Clinical News
MEDICAL AND PRODUCT UPDATES

CONTACT LENSES
New coating may banish bacteria

Coating contact lenses with an extremely thin layer of selenium appears to keep them virtually bacteria-free without causing irritation or interfering with vision or oxygen transmission, according to Ted Reid, Ph.D., of Texas Tech University Health Sciences Center in Lubbock, Texas. He presented his findings at the 224th national meeting of the American Chemical Society in August.

An inexpensive selenium coating that eliminates bacteria could make it possible to wear lenses for at least 2 months.

Selenium, an essential, naturally occurring element of our diet, kills bacteria by forming superoxide radicals. The normal presence of selenium in the environment may explain the apparent lack of health effects when coated lenses were worn by rabbits for 2 months, and the researcher himself for a week. Reid believes that the coating will make it possible for lenses to be left in the eye for at least 2 months.

After completing the rabbit trial, Reid placed a coated lens in one of his own eyes -- and an uncoated lens in the other. After wearing the lenses for a week, he placed them in a lab dish. Four days later the noncoated lens was covered with a thick biofilm; the coated lens had a total of three bacteria on its surface.

The inexpensive coating, which is applied by dipping the contact lens briefly in a selenium solution, is only one molecule thick. It appears to stay attached for at least 2 years. However, according to Reid, the coating wouldn't cause any harm even if it came off. "The amount of selenium that's on this device is probably .01 percent of what you had for lunch," he says.

Reid says the coating may also be able to prevent cells from multiplying on the surface of an implanted IOL, and shows promise as a means to deactivate the AIDS virus when attached to antibody peptides. Reid, who holds six patents on the coating, says he's in contact with two contact lens companies, as well as makers of heart valves.

PHOTODYNAMIC THERAPY
New hope for Miravant treatment

Earlier this year, results of the clinical trials of Miravant's PhotoPoint SnET2 therapy for wet age-related macular degeneration indicated that the treatment had failed to achieve the intended results. Now, however, Miravant reports that a careful analysis of the phase III trial data indicates that two specific subgroups did seem to benefit from the treatment.

During the trial, 920 patients were intravenously treated with either 0.5 mg/kg of the drug, a 0.75 mg/kg dose, or a placebo, followed by a 1-minute photodynamic light treatment.

Results were not statistically significant when all patients were included. However:

• More than 65% of patients who were treated three or more times over a 2-year period maintained stable vision, while only 39% of the placebo group did.
• In a small subset of patients who had only subfoveal choroidal neovascularization, and who received the lower dosage of the drug, 67.7% maintained stable vision, compared with 40% of those receiving the placebo.

Miravant plans to present the new analysis to the U.S. Food and Drug Administration for review; the company hopes that these statistics will be the basis for a new clinical trial.

TELEMEDICINE AND RETINOPATHY
Remote screening is effective

A recent study conducted in Spain compared diagnoses of diabetic retinopathy made by firsthand examination with diagnoses made by examining nonstereoscopic digital retinal images sent over the Internet. Both methods detected the disease in the same group of patients, and grading of severity was in agreement in 94% of eyes.

The study authors point out that teleophthalmology makes it possible to detect diabetic retinopathy in many more patients, at a low cost, extending the benefits of health care to a much broader population. However, they also note that remote screening does have limitations in areas such as diagnosis of macular edema with no hard exudates and diagnosis of vascular lesions in hemorrhagic forms of diabetic retinopathy.

The study was reported in the August issue of Diabetes Care.

CATARACTS
Surgery means fewer accidents

Older individuals who've had cataracts surgically removed have half the car accidents of those who don't have cataracts removed. The study, which appeared in the August issue of the Journal of the American Medical Association, followed 277 patients ranging in age from 55 to 84 years for 4 to 6 years; 174 of the participants had surgery, while 103 did not.

Even after adjusting for visual acuity and contrast sensitivity, those who had the surgery had less than half the number of automobile accidents.

HYPERTENSIVE RETINOPATHY
The coronary connection

Evidence continues to verify the connection between retinopathy and heart disease. A study reported in the September issue of the British Journal of Ophthalmology found that the presence of hypertensive retinopathy correlates with a dramatic increase in the likelihood of suffering a coronary event.

Dr. Tien Yin Wong at the National University of Singapore followed 560 middle-age men for a median period of 7.8 years. During this time, 51 coronary problems were documented. After adjusting for age, smoking, blood pressure, left ventricular hypertrophy, glucose levels, creatinine levels, and cholesterol levels and treatment, patients with hypertensive retinopathy were found to be twice as likely to have coronary problems as patients with no sign of the disease. Patients with either generalized or focal arteriolar narrowing were three times as likely to have a coronary problem.

The study's authors noted that the correlation held even when the results were based on patients with only stage- one hypertension.

CORNEAL ABRASION
Eye patches don't help

A study reported in a recent issue of the Annals of Emergency Medicine found that eye patches made no noticeable difference in the healing of corneal abrasions -- but did interfere with quality of life. The study compared the healing of 35 children between the ages of 3 and 17 who suffered corneal abrasions. Seven-teen of the children wore an eye patch while healing; eighteen did not.

The data showed that healing rates were identical, even after adjusting for age and size of abrasion. 86% of the patients were 95% healed within 24 hours of presentation. The amount of pain medication required was the same for both groups, and neither group experienced complications. However, patients wearing a patch had significantly more difficulty walking.

	If your AMD patients are depressed, treating the depression might prevent worsening of their visual function.

THE BODY/MIND CONNECTION
Depression makes AMD worse

Suffering from poor vision as a result of AMD in both eyes may seem like a legitimate reason to be depressed. However, new evidence indicates that worsening depression is accompanied by a drop in level of visual function.

A longitudinal analysis conducted at Wills Eye Hospital in Philadelphia found a significant correlation between worsening depression and decline in vision function among patients with AMD in both eyes. Researchers examined 51 patients with pre-existing AMD in one eye who had recently lost vision in the second eye as a result of exudative AMD. At the beginning of the study all eyes were 20/70 or worse, and 17 of the patients tested as clinically depressed. (Their mental state was analyzed using the Center for Epidemiological Studies-Depression [CES-D] Scale.)

After 6 months, researchers re-examined 40 of the subjects and found significant declines in both visual function and general function. A comparison of different variables showed that only worsening depression, indicated by a change in CES-D score, correlated with declining vision function.

The data suggest that identifying patients who are depressed and treating this as a separate condition could prevent worsening vision -- as well as improve the patients' quality of life.

The study was reported in the August issue of the Archives of Ophthalmology.

LASER TRABECULOPLASTY
Popularity and payments drop

A study published in the July/August issue of Ophthalmic Surgery and Lasers reported that the number of laser trabeculoplasties performed in the United States increased between 1986 and 1992, but declined by 57% between 1992 and 2000 (176,670 procedures in 1992; 75,838 in 2000). Figures from the Center for Medicare and Medicaid Services indicate that the total allowed charges also declined, from a peak of $137,127,436 in 1991 to $27,622,073 in 2000 -- an 80% reduction.

It's interesting to note that the average allowed charge per procedure began to drop after peaking in 1989 at $893, hitting $359 per procedure by 2000 -- a 60% reduction.

The study was conducted at the University of Tennessee in Memphis.

PREVENTING INFECTION
Alcohol rub vs. surgical scrub

A recent study conducted in France found that 5 minutes of rubbing the hands with an aqueous alcohol solution is just as effective at preventing surgical site infections as scrubbing with povidone iodine or chlorhexidine gluconate for 5 minutes -- and the former protocol is better tolerated by medical personnel, dramatically improving compliance with hygiene guidelines.

The 16-month study involved six surgical services, performing a total of 4,387 surgeries; each service alternated between the two hand cleaning methods on a monthly basis. Surgical site infection rates, staff compliance and effect on skin condition were all monitored. The study found:

• The infection rate following rubbing with the alcohol solution was 2.44%; the infection rate following the traditional protocol was 2.48%.
• Rubbing with the alcohol solution produced less skin irritation and dryness.
• When using the alcohol solution, 44% of medical personnel followed guidelines; using the traditional protocol, only 28% did.

The authors point out that sterile gloves do a lot to prevent bacterial contamination, but that some are bacteria-permeable, and all gloves are susceptible to damage during use.