The following article appeared in
"European Lenses & Technology"
© 1998 Jobson Publishing L.L.C.
therapeutic effects wearing tinted lenses is a subject that fascinates me"
Prof. Dr. Herbert Wertheim is the Chairman of Brain Power Inc. A Florida-based company that has been providing optical tinting technology and services for over 30 years. Among his academic honors are positions as resident Professor in Physics at the University of Miami, and Visiting Lecturer in Physiological Optics at Bascom Palmer Eye Institute, Miami, Florida.
In our on-going study of the lens tinting sector, EL&T asked him to highlight what European Optical practices can gain from tinting and UV-coating ophthalmic lenses.
EL&T: What are the benefits of lens tinting for the practitioner?
Dr.W: When capital is invested in a tinting outfit for a business the financial benefits can be very substantial. The costs of consumable products and energy are minimal. Personnel time is going to vary, but the average time needed by technical staff to tint a pair of lenses is five minutes. This can add up to financial rewards of between £15,000 and £30,000 resulting from a £600 investment.
Paramount to the practitioner, however, is his/her ability to enhance their customers' visual functionality and eye health. The prevention of cataracts, headaches, macular degeneration and other ailments can be alleviated with the correct tint. This way, the optician gains prestige from his/her patient base, from the community and fellow professionals, who will appreciate your extra knowledge and dedication to your customers' eye care. This will encourage additional referrals.
EL&T: And the benefits for the wearers?
Dr.W: There are five principal advantages for users of tinted lenses. Firstly, improved visual function; secondly, protection of the health of the eyes; thirdly, the enhanced cosmetic appearance of the wearer; next, increased physical and emotional stamina due to enhanced visual functionality; and finally, protection of the lens' optical surfaces.
EL&T: What are the practical requirements to set up a tinting operation and what type of training is necessary?
Dr.W: The space needed is very small - usually less than a few feet of workshop space. An electrical point, a water supply and proper lab ventilation are the sole mechanical needs.
The training of the practitioner is important; the practitioner must determine which fashion tints, therapeutic colors of sunlenses will provide the most benefit to each customer. This training process should make use of high-quality light sensitivity and photometry instruments, which help determine the correct darkness, density and color of the tints appropriate for the wearers' needs.
EL&T: Are there special skills required to train and begin to tint lenses?
Dr.W: It doesn't take any previous experience in the lab. Good color appreciation and attention to detail are all that is required. Virtually anyone can learn to do it in less than an hour. With a little practice and background information, the technician should be able to tint all types of lenses.
EL&T: Could you tell us about tints for therapeutic purposes?
Dr.W: The therapeutic effects of wearing tinted lenses is a subject that fascinates me. The benefits of tinted ophthalmic lenses extend beyond merely enhancing appearance. If you reduce the amount of blue light and UV radiation reaching the eye it can benefit light-sensitive patients with several conditions including, among others, developing cataracts, macular degeneration and glaucoma.
Ultraviolet light (UV) is that portion of the spectrum of invisible light below 286nm to 400nm. While the primary source of UV is the sun, other sources include video display terminals and lighting. UVA (320-4OOnm) is the part of the invisible spectrum of particular concern to eyecare professionals. It is the most damaging, as it is transmitted to the crystalline lens of the human eye. Constant bombardment of the eye by near-UV (300-400nm) may result in photochemical eye damage. As the human eye ages penetration of this near-UV increases, generating more and more pigments which cause cataracts as the eye becomes progressively more discolored. It is reported that 10% of all cataract operations are due to this type of UV exposure. UV treated lenses prevent development of this type of cataract, as they do not allow UV exposure of the crystalline lens.
It is reported by experts that macular degeneration, solar retinitis, and corneal dystrophy's are all related to UV exposure. Again, properly treated lenses for UV absorption prevent these problems. If people work in an environment which is brightly lit with fluorescent fixtures, or spend hours in front of a computer terminal then they would benefit by having UV-absorbing lenses.
What progress has BPI made in combating ocular damage caused by near-UV?
Dr.W: BPI developed a group of therapeutic tints and lenses called 'Enhanced Visual Amplification' (EVA) for the purpose of visual function improvement. One of these can help people who have difficulty seeing at night, a condition which becomes more apparent in aging and near-sighted patients. This tint works by protecting the Rhodopsin and Iodopsin protein chemical in the retina (this is a chemical 'amplifier' that allows the eye to see in dim light); as a consequence of intense daylight bleaching, many sufferers can not reproduce this chemical fast enough to replace it for night vision. The EVA lenses help prevent the chemicals from bleaching out. They should be worn for a couple of hours in the late afternoon and removed thirty minutes before sunset.
EL&T: Is it true that tinted lenses can also help alleviate dyslexia?
Dr.W: Indeed. University researchers have found that more than 85% of dyslexics are helped by tinted lenses. Researchers think dyslexia may involve an abnormality that slows down one of two major visual pathways in the brain, so that the two kinds of visual information are not received in the right sequence. One pathway, the magnocellular system, has large cells that carry out fast processes for perceiving position, motion, shape and low contrast. The smaller parvo cells carry out slower processes for perceiving still images, color, detail and high contrasts.
In reading, light strikes photoreceptors in the retina; the information is then processed by magno cells and parvo cells in the brain. In a study of dyslexics, the magno cells were found to be smaller than normal, as was low-contrast information processing. It has been found that reading through various blue filters of differing shades helps 80% percent of the children read better.
Exactly how the filters help the problem remains a mystery. The nerve cells of the fast magno pathway are inhibited by diffuse red light, so a series of blue filters may remove enough of the red to what a dyslexic person sees to thus allow the magno cells to work normally.
EL&T: How wide spread is the problem of near-UV light in every-day life?
Dr.W: Computer monitors are used daily in virtually every office and increasingly in homes. Computers are frequently blamed for eye fatigue, burning and blurred vision. Glare produced by light sources in the office environment tends to add further to visual discomfort in the workplace, as computer screens reflect images. Tints reduce glare and reflections, and increase contrast by blocking portions of the light spectrum that cause eye strain and discomfort.
Lens tinting, whether for adding color for cosmetic effect, UV blocking or for scientifically proven therapeutic benefits, is a simple process. All you require is a little space in the workshop/lab and a tint bath. The objective - in terms of chemistry - is to transfer the dye molecules from the dye solution to the lens surface.
All sounds very simple, but the range of benefits are too great for a modern optical practice to ignore.