LASIK Candidacy

1/9 | http://www.docshop.com/education/vision/refractive/lasik/candidacy

•

•

•

BY

Francis Clark, MD SENIOR SECTIONAL EDITOR

updated March 12, 2015

Source:http://www.docshop.com/education/vision/refractive/lasik/candidacy

Generally speaking, candidates for LASIK (laser-assisted in situkeratomileusis) surgery are those who:

Are nearsighted, farsighted, or have astigmatism

Wish to reduce or eliminate the need for corrective eyewear

Are at least 18 years of age

LASIK Candidacy

http://www.docshop.com/

http://www.docshop.com/education/vision/refractive/lasik/candidacy

https://plus.google.com/107156977116520985461?rel=author



•

•

•

•

•

•

Are in good overall health

Have adequate corneal thickness

Have a stable corrective eyewear prescription

Are not pregnant or breastfeeding

Do not have glaucoma, or have highly controlled glaucoma

Are taking aggressive measures to control dry eye syndrome, or havebeen rehabilitated following a diagnosis of dry eye syndrome.

However, as with any medical procedure, there are no absolutes, andthe only way to accurately determine whether a patient is anappropriate candidate for LASIK is to undergo an in-depth evaluation byan eye care professional. Today, we are all well aware of the life-changing benefits that many have experienced as a result of thissophisticated refractive surgery. As anyone who has worn glasses orcontacts can tell you, the idea of being able to depend on your own eyesis appealing, to say the least.

For the right patient, LASIK can make freedom from corrective eyeweara reality. During initial consultations, my staff will spend at least 90minutes or more asking and answering questions, and getting an idea oftheir expectations to make certain that they are candidates for theprocedure.

Of course, a LASIK candidate also must feel confident undergoing theprocedure. My colleague Jon Peet, M.D. says advancements in LASIKtechnology have been the single greatest factor in helping to make morepatients comfortable with undergoing refractive surgery.

"Wavefront measurements (digital mapping of the cornea) and eyetracking (a safety measure that immediately deactivates the excimerlaser if the eye moves to the slightest degree) have contributed to morepredictable outcomes, which improves patient confidence and thereforeencourages more people to seek treatment," Dr. Peet said. "Meanwhile,



this potentially drives down cost to some extent, further broadeningaccess."

Patient education plays a crucial role in the success of LASIK eyesurgery. If you are considering taking steps toward permanentlycorrecting refractive errors, it pays to become as familiar as possiblewith the principles of LASIK, as well as the distinguishingcharacteristics of a suitable candidate. This knowledge will allow you toask informed questions and play a more active role in determining ifLASIK or another procedure is the appropriate way for you to achieveimproved vision.

The LASIK ProcedureThe cornea is the dome-shaped front surface of your eye. It is the pointat which light enters the eye and becomes refracted. Tiny irregularitiesin the corneal surface can have a profound effect on how light isrefracted, which can result in nearsightedness (having difficultiesfocusing on far objects), farsightedness (having difficulties focusing onclose objects), or astigmatism (vision at every distance is distorted).Your glasses or contact lenses have specific contours, or correction,that are intended to compensate for corneal irregularities, resulting inclearer vision.

LASIK surgery is a process of using an excimer laser to vaporize smallportions of the cornea in order to refine its shape. This requires using aspecial laser to create a small hinged flap in the outermost layer of thecornea (epithelium) to expose the stroma. After reshaping the cornea,the flap is replaced.

Because LASIK involves refining the stroma, and depends on thecorneal flap to facilitate healing, having especially thin corneas canpreclude some patients from undergoing the procedure.

Corneal ThicknessIn the evolution of laser refractive eye surgery, LASIK is preceded by



photorefractive keratectomy, or PRK. PRK involves the removal of theepithelium, rather than the creation of a flap, to access the underlyingtissue. As such, it requires a longer and less comfortable recoveryperiod, which prompted doctors to begin researching and developingmodern LASIK surgery. However, PRK is still commonly used to treatsome patients whose corneas are too thin to accommodate a flap.

Fortunately, technology is continuing to evolve, making it possible forsome patients with borderline corneal thickness to undergo LASIK.Many practices, such as mine, have adopted the femtosecond laser, aprecise tool that replaces the keratome blade in creating the cornealflap. This increased precision makes creating the corneal flap much lessinvasive, so those who are not candidates for traditional LASIK may becandidates for all-laser LASIK (sometimes called iLASIK). However, inaddition to thickness, several other characteristics of the cornea arecrucial distinguishing characteristics of a LASIK surgery candidate.

Prescription StabilityIf you have had to change your corrective eyewear prescription in thelast two years, you probably should not undergo LASIK surgery at thistime. Any changes could indicate that your corneas are in a state offlux, and that the results of LASIK surgery could potentially be shortlived. I require that patients have a stable prescription for at least twoyears before moving ahead with refractive surgery.

Although vision can fluctuate atany age, we find that patients aremost likely to have achievedstable vision by around age 22.While many 18-year-old patientsare anxious to achieve freedomfrom glasses and contact lenses,it is often recommended that theywait until their mid-20s,increasing their chances of experiencing the greatest long-term benefitsof LASIK.

Pregnancy can also cause vision to fluctuate because of the dramatic

We find that patients aremost likely to haveachieved stable vision byaround age 22



hormonal changes that take place. This is true even among patients whohave 20/20 vision. That is why I always recommend that any patientwho is pregnant, or planning to become pregnant, wait until a year afterpregnancy to undergo LASIK. By that time, the hormones have usuallyreturned to a normal balance that will no longer affect vision.Meanwhile, I recommend that women who undergo LASIK avoidbecoming pregnant for at least 6 months following surgery.

While prescription stability is a major issue among younger patientsconsidering LASIK, patients beyond age 40 have their own unique risksand characteristics that must be considered before moving ahead withlaser refractive surgery.

CataractsThe crystalline lens lies behind the cornea, the colored ring of tissuethat surrounds the pupil. It focuses light upon the retina, whichgenerates nerve impulses that the brain eventually perceives as visualimages. The lens is composed of water and protein. For reasons thatare not entirely understood, the protein within the lens can begin toclump, obstructing vision.

This chronic and progressive condition is called cataracts, and iteventually requires the surgical replacement of the lens with a syntheticintraocular lens (IOL). Your risk of developing cataracts increasesdramatically past age 40. Patients diagnosed with cataracts are notnecessarily precluded from undergoing LASIK. After a thoroughevaluation, the doctor can determine your options.

The advent of all-laser LASIK surgery has made it possible for thosewho have undergone cataract surgery in the past to undergo LASIKsurgery. IOLs contain correction, and can help those who arenearsighted, farsighted, or have astigmatism to see more clearly.

However, some patients with IOLs still require glasses. In these cases,if a patient wishes to achieve 20/20 vision, LASIK can help themachieve their goals.



Conversely, if a patient who has undergone LASIK eventually begins todevelop cataracts, modern cataract surgery makes it possible to replacethe crystalline lens without affecting the corneal refinements createdduring LASIK.

Monovision LASIKMonovision LASIK is a treatment that was developed to help patientswith presbyopia, a condition that usually presents after age 40, in whichthe crystalline lens begins losing its ability to focus on close objects.

I often receive inquiries from professionals age 40 or older who mustspend considerable time at work reading, including educators,attorneys, and clergy. LASIK is most effective for correcting distancevision, but there are ways to use this treatment to help those who wantbetter close-up vision.

True monovision involves correcting the dominant eye for distancevision, and correcting the other for close vision. Patients can gain anunderstanding of the effects of monovision by wearing two differentprescriptions of contact lenses during a trial period. If a patient does notfind this imbalance agreeable, I may recommend modified monovision.In this instance, I will back off a little and just preserve some readingpower in one eye, which usually satisfies the patient's desire to reducetheir need for reading glasses, but with a less pronounced difference infocusing ability from one eye to the other.

Dry Eye SyndromeIf you do not produce enough tears to keep the eye adequatelylubricated, or if one of the layers of your tears - water, mucus, or oil - isout of balance, it can result in constant irritation, redness, excessivetear production, and other symptoms. Dry eye syndrome is fairlycommon - in fact, more than half of the patients who approach mypractice about LASIK are unaware that they have dry eye syndrome.They just know that wearing contact lenses is very uncomfortable.



This condition must be controlled before a patient can safely undergoLASIK, because dry eyes can seriously impede the healing process. Ipursue dry eye diagnosis very aggressively during pre-LASIKconsultations to make certain dry eye is not missed. In some cases, theeye can be rehabilitated through procedures that close the tear ducts.Meanwhile, if a patient is aggressively taking care of dry eyes withtreatments like prescription eye drops, artificial tears or punctual plugs,they may be able to safely undergo LASIK.

It should be noted that all patients will experience some degree of dryeye following LASIK surgery. It usually corrects after a couple ofmonths.

GlaucomaAqueous humor is a fluid that maintains pressure within the anteriorchamber, the space between the lens and the cornea, which is alsooccupied by the iris. Glaucoma occurs when this fluid cannot properlydrain, causing pressure to build within the eye. This pressure candamage the optic nerve, leading to compromised vision or blindness.

Patients with controlled glaucoma may be able to safely undergo LASIK.

OccupationVirtually anyone who wears glasses or contact lenses would probablychoose to have 20/20 vision using their own eyes. However, those incertain professional occupations can be especially suited for LASIK eyesurgery because their jobs are easier to perform when unencumberedby corrective eyewear. This can include technicians of all stripes, aswell as physicians and other medical professionals. LASIK can alsooffer tremendous benefits for those who love to take part in outdoor

All patients will experience some degreeof dry eye following LASIK surgery



activities such as skiing and diving.

In Her Own Words: Julia's LASIK Pre-screeningJulia is a patient of mine who recently underwent LASIK surgery. Shewasn't very familiar with the details of the procedure, so we had a lot toreview during her consultation.

"I knew nothing about LASIK prior to my consultation, so I guess youcould say I went in blind, no pun intended," she said. "All I was sure ofwas that I was tired of not being able to see well, and feeling like I wasmissing out on life. The consultation was informative and exciting."

As always, we conducted a battery of tests to make certain that shewas a candidate for surgery.

"Prior to meeting with Dr. Clark, Ihad not considered conditionslike glaucoma or dry eye to be afactor in candidacy," Julia said."The consultation was helpful infully explaining every aspect ofLASIK, from general procedureinformation to specific detailsregarding both of my eyes."

Julia was fortunate to have no issues with glaucoma or dry eye thatwould preclude her from undergoing surgery.

"Preparation was easy," she said. "There were some appointments priorto surgery in order to get proper measurements and readings. The staffwas so knowledgeable, and that made me feel comfortable. You aregiven eye drops and specific instructions for their use before and afterthe procedure. Dr. Clark and his staff are very clear on the entireprocess, so you know exactly what to expect every step of the way."

Prior to meeting with Dr.Clark, I had notconsidered conditions likeglaucoma or dry eye to bea factor in candidacy



•

•

•

Make Sure LASIK is Right for YouLASIK has helped millions to experience a better quality of life, but it isnot suitable for everybody. If you suffer with nearsightedness,farsightedness, or astigmatism, and would like to reduce or eliminateyour dependency on glasses or contact lenses, consult with an eyeprofessional. Your refractive surgeon and his staff should spend ampletime examining your medical history, asking plenty of questions aboutyour health and goals, and, of course, listening to your concerns andanswering all of your questions.

Advancements in medical technology have made it possible for moremen and women than ever before to safely undergo LASIK surgery.However, if your surgeon determines that you are not a candidate, thereare alternatives that can help you reduce your need for corrective eyewear. There is no better way to determine your candidacy for LASIKthan to select a reputable, credentialed ophthalmologist. Listen tofriends' recommendations, conduct extensive online research, and don'tbe afraid to consult with more than one surgeon to determine if LASIKis the right way to reach your goals.

References & Resources

Source:http://www.docshop.com/education/vision/refractive/lasik/candidacy

Author: Francis Clark, MD

Publisher: DocShop

http://www.docshop.com/

http://www.eyeops.com/



Health & Medicine

LASIK Candidacy