Researchers share data on contact lenses, posterior segment, glaucoma at AAO

At the American Academy of Optometry’s annual meeting in Dallas, contact lens research ranged from sharing lenses to continuous wear, and posterior segment issues ranged from West Nile Virus to interferon-associated retinopathy. This second part of a three-part series summarizes some of these study results.

Daily disposables: to rinse or not

Private practitioners Mary Jo Stiegemeier, OD, FAAO, and Anne Neubert, OD, evaluated 17 experienced daily disposable contact lens wearers and found that some may have mild, non-symptomatic corneal staining after inserting new lenses directly from the package without rinsing.

The patients wore either Focus Dailies (CIBA Vision, Duluth, Ga.) or 1-Day Acuvue (Vistakon, Jacksonville, Fla.) in this 2-week crossover study. They were evaluated on day 0 and day 14 of each 2-week period. They randomly either inserted lenses directly from the package or first rinsed them with Opti-Free Express (Alcon, Ft. Worth, Texas).

Drs. Stiegemeier and Neubert saw significantly more corneal staining in the no-rinse group (53%) compared to the rinse group (12%). According to the study abstract, “Increased staining was primarily associated with Focus Dailies, with 80% of no-rinse subjects wearing this brand experiencing staining compared to 14% of the no-rinse 1-Day Acuvue wearers.”

CRT-induced aberrations

Researchers from the University of Illinois, Chicago, have found that Corneal Refractive Therapy (Paragon Vision Sciences, Mesa, Ariz.) increases higher-order and spherical aberrations of the whole eye and corneal surface.

Charlotte E. Joslin, OD, FAAO, and colleagues fitted 12 eyes of six myopic patients (–2.25 D to –6.00 D; –3.23 ± 1.06 D; mean ± SD) with CRT lenses and measured whole-eye aberrations with a Hartmann-Shack aberrometer with dilation. According to the study abstract, corneal aberrations were measured using Keratron (Optikon, Italy) elevation maps and were converted to wavefront error using CTView (Sarver & Assoc., Celebration, Fla.) The average of nine Hartmann-Shack and two topography exams taken at baseline and 1 month post-treatment were used.

Dr. Joslin and colleagues found the mean myopia reduction to be 3.00 D ± 0.88 D. Whole higher-order values increased after CRT (0.35 ± 0.13 to 0.80 ± 0.37 µm; p=0.0005) as did corneal (0.27 ± 0.10 to 0.63 ± 0.39; p=0.005) and internal higher-order RMS values (0.34 ± 0.11 to 0.62 ± 0.42; p=0.02). The Zernike coefficient most affected by CRT was spherical aberration, which significantly increased for all eyes.

Sharing contacts: a public health issue

Crystal Klaahsen, BS; and Catherine Johnson, BS; Christopher Crawford, BA; and fellow students, from the New England College of Optometry concluded that the social swapping of color contact lenses among teenagers is an emerging public health issue. They administered a 10-question survey to 30 teenage contact lens wearers (24 girls, 6 boys, ages 14 to 18 years) in the greater Boston area.

Twenty-six percent of the students (all girls, most 14 to 15 years old) indicated that they have shared contact lenses, according to the study abstract. After the students were made aware of the dangers of sharing contacts, they said they would reconsider doing it.

To prevent this problem from becoming an epidemic, the researchers recommended a larger-scale survey and proposed that educational posters be provided to schools, a Web site be created and an educational pamphlet be created and distributed to school nurses.

Patients satisfied with high-Dk lenses

In a study of high-Dk silicone hydrogels, patients were found to be very satisfied with the lenses, few base curve and power changes were needed, the incidence of complications was low in the first year and patients followed practitioner recommendations for wearing schedule.

Sally M. Dillehay, OD, MS, FAAO, of CIBA Vision Corp., reported that researchers at 19 sites across the United States fitted 317 patients with high-Dk lenses (lotrafilcon A). Clinical and subjective data were collected at 1 week and 1, 6 and 12 months. At 1 month, satisfaction with lens handling for insertion and removal was 88% and 82%, respectively, and it improved to 99% in both categories at 12 months. The base curve was changed for 3%, and the power was changed for 8% over the course of the year.

According to the study abstract, practitioners recommended 6-night wear for 40% and 30-night wear for 46% at initial dispensing. At 6 months, 89% recommended 30-night wear, and 85% of patients reported compliance with the wearing schedule. At 1 year, patients reported a >90% satisfaction score for comfort, handling and vision. Thirty-one complications were reported in 25 patients, with only 18 complications in 17 patients (5.4% of the study population) attributed to the lenses themselves. No cases of microbial keratitis were reported.

Corneal thickness affects field loss

Central corneal thickness (CCT) was found to be an important and relatively independent risk factor for the development of visual field loss in patients with primary open-angle glaucoma in an urban, predominantly black, glaucoma population, reported Richard Madonna, OD, MA, FAAO, and colleagues from the State University of New York.

The researchers reviewed charts of all primary open-angle glaucoma (POAG) patients seen during July 2003 at SUNY’s Glaucoma Institute, and 56 patients met the study criteria. According to the study abstract, the patients were divided into three groups: thick corneas (CCT >580 µm), average corneas (CCT between 501 and 579 µm) and thin corneas (CCT <500 µm). Their visual fields were scored on a scale of 0 to 4, with 4 as the most severe.

Ten patients had thick corneas, 29 had average corneas and 17 had thin corneas. The average visual field score was 1.76 for the thin corneas, 1.31 for the average corneas and 0.80 for the thick corneas. The researchers found no significant difference in age, number of years with glaucoma or maximum IOP among the groups. After patients were grouped according to field loss, those with more advanced loss had an average CCT of 514.5 µm compared with those with less or no loss, who had an average CCT of 532.1 µm. “The thin-cornea group was much more likely to have visual field loss at presentation (70.6%) than the thick and average groups (28.2%),” stated the study results.

Systemic hypertension underreported

Barbara E. Robinson, OD, MPH, PhD, FAAO, of the University of Waterloo, found that systemic hypertension is underreported by the optometric patient population. Patient data were collected for 24,570 patients (57.2% women, 42.8% men) from the practices of 133 optometrists across Canada from mid-October 2000 to the end of January 2001.

According to the study abstract, systemic hypertension was the most frequently recorded risk factor for eye disease, and it was reported by 2,191, or 8.94% (95% confidence interval, 8.56% to 9.28%) of the patients. Hypertension was reported by 9.37% of women and 8.46% of men, and the prevalence increased dramatically in each decade of life after the age of 44.

For patients 35 to 64 years old, the prevalence of self-reported hypertension was 7.68% (95% CI, 7.17% to 8.22%) or less than one-third of the actual measured prevalence of 27.4% for this age group in Canada. The study showed that the proportion of patients with self-reported hypertension who had retinal defects or nonmacular disorders was 6.07% (95% CI, 5.11% to 7.15%), which was four times the overall prevalence of retinal defects or disorders.

Dr. Robinson concluded that many patients were either unaware of their condition or did not report it to their optometrists, and she recommended that optometrists should not rely on patient report alone to identify systemic hypertension.

Lid-wiper epitheliopathy evaluated

Donald R. Korb, OD, FAAO, and colleagues sought to determine if lid-wiper epitheliopathy, recently discovered in contact lens wearers, can also be found in non-contact lens wearers who report dry eye symptoms but have no significant ocular signs.

The non-lens-wearing subjects were evaluated for their dry eye symptoms and were placed into two groups. Based on answers to a questionnaire, those with comfort scores of 0 or 1 point were placed in the asymptomatic group (n=50), and those with comfort scores greater than 5 were placed into the symptomatic group (n=50). The others were not admitted into the study. According to the study abstract, the patients were examined at least 4 hours after waking and following instillation of 2% fluorescein and 1% rose bengal. The upper eyelid was everted, and the lid wiper staining was graded from 0 to 3, with 3 being the most severe (considering area and intensity).

The researchers reported that, in the symptomatic patients, 24% showed no staining, 44% had grade 1 staining, 22% had grade 2 staining and 10% were grade 3. Of the asymptomatic patients, 88% showed no staining, 8% showed grade 1 staining, 4% showed grade 2 and none showed grade 3. The difference between the two groups was significant, and the degree of staining correlated with the severity of symptoms.

Statistical trends in exotropia

According to a study conducted by David E. FitzGerald, OD, FAAO, FCOVD, and colleagues from the State University of New York, exotropia had a positive correlation with an onset prior to age 2, alternating deviation, hypoxia at birth, delayed developmental milestones and neurologic involvement, but no gender predilection was found.

Dr. Fitzgerald and colleagues sought to show statistical trends in exotropia by reviewing the records of children younger than 6 years old who were examined at the University Optometric Center, State University of New York, State College of Optometry in New York between Jan. 1, 1992, and Dec. 31, 2001.

According to the study abstract, 40 of the 2,736 patients had exotropia by age 6, for a prevalence of 1.46%. Sixty-three percent of these children had exotropia by age 2.

Fifty-eight percent of the exotropic children were boys, and 42% were girls. Seventy-three percent had alternating exotropia. Forty-eight percent of the children experienced hypoxia at birth, while half had developmental or speech delays.

Retinopathy with interferon

While interferon is a commonly used antiviral, antineoplastic and antiangiogenic agent, it carries an incidence of retinopathy that may exceed 50%. Peter A. Russo, OD, FAAO, and Susanne Tidow-Kebritchi, MD, of Loyola University Medical Center, shared three cases of patients with interferon-associated retinopathy.

According to the study abstract, the first patient, who was treated for hepatitis C, was asymptomatic and was diagnosed with severe retinopathy after 4 months of therapy. The interferon was discontinued, the condition totally resolved over 6 weeks and no vision was lost.

The second patient underwent 2 months of interferon therapy for metastatic melanoma, sought care for blurred vision and was found to have significant retinopathy. The retinopathy resolved over 4 months after the therapy was discontinued, and no vision was lost.

The third patient, also being treated for hepatitis C, was functionally monocular from a traumatic retinal scar. The patient was asymptomatic but mild retinopathy was found. The interferon therapy was continued, but the retinopathy slowly resolved. All three cases showed peripapillary cotton-wool spots and splinter hemorrhages.

The researchers concluded that, although these patients retained normal vision, the potential for permanent vision loss exists, especially in those receiving high-dose interferon therapy and those with concurrent diabetes and hypertension. These patients need to be examined pre-treatment, educated and carefully monitored, they said.

Chorioretinal lesions, West Nile

Bruce A. Teitelbaum, OD, FAAO, and colleagues from the Illinois College of Optometry recommended that clinicians who see retinal lesions in patients with constitutional symptoms or encephalitis should suspect West Nile Virus, especially in endemic areas.

West Nile Virus can cause a range of systemic findings, from viral or flu-like symptoms to severe neurological disease. Six cases of chorioretinitis have been reported since the West Nile Virus was first identified in the United States in 1999. The lesions are described as round, cream-colored to punched-out with surrounding pigmentation, ranging in size from 300 to 1,000 µm. Visual acuity was minimally affected. Supportive treatment along with topical steroids to control the anterior segment inflammation was prescribed.

Teitelbaum and colleagues reported on two cases of peripheral chorioretinal lesions in patients with confirmed West Nile Virus. Both reported decreased visual acuity with disease onset. The exam revealed no active inflammation in the posterior or anterior segment.

For Your Information:

• Mary Jo Stiegemeier, OD, FAAO, can be reached at 3690 Orange Place #150, Beachwood, OH 44122; (216) 839-0200; fax: (216) 839-0808; e-mail: IMDOCSTIEG@aol.com.
• Charlotte E. Joslin, OD, FAAO, can be reached at the University of Illinois Chicago, Department of Ophthalmology & Visual Sciences, 1855 W. Taylor Street, Ste. 3.164, Chicago, IL 60612; (312) 996-5410; fax: (312) 996-4908; e-mail: charjosl@uic.edu.
• Crystal Klaahsen, BS, and Catherine Johnson, BS, can be reached at New England College of Optometry, 424 Beacon St., Boston, MA 02115; (617) 645-1445; e-mail: crystal_klaahsen@ncopost.ne-optometry.edu; catherine_johnson@ncopost.ne-optometry.edu.
• Sally M. Dillehay, OD, MS, FAAO, can be reached at CIBA Vision Corp., 11460 Johns Creek Parkway, Duluth, GA 30097; (678) 415-3198; fax: (678) 415-3048; e-mail: sally.dillehay@cibavision.novartis.com.
• Richard Madonna, OD, MA, FAAO, can be reached at the State University of New York at 33 West 42^nd Street, New York, NY 10036-8003; (212) 780-5043; e-mail: rmadonna@sunyopt.edu.
• Barbara E. Robinson, OD, MPH, PhD, FAAO, can be reached at the University of Waterloo School of Optometry, 200 University Ave. West, Waterloo, Ontario, Canada N2L 3G1; (519) 885-1211, Ext. 2057; fax: (519) 725-0784; e-mail: robinson@sciborg.uwaterloo.ca.
• Donald R. Korb, OD, FAAO, can be reached at 100 Boylston Street, Ste. 550, Boston, MA 02116-4610; (617) 423-6370; fax: (617) 482-7373; e-mail: DRKorb@aol.com.
• David E. FitzGerald, OD, FAAO, FCOVD, can be reached at the State University of New York, State College of Optometry, 33 West 42^nd Street, New York, NY 10036-8003; (212) 780-4030; fax: (212) 780-4980.
• Peter A. Russo, OD, FAAO, can be reached at Loyola University Medical Center, Department of Ophthalmology, 2160 South First Ave., Maywood, IL 60153; (708) 216-3408; fax: (708) 216-3557; e-mail: prusso2@lumc.edu.
• Bruce A. Teitelbaum, OD, FAAO, of the Illinois College of Optometry, can be reached at 3241 S. Michigan Ave., Chicago, IL 60616; (312) 949-7120; fax: (312) 949-7660; e-mail: bteitelb@eyecare.ico.edu.