eyedrops are to be used, then newer preservatives like GenAqua are preferable to Benzalkonium chloride (BAC). Oil containing eyedrops (Refresh Endura, Soothe) may be added if meibomian gland dysfunction is present. These eyedrops will replenish the lipid layer or tear film. Warm compresses over closed eyelids for 5 minutes will also replenish the lipid layer. In severe dry eyes and unresponsive surface disease patients have significant visual impairment and disability. In such patients the use of autologus serum eye drops has been shown to help.. Natural human tears contain many growth factors, antibodies etc. Since these growth factors are present in serum, using serum eyedrops may provide the surface healing properties of natural tears. The major disadvantage of serum treatment is the requirement for blood donation. The active components of serum are stable for up to 6 months therefore bleeding and serum preparation are required two to three times a year. A standard method to prepare the serum eyedrops has been described. Blood banks may help you in preparing serum eyedrops.(br J Ophthalmol May;88(5):647-52, Graefes Arch Clin Exp Ophthalmol Mar 9) It is apparent that there is no single artificial tear eyedrop that provides all of the surface healing strategies (bicarbonate ions, hypotonicity, viscosity, non-preserved). Therefore perhaps it may be beneficial to use different eyedrops interchangeably or sequentially - i.e. a drop of Systane or Refresh liquigel followed 5 minutes later by a drop of Bion Tears (Murine Tears has the preservative BAC, therefore avoid it) followed 5 minutes later by a drop of Thera Tears or Thera Tears liquid gel (Hypo Tears and Akwa Tears has BAC, therefore avoid them). This cycle may be repeated every 2 to 4 hours. At night use a non-preserved ointment like Refresh PM ointment. Some experts suggest avoiding Lacrilube as it has preservative (chlorbutanol). Avoid the use of redness relieving eyedrops (naphazoline or tetrahydrozoline eyedrops) such as Clear Eyes, Murine Plus and Visine and herbals such as witch hazel. Also avoid using Vaseline in the eye. Avoid aggressive washing of the eye with running water or saline.

4 Artificial Tears Artificial Tears Hydroxypropyl Methylellulose (HPMC) Artificial Tears Bion Tears Tears Naturale Forte 0.3% HPMC, 0.1% Dextran 70. (bicarbonate & zinc help mucus & surface cells) Preservative-Free. $13.99 for 28 single-use vial pack 0.3% HPMC, 0.1% Dextran 70, 0.2% Glycerin Polyquad 0.001% as preservative. $12.99 for 30 ml bottle Tears Natural II 0.3% HPMC, 0.1% Dextran 70 Polyquad 0.001% as preservative. $12.99 for 30 ml bottle Tears Natural Free 0.3% HPMC, 0.1% Dextran 70 Preservative-Free. $9.99 for 36 Re-Closable vial pack Genteal Genteal Mild 0.3% HPMC GenAqua (Sodium Perborate) as preservative. $8.99 for 15 ml bottle. Genteal is also available as Preservative Free single-use vials 0.2% HPMC GenAqua (Sodium Perborate) as preservative. $8.99 for 15 ml bottle Visine tears 0.2% HPMC, 0.2% Glycerin, 1% Polyethylene Glycol 400 Benzalkonium Chloride (0.01%) as preservative. $5.49 for 15 ml bottle. Visine is also available as Preservative Free single-use vials Carboxyl Methylcellulose (CMC) Artificial Tears Refresh Tears Refresh Liguigel Thera Tears 0.5% CMC Purite as preservative. $7.99 for 15 ml bottle. Refresh Plus Tears also has 0.5% CMC, but is preservative free & comes in single use vials. 1% CMC Purite as preservative. $11.99 for 30 ml bottle. Refresh Celluvisc also has 1% CMC, but is preservative free & comes in single use vials. 0.25% CMC, HYPOTONIC Preservative Free. $10.99 for 32 Single-Use Container pack. Polyvinyl Alcohol (PVA) Artificial Tears Murine Tears Hypotears 0.5% Polyvinyl Alcohol, 0.6% Povidone. (has Bicarbonate) Benzalkonium Chloride (0.01%) as preservative. $5.99 for 30 ml bottle. Manufactured by Ross (Abbott Labs) 1% Polyvinyl Alcohol, 1% Polyethylene Glycol 400. HYPOTONIC Benzalkonium Chloride (0.01%) as preservative. $14.99 for 30 ml bottle. Hypotears is also available as Preservative Free single-use vials

5 Akwa Tears Tears Again 1.4% Polyvinyl Alcohol. HYPOTONIC Benzalkonium Chloride (0.005%) as preservative. $4.99 for 15 ml bottle. 1.4% Polyvinyl Alcohol. Glycerine Artificial Tears & Others Systane Computer Eye Drops Moisture Eyes Similasan homeopathic Polyethylene Glycol % (lubricant), Propylene Glycol 0.3% (lubricant), Hydroxypropyl Guar (Gel forming Matrix) Polyquaternium-1 as preservative. $9.99 for 15 ml bottle. More Info 1% Glycerin Benzalkonium Chloride (0.01%) as preservative. 1% Propylene Glycol, 0.3% Glycerin Benzalkonium Chloride (0.01%) as preservative. $10.99 for 30 ml bottle. Belladonna HPUS 6X alkaloids, Euphrasia, Mercurius sublimatus. Sodium silver chloride complex 0.001% as preservative. $8.99 for 10 ml bottle. Oil Containing Eye Drops - Prevent Evaporation of Tears Refresh Endura Soothe Emollient Eye Drops Castor oil, polysorbate-80, Carbomer 1342 & Glycerin Preservative Free. $14.99 for 20 single-use vial pack. More Info Light mineral oil 1.0%, Mineral oil 4.5% (Restoryl), polysorbate-80 Polyhexamethylene biguanide as preservative. More Info Contact Lens Rewetting Drops (can be used while wearing soft or hard/gas permeable contact lens) Clerz Plus Tetronic 1304 helps lens retain moisture & shields from protein build up. RLM-100 removes lens deposits. Polyquad is the preservative. $4.99 for 8ml bottle. Aquify Comfort Drops Sodium Hyaluronate 0.1% Sodium Perborate is the preservative. Complete Blink-N-Clean Lens Drops Opti-Free Express Rewetting drops Lens Plus Rewetting drops ReNu Rewetting drops Hydroxypropyl methylcellulose is the lubricant, tyloxapol is the surfactant. polyhexamethylene biguanide is the preservative. $6.49 for 20ml bottle. Sterile, buffered, isotonic, aqueous solution. No hydrogel lubricants. Polyquad is the preservative. $8.49 for 20ml bottle. Sterile, buffered, isotonic, aqueous solution. No hydrogel lubricants. Preservative Free. $6.99 for 30ml single use vials. Poloxamine removes dirt & protein deposits. Sorbic Acid is the preservative. $5.99 for 15ml bottle. Eye Ointments & Gels Refresh PM ointment Tears Naturale PM ointment Lacrilube ointment 57.3% White Petrolatum, 42.5% Mineral Oil Preservative Free. $8.99 for 3.5 g tube. 56.8% White Petrolatum, 42.5% Mineral Oil Preservative Free. $9.99 for 3.5 g tube. White Petrolatum, Mineral Oil Chlorobutanol (0.5%) as Preservative. $9.49 for 3.5 g tube. Manufactured by Allergan Genteal Gel 0.3% Hydroxypropyl Methylcellulose, Carbopol 980 GenAqua (Sodium Perborate) as preservative. $8.99 for 10 ml bottle. Tears Again NIGHT & DAY Gel 1.5% Carboxy Methylcellulose Dissipate (stabilized oxyborate complex) as a preservative. $8.79.

6 Human tears are composed of water, electrolytes, small molecules such as carbohydrates and lipids, and a variety of proteins, several of which have an enzymic function. The principal proteins of tears include lysozyme (an enzyme which attacks bacterial cell walls), lactoferrin (a bacteriostatic protein), secretory IgA antibodies, and lipid binding proteins. The use of artificial tears has obvious limitations. Artificial tears cannot completely substitute complex composition of natural tears. The integrity of the three-layered lipid, aqueous, and mucin structure, vital to the effective functioning of the tear film is not reproduced. Artificial tears act by adding volume of the tear film, but they can only do this while they remain in contact with the surface of the eye. A simple saline eyedrop will remain in contact with the eye surface for only a few seconds. Therefore to be effective, a viscosity enhancing component is required in the artificial tear formulation. Hydrogels are the viscosity enhancing ingredients of artificial tears. Hydrogels make the artificial tears more viscous so they stay on the eye for longer time. The mucous adhesive property of hydrogels also help in prolonging the time tears stay on the eye. Hydrogels are actually polymers that are endowed with the property of swelling up in water and retaining the moisture. The following hydrogels have been used in artificial tears: Hydroxypropyl Methylcellulose (HPMC), Carboxy Methylcellulose (CMC), Polyvinyl Alcohol (PVA), Carbopol, polyvinyl pyrrolidone, polyethylene glycol, dextran, hyaluronic acid, or carbomer 940 (polyacrylic acid). Artificial tears may also contain glycine, magnesium chloride, and zinc chloride, all of which are found in natural tears. Sodium borate, a mild antiseptic, and other desirable ingredients may also be included. Preservatives are added to increase the shelf life of artificial tears and to facilitate the use of multi-dose bottles. The more commonly used preservatives are Benzalkonium Chloride (BAC) and Chlorobutanol. Benzalkoniun Chloride (BAC) can increase the eye surface irritation and disease. The newer preservatives such as GenAqua (Sodium Perborate) and Polyquad (Polyquaternium-1) are less damaging to the eye surface than BAC. (Graefes Arch Clin Exp Ophthalmol. 1989;227(2):139-41, Curr Eye Res Jul;10(7):645-56). Patients with severe dry-eye who use artificial tears frequently should avoid tear solutions containing BAC. If preserved solutions are used then GenAua or Polyquad containing tears are better choices. Non-preserved solutions are preferable for treatment of these patients. However, non-preserved tears are more expensive and are dispensed in single use vials. A recent study showed that refrigeration of opened preservative free tears in closed zip-lock plastic bags for 12 hours does not have a significant effect on the solution. Storage of preservative free artificial tears for 12 hours in a refrigerator, therefore seems to be reasonable (Optom Vis Sci 2001;78:37-9).

7 Despite the addition of hydrogels, artificial tears provide short term relief because of brief retention time on the eye surface. There are currently two strategies available to increase the retention time of artificial tears. The more recent development is the introduction of ingredients that have some bioadhesive properties. Systane uses this strategy. It contains HP-Guar. Once exposed to the eye surface ph (7.5), HP-Guar in Systane forms a 'sof gel' with increased viscosity and bioadhesive properties that promote the retention of its two demulcents (polyethylene glycol 400 & polypropylene glycol). (Curr Eye Res Jan;28(1):55-62). The other strategy to increase the retention time is to make more viscous artificial tears. The viscous tears are not easily drained out of the eye through the lacrimal outflow system and therefore have a longer retention time. Viscous artificial tears may cause unacceptable blurry vision in some individuals. Celluvisc is a 1.0% solution of a high-viscosity Carboxymethyl Cellulose (CMC). Liquigel is also a 1.0% solution of CMC, however it is blended from a 0.35% high-viscosity and a 0.65% medium-viscosity CMC. This results in Liquigel being less viscous than Celluvisc. The viscous Celluvisc results in a moderate amount of blurry vision that gradually subsides. It takes about 24 minutes for the vision (contrast sensitivity function) to return to baseline values after a drop of Celluvisc is instilled in the eye. In contrast, after a drop of Liquigel it takes about 13 minutes to return to baseline contrast values. In patients who find the vision blurring after highly viscous artificial tears like Celluvisc unacceptable, the shorter duration of blurry vision with Liquigel, (approximately half that of Celluvisc), may be more acceptable. Higher viscosity tears can cause eye irritation by the crystallization on lids and lashes.(optom Vis Sci 2005;82: ) Viscosity Retention time on eye surface Celluvisc Liquigel Systane Refresh Tears 3 + Temporary punctal occlusion. Sometimes it is necessary to close the ducts that drain tears out of the eye. This is done via a painless procedure where a plug that will dissolve quickly is inserted into the tear drain of the lower eyelid. This is a temporary procedure, done to determine whether permanent plugs can provide an adequate supply of tears. Temporary punctual plugs are intended to block tear drainage by the occlusion of the canaliculus. Depending upon the plug used, the occlusion duration ranges from 7 days to 180 days. The plugs dissolve by themselves or may be removed by saline irrigation. Permanent punctal occlusion. If temporary plugging of the tear drains works well, then silicone plugs (punctal occlusion) may be used. The

8 plugs will hold tears around the eyes as long as they are in place. They can be removed. Rarely, the plugs may come out spontaneously or migrate down the tear drain. Many patients find that the plugs improve comfort and reduce the need for artificial tears. About 40% of punctual plugs are lost within 6 months of insertion. Most of the punctal plugs lost are due to spontaneous extrusion, and this happens usually within the initial 3 months post insertion. In addition, about 10% patients may complain of local discomfort at the plug site or excessive tearing (especially if both upper and lower puncta are blocked) and the punctual plug may have to be removed in these patients. This is a simple procedure and is painless. Patients who have lost the initial plug are twice as likely to lose the replacement plug. Upper punctal plugs have a higher risk of loss compared with plugs inserted in lower puncta. Blocking the nasolacrimal drainage by inserting punctal plugs will prevent the tears from being drained into the nose resulting in greater retention on the eye surface. Sleeping with the eye surface isolated from the environment using moisture chambers or swimming goggles may help to preserve the tears. PanOptx Windless Eyewear are sunglasses that are fashionable enough to be worn in public, yet retain the function of a moisture chamber. Restasis. In 2002, the FDA approved the prescription eye drop Restasis for the treatment of chronic dry eye. It is currently the only prescription eye drop that helps your eyes increase their own tear production with continued use. This drop may burn when instilled and takes 3-6 weeks for patients to notice an effect. ORAL MEDICATION Treat Meibomian Gland Dysfunction (MGD) The superficial lipid layer of the tear film is derived from the meibomian glands which are embedded within the eyelids. The meibomian gland ducts open on the eyelid margin. The lipid layer serves to reduce evaporation of underlying aqueous in the open eye. Meibomian Gland Dysfunction (MGD) causes abnormalities in the secreted lipids and dry eye results from increased evaporation of tears. MGD is treated with warm compresses, eyelid scrubs and the use of oral tetracycline/doxycyline (Cleeravue M). Oral supplements & Dietary advice Maintain a good water intake. Avoid diuretics such as alcohol and caffeine. Recent research has shown that oral therapy with polyunsaturated fatty acids reduces ocular surface inflammation and improves dry eye symptoms (Cornea 2003;22:97-101). It does make sense to increase omega-3 fatty acid intake i.e. eat more fish, or take oral flaxseed oil supplement, if you wish. Thera Tears Nutrition & HydroEye are oral pills that provide these supplements.

9 Dietary Fatty acids (Flaxseed oil) and Dry Eyes Our diet contains two types of fat (saturated and unsaturated ). Recent research has shown that oral therapy with polyunsaturated fatty acids reduces ocular surface inflammation and improves dry eye symptoms (Cornea 2003;22:97-101). In this study patients received tablets containing 28.5 mg linoleic (omega-6 fatty acid) and 15 mg gamma-linolenic acid (omega-3 fatty acid) twice daily for 45 days. Both of these are polyunsaturated fats. Americans obtain an excess of linoleic (omega-6 fatty acid) through their consumption of beef, dairy, vegetable cooking oils, and vegetable shortenings (i.e. cookies, potato chips, snacks etc). However, the American diet is deficient in gamma-linolenic acid (omega-3 fatty acid). The two best sources of omega-3 fatty acid are fish oil and flaxseed oil. TheraTears Nutrition is an oral Flaxseed Oil Supplement. HydroEye is an oral prepration of black currant seed oil and cod liver oil. These provide both omega-3 & omega-6 fatty acids. Salagen The active ingredient in Salagen is 'pilocarpine'. It stimulates specific receptors in lacrimal gland and cause increased secretion of tears. The medicinal properties of pilocarpine, including its ability to stimulate salivation, have been recognized for many centuries by the Tupi Indian tribe of northern Brazil, who named this indigenous shrub "jaborandi," or the "slobbermouth plant." SALAGEN tablets are currently indicated for 1) the treatment of symptoms of dry mouth from salivary gland hypofunction caused by radiotherapy for cancer of the head and neck; and 2) the treatment of symptoms of dry mouth in patients with Sjogren's syndrome. Several studies have shown that Salagen is beneficial in dry eye patients. In one study 20 mg per day (four tablets per day) did help (Arch Intern Med.1999;159: ), but a higher dose of 30 mg per day was shown to be more beneficial in a different study (Arthritis Rheum. 1997;40(suppl):S202). Salagen was also reported to help in dry eye induced because of radiation therapy (Clin Oncol (R Coll Radiol) 1997;9:62-3). The most common drug-related adverse experiences included sweating, urinary frequency, and flushing. Salagen cannot be given to patients who have iritis or to those with anatomically narrow angles (gonioscopy finding) because of the risk of precipitating acute angle closure glaucoma. Muscarinic agonists like pilocarpine have been reported to cause visual blurring which may result in decreased visual acuity, especially at night and in patients with central lens changes, and to cause impairment of depth perception. Caution should be advised while driving at night or performing hazardous activities in reduced lighting. Given what we know so far, the use of Salagen in severe dry eyes especially in patients who have Sjogren's syndrome may be a reasonable management strategy. Evoxac The active ingredient in Evoxac is 'cevimeline'. Like salagen, Evoxac stimulates secretion from the lacrimal and salivary glands. As compared with Salagen, Evoxac has a much higher affinity for lacrimal gland receptors, therefore is more effective. Cevimeline was recently approved by the Food and Drug Administration for the treatment of dry mouth in patients with Sjögren syndrome. Because of its extended 5-hour half-life, cevimeline is taken 3 times daily; it seems to have minimal adverse effects at doses of 90 mg/d and is tolerated at doses up to 180

10 mg/d. The monthly cost of treatment with cevimeline, at the recommended dosage for xerostomia in Sjögren syndrome, is approximately $118 (Archives of Internal Medicine 2002;162: ). A recent study showed that cevimeline treatment for 12 weeks is associated with significant improvement of dry eye symptoms in patients with Sjögren's syndrome (Arthritis Rheum 2002;46:3:748-54). Other medications (drops). Other medications, including topical steroids, may also be beneficial in some cases. Treat Eye Surface Inflammation (red irritated eye, sore eye, tearing) Once dry eye has developed, inflammation becomes the key mechanism of ocular surface injury, as both the cause and consequence of cell damage. Inflammation may be initiated by dryness, hypertonicity of tears, microtrauma from eyelids during blinking, proinflammatory substances released by the lacrimal glands or eyelids, and a reduced supply of supportive factors from tears and corneal nerves. When it is present, inflammation is enhanced by cytokines secreted by damaged surface epithelial cells; and lymphocytes and leukocytes that leak out from dilated conjunctival blood vessels. Thus patients with severe dry eyes can become trapped in an increasing cycle of inflammation and ocular surface injury. Ocular surface inflammation reduces surface wettability and tear film stability. (Prog Retin Eye Res Jul;23(4):449-74) Available antiinflammatory treatments include cyclosporin A (Restasis) eyedrops and steroid eye drops (Alrex, Lotemax, FML or Vexol). It may require several weeks of Restasis treatment (one drop twice a day) to produce a clinical therapeutic effect and it may take up to 6 months for maximum improvement. Therefore, Restasis is not an appropriate drug for immediate relief of an uncomfortable irritated eye. Topical corticosteroids have a rapid onset of anti-inflammatory action. They may be used for the short-term (2 to 4 weeks). It is worth remembering here that long-term use of steroid eyedrops can cause a rise in eye pressure (perhaps even glaucoma) and development of a cataract. Therefore, Restasis, which is devoid of these steroid-related side effects, seems to be a reasonable choice for long-term antiinflammatory effect. Treat Eye Allergy (itching, mucus strands in the eye) If present, eye allergy may be treated with eyedrops such as Patanol and Alrex. (Note: Systemic antihistaminics like Claritin and Benadryl will increase dry eye symptoms - Ann Allergy Asthma Immunol Nov;93(5):460-4) Surgery. If needed, the ducts that drain tears into the nose can be permanently closed to allow more tears to remain around the eye. This is done with local anesthetic on an outpatient basis. There are no limitations in activity after having this surgery.

11 Treat eyelid issues that may impact the tear film If present, treat conjunctivalchalsis, lower lid laxity, floppy eyelid syndrome, inadequate eyelid closure while sleeping, seborrheic blepharitis, ectropion, entropion, trichiasis and nasal mucosa/sinus inflammations. Environmental Issues. Address Environmental issues Air currents increase tear evaporation, therefore avoid car air conditioning, wood burning fireplaces, ceiling fans and heaters. Use a humidifier to increase humidity in your surroundings which in its most basic form consists of a dish containing water on a windowsill or radiator. Avoid dry eye due to computer vision syndrome. Keep the monitor below eye level in order to reduce the exposed area of the eye. When looking down, the upper eyelid partially covers the eye, thus reducing the exposed area of the eye. Switching to a laptop may make working in downgaze easier. Avoid smoke and dust. (Do not party too much in smoke filled bars/rooms). Use wraparound sunglasses or side shields when outside. Moisture Chambers The basic idea behind moisture chambers is to enclose the eye so that evaporative loss of tears is prevented. Since approximately 25% tears are lost by way of evaporation, this strategy will preserve tears in the eye for a longer time by limiting evaporation. We list below the moisture chambers we are aware of, including contact information to order them. PanOptx Dry Eye / Windless Eyewear PanOptx has designed these sunglasses to be fashionable enough to be worn in public, yet retain the function of a moisture chamber. PanOptx sunglasses create an orbital seal that protects against wind drafts, dust/pollen etc. and helps to conserve the eye moisture. NitEye Dry Eye Comforter MoistEye Moisture Panel Moisture Chamber Occluder Swimming Goggles Moisturizing Mist Nature's Tears is an all-natural moisturizing mist for the eyes made of tissueculture grade, ph correct water. By spraying the mist on the face, the tear film is claimed to replenish.