A new laser therapy that can potentially remove cataracts from people's eyes more efficiently and with greater precision was presented on October 24, 2009 at the American Academy of Ophthalmology (AAO) annual meeting. The technology, currently undergoing clinical trials outside the USA, was developed by LenSar, a start-up company which is in a head-to-head competition with two other players to be the first to commercialize the technology. LenSar plans to start treating patients if the FDA will consider the results of the remaining trials to be both safe and effective.
Although the new device will cost more than existing technologies, the speed of surgery may compensate for that by allowing more procedures to be performed in less time. The new laser cataract device is designed to be safer and easier to use, and it is believed that most cataract surgeons can learn to use it to perform surgeries with less complications. The laser will allow for the use of "premium" implants which set up bifocal vision as well as provide a better way to treat astigmatism.
The LensAR system will not only deliver precise all laser capsulotomies, CCIs and LRIs, but laser fragmentation of the cataract. This approach will significantly reduce, and even eliminate the use of ultrasound power in most cases.
Five years ago, I brought together a group of gifted engineers and scientists, many of whom, I had worked with on the successful development and launch of the Autonomous laser-radar tracking and small spot scanning excimer system that set a new standard in precision in LASIK surgery, when approved by the FDA in 1998. Measurement guided beam delivery was taken to a whole new frontier when Autonomous delivered wavefront guided custom LASIK treatments to ophthalmology.
This time, I challenged the team to design and develop a highly integrated measurement technology within a 3-dimensional scanning femtosecond laser system capable of performing many types of surgical incisions, in eyes of all shapes and sizes. We are specializing in laser cuts in refractive cataract surgery that are critical to successful surgical outcomes: cuts that are currently performed with a blade, or with ultrasound, and therefore, prone to a measureable degree of variability.
The LensAR approach is to bring the accuracy and precision of lasers into the operating room to replace blades and greatly reduce, if not eliminate, the need for ultrasound power to perform the majority of cataract removals. The design goals also requires that the system increase the overall surgical efficiency and safety of lens removal, and improve the stability of the intraocular lens placement.
The result is the LensAR (femtosecond) laser system, a seamless integration of an advanced femtosecond laser and proprietary measurement and laser scanning technology. The LensAR laser system is being designed to provide flexible, all laser surgical options for clear corneal incisions, paracenteses, limbal relaxing incisions, lens fragmentation and customizable capsulotomies - all in one procedure.
To date, the LensAR laser system has been successfully used in well over a hundred eyes outside of the US, and is actively under review with the FDA for approval for use in the US.
As we complete our surgical and technology webpages, you will be able to look at surgical footage of our investigators Dr. Ramon Naranjo and Dr. Jorge Villar from Mexico City, and to hear candid comments from leading US surgeons that also have experience with the LensAR laser: David Chang, MD, William Fishkind, MD and Louis “Skip” Nichamin, MD.
The 2009 contest "Changing the Way People See the World" on the other hand, aims at encouraging people to do anything positive that helps someone else, and record it on video.
Each person that submits a video will receive a $1000 discount on LASIK, and the winning entry will be awarded a 100% free LASIK eye surgery procedure.
In addition to rewarding those who enter videos, Eye Doctors of Washington’s Washington, DC and Maryland LASIK practice will donate a free pair of glasses to charity for each video submitted.
Participants may videotape themselves, a friend, a family member, or even a stranger performing a good deed.
Contestants can submit their videos from now until May 31st, 2009.
For more information on the "Changing the Way People See the World" contest, visit: http://www.edow.com/contest/
The popularity of laser hair removal has increasingly grown, prompting many laser manufacturers to conduct research and seek FDA clearance for their lasers for this indication. The market is growing so quickly that FDA cannot maintain an up-to-date list of all laser manufacturers whose devices have been cleared for hair removal, as this list continues to change. To learn if a specific manufacturer has received FDA clearance, you can check FDA's Website at http://www.fda.gov/cdrh/databases.html under the 510(k) database.
You will need to know the manufacturer or device name of the laser.
Manufacturers should be aware that receiving an FDA clearance for general permission to market their devices does not permit them to advertise the lasers for either hair removal or wrinkle treatment, even though hair removal or wrinkle treatment may be a by-product of any cleared laser procedure. Further, manufacturers may not claim that laser hair removal is either painless or permanent unless the FDA determines that there are sufficient data to demonstrate such results. Several manufacturers received FDA permission to claim, "permanent reduction," NOT "permanent removal" for their lasers. This means that although laser treatments with these devices will permanently reduce the total number of body hairs, they will not result in a permanent removal of all hair. The specific claim granted is "intended to effect stable, long-term, or permanent reduction" through selective targeting of melanin in hair follicles. Permanent hair reduction is defined as the long-term, stable reduction in the number of hairs re-growing after a treatment regime, which may include several sessions. The number of hairs regrowing must be stable over time greater than the duration of the complete growth cycle of hair follicles, which varies from four to twelve months according to body location. Permanent hair reduction does not necessarily imply the elimination of all hairs in the treatment area.
FDA does not make comparisons between systems or how well or safely they work compared to another company's system. FDA does not recommend one laser system over another.
Lasers cleared for body hair removal are also cleared for facial hair removal.
WRINKLE TREATMENT
Lasers are also being used to treat wrinkles. Several manufacturers have received FDA clearance to claim treatment of wrinkles, while others may claim skin resurfacing. Patients have reported reddening of the skin, which lasted from one to four months. Pain was mild and could be treated with over-the-counter analgesics. Consumers should bear in mind that skin abrasion, whether achieved by lasers, chemicals or abrasive materials, means removing one or more layers of skin, which can be painful and could cause redness, swelling or scarring, depending on how each person heals.
People considering this procedure should consult a dermatologist or the manufacturer to determine whether or not they would be good candidates. Be sure to ask your dermatologist for a copy of the patient labeling for the specific laser device used to understand the risks.
DENTAL TREATMENTS
Several manufacturers have received clearance for argon and carbon dioxide lasers to activate tooth-bleaching solutions and to treat gum disease. Several lasers have clearance for hard tissue use on teeth. On May 7, 1997 FDA cleared the first laser system for treating tooth decay, an erbium YAG laser made by Premier Laser Systems. Recently, American Dental Technologies received FDA clearance to market its laser for caries removal; it is not cleared to remove tooth enamel.
Studies conducted by the manufacturers showed that the laser is as safe and effective as a high-speed drill for removing dental decay and preparing a cavity for a filling. The manufacturer's study indicated that fewer patients needed anesthetic for pain. Any inquiries regarding this method of cavity treatment should be directed to your dentist, who can provide you with patient labeling including risks for the specific laser.
EYE SURGERY
Lasers may be used to remove tissue in eye surgery as well. This may include removing tumors, cataracts, or proliferating blood vessels common to diabetic retinopathy. Several manufacturers have lasers cleared for photorefractive keratectomy (PRK) and Laser-Assisted In Situ Keratomileusis (LASIK), two procedures for correcting nearsightedness, farsightedness, and astigmatism. The laser is used to reshape the cornea and focus images correctly on the retina. For information on eye surgery and which lasers have received clearance, you can access FDA's Website at: http://www.fda.gov/cdrh/LASIK. As with the other types of patient labeling, be sure to ask the surgeon for the patient labeling for the specific laser device being used.
OTHER MEDICAL USES
Some lasers have been cleared for medical uses such as removing tissue. Because heat from lasers cauterizes blood vessels, there is less bleeding compared to scalpel use. Usually, FDA gives manufacturers general surgical clearances; in order to promote the laser for a specific surgical procedure, manufacturers must first provide FDA with clinical evidence that their lasers are safe and effective for that specific procedure. If you wish to learn whether a specific laser has been cleared for a specific indication, you may contact FDA's Consumer Staff. You will need to provide the name of the manufacturer and the specific product name of the device before contacting the Consumer Staff.
PRACTITIONERS
States regulate who can use lasers for various therapeutic procedures. Medical lasers are prescription devices available for sale only to licensed practitioners. You should check with your state medical licensing board to determine who qualifies as a licensed practitioner in your state.
BIOSTIMULATION LASERS
Biostimulation lasers, also called low level laser therapy (LLLT), cold lasers, soft lasers, or laser acupuncture devices, were cleared for marketing by FDA through the Premarket Notification/510(k) process as adjunctive devices for the temporary relief of pain. These clearances were based on the presentation of clinical data to support such claims. FDA will consider similar applications for these and other claims with the decision to require clinical data being made on an individual basis, taking into consideration both the device and the claim.
LASER RADIATION SAFETY
All laser devices distributed for both human and animal treatment in the U.S. are subject to Mandatory Performance Standards. They must meet the Federal laser product performance standard and must submit an "initial report" to CDRH's Office of Compliance prior to distributing the product (see 21 CFR 1000-1040.11). This performance standard specifies the safety features and labeling that all laser products must have in order to provide adequate safety to users and patients. A laser product manufacturer must certify that each model complies with the standard before introducing the laser into U.S. commerce. This includes distribution for use during clinical investigations prior to device approval.
Certification of a laser product means that each unit has passed a quality assurance test and that it complies with the performance standard. The firm that certifies a laser product assumes responsibility for product reporting, recordkeeping, and notification of defects, noncompliances, and accidental radiation occurrences, as specified in sections 21 CFR 1000-1010. A certifier of a laser product is required to report the product via a Laser Product Report submitted to CDRH. Reporting guides and related regulatory information are available from the DSMICA web site at: http://www.fda.gov/cdrh/devadvice.
Distribution of any certified laser products internationally would also require submission of the report.
Electro-Optical Synergy (ELOS) is a selective photothermolysis technology developed by the corporation Israel's Syneron Medical Ltd, that uses various forms of radio and light frequencies principally for cosmetic medicial purposes.
Syneron has recently presented its new line of skin ablation fractional devices that include the Matrix RF applicator for Syneron's eLight, eLaser and eMax at the 66th Annual Meeting of the American Academy of Dermatology.
The company has also presented a device that has received clearance from the U.S. Food and Drug Administration for laser-assisted lipolysis and features disposable fiber optics.
In addition to these two new devices, Syneron has also presented its VelaShape™ device, the first FDA-cleared Class II device for the temporary reduction of the appearance of cellulite that delivers non-invasive cellulite and circumferential reduction treatments.
All devices are powered by proprietary elōs™ Technology, and deliver Bi-Polar Radio Frequency and Light energies that allows the devices to treat a wide range of conditions, such as Hair Removal, Wrinkle Reduction, Vascular Advanced or Fractional Skin Treatment, while minimizing the applied light energy and its long list of associated undesired side effects.
elōs™ Technology was developed by IPL inventor/patent-holder Dr. Shimon Eckhouse and master physicist, Dr. Michael Kreindel.
This revolutionary technology platform effectively overcomes the safety and procedural limitations of intense pulse light (IPL) and conventional lasers.
Clinical Applications
Delivers treatment to the deep dermal levels to allow for new collagen generation, while protecting the epidermis
Selective heating within matrix thermal bands allows surrounding tissue to remain undamaged, promoting quicker healing time and minimizes the downtime
Light and RF energies reduce sebaceous gland activity while blue light destroys acne
Treat even minimally-pigmented hair colors and all skin colors
Treat superficial benign vascular and pigmented lesions including Telangiectasias, Rosacea, Poikiloderma and Angioma. FotoFacialRF.
Resolve vascular lesions in 1-3 treatments
Selective thermolysis to vascular lesions and leg veins up to 4-mm
Can also be applied on advanced vascular and smaller resistant vessels including fine telangiectasias
Cosmetic laser surgery came about almost by accident when you consider how it began. In the 1950’s lasers were created for various things including that of the medical field. Lasers in the medical field were used as medical instruments. The lasers were designed to cut through the tissue in order to keep the bleeding of the patient to a minimum. Lasers were also used to help reach those body parts that were in some way obstructed.
So now, the medical field is filled with laser surgery as a better way to operate on a patient making the surgeon’s life a little easier. The best part about the laser instrument is the ability to adjust the wavelength of the laser without harming other aspects of the body. Cosmetic laser surgery is used for resurfacing. In other words, skin is replenished by the use of lasers to creating younger looking skin. Below are a few important points about cosmetic laser surgery.
* Younger looking skin. When you under go cosmetic laser surgery you are obtaining a fresh look. This means you can look ten to twenty years younger depending on how much you took care of your skin in your early life. Those who used products during their youth and did not let the sun harm their skin can look twenty years younger after cosmetic laser surgery.
* Precautions for those looking to have cosmetic laser surgery include reducing sunbathing to nil to avoid damaging their skin again.
* Laser surgery typically lasts for eight to ten years before you need another treatment.
* Speaking with at least two cosmetic laser surgery doctors may benefit you. This surgery is not easy. You may find that you are not comfortable with the procedure and it is not always the right move for everyone. You may also find that you are more comfortable with another physician than the first person you spoke with.
* Sensitive skin is one type of skin that may not suit well for cosmetic laser surgery. The people with sensitive skin have a higher risk for damage during surgery. There are also post- treatment medications that the skin may be too sensitive for.
* Disadvantages of cosmetic laser surgery are side effects that may be quite severe depending on you. They are temporary, but the uncomfortable feeling may be too much for the process. Side effects include skin reddening, tenderness, and swelling.
* Another disadvantage is the loss of pigmentation. Some who have undergone cosmetic laser surgery suffer from loss of skin color making you fairer because the laser has damaged the cells that produce the pigmentation. * Scarring can also result during the procedure if the laser is left on a spot to long. This is why it is important to have a highly credible surgeon.
If you are interested in cosmetic laser surgery you will want to be aware of all the facts before you under go the surgery. This is not something you should undertake lightly if for no other reason than the risks associated with the surgery.
Low Level Laser Therapy ( LLLT ), also known as Photobiomodulation, is a form of phototherapy or light therapy. It involves the application of low power light to areas of the body in order to stimulate healing. Photons, which are particles of electromagnetic energy, are emitted from the low power laser. These particles enter the tissues and are absorbed in the mitochondria, which are tiny structures within the substance of each individual cell. The energy is converted to chemical energy within the cell. The permeability of the cell membrane changes which in turn produces various physiological effects. These physiological changes affect a variety of cell types including macrophages, fibroblasts, endothelial cells and mast cells.
Clinical applications
Low Level Laser Therapy has a variety of uses in rural, field and military conditions, schools, sport centers, industrial enterprises and correctional facilities.
Some of its applications are:
Soft tissue injuries, including sprains and strains, tendonitis and haematomas
Joint conditions, including arthritis, tenosynovitis and capsulitis
Chronic pain, including trigeminal neuralgia and chronic neck and back pain
Wound management, including skin ulcers, pressure sores and burns
Skin infections, including cold sores, warts, verruca
Adjunctive use in the relief of hand and wrist pain associated with Carpal Tunnel Syndrome.
Muscle spasm
Relief of stiffness
Promotion of muscle relaxation
The laser may also be focussed on acupuncture points to assist with smoking cessation and the relief of short or long-term pain.
Effects of Laser Therapy
Low level laser therapy (LLLT) is believed to enhance tissue growth and as a result, to have other beneficial effects such as resolve inflammation, relieve pain and boost the immune system. The exact mechanism to produce these effects is still being studied, but it is agreed that the mechanism is photochemical rather than heat-related.
In any case, Low Level Laser Therapy (LLLT) has demonstrated the ability to significantly accelerate and enhance the body’s natural defense and repair components in the presence of injury, inflammation and certain disease processes. By modifying the effects and limiting the duration of inflammation as well as enhancing specific repair and healing processes, LLLT is consistent in providing pain relief, reducing injury damage and loss of function, in addition to facilitating more rapid repair and stronger healed tissue structures.
Several clinical studies have noted the following results of LLLT:
Increased collagen production
Enhanced nerve regeneration
Increased vasodilation
Reduced inflammatory duration
Increased cell metabolism
Increased pain threshold
Increased cell membrane potential
Reduced edema magnitude
Increased microcirculation
Increased tissue and bone repair
Increased lymphatic response
Increased enzyme response
Observed biological and physiological effects include changes in cell membrane permeability, up-regulation and down-regulation of adenosine triphosphate and nitric oxide.
Cold laser therapy is a treatment whereby a cold laser is utilized to treat chronic and acute pain. Cold lasers treat the same meridian points that Acupuncture, with laser beams stimulating the body's acupoints rather than needles. The laser mimics solar radiation, producing collagen and Vitamin D, and increasing epithelial cell activity and capillary blood vessel formation at the treatment site. The electric pulse increases serotonin levels and thus the body is guided towards healing, and pain is alleviated.
Clinical applications
Clinical applications of Cold laser therapy include treating soft tissue injuries and chronic pain in persons suffering from back and neck pain, musculoskeletal pain, joint pain associated with arthritis, tendonitis, busiitis, neuropathy, achilles tendon pain, migraine headaces, carpal tunnel and other associated pains.
These are some other conditions that can be treated with this therapy:
Fibromyalgia
Epicondylitis
Migraines
TMJ
Plantar fasciitis
Sprains and strains
Tendinitis/bursitis
Neuritis
Arthritis
Back pain
Muscle tension
Headaches
Cold laser therapy also treats conditions such as TMJ, reflex sympathetic dystrophy (RSD) and other inflammatory and scarring conditions.
Effects of Laser Therapy
Certain wavelengths of light at certain intensities will aid tissue regeneration, resolve inflammation and relieve pain. Cold laser therapy increases serotonin levels which allow the body to heal itself. Cold laser therapy is non-thermal and noninvasive. Combined with electric stimulation, cold laser therapy is one of the most effective healing therapies in the medical community today.
The structure of the eye is composed of a single, outwardly curved (convex) clear lens, the cornea, at the front and a lengthy 'fiber optic' cable, the optic nerve, extending from the back. It is essentially an empty structure, except for the colored iris, a circular band of muscles that controls the size of the pupil, which allows variable amounts of light to pass to the back inside the surface of the eye. The amount of pigmentation of the iris determines its color. Blue eyes, for example, have very little amount of pigment, and black eyes have the most. The pupil is the central transparent area, that is controlled by the ciliary muscles in the iris, that make the pupil smaller when the amount of light is excessive, and vice versa.
Light rays pass through the clear cornea, which due to its curved surface, is able to bend (refract) the light rays. These light rays are concentrated together and pass through the pupil. Then, they go through the normally clear lens which has two curved surfaces, the front and the back. Therefore, these light rays are bent (refracted) two more times on their trip to the back of the eye.
The light rays travel to the back surface of the eye through the vitreous, a clear jelly which fills the space between the back of the lens and the retina, the inside lining of the back surface of the eye which contains specialized cells which convert light energy into electrical impulses. These cells are either called rods, specialized for black and white images, or cones, that mainly process color images. In dim light, we use our rods, which cannot work in bright light. To deal with bright or moderate light, we use our cones, that beside providing color vision, they also process some aspects of black and white vision and the ability to discern fine detail.
What is truly amazing about the eye is how part of these cells in the retina (photosensitive cells) actually are a six inch appendage of the cell, the axon, which joins with other axons to compose the optic nerve which travels to the brain stem, the very top of the spinal cord, located at the very center of the brain. There, each axon connects (synapses) with a cell or cells, and the axon of the receiving cell(s) travels another six inches to the back of the brain, the occipital lobe, where it synapses with a brain cell(s) to produce what we call vision.
Therefore, the major functions of these parts of the visual system are composed by:
Cornea: Refracts light rays
Pupil: Controls the amount of light entering the eye
Lens: Refracts light rays
Vitreous: Light traverses this space
Retina: Converts light energy to electrical energy
Optic Nerve: Transmits electrical energy from the retina to the brain stem
Brain Stem: Intermediate 'relay station' for visual fibers
Occipital Cortex: Final destination. Converts electrical energy to visual images
A "Perfect Eye" would therefore have:
a clear and unobstructed path from the front of the eye to the back of the eye.
the proper balance between the length of the eye and the curvatures of the three refracting surfaces.
properly functioning cells in the retina and brain which allow the conversion of light energy to electrical energy, the transmission of this energy, and the interpretation of the energy into what we call vision.
Unfortunately, most people do not have "perfect eyes".
Eyes that are too long or have too much refracting power (from the cornea and the lens) are nearsighted eyes, as images are focused in front of the retina. The image received by the retina is not a 'dot for dot' representation of what the image viewed by the eye. Instead, each of these 'dots' of light becomes enlarged to form a 'disc' of light with a consequent spread of the dot image to adjacent parts of the retina. This is what causes blurring of vision.
The opposite results when eyes or too short or have too little refracting poser. These eyes are farsighted, as images are focused (or would be) behind the retina. The same type of dot to disc representation occurs.
When light rays that are vertically oriented are not refracted the same amount as the light rays that are horizontally oriented, this condition is called astigmatism. An example would be when that eye looks at a building that is built as a square, it would appear as a rectangle with different vertical and horizontal dimensions being visualized. This example refers to strictly vertical (90 degrees) and strictly horizontal (0 degrees); astigmatism can occur at any angle between 0-180 degrees.
On a more dynamic level, the eye can possess no refractive error whatsoever but is unable to adjust to near images by increasing its refractive powers. This condition is termed presbyopia and normally affects persons in their 40s and early 50s. The mechanisms within the eye that can increase the curvature of the lens (accommodation) become less efficient and external plus lenses are necessary to bring the near images into focus.
The eye is truly like a camera because it not only requires proper focusing (refraction) but it requires a clear media through which light rays must pass. Any loss of clarity of the structures through which these light rays must pass will interfere with their successful interpretation within the visual cortex of the brain. Examples of disorders which might cause this scattering or absorption of light rays are opacities or swelling of the cornea (scars, edema, abrasions, etc.), opacification of the lens (cataract), and cloudiness of the vitreous (hemorrhage or inflammation.)
Also, the receiving tissue, the retina must be functioning properly, as opposed to aged related macular degeneration, in which there is deterioration of the most important part of the retina, the macula, which is responsible for our finest and our reading vision.
The range of patologies which can be treated with Laser Eye Surgery are:
Myopia (nearsightedness): -0.75 diopters to -10.0 diopters
Hyperopia (farsightedness): +0.75 diopters to +5.0 diopters
Astigmatism (associated with myopia): 0 to 4.0 diopters
Presbyopia (the eye's diminished ability to focus that occurs with aging).
Traditionally, many of these conditions were often treated with prescription glasses or contact lenses. Today, a number of innovative Laser Eye Surgery procedures are widely available. There are three main types of Laser Eye Surgery:
PRK (Photo Refractive Keratectomy) has been the standard eye laser surgery for many years. It involves the complete removal of the epithelium or the outer layer of cells on the eye, with the use of a "cold" laser light. PRK is mostly used on patients with low to moderate amounts of Myopia Astigmatism. Below you can watch a video showing a PRK surgical intervention:
LASEK (Laser Assisted Sub-Epithelial Keratectomy) or EPIFLAP (Laser Assisted Epithelial Keratomileusis) surgery involves the fractional removal of the epithelium to reveal the cornea, which is then firmed or reshaped by a laser. The outer layer of cells is then pushed back, and the eye heals shortly after. LASEK is used on patients with low to moderate amounts of Myopia or Astigmatism. Below you can watch a video showing a LASEK surgical intervention:
LASIK (Laser Assisted in Situ Keratomileusis) is the newest and most popular type of eye laser surgery. Initially developed by Spanish ophthalmologist José Barraquer, with this procedure a thin layer of the eye's cornea is sliced off to create a flap. This enables the laser to target the tissue underneath. The flap is simply replaced and grows back naturally. Vision is restored almost immediately. LASIK is usually used on patients with severe Myopia (nearsightedness): -0.75 diopters to 10.0 diopters. Below you can watch a video showing a LASIK surgical intervention:
All of these treatments have been approved for use in many countries around the world and are therefore considered to be safe. But it must be taken into account that all types of surgery does involve risks and eye surgery is no different. There have been cases during which patients have suffered major complications and required cornea transplants following laser treatment.
Not everyone can have laser eye surgery. Although eye laser surgery is usually suitable for healthy adults and can be performed on virtually any eye, sometimes it is not advisable. Several factors could influence negatively the outcome of these operations: AGE: It is advisable that a person undergoing Laser Eye Surgery should be at least eighteen years old. It is assumed that the refractive error (prescription) of the patient will be fairly stable at this time. However, there's no upper age limit for Laser Eye Surgery eligibility, since it does not affect the nature or outcome of the surgery. ENDOCRINE: Hormone fluctuations can affect the refractive error of a person's eye. Surgery during a period of such instability would probably produce changes which would not be correct once the endocrine system returns to normal. Therefore, Laser Eye Surgery is not recommended for women who may be pregnant, nursing, or undergoing changes in oral contraceptive therapy. HEALTH: Because the cornea is composed of a matrix of collagen fibers, the same material which comprises tendons and other connective tissue, people who have autoimmune disorders, e.g., rheumatoid arthritis, Sjogren's Syndrome, Systemic Lupus Erythematosis, etc., may be at risk for unpredicted changes following surgery. Other medical problems, such as diabetes mellitus, high blood pressure, heart problems, etc. do not affect the outcome of Laser Eye Surgery surgery. HERPES VIRUS INFECTION: A history of herpes simplex infection of the eye may be a contraindication to Laser Eye Surgery surgery. It is believed that the virus may permanently reside in nerve cells outside the eye and that any kind of surgery might reactivate an infection. However, this area is undergoing change. Studies are being done to see if treatment with antiviral medication prior and after the operation might prevent such a recurrence. Herpes infections in other parts of the body do not pertain to qualifying for Laser Eye Surgery surgery. PUPIL SIZE: The excimer lasers currently treat an area of the cornea that measures about 7 to 8 mm in diameter. Therefore, it is important that the pupil size be less than the area of treatment. Most of the reported difficulties with glare experienced by patients come from those with pupillary size irregularities. REFRACTIVE ERROR: Most persons are either nearsighted or farsighted with some degree of astigmatism. After age of 40, people also experienced difficulties with focusing at near, a condition known as presbyopia. Although none of the procedures described above can be used for this condition, for such patients there exists laser thermal keratoplasty (LAPR), in which mild laser heat is used in a three-second procedure to shrink collagen in the periphery of the cornea to steepen the eye's surface for correction of near vision in farsightedness or presbyopia. End results are similar to Conductive Keratoplasty (CK), which is also used to treat this condition. This procedure uses radio frequency energy to apply heat to very tiny spots around the cornea.
Despite their prevalence, acne scars have always been a condition notoriously difficult to treat. In the past, Dermatologists have used all kinds of treatments, such as excision, punch grafts, dermabrasion and chemical peels, with a low degree of success. It wasn't until the late 1980's that experiments using pulsed dye lasers were initiated on thickened, overgrown scars.
Dr. Alster, MD, Washington Institute of Dermatologic Laser Surgery and Georgetown University and her colleagues have since then reported prolonged improvement in the appearance of most scars after pulsed dye laser treatment. "Clinical assessments and skin surface texture analyzes using a computer image analyzer showed that the laser-irradiated scars approximated normal skin characteristics."
Clinical research over the years has led to textural improvements of both thickened and deeply colored red scars. "After one or two pulsed dye laser treatments, a 57% to 83% improvement was observed. Facial acne scars have been very responsive to this treatment."
Research has shown that combining the use of the pulsed dye technology with carbon dioxide laser vaporization was found to provide improvement in non-reddened, minimally thickened scars. Atrophic acne scars where there is a breakdown of the skin, have been found to respond most favorably to carbon dioxide laser resurfacing. The number of treatments necessary depends on the type of lesion and each individual's collagen and wound healing response. Usually two or more treatments are needed for hypertrophic (thick) acne scars.
Advances in laser technology have progressed so rapidly during the past decade that successful treatment of many cutaneous concerns and congenital defects, including vascular and pigmented lesions, tattoos, scars, and unwanted hair-can be achieved. The demand for laser surgery has increased substantially by patients and dermatologists alike as a result of the relative ease with which many of these lesions can be removed, combined with a low incidence of adverse postoperative sequels. Refinements in laser technology and technique have provided patients and practitioners with more therapeutic choices and improved clinical results. In this review, the currently available laser systems with cutaneous applications are outlined, with primary focus placed on recent advancements and modifications in laser technology that have greatly expanded the cutaneous laser surgeon's armamentarium and improved overall treatment efficacy and safety.
The pulsed dye laser procedure is typically performed on an outpatient basis without general anesthesia. Local anesthesia is usually administered with a topical anesthetic cream, intralesional injections or nerve blocks. Adjacent, non-overlapping laser pulses are delivered over the scars. The immediate result may produce a purplish coloring. The treated scars are then evaluated 6-8 weeks later, where another treatment, at the same or slightly higher strength may be necessary.
Local, regional nerve block, or intravenous sedation may be required for CO2 laser resurfacing of atrophic acne scars depending on the extent of damage. Follow-up examinations and skin cleanings are scheduled often during the first postoperative week and patients are encouraged to keep the area moistened with healing ointments and/or cooled compresses. Early evaluation and intervention are important in order to prevent long-term scarring.
The American Academy of Dermatology is the largest medical society representing physicians who specialize in treating skin, hair and nail conditions.
Dr. Tina Alster is widely recognized as one of the world's leading authorities on dermasurgery.
Photodynamic Therapy (PDT), is a new procedure to remove skin tumors without the need for an anaesthetic or even a hospital stay.
PDT uses a class of drug which starts working only when activated by light. This then produces a damaging form of oxygen that destroys tissue.
For internal cancers, the drug is injected a few days before treatment. Once injected, the patient must be careful to avoid bright light, such as fluorescent light and sunlight, until treatment has taken place.
During treatment, a narrow beam of red light, usually from a laser, is shone onto the tumour, activating the drug and killing the malignant cells. It takes only a few minutes and the patient can go home immediately.
Patients describe a 'tingling' sensation as the light is applied, but this usually dissipates after half an hour.
The National Institute of Health and Clinical Excellence has recently approved PDT for the treatment of nonmelanoma skin tumours. 'There are no major safety concerns,' its guidelines state. 'Cosmetic outcomes...(are) good or excellent.'
For skin cancers, the drug is applied in the form of a cream. The patient is then bathed in laser light, but only the cream covered area reacts.
The main PDT research centre is at the National Medical Laser Centre in University College Hospital, London (UCH), where they are investigating other uses of the therapy. Essentially, it should work well anywhere inside the body where an endoscope - an examination tube carrying a light - can get to.
'Besides treating skin cancer, we've also seen more than 600 patients with tumours in the mouth and neck,' says Stephen Brown, professor of Laser Medicine and Surgery at UCH. 'It works best when the cancer isn't too far advanced.'
Light can also be taken down the esophagus - the tube from the throat to the stomach. Acid escaping from the stomach can damage cells that line the bottom of the esophagus, turning them pre-cancerous - a condition known as Barrett's esophagus.
A trial has found PDT is twice as effective in treating pre-cancerous cells in the esophagus as anti-acid drugs (a conventional treatment).
One of the main advantages of PDT is the lack of side-effects. While chemotherapy drugs have to be infused over weeks and often cause nausea, as well as damaging fast-growing cells (the reason why patients lose their hair) and the gut lining, PDT's side-effects are nearly always relatively mild and usually limited to some pain, swelling and nausea.
Furthermore, any surrounding healthy tissue that is damaged grows back in a matter of weeks. Healing is quick because, unlike radiotherapy, PDT doesn't damage the underlying collagen scaffolding of healthy cells, making repair much easier.
If pre-cancerous cells do reappear, PDT can be done twice more and then, if necessary, there is still the option of the operation.
'Sometimes PDT can be used to salvage the situation when surgery, chemo or radiation has failed,' says Professor Brown. 'But it makes much more sense to use it first.'
Yet despite its apparent benefits, PDT is still regarded with skepticism by conventional cancer experts. Cancer charity BACUP describes it as 'not yet established...still being tested', and warns about possible side-effects.
The history of the treatment is partly to blame. 'When it first appeared in the 1980s, various wild claims were made for it,' Brown says. 'I think some people are still distrustful because of that.'
Since then, however, the drugs and techniques have been refined and trials show its benefits.
Another possible reason for PDT's marginalization is that it requires a new approach. 'If you are a cancer surgeon or a radiologist, or you have a unit set up to do chemotherapy, you've got a huge investment in existing technology, and PDT doesn't use any of it,' says Bown.
'But we are not trying to put anyone out of business. The beauty of PDT is that it is simpler, cheaper and less invasive to begin with, but if it doesn't work, the more conventional techniques can also be used.'
Research is already underway at the UCL unit to add PDT to the list of options for prostate cancer. This is because of changing attitudes to treatment.
'In the past, as soon as cancer was detected, the advice was to remove the whole organ,' says Brown. 'That usually got rid of the cancer, but it often left the patient impotent or incontinent.
'Now the trend is to treat the main tumour but leave smaller ones and then monitor the patient carefully. PDT can be repeated if the cancer rears its head again.'
Removing a cancer with minimum surrounding damage is what makes PDT so effective. But there is a difference between using PDT on body surfaces and in the prostate, which is not accessible to an endoscope.
'You have to locate accurately the tumour, which you can't do with scans,' says Brown. 'So we may have to take up to 20 biopsies.' However, this is still only a research procedure.
There are only two or three other major centres researching PDT in the UK and while experts still differ on when PDT is appropriate, everyone agrees there should be more trials to test it.
Photoimmunology is the study of the effects of ultraviolet radiation (UVR) on immunologic processes. Most work has examined UVR effects in animal models and in vitro systems, with limited data from humans.
Effects of Ultraviolet Radiation
Increased exposure to UV rays in animals and humans has been linked to elevated risk from the following diseases:
Herpes viruses
Human immunodeficiency virus HIV- 1
Papilloma viruses
Leishmaniasis, malaria
Tuberculosis
Leprosy
Lupus erthematodes
Dermatitis
E. coli
Staphylococcus aureus.
Since UV rays readily damage DNA in all cells, it is not unrealistic to hypothesize that this will play an additional role in the mutation of existing disease bacteria and viruses and may produce totally new strains of pathogens. Physicians are finding that infection and disease is a greater global challenge than cancer, as people of all skin pigmentation are at equal risk from the effects of immuno-suppression.
UVB irradiation inhibits induction of immunity systematically at high doses and locally at low doses in animals, and is associated with the appearance of transferable T suppressor lymphocytes. Photosensitized UVA and visible irradiation can have similar effects. In some mouse strains, chronic UVB exposure leads to highly immunogenic cutaneous malignancies, which are able to escape immunologic destruction in part because of protection from suppressor T lymphocytes. Immunosuppressed patients also have increased rates of skin cancer, suggesting immunologic involvement in regulation of skin cancer development. UVB or psoralen photochemotherapy (PUVA) irradiation alters circulating lymphocyte subtypes and contact hypersensitivity responses in man. UVB irradiation also induces the appearance of epidermal non-Langerhans antigen presenting cells, which may have suppressive functions. In vitro UVR exposure decreases antigen presenting cell function, lymphocyte responses to mitogens or antigens, and lymphocyte viability. UVB irradiation of keratinocytes alters interleukin 1 (IL-1) production and induces the release of immunosuppressive factors. It is clear that even modest amounts of UVR alter immunologic function and human avoidance of prolonged sun exposure would seem prudent.
Photomedicine is an interdisciplinary branch of medicine that involves the study and application of light with respect to health and disease. Photomedicine may be related to the practice of various fields of medicine including dermatology, surgery, dentistry, optical diagnostics, cardiology, and oncology.
The ancient Greek historian Herodotus recorded the therapeutic use of sunlight or heliotherapy for skin lesions. Photomedicine was developed into a science and popularized by Niels Finsen, a Faroe Island physician who won the Nobel Prize in 1903.
Photomedicine can be divided into several specialities:
Photomedicine, which includes photodynamic diagnosis (PDD) and photodynamic therapy (PDT), is based on the application of a photosensitizer relatively selective for malignant tissue. Light activation of appropriate wavelength leads to either fluorescence for diagnostic purposes or to oxidation-mediated tissue destruction for treatment.
There are broad, fundamental reasons to pursue photomedicine – light has the right quantum energy to trigger specific non-ionizing chemistry in drugs and tissues; tissue interactions unique to high-intensity laser light are very useful in medicine; and light based diagnostic and therapeutic interventions can often be designed to be minimally invasive and selectively targeted.
Because of its high tumor selectivity, excellent cosmetic effect and low toxicity, photomedicine seems to be a promising tool for the diagnosis and treatment of superficial skin cancer, lung and tracheobronchial cancer, esophageal cancer, Barrett’s esophagus, bladder cancer and pituitary tumors.
In the field of Gynecology, photomedicine is a fairly new method. Preliminary studies have been done in certain areas like vulva and cervical neoplasm, intraperitoneal ovarian metastasis and some begin diseases like endometriosis and menorrhagia.
Photobiomodulation, also known as low level laser therapy (LLLT), cold laser therapy, and laser biostimulation, is a controversial medical and veterinary technique in which exposure to low-level laser light is claimed to enhance tissue growth and have other beneficial effects. The technique is also known by the more ambiguous terms phototherapy and laser therapy, which may also be used to describe other medical techniques.
Credit for the development of laser theory is generally given to Albert Einstein. In his theory "Zur Quantum Theories der Strahlung", published in 1916, he first used the name stimulated emission.
The word LASER is an acronym for Light Amplification by Stimulated Emission of Radiation.
In 1967 a few years after the first working laser was invented, Endre Mester in Semmelweis University Budapest, Hungary wanted to find out if laser light could cause cancer. He took some mice, shaved the hair off their backs, divided them into two groups and gave a laser treatment with a low-powered ruby laser to one group. They did not get cancer and to his surprise the shaved hair grew back more quickly on the treated group than the untreated group. That was how "laser biostimulation" was discovered.
Clinical applications
Clinical applications include treating soft tissue injuries and chronic pain, aiding smoking cessation, wound healing and nerve regeneration, and possibly even resolving viral and bacterial infections.
The best documented laser type is the HeNe laser (Helium-neon, visible red light, 632.8 nm, continuous or chopped, usually non-polarized but with very high degree of coherence). The HeNe-laser is a gas laser, powered with high voltage and hence usually voluminous and expensive per milliwatt. Available on the market in Europe since 1975. As an alternative one could choose an InGaAlP-laser diode laser (Indium gallium aluminum phosphide laser, visible red light, semiconductor laser type, and usually just named Indium laser) with wavelength 635 to 700 nm. The most common wavelength is 650 nm. The Indium lasers are cheaper per milliwatt than the HeNe-laser. Their light is polarized but less coherent light. Available since 1990. Both HeNe and Indium lasers seem to be best on problems in skin and mucosa (superficial).
The second best documented laser type is the GaAs-laser (invisible infrared, 904 nm, semiconductor type, always super-pulsed with very high peak power, often polarized but less coherent). Available on the European market since 1985. This laser is best suited for deep lying problems such as back, shoulders, spine and other joints, fibromyalgia, whiplash injury, lymph edema, trismus etc.
For the GaAs-lasers there is one extra factor to be aware of. Traditionally these lasers have low output at low pulse frequencies and high at high frequencies. Often the average output power is more or less proportional to the frequency set. This means that if the average output is 10 mW at 10,000 Hz, it is 1 mW at 1000 Hz and 0.1 mW at 100 Hz etc. Such a laser is more or less useless on all frequency settings except 10.000 Hz.
However, there are GaAs-laser (904 nm) instruments available where the output average power is independent on the frequency. This is very valuable as the dose given then simply is proportional to the treatment time. Such lasers are pulse train modulated.
The most commonly sold laser type today is found within a group of lasers - the so called GaAlAs-lasers. In this group there are lasers from about 750 nm and up to 980 nm. Originally the wavelength was 820 or 830 nm, invisible, infrared. Today there are two main types, the 808 nm one, usually produced in Europe and recently also in the USA and the 890 nm one, usually produced in Russia. The reason why so many lasers of this type are offered today is that they are the producers’ favorite; they are cheap (per mW) and easy to drive electrically. They can be made with powers up to hundreds of watts, e.g. for surgery and hair removal and in laser therapy they are usually emitting 100 mW and upwards. The light is invisible and always polarized. It is either continuous or chopped. These lasers are often suggested for the treatment of tendonitis and tinnitus.
Apart from this, also strong (surgical/aesthetic lasers, such as CO2-, Ruby-, Nd:YAG-, Ho:YAG and some other types) can be used as therapeutic tools. Just set lower power.
For deep lying problems the GaAs laser is penetrating best (because of its high peak power) and for problems in skin and mucosa the HeNe laser is the most effective one (due to the high degree of coherency). The 808 or 890 nm lasers are more all-round types and often battery powered. There are single- or multi probes. For a multi probe, all the lasers should have the same wavelength (same laser type).
Effects of Laser Therapy
Certain wavelengths of light at certain intensities (delivered by laser, LED or another monochromatic source) will aid tissue regeneration, resolve inflammation, relieve pain and boost the immune system. The exact mechanism is still being explored and debated but it is agreed that the mechanism is photochemical rather than heat-related. Observed biological and physiological effects include changes in cell membrane permeability, up-regulation and down-regulation of adenosine triphosphate and nitric oxide.
Contentious areas are: "best" wavelength, dose, dose-rate effects, beam penetration, the role of coherence and pulses (peak power and repetition rates). Laser average power is typically in the range of 1-500 mW; some high peak power, short pulse width devices are in the range of 1-100 W with typically 200 ns pulse widths. The average beam irradiance then is typically 10 mW/cm2 - 5 W/cm2. The wavelength is typically in the range 600-1000 nm but some research has been done and products are available outside this range.
Side effects
There appear to be no safety concerns in its application for therapy in people or animals, but the operator and patient should wear appropriate protection for the eyes (dense filter spectacles) in case of accidental or reflected exposure, and the laser beam should never be directed at the eyes.
