The National Weather service predicts that this years allergy season, heading into full swing now, will be one of the worst Americans have seen in years. That means your office may soon be full of complaints about itchy, watery, irritated eyes due to the high pollen count.
Some studies show that those problems could be more complicated for allergy sufferers who also wear contact lenses. New lens options could further complicate the problem. Here, well discuss the latest findings on allergy, contact lenses and disease treatment released at this years Association for Research in Vision and Ophthalmology (ARVO) meeting.
Allergy Action
One study compares the effect of Zaditor and Crolom in patients with allergic conjunctivitis.
Zyrtec (cetirizine) and Claritin (loratadine) are two of the most widely prescribed antihistamines for allergy sufferers today. However, the antimuscarinic action of oral antihistamines may diminish the aqueous phase of tear film, exacerbating signs and symptoms of dry eye.70 Researchers from Ophthalmic Research Associates and Harvard Universitys Schepens Eye Research Institute, both in Massachusetts, teamed up to investigate the possible ocular drying effects associated with the two drugs. They assessed the blink rate, tear break-up time (TBUT), corneal staining, tear volume and flow. They also recorded any ocular discomfort patients reported after four days of taking one of the two drugs. Increased corneal and conjunctival staining, decreased TBUT and increased ocular discomfort were associated with both Zyrtec and Claritin. However, Claritin increased conjunctival staining significantly more than Zyrtec did, suggesting that the former may cause more clinically significant ocular surface damage.
Schepens and Ophthalmic Research Associates joined efforts again, along with Novartis Ophthalmics in Duluth, Ga., to compare two popular treatments for allergic conjunctivitis: Zaditor (ketotifen fumarate, Novartis) and Crolom (cromolyn sodium, Bausch & Lomb).117 Results indicate that the Zaditor-treated eyes exhibited less itching and conjunctival hyperemia than those treated with cromolyn sodium.
A Turkish study compared the tear cytokines of Vernal Keratoconjunctivitis (VKC) patients who responded clinically to topical Patanol (olopatadine, Alcon) to those who were unresponsive.106 Researchers treated 24 patients with limbal VKC with topical Patanol bid for two weeks. In the following two weeks, 12 patients who did not respond to initial treatment were given additional topical Vexol 1% (rimexolone, Alcon) tid. VKC patients who did not respond to the initial treatment had a higher concentration of cytokines and might benefit from additional mild corticosteroids.
A multi-center clinical trial studied treatment of patients with a history of allergic conjunctivitis and contact lens intolerance.116 Fifty-nine disposable contact lens wearers were given either Alocril (nedocromil sodium, Allergan) ophthalmic solution or artificial tears bid. After four weeks, researchers concluded that both treatments extended wearing time for patients with a history of lens intolerance, but that Alocril allowed for a greater increase in wear time than did the artificial tears.
Nature Leads to Nurture
German researchers explored the hypothesis that dry eye is an autoimmune disease by analyzing the immunoglobulin A (IgA) antibody repertoire against ocular allergens in the tears of dry eye sufferers.64 The staining pattern of dry eye patient repertoires showed significantly higher peaks than those of healthy individuals. They conclude that the complex antibody repertoires of dry eye patients differ dramatically from those found in healthy individuals, further supporting the hypothesis that dry eye disease has an underlying autoimmune response.
Another tear study examined a dry eye treatment derived from a hormone that is naturally produced by the adrenal gland.66 Researchers at Southern College of Optometry in Memphis, Tenn., compared the efficacy of artificial tears to tears supplemented with DHEA (a ster-oid hormone with 5% the androgenic activity of testosterone) and testosterone. Subjects were given artificial tears supplemented with 1% testoster-one, tears supplemented with 1% DHEA, or artificial tears alone. TBUT and Schirmer test results improved with DHEA-supplemented tears. Patients reported more subjective relief from the DHEA than from artificial tears or testosterone. Dry eye patients may benefit from the addition of androgenic hormones to artificial tears.
Material World
Patients with Vernal Keratoconjunctivitis who fail to respond to Patanol may have a higher concentration of tear cytokines.
The recent advent of newer contact lens materials and the rebirth of 30-day extended wear spurred scientists to investigate further the effects of contact lenses on eyes.
Researchers from Glasgow Caledonian University in the United Kingdom collaborated with researchers at Schepens Eye Research Institute to study the effects of different soft contact lens materials on tear film.66 The study measured evaporation rate, thinning characteristics and lipid layer changes in the pre-lens tear film (PLTF) of 20 habitual contact lens wearers. Participants alternated between five different soft lens materials in a random order in the left eye. All soft lens materials significantly affected tear physiology by increasing evaporation rate and decreasing tear-thinning time.
Another study looked at the effect of contact lenses on secretory phospholipase A2 (sPLA2). This potent antibacterial enzyme, which is present in tears, has been found to rapidly kill Staphylococcus aureus in vitro.71 Patients wore lenses made of etafilcon A or polymacon. Etafilcon A contact lenses absorbed more sPLA2 than polymacon lenses; the amount increased over the wear schedule. The transfer of this antibacterial agent from the tear film to the contact lens may help protect the cornea against staphylococcal infection.
CIBA Vision studied the efficacy of five competing contact lens care products against Acanthamoeba castellanii after six hours of exposure.3084 Researchers tested five different solutions. Opti-Free Express with Aldox (Alcon) and easyvision one step+ showed virtually no activity against Acanthameoba. Oxysept 1 step (Allergan) showed mild activity, but only Blue Vision BlueSept (CIBA Vision) and AOSept Plus Clear Care (CIBA Vision) exhibited significant antimicrobial activity against Acanthamoeba castellanii.
A newly defined contact lens-related condition called lid wiper epitheliopathy was identified in a study of hydrogel contact lens wearers with dry eye symptoms.55 Researchers examined the lid wipersthe portion of the marginal conjunctiva of the upper eyelid that wipes the ocular surfaceof 75 asymptomatic and 30 symptomatic soft contact lens wearers after five hours of wear. They found that lid wiper epitheliopathy is more than four times as common in wearers of soft contact lenses who experience dry eye symptoms within the first four hours of wear than in those who are asymptomatic.
There has been a rising interest in the applications and effects of reverse geometry orthokeratology lenses.3086 A study done at Indiana Universitys School of Optometry in Bloomington, Ill., sought to determine which major corneal parameteranterior curvature, posterior curvature or corneal thicknessis the most sensitive to change under acute application of RGP ortho-K lenses. There was no significant difference in posterior curvature or corneal thickness, but there was significant flattening of the central anterior cornea with a tendency for greater flattening towards the nasal cornea. This led the researchers to conclude that anterior corneal curvature is the most sensitive parameter to acute change from RGP ortho-K lenses.
Battling Corneal Disease
Corneal dystrophies treated with Penetrating Keratoplasty may recur.
Ocular infections with the Gram-negative pathogen Pseudomonas aeruginosa require aggressive therapy.43 Researchers at Allergan Inc. and LAB Pre-Clinical Inc. compared gatifloxacin, a novel fourth-generation fluoroquinolone being developed for the treatment of ocular bacterial infections, to Ciloxan (ciprofloxacin HCl 0.3%, Alcon) in a corneal ulcer model of Pseudomonas keratitis in rabbits. Ophthal-mic gatifloxacin 0.3% was found to be at least as effective as Ciloxan at healing corneal ulcers infected with Pseudomonas aeruginosa, even when administered on a less frequent dosing regimen.
We may soon need newer fluoroquinolones to treat bacterial infection.43These drugs are currently used to treat Gram-negative bacteria and methicillin-sensitive Staphylococcus aureus keratitis and conjunctivitis pathogens.
Scientists at Bascom Palmer Eye Institute in Miami studied the emergence of fluoroquinolone resistance among methicillin-sensitive Staphylococcus aureus keratoconjunctivitis isolates. They began by analyzing the susceptibility profiles of patients positive for S. aureus keratitis and conjunctivitis as well as the historical and current prevalence of emergent quinolone resistance. In the last 5.5 years, cipro-floxacin resistance has increased 166%. Results indicate that quinolone resistance among methicillin-sensitive S. aureus keratitis and conjunctivitis isolates is increasing.
Treatment Effects
A French group aimed to assess the ocular surface changes during refractive surgery.54 They examined the corneal sensitivity, tear break-up time and Schirmer test results of patients who had undergone myopic LASIK or PRK. LASIK in-duced more ocular surface changes than PRK. Researchers concluded this might be partly due to the neurotrophic damage induced by refractive surgery. Mucus production, however, seemed to be influenced by both methods of correction.
Researchers at Wills Eye Hospital in Philadelphia, conducted a retrospective review of 48 patients with stromal dystrophies who had undergone penetrating keratoplasties (PK).1723 Their aim was to assess the rate of recurrence of stromal dystrophies in corneal grafts. Patients were diagnosed with dystrophy of Bowmans membrane, granular dystrophy, lattice dystrophy, macular dystrophy or Schnyders crystalline dystrophy. The corneal dystrophies studied can be successfully treated with PK, but some degree of recurrence can be expected eventually. Dystrophy of Bowmans membrane and granular dystrophy are likely to recur earlier than other stromal dystrophies. Lattice dystrophy showed the highest incidence of recurrence, with a 100% recurrence rate during the study period.
Wills Eye Hospital researchers did another retrospective review to evaluate the presentation and treatment of Thygesons Superficial Punctate Keratopathy (TSPK), a potentially chronic condition that affects people of all ages.1656 They reviewed the charts of 38 patients. The most common presenting symptoms for Thygesons SPK are photophobia, blurred vision and ocular irritation. The disorder is typically bilateral, but may be unilateral as well. Mainstays for treatment are topical corticosteroids. Extended wear contact lenses and cyclosporine are reserved as secondary agents.
Dr. Shovlin is editor-in-chief of Review of Contact Lenses. He writes and lectures extensively on contact lenses. He is in private practice in Scranton, Pa.
References.
37. Marangon FB, Miller D, Romano A, Alfonso EC. Emergence of Quinolone Resistance Among Methicillin Sensitive Staphylococcus Aureus Keratitis and Conjunctivitis Isolates.
43. Jensen HG, Carpenter T, Zerouala C, et al. Comparison of Ophthalmic Gatifloxacin 0.3% and Ciprofloxacin 0.3% in Healing of Corneal Ulcers Associated with Pseudomonas Keratitis in Rabbits.
54. Garcher C, Pisella PJ, Fournier P, et al. Assessment of Ocular Surface Chances During Refractive Surgery.
55. Korb DR, Greiner JV, Herman JP, et al. Lid Wiper Epitheliopathy and Associated Dry Eye Symptoms in Contact Lens Wearers.
66. Connor CG, Fender J. Comparison of Androgenic Supplemented Artificial Tears.
64. Grus FH, Augustin AJ, Pfeiffer N. Analysis of Autoantibodies in Tears of Dry Eye Patients.
70. Gupta G, Ousler GW, Pollard SD, Abelson MB. The Comparative Ocular Drying Effects between Claritin and Zyrtec in Normal Adults.
71. Hume EB, Tan ME, Parmar A, Willcox P. Secretory Phospholipase A2 levels in Tears and Lens Extracts During Contact Lens Wear.
106. Irkec MT, Bozkurt B, Kerimoglu H. Tear Cytokines in Patients with Vernal Keratoconjunctivitis (VKC) Responding Clinically to Topical Olopatadine or Additional Rimexolone.
116. Tauber J. Nedocromil Sodium 2% Ophthalmic Solution vs. Artificial Tears Used Twice Daily in Patients with Contact Lens Intolerance and a History of Allergic Conjunctivitis.
117. Greiner JV, Gomes PJ, Minno G. Comparison of a Single Does of Zaditor (Ketotifen Fumarate 0.025%) to a Two-Week Regimen of Cromolyn Sodium 4$ in Subjects with Allergic Conjunctivitis.
1656. Nagra PK, Rapuano CJ, Cohen EJ, Laibson PR. Thygesons Superficial Punctate Keratopathy: Ten Years Experience at Wills Eye Hospital.
1723. Marcon AS, Rapuano CJ, Laibson PR, Cohen EJ. Recurrence of Corneal Stromal Dystrophies after Penetrating Keratoplasty.
3083. Thai L, Doane MG, Tomlinson A. Effect of Different Soft Contact Lens Material on the Tear Film.
3084. Morew-McKee MF. Contact Lens Solution Efficacy against Acanthamoeba castellani.
3086. Soni P, Nguyen T. Which Corneal Parameter, Anterior Corneal Curvature, Posterior Corneal Curvature or Corneal Thickness is Most Sensitive to Acute Changes With Reverse Geometry Orthokeratology Lenses.
