Laser As A Medical Device - Term Paper Example

 Laser As A Medical Device Abstract Key Words: Laser, LASIK, Refractive eye surgery. Abstract This paper describes the revolutionary development in the field of laser and eye surgery, which is known as LASIK. This refractive eye surgery has undergone a lot of research due to which there are several types of LASIK in the field today. All the types have their own procedures, merits and demerits which have been discussed in the paper. There are different school of thoughts regarding which procedure is better than the other; in terms of greater accuracy and minimal complications. There are several ethical issues regarding LASIK that can be overcome if the treatment is used for genuine reasons only. 1. Introduction [1] Laser (light amplification by stimulated emission of radiation) is a device that emits light through a process called stimulated emission; this process was first theorized by Albert Einstein. The word ‘light’ used in the definition is used in the broader sense, referring to electromagnetic radiation of any frequency; some electromagnetic radiation might not even be visible. Some common examples of lasers are infrared lasers, ultraviolet lasers and X-ray lasers. It is said that Theodore Maiman invented the first successful light laser which was called ruby laser; this laser was only capable of pulsed operations due to its 3 energy level transitions. After this, began great developments in the field of lasers. Nowadays, laser are used in many fields e.g. science, defense and medical technology. Laser has revolutionized the field of medicine and still facilitating new inventions and procedures. There are mainly three categories in medicine with respect to the use of lasers; laser diagnostics, photo medicine and laser surgery. Laser Surgery seems to be the most popular one amongst these three. A very common method today uses the excimer laser to reshape curvature of the cornea. One such treatment is called LASIK. [1] LASIK (laser-assisted in situ keratomileusis) is a refractive surgery which can correct myopia, hyperopia, and astigmatism. It is generally known as an alternate to photorefractive keratectomy, PRK; because the patients tend to recover faster and is less painful. LASIK eye surgery is a treatment that reshapes the cornea in order to produce clear vision. Many people opt for this surgery so that they are not dependant on eyeglasses and contact lenses for better vision. It is a remarkable treatment because patients experience dramatically improved vision after moments of undergoing the successful surgery, which makes them immediately discontinue the use of eyeglasses. 2. Background of LASIK [2] In the mid-1800’s, a physician J. Ball devised the first concept for correction of vision. He presented a cup that contained a spring-loaded mallet which supposedly flattened the cornea by striking it through the eyelid. He claimed that it restored eyesight and made it possible to see clearly without the dependence on glasses. Then in Japan, principles of transverse and radial keratotomy (RK) were established by Dr.Tutomu. This approach proved unsuccessful as the corneas on which he operated became cloudy and swollen, due to the destruction of the important inner layer of the cornea. In the 1960’s, Dr. Fyordorov in the former USSR, converted the incisions to the front of the cornea, and by making cuts 90% through the thickness of the cornea and was able to devise a system of correction. This way commendable development took place in the mid-1980's to early 1990's and RK reached its peak. A milestone paper was published in 1983 by Dr. Stephen Trokel in the American Journal of Ophthalmology. It outlined the benefits and potential of using the excimer laser for eye surgeries and to reshape the cornea for correctness of vision. Jose Ignacio Barraquer, M.D. of Bogota, Columbia, is the man who is known as the ‘father of refractive surgery’ and marked the beginnings of LASIK. Dr. Barraquer’s notion on the subject was to remove or add sufficient tissue to change the shape of the cornea and thus refraction of the eye. After some development, he combined the precision of the excimer laser in his procedures and gave birth to a new hybrid procedure. Ioannis Pallikaris, M.D. coined the term ‘LASIK’, and was the first to create a flap of tissue with the microkeratome, rather than remove the entire top layer. He conducted first trials of LASIK in the 1980’s in Greece on animals. 3. 2. IK with your eye's surface.980'p of tissuocedures and gave birth to what we eye.nd swollen.000000000000000000000000000000000Types of LASIK In addition to conventional LASIK surgery, several different types of LASIK vision corrections are available, including: 3.1 Custom Wavefront LASIK Procedure [3] Custom LASIK surgery, also known as wavefront LASIK or wavefront-guided LASIK makes use of 3-dimensional measurement of how the eye processes image to guide the laser in reshaping the front part of the cornea. It is known as a customized procedure because the surgeon customizes the treatment according to individual’s unique visual requirement. Benefits With the wavefront measurement system, extremely precise correctness of vision is achieved which would be impossible with the traditional LASIK. The customized aspect of it helps every individual in getting better outcomes from the procedure. This procedure not only corrects your vision but also refines how well a person can see in terms of contrast sensitivity and fine detail. Drawbacks Custom Wavefront is more expensive as it uses higher technology for better precision result. 3.2 LASEK [7] LASEK (laser epithelial keratomileusis) is considered as a new variation of PRK. It is a treatment that allows the laser energy to be applied directly to the eye's outer surface for reshaping the cornea and thus correcting vision. LASEK is a no-flap procedure used mostly for thin corneas. Procedure In order to understand the procedure of LASEK, we must first know the difference between LASEK, LASIK and PRK; LASIK: A thin flap is cut on the eye’s surface, which is lifted to allow the laser energy to reshape the cornea to correct the vision. Then the flap is put back in its place so that the healing process may begin. PRK: PRK is a slightly different procedure than LASIK as it does not involve the cutting of any flap. Instead, the laser energy is applied directly to the eye’s surface. Due to this exposure to the laser, the ultra thin, outer layer of the eye (epithelium) is completely removed. Thus, grows back after some time. LASEK: Whereas, LASEK procedure preserves the extremely thin epithelial layer by not letting it have any exposure to laser. On the contrary, the thin layer is lifted; changes are made to correct vision and finally replaced on the eye’s surface. The thicker flap is created during the procedures of LASIK, with a microkeratome cutting tool or a special laser. Whereas an ultra thin flap is created with a special cutting tool called trephine. LASEK was developed to overcome any difficulty that may arise if the flap is not cut according to the required thickness or diameter. Benefits Many doctors consider LASEK to be a better and safer treatment for patients who are not good candidates for LASIK. LASEK is a variation of PRK; fit for people who have thin or flat cornea Drawbacks It has been reported that the patients who undergo this treatment heal more slowly and have complaints of discomfort. 3.3 Epi-LASIK [4] Epi-LASIK is a procedure that was developed to overcome the potential problems of LASEK and LASIK. It is a cross between both the two treatments. Procedure A surgeon cuts a flap with a sharp laser in the cornea in LASIK procedure. This involves the risk of cutting the flap too thickly. Whereas during LASEK, the cornea’s outer layer, the epithelium, is cut in a thin sheet that retains its crux on the eye with a fine blade. This is done in Epi-Lasek, but the surgeon uses a different blade which is blunter. Alcohol is used during LASEK to loosen the epithelial sheet, while a plastic blade, called an epithelial separator, is used to separate the sheet from the eye. Using the separator has proved to be a better approach as it avoids the possibility of a reaction from the usage of alcohol. However, alcohol is still used by some surgeons in Epi-Lasik procedures. Benefits Epi-Lasik is considered to be a safer treatment for people who have increased chances of being hit in the eye for e.g. soldiers, policemen or boxers, because there’s no risk of the flap being dislodged. Patients tend to have some discomfort after the surgery; they are comforted by the intake of painkillers. However, the discomfort after Epi-Lasik is lesser than that felt after PRK or LASEK. Drawbacks This procedure does not produce the same results for all, therefore is better for people with less steep corneas i.e. who have low myopia. The recovery time for Epi-Lasik patients is considerably longer than with LASIK, as LASIK patients achieve good vision from the same day up to a few weeks later. 3.4 IntraLase "Bladeless" LASIK [5] In IntraLase "Bladeless" LASIK, lasers have even replaced the cutting tool which was previously done with original LASIK. The corneal flap is made with a laser, instead of a knife. Procedure Instead of the cutting tool (microkeratome), bladeless LASIK uses two different kinds of lasers: Femtosecond laser: This laser is allowed to direct laser energy accurately to create a thin, hinged flap. The flap is then lifted from the eye’s surface for a small amount of time. Excimer laser: The energy from this laser is used to remove the tissue from the newly exposed eye surface, to reshape the cornea according to the patient’s condition and requirement. Then finally, just like any other LASIK procedure, the flap is put back in its place so that the healing process can begin. IntraLase laser was the first femtosecond laser that was approved for bladeless LASIK in the United States of America, in 2001. It can be used in combination with any other approved excimer laser to perform bladeless LASIK procedures. There are many new bladeless laser systems being introduced in the market today. They are: zLASIK: Approved by FDA in March 2008. Femtec: Approved by FDA in 2004. VisuMax. Approved by FDA in March 2007. Benefits This procedure is termed very precise because it is safe from any errors that can occur due to a surgical blade. It is reported that patients after a bladeless surgery, show a lower probability of dry eye. Drawbacks IntraLASIK takes a minute to create a corneal flap, as opposed to the seconds required in standard LASIK surgery. [6] Although IntraLASIK poses lowers risk as compared to other refractive surgery, still there are some complications to consider. The excimer laser is still subject to possible visual errors; as some patients have reported to have problems with light sensitivity. Also, the cost of this treatment can be much higher than other forms of eye corrective surgeries. 3.5 Presby LASIK [8] Multifocal LASIK (presbyLASIK) is an advanced type of laser vision correction surgery. It changes the shape of the eye's cornea so that different power zones are created for one’s sight at varying distances. Many clinical trials have taken place over the past several years regarding this procedure in U.S. Promising results have been achieved from these tests. Although it is unclear as to when FDA will approve this procedure. This can prove to be an innovative mode of correcting presbyopia, which causes near vision to blur as the eye's natural lens begins to lose its focusing flexibility. Presbyopia is something that no one can escape as it starts beginning to show at the age of 40 in most individuals. The solutions for this are multifocal eyeglasses, multifocal contact lenses, artificial lenses and now it shall be treated by a multifocal LASIK eye surgery. LASIK Presby is also called multifocal LASIK because it is devised to work on the principles which are nearly the same to those used for artificial multifocal lenses. Procedure [9]Presby Lasik is like any other LASIK procedure with some variations. The same laser technology is used to correct the cornea, but the difference is that the laser energy reshapes its clear surface in different areas. This way the light is bent or refracted differently in each area and thus, both near and distance vision can be achieved at the same time. As Presby Lasik is still undergoing research, therefore different approaches are being tried and tested for their efficiency and accuracy of results. Benefits There are some other methods of presby LASIK that are intended to be customized and to provide personalized procedures uniquely tailored to the individual’s needs and lifestyle. Drawbacks Presby LASIK is reported to produce very accurate results for far-sighted people but has shown only moderate amount of ability to correct near-sightedness. It has been studied that Presby LASIK seems to work most accurately when the candidates are chosen very carefully; in reference to their past medical and eye surgery history (if any). Therefore, not everyone can pass for the respective surgery. The results of the survey prove that presby LASIK is unlikely to provide a permanent solution to vision-related presbyopia. Future surgeries might even be necessary. 3.6 PRK [10] Before the emergence of LASIK; PRK (photorefractive keratectomy) used to be the most common refractive surgery. It is an eye surgery that is designed to correct low myopia and astigmatism. At times, surgeons tend to prefer the PRK procedure over the traditional LASIK because it avoids the flap complications. Procedure The surgeon uses the laser to remove the surface layer found on the cornea and then reshapes the cornea as needed. The procedure takes only about 15 minutes, although the preparations for th procedure might take longer. Both eyes can be done at the same time but doing them separately is a preference. Benefits The corneal flap in LASIK might take years to close and might cause corneal weakness. The weakness might not be noticed by all but can become significant in case the patient is a pilot, athlete or anyone who has a higher probability of having a corneal trauma. In such cases, PRK is always a better option. Most people don’t feel pain during the procedure. Patients, who are not good candidates for LASIK due to their corneal conditions or corneal scars, can get the PKR procedure done and avoid dependence on eye glasses and contact lenses. Drawbacks The healing time required for PKR is longer than for LASIK and improved vision might not be noticeable before one or two weeks. [9] Some complications experienced after the surgery can include infection and/or night glare or halos that are most noticeable when you're viewing lights at night, such as while you're driving. 4. Blade versus Bladeless This section discusses a comparison between the two main different techniques through which refractive eye surgeries are performed and to judge which approach is better. The two approaches are by LASIK and IntraLase; LASIK devises an approach in which the thin flap on the eye’s surface is cut with an instrument known as a microkeratome, whereas IntraLase uses another laser (femtosecond laser or IntraLase) to do the job under discussion. [11] It is studied that LASIK is (blade) preferred by some surgeons as they are much faster and more comfortable for the patient. They tend to be more comfortable because the suction in a microkeratome procedure lasts about three seconds, whereas it lasts around 15-20 seconds in IntraLase. It has also been recorded that the blade or microkeratome flaps were the main source of any vision threatening complications in LASIK. With the emergence of IntraLase; it was found that the risks could be avoided by laser flap maker. Some surgeons are of the opinion that flap quality is very fine and predictable with the laser. Whereas other surgeons feel that modern-day microkeratomes are also very reliable in cutting fine flaps and that complications can occur in both. 5. Ethical Issues of LASIK Everything in the world has its merits and demerits; depending upon its usage and perception by different people. LASIK; not being any different has its dark side too. The controversy that is prevailing is that this medical procedure is at times used by athletes and sport figures to enhance their sense of sight which gives them an unethical edge over their competitors. The basic premise is that this procedure is also a performance enhancement for athletes, but it is not banned like steroids etc. [12] According to an article; players are usually scrutinized for the use of drugs and steroids which enhance their performance. Whereas sport figures who enhance their visions with the laser surgeries are not questioned. It is reported that it has proved to be a fruitful approach; being adapted by golfers and baseball players etc. As both of these games require the precision to turn the game to their side. Few real life cases are discussed in the respective article in which a golfer is discussed who aimed for a 20/15 when the signed up for LASIK. He made his game from better to perfect and won many championships. Another example is of a pitcher who was 0-3 in six matches before his surgery. Later, he won nine of his next 10 games. It is unfair for the normal athletes to compete with these sport figures who have been operated with the performance enhancement procedures. With the advancement in medical technology, there are fewer risks involved in these procedures because of which they seem more tempting to the masses. Successful sport figures are generally richer than their community and therefore would not mind in spending a hefty amount on e.g. Wavefront LASIK to get the precise and accurate result that they want from their procedures. They consider their eyes as equipment; if they don’t like it they will just get it changed. It is reported that golfers tend to have an improved ability to judge distances after they have LASIK. Another common improvement is that the golfers are able to see slopes in greens a lot clearer as they get a different three-dimensional view of the green after LASIK. LASIK actually produces an aspherical cornea instead of a spherical cornea. This might give them a better vision than normal. [13] Sport intends to reveal the most capable or physically strong human amongst the others. LASIK and such enhancement procedures tend to change the course of sport, as now we cannot be sure if the capability of that individual is inborn or artificial. This also gives way for the rich people to become inevitable as they have the money and the resources to alter whatever they want and to whatever degree they want. If this is not ceased then what would be the fate of such enhancement and who would decide the final point in their development. For.e.g. sight might be enhanced so much one day that people can cease the need for telescopes and binoculars. [14] Another ethical issue that surrounds LASIK is the fees of the procedure. This procedure is rarely covered by medical insurances as they usually term it as cosmetic treatment, similar to the lack of insurance coverage for cosmetic plastic surgery. The other issue related to the pricing of the procedure is that some doctors are not clear about the payments before the procedure. Due to this, the patients end up paying more than what they had been told before. [15] Another ethical issue; which is the question whether a physician and the patient risk the potential consequences of refractive eye surgery to reduce or eliminate the dependence of an individual on eyeglasses or contact lenses? The complications of the surgery get severe at times due to which vision gets worse than it already was. Therefore the question is raised if it is ethical to promote such a procedure. Doctors all over the world work on the betterment and development of these procedures to ensure that minimal risks are involved. Due to these researches and studies, doctors have been able to devise precise and accurate procedures like Wavefront LASIK etc. LASIK is a revolutionary treatment for people with vision problems and should remain as a procedure to help them experience better sight, rather than being used for unethical purposes. 6. LASIK Statistics [16] More than one million patients undergo the LASIK procedure in the United States each year. The U.S. Food and Drug Administration (FDA) reports that LASIK eye surgery complications occur in only 1 to 5 percent of cases. According to the FDA’s LASIK surgery statistics: Glare and sensitivity to light affect 1.7 percent of LASIK patients. Visual fluctuations occur in 2.6 percent of LASIK patients. Halos around light sources are experienced by 3.5 percent of patients. About 3 percent of patients report vision worse than before LASIK. According to another survey, American Association of Professional Eyecare Specialists (AAPECS) concluded that 55.3 percent of LASIK patients achieve visual acuity of 20/20 or better, while 92.6 percent of patients achieve vision of 20/40 or better. However, other sources contend that the national average of patients who achieve 20/20 vision or better after LASIK is closer to 85 percent. [17] “Globally, more than 17 million people have had LASIK surgery.” Source: Market Scope (2007) “Approximately 8 million Americans have had LASIK surgery.” Source: Market Scope (2007) “In 2005, approximately 1.3 million Americans had LASIK surgery.” Source: Market Scope 7. LASIK Patients [17] Here are some statistics regarding feedbacks from patients after LASIK: “Nearly 90% of LASIK (and other vision correction surgery) patients recommend it to others. About 25% recommend it to more than 10 people.” Source: VisionWatch survey - data for 6-month period ending Mar 2007. (Jobson/VCA) “When surveyed 3 or more months after surgery, 70% of LASIK patients said they felt "amazed and delighted that I could see so well." Source: VisionWatch - data for 6-month period ending Dec 2006. (Jobson/VCA) [18] Melissa, a 22 year old had LASIK and said this: “Being able to wake up every morning and actually see the alarm clock is something that I thought would never happen again to me. Since my experience with LASIK, I feel that I have been blessed with a miracle.” Robert, who is 42 years of age had to say this about LASIK: “LASIK changed my life! Because I was blind without my glasses, I was concerned that in an emergency situation (if I couldn't find my glasses) I wouldn't be able to help my loved ones or myself.” 8. Conclusion With the advancement of technology, the procedures are becoming more precise and have minimal risks of complications. The pace of technology is so fast that, many problems once associated with LASIK will cease to exist. Presby LASIK will undergo more trials until it is approved by FDA. It will be a new revolution as it will help to correct far-sightedness and nearsightedness both. [19] Advances in LASIK technology provide patients with choices that can reduce the risk of post- laser eye surgery complications and provide more precise results. With IntraLASIK, the surgeon uses a laser instead of a blade, or microkeratome, when creating the corneal flap, ensuring fewer flap-related complications. During custom LASIK surgery, a three-dimensional map of the eye is used to guide the excimer laser, providing superior visual results and less risk of corneal irregularity and over- or under correction. A new procedure has been devised in the field of refractive eye surgery which is Implantable Contact Lens. The Implantable Collamer Lens (Visian ICL) has been approved by the FDA, and is produced by STAAR Surgical Company. The product and procedure is most suitable for patients who are near-sighted or for those who have thin corneas. This can be considered as an improvement as compared to LASIK because LASIK has not been able to treat both these conditions effectively. 9. References [1] Wikimedia Foundation, Inc. LASIK. 2009. http://en.wikipedia.org/wiki/LASIK [2] North Dallas Eye Associates. A Brief History of Refractive Surgery. http://www.northdallaseye.com/lasikhistory.html [3] Keith Croes. Custom LASIK or Wavefront LASIK: Individualized Vision Correction. 2009. http://www.allaboutvision.com/visionsurgery/custom_lasik.htm [4] Liz Segre. Epi-LASIK Eye Surgery: How It Works. 2009 http://www.allaboutvision.com/visionsurgery/epi-lasik.htm [5] Marilyn Haddrill. Bladeless LASIK: Creating a LASIK Flap With Precision. 2009 http://www.allaboutvision.com/visionsurgery/intralasik.htm [6] Keion Moradi.Understand the Different Types of Lasik Surgery http://ezinearticles.com/?Understand-the-Different-Types-of-Lasik-Surgery&id=737393 [7] Liz Segre. LASEK Eye Surgery: How It Works http://www.allaboutvision.com/visionsurgery/lasek.htm [8] Marilyn Haddrill. PresbyLASIK (Multifocal LASIK, Bifocal LASIK or LASIK for Presbyopia) http://www.allaboutvision.com/visionsurgery/presby-lasik.htm [9] Presby LASIK (Multifocal LASIK, Bifocal LASIK, or LASIK for Presbyopia). June 11th, 2008. http://www.lasika.org/lasik-procedures/presby-lasik-multifocal-lasik-bifocal-lasik-or-lasik-for-presbyopia/ [10] PRK Laser Surgery Procedure http://www.docshop.com/education/vision/refractive/prk/procedure/ [11] Marilyn Haddrill. "Blade Versus Bladeless" LASIK Debate http://www.allaboutvision.com/visionsurgery/blade-vs-bladeless.htm [12] William Saletan. The Beam in Your Eye. If steroids are cheating, why isn't LASIK? April 18, 2005, http://slate.msn.com/id/2116858/ [13] Andymiah The Beam in Your Eye – LASIK. April 21, 2005 http://bioethics-sport.blogspot.com/2005/04/beam-in-your-eye-lasik.html [14] Ronald L. Scott. Laser Eye Surgery Referral Fees Raise Ethical Concern. Aug 2000 http://www.law.uh.edu/healthlaw/perspectives/medicalprofessionals/000828lasik.html [15] Jennifer Kreatsoulas. CRSToday Europe News. March 2009. http://www.crstodayeurope.com/Pages/News.php [16] LASIK Surgery Statistics http://www.docshop.com/education/vision/refractive/lasik/statistics/ [17] LASIK Statistics http://www.lasiksurgerynews.com/news/eye-vision-statistics.shtml [18] LASIK Testimonials http://www.docshop.com/education/vision/refractive/lasik/testimonials/ [19] LASIK Risks http://www.docshop.com/education/vision/refractive/lasik/risks/ Read More