Patient Care

FL-41: New scientific validation for "rose-colored glasses"

FL-41 Frequently Asked Questions | What is FL-41?

Thirteen years ago Dale Erickson was living what has been described as a "Rocky Mountain High." Married with 5 children, Dale was a successful businessman living in beautiful Pagosa Springs, Colorado. With his own hands, he personally built a beautiful home at an altitude of 8,000 feet in the southern Colorado Rockies. Unfortunately, not long after the last nail was hammered, Dale's health began to deteriorate.

During the next dozen years, Dale developed migraine headaches, severe light sensitivity, and eventually a physical malfunction of his nervous system. He was diagnosed with a neurological condition with a name as long as the symptoms: "syndrome of transient headache and neurological deficits with cerebrospinal fluid lymphocytosis" or HaNDL. One symptom of Dale's illness is extreme sensitivity to bright lights, particularly the sun and fluorescent lights. "Over the last twelve years my body has progressively developed excruciating pain that is beyond description," Dale says.

The ophthalmic component of Dale's neurological con-dition is called photophobia, a fear of or sensitivity to light. Photophobia is known to be associated with migraines and also blepharospasm, a disease characterized by involuntary closure of the eyelids. In one survey, four out of five blepharospasm patients cited bright lights, television viewing, driving, reading, and stress as factors that aggravate their condition.

John D. Steffens, M.D., at the University of Utah Neurology Clinic is treating Dale now, and referred him to Kathleen B. Digre, M.D., a neuro-ophthalmologist at the Moran Eye Center. Photophobia is a very common problem, and most ophthalmologists-most physicians in general-don't know what to do with it. "Fortunately Dr. Steffens knew these were real symptoms and not figments of Dale's imagination," said Dr. Digre.

Bradley J. Katz, M.D., and Judith Warner, M.D., are also neuro-ophthalmologists at the Moran Eye Center. Along with Dr. Digre, they are experts in the use of fl-41 tinted eye glasses to treat some forms of light sensitivity and blepharospasm. fl-41 is a rose-colored tint put on glasses to reduce light-sensitivity and headaches. Dr. Digre and her colleagues at the Moran Eye Center have published numerous studies regarding the effectiveness of these lenses. She says patients like Dale have suffered unnecessarily because the literature is rife with references to psychiatric disease among people complaining of photophobia. There have been suggestions that photophobia doesn't really have any pathophysiology.

All this is changing now. In three new studies, the Moran Eye Center team of neuro-ophthalmologists monitored light sensitivity in blepharospasm patients using electromyog-raphy to measure blink frequency, duration, and amplitude in blepharospasm patients. The results: fl-41 does reduce light sensitivity and involuntary blinking.

Dr. Digre explains, "In one of our research projects, we studied the subjective complaints in patients with blepharospasm. Patients preferred the fl-41 to gray glass. Then we did a blink study with fl-41 tint. In this study, we showed that a "placebo" tint that looked just like fl-41 didn't help, but the real fl-41 did. In each study, the tinted fl-41 lens seemed to help our patients with photophobia and even reduced disability for patients with blepharospasm. We also studied tinted formulas from other optical shops and found that some shops said they had the tint, but the optical characteristics were not the same as the blue-blocking properties of true FL-41."

Co-investigator Bradley J. Katz, M.D., Ph.D., and co-author of the studies says, "We have now shown that photophobia is not a psychological problem. It is a neurologic problem, and physicians should take it seriously. The beauty of the fl-41 lenses are non-invasive, they have no side effects, and they're not expensive. So it's a cheap, easy way to improve the lives of these patients, who in some cases are very disabled by their disease."

So how is Dale doing with his new rose-colored glasses? Today, he and his wife Kristine take long walks together in the beautiful Colorado ranges. He has lost almost 50 pounds since he first got the tinted glasses in February. "It is a miracle in my life," Dale says. "I started wearing the fl-41 lenses in February and in just a few weeks I went from daily migraines to a couple a month, or less. I'll never forget when my wife said, 'It's so wonderful to not see you lying in bed.' I had literally retreated into darkness and now I've come out into the light of the world again."

Charles "Chuck" Swallow

One of the first investigators to conduct light sensitivity trials with various lens tints, is the manager of the Moran Eye Center lens crafting department, Charles "Chuck" Swallow. Chuck recalls Dr. Digre bringing a study to his attention. "I still have the study," Chuck says. "The fl-41 tint got its beginning in Birmingham, England. It was used to help children with migraine headaches. In fact, it came about because they changed the light bulbs in all the schools to fluorescent and an unusual number of children started having headaches. The fl-41 rose tint (as opposed to a blue tinted lens) reduced migraines by one-half in these children after four months of wear," Chuck says. "Dr. Digre came to me and asked if I could make this tint up. We first tried it out on migraine patients. We were then studying light sensitivity in blepharospasm and received a grant to study this tint. I've been making them ever since and you wouldn't believe the calls and letters of appreciation we receive. I remember one man who called me and said, 'I'm standing on the golf course and wanted to call you and thank you for the fl-41 glasses. It's the first game of golf I've played in twenty years.'"

Chuck says he gets similar calls from England, Japan, Australia and other countries every month. "It's a part of my job that touches me deeply," he says.

Photophobia

In a presentation at the 2005 NANOS meeting, Dr. Digre highlighted some of what is known about the pathophysiology of photophobia. In addition to the associations with migraine and blepharospasm, the following are among the findings about light and photophobia:

Individual thresholds of light sensitivity vary among most people.
Light sensitivity may be modulated by seasons, with lower discomfort thresholds in the winter months than in the summer months.
The total amount of light influences the discomfort threshold. For example, binocular viewing of a light stimulus is associated with a higher discomfort threshold than uniocular viewing.
Retinal adaptation (dark adaptation, for example) determines the interpretation of light brightness.
Different wavelengths affect an individual's comfort level. Some studies have indicated that migraine sufferers experience more discomfort with blue-wavelength light.
Flickering lights cause discomfort in people with migraines. A photogenic stimulus of 2 to 8 cycles/second has been shown to cause the greatest discomfort among people with migraine or photoinduced epilepsy.
Certain patterns of light, especially stripes, also cause greater discomfort for people with migraine or photoinduced epilepsy.
Migraine patients appear to have a hyperexcitable occipital lobe, that increases sensitivity to stimulation by light, sound, odors and touch.
Light-sensitive individuals may have different levels of photopigments in the retina. People with blepharospasm or migraine, for example, have been found to have higher macular levels of the carotenoids lutein and zeaxanthin, perhaps as protective mechanisms.

For now, the most important step is to diagnose and treat any associated conditions, and to talk with patients about a few things they can do, including not wearing sunglasses indoors. "People who wear really dark glasses can actually dark-adapt themselves and increase their photosensitivity," Dr. Digre said. "Sunglasses outside, of course, are fine, but the darker the glasses inside, the more light-sensitive the person will become."