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Dry eye treatment: a growing priority in the future of optometry
The emergence of dry eye treatment as an important priority in optometry is evidenced by the abundance of dry eye medications currently available. This increased emphasis promises to continue in the coming year and throughout the next decade, practitioners claim.
“There will be a huge push during the next decade, and the area of dry eye will become one of the most focused-on areas in therapeutics,” said Paul M. Karpecki, OD, FAAO, of Moyes Eye Center in Kansas City, Mo. “This is going to be a very interesting year.”
Diquafosol: a topical secretagogue
Although it has not yet gained approval from the U.S. Food and Drug Administration, diquafosol tetrasodium ophthalmic solution (Inspire Pharmaceuticals, Durham, N.C.) is a “very exciting product,” said Dr. Karpecki. “It is a P2Y2 agonist, so it has been shown to increase mucin production and tear volume. It is a true topical secretagogue, something that is really going to stimulate tear production at the local site.”
In 2003, the FDA granted diquafosol priority review, which is “a procedure designed to accelerate the review of potential products that address a significant unmet medical need,” according to an Inspire press release.
Gary Foulks, MD, a clinical investigator involved in phase 2 and phase 3 trials for diquafosol, told Primary Care Optometry News the product has demonstrated favorable effects on dry eye patients.
“The phase 2 trial and one of the phase 3 trials showed statistically significant improvement in ocular surface staining,” he said. “In addition, the positive phase 3 trial showed statistically significant improvement of the patient’s worst symptom at the 6-week time point.”
Dr. Foulks said that although he was masked for most of the trials, he found out afterwards what agents had been used. “I was very impressed at the dramatic response in some rather severe dry eye patients with the diquafosol,” he said.
Dr. Foulks said because diquafosol’s mechanism of action is quite different from that of cyclosporine, it can most likely be used in conjunction with cyclosporine. He added that the medication, which is instilled four times daily as a drop, is very well tolerated and boasts an excellent acceptance by patients.
Restasis for inflammation
Allergan’s prescription dry eye medication, Restasis (cyclosporine ophthalmic solution 0.05%), is an ophthalmic emulsion designed to treat inflammation-related dry eye.
The product increases tear production that may have been stifled by inflammation, according to David Sendrowski, OD, associate professor at the Southern California College of Optometry. Dr. Sendrowski said in an interview that practitioners prescribe Restasis specifically in cases of inflammatory dry eye.
“Ocular surface disorders such as dry eye come in many forms and have many etiologies. You should make sure that the particular etiology is inflammatory if you’re going to prescribe Restasis,” he said. “If the dry eye is due to lid disease or mucin disorders, for example, the Restasis will probably not be as effective.”
Restasis also appears to work very well for LASIK-induced dry eye, Dr. Sendrowski added. “With LASIK, you could lose the neuronal feedback loop, and when you lose the normal feedback loop, the eye interprets that as inflammatory in origin,” he said. “Some patients might benefit from Restasis after LASIK for dry eye therapy.”
Dr. Sendrowski said, overall, Restasis is a very safe, effective medication for dry eye. “Studies have shown that very little of the drug gets into the blood system, so, unlike certain glaucoma medications, you can use it over a long period of time without worrying about systemic or local adverse side effects,” he said. “And because Restasis takes about 30 days to take effect, topical steroids are sometimes prescribed to help the patients with ocular symptomatology through those first 30 days.”
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Zylet: new combination
Bausch & Lomb (Rochester, N.Y.) has received an approvable letter from the FDA for its new combination antibiotic and anti-inflammatory drop, Zylet.
A combination of tobramycin and loteprednol, Zylet is indicated for steroid-responsive ocular inflammatory conditions where superficial bacterial ocular infection — or a risk of it — exists, according to the manufacturer.
“A few papers came out in 2004 that indicated that loteprednol might be a good treatment for chronic conditions,” Dr. Karpecki said. “I would call this an ocular surface disease product, because I think it will play a role in conditions such as blepharitis and meibomianitis.”
Dr. Karpecki said Zylet is expected to become available in 2005.
New dosage of rimexolone
A lower dose of Alcon’s topical Vexol (rimexolone) is currently being formulated. According to Daniel A. Gamache, PhD, Alcon’s associate director of ophthalmology research, trials are going well thus far.
In these studies, steroid-sensitive cats showed no significant increase in intraocular pressure after 6 weeks of rimexolone dosing (concentrations ranged from 0.005% to 0.1%).
Dr. Gamache reported at Alcon’s Informed OD Educator’s Meeting earlier this year that rimexolone was also shown to extend tear film breakup time in a rabbit model of dry eye. Phase 3 clinical trials of low-dose rimexolone are slated to begin in the near future.
Androgens and dry eye
Research into a link between androgen deficiency and dry eye may also lead to more treatment options. According to David A. Sullivan, PhD, associate professor at Schepens Eye Institute, Harvard Medical School, Boston, androgen deficiency may be a critical etiologic factor in the pathogenesis of aqueous-deficient and evaporative dry eye syndrome.
Dr. Sullivan told Primary Care Optometry News that androgens regulate a number of functional aspects of the lacrimal and meibomian glands.
In addition, androgen deficiency appears to be associated with glandular dysfunctions and a significant increase in dry eye signs and symptoms. Androgen deficiency occurs during aging, menopause, in association with autoimmune disease (such as Sjögren’s syndrome, systemic lupus erythematosus and rheumatoid arthritis), with complete androgen insensitivity syndrome and with the use of anti-androgen medications (such as those used for prostatic hypertrophy or cancer).
Dr. Sullivan said that alleviating the endocrine imbalance in ocular surface tissues may help treat lacrimal and meibomian gland dysfunction and, in turn, treat the associated dry eye in those with androgen deficiencies. He said that Allergan has licensed exclusive patent rights to topical androgens from Schepens and is overseeing clinical trials in the United States and in Europe that will assess the efficacy of topical androgens for treating dry eye.
Oral doxycycline: various indications
Oral doxycycline is helpful for both its antibiotic capabilities and its anti-inflammatory properties. Studies have indicated that doxycycline’s benefits are based on its ability to accumulate in oil glands, to regulate staphylococcal enzymes such as lipase and to act as an anti-inflammatory.
This combination makes it effective for conditions associated with inflammation surrounding oil glands, such as meibomian gland dysfunction, internal hordeolum, blepharitis and acne rosacea.
“Patients with dry eye and concurrent lid disease, as well as patients with dry eye related to acne rosacea, tend to respond best to oral doxycycline,” Dr. Karpecki told Primary Care Optometry News . “But I have also found success in patients with poor tear quality and relatively inflamed ocular surfaces.”
Dr. Karpecki recommends a dosage of 50 mg twice a day for 1 month, followed by once a day for 1 month. Longer term, Periostat (20 mg of doxycycline, CollaGenex) can be prescribed twice daily, he said.
Systane: “power nap” for corneal surface
Another new type of formulation for dry eye treatment is the over-the-counter artificial tear product Systane (Alcon Labs, Fort Worth, Texas).
This product is transformed from a solution in the bottle into a soft gel upon instillation, spreading over the ocular surface in a thin, protective layer, integrating with the tear film to enhance repair of damaged epithelium.
Stephen M. Cohen, OD, principal investigator for the Systane FDA clinical trial and an optometrist in private practice in Scottsdale, Ariz., said Systane performed very well in terms of providing patient comfort. “The study resulted in several significant findings. One was a difference in end-of-the-day comfort for patients using Systane vs. the control,” he said in an interview. “Another was decreased clinical findings in terms of corneal and conjunctival staining.”
Dr. Cohen said the significant subjective improvements expressed by patients were a strong indication of Systane’s efficacy. “Patients claimed that the drops made them feel more comfortable for a longer period of time,” he said. “Their reaction was very positive.”
Dr. Cohen attributed some of this lasting comfort to the increased viscosity of Systane, the “coating on the eye” formed by the product.
“This actually allows the cornea to heal, because the epithelium is constantly replenishing itself and requires a stable surface to maintain wettability,” he said. “With a drop that stays on the eye longer, you are providing an opportunity for the eye to heal itself. It’s like a ‘power nap’ — the eye is not working quite so hard as it’s building those new epithelial cells.”
OptiZen: long-term relief
A new over-the-counter eye drop, OptiZen (InnoZen, Inc. Woodland Hills, Calif.), has been specifically designed to relieve dry eye caused by computer vision syndrome (CVS).
OptiZen contains a proprietary emulsified lecithin that assists in the delivery of the active ingredient, polysorbate 80, according to a company press release.
Jeffrey Anshel, OD, a practitioner in Carlsbad, Calif., told Primary Care Optometry News that OptiZen’s formulation makes it particularly effective.
Dr. Anshel said, the emulsion helps reduce inflammation. “It actually does heal the eye at some level,” he said. “It has long-term effects.”
Dr. Anshel said he has received extremely positive feedback from patients. “Every patient’s initial reaction so far has been: ‘It feels great,’” Dr. Anshel said. “But in the long term, they have noticed that it works, and they don’t need to put it in as often. Compliance is a huge issue when it comes to dry eye.”
Over-the-counter Refresh products
Another line of over-the-counter lubricant eye drops is Refresh by Allergan. Refresh Endura has been shown in clinical trials to improve symptoms of dryness in patients within 90 days.
Refresh Endura drops contain billions of emulsion structures. When the drop is administered, the electrolytes in the tear film dissolve the polymer matrix, releasing the emulsion components.
“Refresh Endura is unique because it’s a castor oil base. A castor oil vehicle tends to work well in ocular surface conditions,” Dr. Karpecki said. “The greatest benefit appears to be in patients who have concurrent dry eye and meibomian gland dysfunction.”
Refresh Liquigel includes extra-strength 1.0% carboxymethylcellulose, which provides enhanced mucoadhesion.
“Any gel product, including Refresh Liquigel or Systane, will do better in patients with corneal staining,” Dr. Karpecki said. “In animal studies, the Purite preservative in Liquigel appears to be the mildest of all the dissolving preservatives. This may benefit patients with dry eye who use tears more than two or three times a day.”
Aquify: “disappearing preservative”
In August, CIBA Vision (Duluth, Ga.) launched Aquify lens drops, which feature a patented “disappearing preservative” that prevents irritation, according to a company press release.
The over-the-counter drops are suitable for soft and gas-permeable lens wearers and imitate the action of natural tears.
“Natural tears provide great lubrication by becoming thinner during blinking, and then thickening to resist drainage. This keeps the eyes moist and provides a smooth surface between blinks,” said Karen Lindley, director of CIBA Vision’s lens care research and development, in a press release. “Aquify mimics the behavior of natural tears. This moisture retention, superior lubrication and protective functions translate into an eye drop that provides long-lasting comfort.”
Blink Contacts for lens wearers
Advanced Medical Optics Inc. launched blink Contacts rewetting drops in June. According to a company press release, “In a clinical trial, patients reported an increase in the amount of time they could wear their contacts compared to previous contact lens drops. The study showed that 86% indicated improved lens-wearing comfort with blink Contacts, and 73% reported improved vision quality.”
The drops contain hyaluronate, a naturally occurring lubricant found throughout the body, including in the eyes, said the release. They can be used with both soft and gas-permeable contact lenses.
ReNu with MoistureLoc
A new multipurpose contact lens solution is ReNu with MoistureLoc by Bausch & Lomb. This product has a dual action to deliver sustained comfort throughout the day.
According to company literature, ReNu with MoistureLoc locks in moisture to create a long-lasting cushion of moisture for sustained comfort. It also locks up protein to prevent the formation of deposits.
For Your Information:
- Paul M. Karpecki, OD, FAAO, practices at Moyes Eye Center in Kansas City, Mo., and is a member of the Primary Care Optometry News Editorial Board. He can be reached at 5844 N.W. Barry Rd., Ste. 200, Kansas City, MO 64154; (816) 746-9800; fax: (816) 587-3555; e-mail: PaulK-VC@kc.rr.com. Dr. Karpecki has no direct financial interest in the products he mentions. He is a paid consultant for Bausch & Lomb and Allergan.
- Gary Foulks, MD, was a clinical investigator for diquafosol. He can be reached at 301 E. Muhammad Ali Blvd., Louisville, KY 40202; (502) 852-5466. Dr. Foulks has a direct financial interest in diquafosol and is a paid consultant for Inspire.
- David Sendrowski, OD, is an associate professor at the Southern California College of Optometry. He can be reached at 2575 Yorba Linda Blvd., Fullerton, CA 92831; (714) 449-7414; fax: (714) 992-7848; e-mail: dsendrowski@scco.edu. Dr. Sendrowski has no direct financial interest in the products he mentions. He is a paid consultant for Allergan.
- Daniel A. Gamache, PhD, is associate director of ophthalmology research for Alcon Labs. He can be reached at 6201 S. Fwy., Ft. Worth, TX 76134; (800) 222-8103; fax: (817) 568-7000.
- David A. Sullivan, PhD, is senior scientist at the Schepens Eye Institute, Harvard Medical School. He can be reached at The Schepens Eye Research Institute, 20 Staniford St., Boston, MA 02114; (617) 912-0100; fax: 617-720-1069. Dr. Sullivan has no direct financial interest in the products he mentions. He is a paid consultant for Allergan.
- Stephen M. Cohen, OD, was a clinical investigator for Systane and practices in Scottsdale, Ariz. He can be reached at 10900 N. Scottsdale Road, #403, Scottsdale, AZ 85254; (408) 513-3937; fax: (480) 367-6711. Dr. Cohen has no direct financial interest in the products he mentions in this article, nor is he a paid consultant for any companies he mentions.
- Jeffrey Anshel, OD, practices in Carlsbad, Calif. He can be reached at 7130 Avenida Encinas, Ste. 103, Carlsbad, CA 92009; (760) 931-1390; fax: (760) 931-9545. Dr. Anshel has no direct financial interest in the products he mentions in this article, nor is he a paid consultant for any companies he mentions.
- Inspire Pharmaceuticals can be reached at 4222 Emperor Boulevard, Suite 200, Durham, NC 27703; (919) 941-9777; fax: (919)941-9797; www.inspirepharm.com.
- Allergan can be reached at P.O. Box 19534, Irvine, CA 92623; (714) 246-4500; fax: (714) 246-4971; www.allergan.com.
- Bausch & Lomb can be reached at Bausch & Lomb World Headquarters, One Bausch & Lomb Place, Rochester, NY 14604-2701; (585) 338-6000; fax: 585-338-6007; Web site: www.bauschandlomb.com.
- Alcon Labs can be reached at 6201 S. Fwy., Ft. Worth, TX 76134; (800) 222-8103; fax: (817) 568-7000; www.alconlabs.com.
- InnoZen can be reached at 6429 Independence Ave., Woodland Hills, CA 91367; (818) 593-4880; fax: (818) 593-4808; Web site: www.optizen.com.
- CIBA Vision can be reached at 11460 Johns Creek Pkwy., Duluth, GA 30097; (678) 415-3937; Web site: www.cibavision.com.
- Advanced Medical Optics Inc. can be reached at 1700 E. St. Andrew Place, PO Box 25162, Santa Ana, CA 92799-5162; (714) 247-8200; Web site: www.amo-inc.com.