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All About Vision

PRK

Photorefractive Keratectomy or PRK is a type of refractive laser eye surgery used to correct a patient’s vision to eliminate or reduce their dependence on glasses or contact lenses. PRK is the style of laser eye surgery that preceded LASIK, having been the former most common type of refractive surgery until LASIK came along.

PRK is effective in correcting nearsightedness (myopia), farsightedness (hyperopia) and astigmatism and has very similar rates of success and outcomes as LASIK. PRK remains a common option for laser eye surgery.

How Does PRK Differ From LASIK

PRK and LASIK both permanently reshape the cornea to improve vision by using a laser (an excimer laser to be exact) to remove part of the tissue underneath the corneal epithelium. The epithelium first needs to be removed in order to get access to the tissue and how this is done is what differentiates the two procedures. While LASIK creates and lifts a flap on the outer corneal layer, reshapes the corneal tissue underneath and then replaces the flap, PRK removes the outer layer of the cornea completely. The outer layer will regenerate usually within a few days.

Advantages of PRK

Since PRK completely removes the outer corneal layer, there is a greater area of the cornea to work with. This is ideal for patients with a thin cornea who would otherwise be at risk with LASIK. It is also usually recommended for patients with chronic dry eyes. With PRK, there is also less risk of infection or issues having to do with the flap and the related healing process. This is an advantage for individuals who lead a lifestyle in which they are at risk for eye injuries (athletes, military, law enforcement etc.) which may subject the flap to injury or complications.

So, Why Is LASIK More Popular?

The main advantages that LASIK has over PRK are two-fold and mainly have to do with comfort and recovery time. First of all, PRK patients usually experience slightly more discomfort during the first couple of days of recovery, mainly because it takes time for the outer corneal layer to heal. They will be prescribed eye drops to be taken for several months to prevent infection, increase comfort and assist the healing process. LASIK patients on the other hand, typically experience less discomfort and if they do, it subsides very quickly.

Additionally, vision recovery takes longer with PRK. While LASIK patients can typically see normally within a few hours after the surgery, with vision gradually continuing to improve within the next few months, PRK patients may experience blurred vision for up to three days and it can take up to six months until they achieve full visual clarity. While patients who undergo LASIK can usually drive and resume normal functioning within a day or two, PRK patients shouldn’t plan on returning to normal for at least several days until the outer layer of the cornea has grown back.

Whether PRK or LASIK is a better option for you depends on a number of factors, including the health and structure of your eye. This is a decision that your eye doctor or surgeon will help you make. Rest assured however, that both procedures have been shown to be incredibly successful in correcting vision, with minimal complications.

What You Need to Know About PRK

Prior to any laser correction surgery, you will meet with a surgeon for a thorough exam to assess your eye health and determine whether you are a candidate and if so, which type of surgery would be best suited to your needs. During this exam it is essential to tell the doctor any relevant medical history (injuries, hospitalizations, diseases etc.) and existing conditions you have. The surgeon will determine if you are currently eligible for surgery and if not, if you will be at a future point, and whether you require any specialized care pre or post surgery.

The surgery itself is an ambulatory procedure. It takes about 15 minutes or less for both eyes and you go home the same day. You will need someone to drive you home from the procedure.

The first step in the procedure is that your eye will be anesthetized using numbing eye drops and then a device will be inserted to prop your eyelids open so you won’t blink. Once the eye is numb, the surgeon will remove the outer epithelial layer of the cornea to expose the underlying tissue. Then the surgeon will use the laser to reshape the corneal tissue. You may feel a small amount of pressure during this step. Lastly, the surgeon will apply medicated eye drops and place a temporary contact lens that is used as a bandage to protect the eye.

Following the surgery you will be instructed to apply medicated eye drops multiple times each day to reduce the risk of infection and you may also be given prescription pain relievers to alleviate any pain or discomfort.

As with any type of surgery, it is critical to carefully follow your surgeon’s instructions after PRK. Make sure that you take your medication as prescribed, get enough rest, and call your eye doctor immediately if you experience any problems.

It is normal for it to take several days or even weeks for your vision to improve and up to 3-6 months for full recovery to clear and stable visual acuity. Usually, your doctor will require you to refrain from driving for a week and up to three weeks depending on how fast your vision recovers.

Risks and Complications of PRK

While serious complications are rare, like any surgery, there are some risks to PRK, and these happen to be very similar to any laser corrective surgery like LASIK. They include:

  • Dry eyes- this condition usually goes away within a couple of months, but there is a chance that it could become chronic.
  • Infection or Inflammation- the risk of infection is greatly reduced if you take proper care to follow your doctor’s instructions following the procedure.
  • Vision Problems- which can include glare, seeing halos around lights poor night vision and sometimes a general haziness.
  • Incomplete Vision Correction – sometimes an additional procedure might be needed to achieve optimal visual acuity.

In general, PRK is considered to be a relatively safe and effective treatment for vision correction. If you wish to live a life without depending on your glasses or contact lenses, speak to your eye doctor about whether PRK is an option for you.

Preparing for an Eye Exam

For both adults and children, an eye exam is a critical part in maintaining your overall health and well-being, and therefore, regular eye exams should be incorporated into your health routine. Comprehensive eye exams assess your vision and the health of your eye, looking for early signs of disease that may not have obvious symptoms. You should not wait until you experience a vision problem or symptoms of an eye condition to schedule a routine exam.

Depending on your age, family history, general health and eye health, it is recommended to have an eye exam every one to two years. Of course if you experience any serious symptoms that affect your eyes or your vision, you should contact your eye doctor immediately.

The Difference Between an Optometrist (OD) and an Ophthalmologist (MD or DO)

Confusion about the difference between optometrists and ophthalmologists is common, and many people are not aware of how the two eye care professionals differ.

Optometrists

Optometrists or Doctors of Optometry attend optometry school which is usually at least four years of graduate level training. They are able to perform eye exams, provide prescriptions for eyeglasses and contact lenses, and diagnose and treat eye diseases as as glaucoma, dry eyes, or eye infections that may require medication or drops. They can consult with and co-manage patients in pre- or post-op surgical care, however they do not perform surgery.

Ophthalmologists

Ophthalmologists are medical doctors that attend medical school and later specialize in ophthalmology. They are able to do all of the services mentioned above but also perform eye surgeries such as cataract surgery, refractive surgery such as LASIK and deal with more urgent eye conditions such as retinal detachment.

Infant and Child Eye Exams

According to the American Optometric Association (AOA) children should have their eyes examined by an eye doctor at 6 months, 3 years, at the start of school and then at least every 2 years following. If there are any signs that there may be a vision problem or if the child has certain risk factors (such as developmental delays, premature birth, crossed eyes, family history or previous injuries) more frequent exams are recommended. A child that wears eyeglasses or contact lenses should have his or her eyes examined yearly.

Adult Eye Exams

Healthy adults under 40 with good vision and who do not wear eyeglasses or contact lenses are recommended to have an eye exam at least every two years. Those that do use vision correction or have a health issue such as diabetes, high blood pressure or another health condition that can have an impact on your eye health should schedule a yearly exam, unless the eye doctor recommends more frequent visits.

Once you reach 40, you become susceptible to a number of age-related eye conditions such as presbyopia, cataracts or macular degeneration, therefore annual or bi-annual exams are strongly recommended.

As you continue to age, particularly after age 55, the risks of eye disease increase, and early detection can be critical to preventing significant vision loss or blindness. Scheduling a yearly eye exam can make all the difference in maintaining your independence and quality of life.

How to Prepare for Your Exam

Prior to your exam you should decide whether you will be seeking special services such as a contact lens exam or LASIK consultation. These services may cost extra. Check with the doctor’s office or your insurance provider to see if they cover any of the exam expenses.

You need to know if you have medical insurance, vision plan coverage or both. Medical insurance usually does not cover “wellness/refractive” exams for glasses or contact lenses. Vision plans will cover exams for glasses or contacts, but usually cannot be used for red eyes, floaters, or other medical eye health problems. Please bring your insurance cards with you.

In addition to bringing your current pair of glasses or contacts if applicable, it is important to be aware of your personal and family history and to have a list of medications or supplements you are currently taking. Your pupils will probably be dilated as apart of your exam, so plan accordingly.

Your Comprehensive Eye Exam

Your eyes are one of the most complex organs in your body. A comprehensive eye exam to assess your visual system and eye health involves a number of different of tests. Unlike a simple vision screening, which only assesses your vision, a comprehensive eye exam includes a battery of tests in order to do a complete evaluation of the health of your eyes and your vision.

The tests that you will undergo in a comprehensive eye examination may vary from eye doctor to eye doctor but here are are some common exams that you may encounter:

Patient Background and History

One of the most important parts in a comprehensive eye exam is your patient health history. This information will alert your doctor to any conditions that should be monitored closely, such as an allergy to any medications, current or family history of systemic or eye pathology or environmental conditions that could be affecting your vision or eye health. This will also help your doctor to determine any preventative eye care measures that are relevant to keep your eyes healthy for years to come.

Visual Acuity

Visual acuity is a measurement of your vision using an eye chart, the Snellen Eye Chart. In this test the patient is seated at a standard distance and is asked to read letters or symbols of various sizes, which get smaller as you move down the chart. The results are the familiar ratio of 20/20, 20/40 etc. which is a comparison of your vision compared to the average person with good vision, which is typically 20/20. For example, a patient that has 20/40 vision, can only see at 20 feet what the normal person can see from a distance of 40 feet. This test is a preliminary test of how clearly you are seeing in each eye but it does not give you a prescription for corrective lenses.

Refraction

Those who don’t have 20/20 vision have what is referred to in most cases as a “Refractive Error.” The patient may have nearsightedness, farsightedness, astigmatism or other eye conditions that prevent the patient from seeing 20/20. A refraction will tell the doctor which prescription lenses will correct your eyesight to achieve 20/20 vision or whichever amount your vision is correctable to.

A refraction may include a couple of steps.

Retinoscopy

Retinoscopy is a test that allows the doctor to obtain an approximate prescription for eyeglasses. In this test the doctor uses a hand-held instrument called a retinoscope that shines a light into the patient’s eye. The doctor then analyzes the reflex of the light from the patient’s eye to determine the patient’s prescription for glasses.

An instrument called a phoropter is something most patients associate with an eye exam. This space age appearing instrument, positioned in front of the patient’s face during the eye exam, gives the doctor the ability to determine the patient’s focusing ability as well as their eye alignment. The phoropter also determines which, out of the hundreds and hundreds of potential eyeglass prescriptions, will help the patient see as clear as possible. Using the phoropter, the doctor will ask the patient which series of lenses makes their vision the clearest.

While retinoscopy is quite effective for children and nonverbal patients, there are now a number of computerized or automated instruments available today to help doctors accurately determine a patient’s eyeglass prescription.

Autorefractors and Aberrometers

Autorefractors and aberrometers are computerized machines that are able to measure your refractive error to determine your prescription for glasses or contact lenses. These instruments are usually used in addition to testing described earlier:

– An autorefractor is similar to retinoscopy, which electronically analyses the light reflex from the patient’s eye.

– An aberrometer measures distortions or aberrations in the cornea and lens of the eye that disrupt proper focus of light on the retina. Using wavefront technology, the instrument measures the rays of light as they pass through your eye to look for imperfections which may indicate a refractive error.

Eye Focusing and Eye Teaming Tests

During the comprehensive eye exam, your eye doctor will also want to test how your eyes function individually and together from a mechanical perspective. In order to see clearly and comfortably, your eyes need to work together as a team.

Eye Health

The final and most important aspect of a comprehensive eye exam is a check of your overall eye health. These tests (below) are done to identify any eye conditions or diseases, both inside the eye as well as the external parts of the eye, that could affect your vision and general health.

Slit Lamp Test

The slit lamp or biomicroscope is an instrument that allows the doctor to examine the internal and external parts of the eye in detail, such as the conjunctiva, iris, lens, cornea, retina and the optic nerve. The patient rests their forehead and chin on a headrest to stabilize the head, while the doctor looks into the eye with the slit lamp microscope, which is magnified with a high-intensity light. A slit lamp test enables the doctor to evaluate the eyes for signs of normal aging and eye pathology, such as conjunctivitis, cataracts, macular degeneration or retinal detachment. Early diagnosis and treatment of eye diseases are essential for preventing vision loss.

Tonometry

Tonometry is a test to detect glaucoma by measuring the pressure inside your eye or IOP (intraocular pressure). Glaucoma can cause vision loss and even blindness if the IOP in the eye is too high and damages the optic nerve.

The applanation tonometer, typically attached to a slit lamp, is one of the most common instruments used to measure the pressure in the eye. Prior to doing this test the doctor will numb the patient’s eyes using an anesthetic, before gently applanating (putting pressure on) the patient’s cornea to measure the pressure in the eye.

Pupil Dilation

During your comprehensive eye exam, your doctor may decide to do a dilated eye exam. In this test, your doctor will instill dilating drops in each eye, which would enlarge your pupils to give the doctor a better view of certain parts of the back of the eye. Dilation is done at the discretion of the doctor, with some patients dilated every year and others at specified intervals; the frequency of dilation will vary for each patient.

Typically the drops take around 20 to 30 minutes to take effect and may last up to several hours following the exam; each patient is different. Since more light enters your eyes when your pupils are dilated, you will be more sensitive to bright light, especially sunlight. Although your doctor may provide disposable sunglasses, you may want to bring a pair of sunglasses to wear after the exam to make it more comfortable until the drops wear off.

A comprehensive eye exam is an important part of your overall general health maintenance and should be scheduled on a regular basis. The findings from your comprehensive eye exam can give your doctor important information about your overall health, particularly diabetes and high blood pressure.

Eye Exams for Contact Lenses

Contact lenses are a great alternative to wearing eyeglasses. An often unknown fact is that not all patients wear contact lenses as their primary source of vision correction. Each patient is different, with some patients wearing contact lenses only on weekends, special occasions or just for sports. That is the beauty of contact lens wear, the flexibility it gives each individual patient and their lifestyle.

If you decide to opt for contact lens wear, it is very important that the lenses fit properly and comfortably and that you understand contact lens safety and hygiene. A contact lens exam will include both a comprehensive eye exam to check your overall eye health, your general vision prescription and then a contact lens consultation and measurement to determine the proper lens fit.

The Importance of a Comprehensive Eye Exam

Whether or not you have vision problems, it is important to have your eyes checked regularly to ensure they are healthy and that there are no signs of a developing eye condition. A comprehensive eye exam will check the general health of your eyes as well as the quality of your vision. During this exam the eye doctor will determine your prescription for eyeglasses, however this prescription alone is not sufficient for contact lenses. The doctor may also check for any eye health issues that could interfere with the comfort and success of contact lens wear.

The Contact Lens Consultation

The contact lens industry is always developing new innovations to make contacts more comfortable, convenient and accessible. Therefore, one of the initial steps in a contact lens consultation is to discuss with your eye doctor some lifestyle and health considerations that could impact the type of contacts that suit you best.

Some of the options to consider are whether you would prefer daily disposables or monthly disposable lenses, as well as soft versus rigid gas permeable (GP) lenses. If you have any particular eye conditions, such as astigmatism or dry eye syndrome, your eye doctor might have specific recommendations for the right type or brand for your optimal comfort and vision needs.

Now is the time to tell your eye doctor if you would like to consider colored contact lenses as well. If you are over 40 and experience problems seeing small print, for which you need bifocals to see close objects, your eye doctor may recommend multifocal lenses or a combination of multifocal and monovision lenses to correct your unique vision needs.

Contact Lens Fitting

One size does not fit all when it comes to contact lenses. Your eye doctor will need to take some measurements to properly fit your contact lenses. Contact lenses that do not fit properly could cause discomfort, blurry vision or even damage the eye. Here are some of the measurements your eye doctor will take for a contact lens fitting:

Corneal Curvature

In order to assure that the fitting curve of the lens properly fits the curve of your eye, your doctor will measure the curvature of the cornea or front surface of the eye. The curvature is measured with an instrument called a keratometer to determine the appropriate curve for your contact lenses. If you have astigmatism, the curvature of your cornea is not perfectly round and therefore a “toric” lens, which is designed specifically for an eye with astigmatism, would be fit to provide the best vision and lens fit. In certain cases your eye doctor may decide to measure your cornea in greater detail with a mapping of the corneal surface called corneal topography.

Pupil or Iris Size

Your eye doctor may measure the size of your pupil or your iris (the colored area of your eye) with an instrument called a biomicroscope or slit lamp or manually with a ruler or card. This measurement is especially important if you are considering specialized lenses such as Gas Permeable (GP) contacts.

Tear Film Evaluation

One of the most common problems affecting contact lens wear is dry eyes. If the lenses are not kept adequately hydrated and moist, they will become uncomfortable and your eyes will feel dry, irritated and itchy. Particularly if you have dry eye syndrome, your doctor will want to make sure that you have a sufficient tear film to keep the lenses moist and comfortable, otherwise, contact lenses may not be a suitable vision option.

A tear film evaluation is performed by the doctor by putting a drop of liquid dye on your eye and then viewing your tears with a slit lamp or by placing a special strip of paper under the lid to absorb the tears to see how much moisture is produced. If your tear film is weak, your eye doctor may recommend certain types of contact lenses that are more successful in maintaining moisture.

Contact Lens Trial and Prescription

After deciding which pair of lenses could work best with your eyes, the eye doctor may have you try on a pair of lenses to confirm the fit and comfort before finalizing and ordering your lenses. The doctor or assistant would insert the lenses and keep them in for 15-20 minutes before the doctor exams the fit, movement and tearing in your eye. If after the fitting, the lenses appear to be a good fit, your eye doctor will order the lenses for you. Your eye doctor will also provide care and hygiene instructions including how to insert and remove your lenses, how long to wear them and how to store them if relevant.

Follow-up

Your eye doctor may request that you schedule a follow-up appointment to check that your contact lenses are fitting properly and that your eyes are adjusting properly. If you are experiencing discomfort or dryness in your eyes you should visit your eye doctor as soon as possible. Your eye doctor may decide to try a different lens, a different contact lens disinfecting solution or to try an adjustment in your wearing schedule.

Eye Exams for Children

According to experts, 80% of learning is visual, which means that if your child is having difficulty seeing clearly, his or her learning can be affected. This also goes for infants who develop and learn about the world around them through their sense of sight. To ensure that your children have the visual resources they need to grow and develop normally, their eyes and vision should be checked by an eye doctor at certain stages of their development.

According to the American Optometric Association (AOA) children should have their eyes examined by an eye doctor at 6 months, 3 years, at the start of school, and then at least every 2 years following. If there are any signs that there may be a vision problem or if the child has certain risk factors (such as developmental delays, premature birth, crossed or lazy eyes, family history or previous injuries) more frequent exams are recommended. A child that wears eyeglasses or contact lenses should have his or her eyes examined yearly. Children’s eyes can change rapidly as they grow.

Eye Exams in Infants: Birth – 24 Months

A baby’s visual system develops gradually over the first few months of life. They have to learn to focus and move their eyes, and use them together as a team. The brain also needs to learn how to process the visual information from the eyes to understand and interact with the world. With the development of eyesight, comes also the foundation for motor development such as crawling, walking and hand-eye coordination.

You can ensure that your baby is reaching milestones by keeping an eye on what is happening with your infant’s development and by ensuring that you schedule a comprehensive infant eye exam at 6 months. At this exam, the eye doctor will check that the child is seeing properly and developing on track and look for conditions that could impair eye health or vision (such as strabismus(misalignment or crossing of the eyes), farsightedness, nearsightedness, or astigmatism).

Since there is a higher risk of eye and vision problems if your infant was born premature or is showing signs of developmental delay, your eye doctor may require more frequent visits to keep watch on his or her progress.

Eye Exams in Preschool Children: 2-5

The toddler and preschool age is a period where children experience drastic growth in intellectual and motor skills. During this time they will develop the fine motor skills, hand-eye coordination and perceptual abilities that will prepare them to read and write, play sports and participate in creative activities such as drawing, sculpting or building. This is all dependent upon good vision and visual processes.

This is the age when parents should be on the lookout for signs of lazy eye (amblyopia) – when one eye doesn’t see clearly, or crossed eyes (strabismus) – when one or both eyes turns inward or outward. The earlier these conditions are treated, the higher the success rate.

Parents should also be aware of any developmental delays having to do with object, number or letter recognition, color recognition or coordination, as the root of such problems can often be visual. If you notice your child squinting, rubbing his eyes frequently, sitting very close to the tv or reading material, or generally avoiding activities such as puzzles or coloring, it is worth a trip to the eye doctor.

Eye Exams in School-Aged Children: Ages 6-18

Undetected or uncorrected vision problems can cause children and teens to suffer academically, socially, athletically and personally. If your child is having trouble in school or afterschool activities there could be an underlying vision problem. Proper learning, motor development, reading, and many other skills are dependent upon not only good vision, but also the ability of your eyes to work together. Children that have problems with focusing, reading, teaming their eyes or hand-eye coordination will often experience frustration, and may exhibit behavioral problems as well. Often they don’t know that the vision they are experiencing is abnormal, so they aren’t able to express that they need help.

In addition to the symptoms written above, signs of vision problems in older children include:

  • Short attention span
  • Headaches
  • Frequent blinking
  • Avoiding reading
  • Tilting the head to one side
  • Losing their place often while reading
  • Double vision
  • Poor reading comprehension

The Eye Exam

In addition to basic visual acuity (distance and near vision) an eye exam may assess the following visual skills that are required for learning and mobility:

  • Binocular vision: how the eyes work together as a team
  • Focusing
  • Peripheral Vision
  • Color Vision
  • Hand-eye Coordination
  • Tracking

The doctor will also examine the area around the eye and inside the eye to check for any eye diseases or health conditions. You should tell the doctor any relevant personal history of your child such as a premature birth, developmental delays, family history of eye problems, eye injuries or medications the child is taking. This would also be the time to address any concerns or issues your child has that might indicate a vision problem.

If the eye doctor does determine that your child has a vision problem, they may discuss a number of therapeutic options such as eyeglasses or contact lenses, an eye patch, vision therapy or Ortho-k, depending on the condition and the doctor’s specialty. Since some conditions are much easier to treat when they are caught early while the eyes are still developing, it is important to diagnose any eye and vision issues as early as possible.

Following the guidelines for children’s eye exams and staying alert to any signs of vision problems can help your child to reach his or her potential.

Controlling Nearsightedness in Children

Childhood myopia or nearsightedness is a common condition that causes blurred distance vision and can usually be easily corrected with either glasses or contact lenses. Unfortunately, simply getting a pair of glasses doesn’t always solve the problem, because often myopia is progressive which means that every year the vision gets worse. This usually continues until sometime around the child’s 20th birthday when his eyes stop growing and eyesight levels off.

It can be worrisome and quite disconcerting for both the parent and the child when each visit to the eye doctor results in a higher prescription. There could be a number of factors involved in progressive myopia, involving hereditary factors as well as possible environmental or behavioral factor such as frequent close-up tasks such as reading or using an electronic device. In fact, studies show that children that spend more time outdoors playing have a lower incidence of myopia. Much research is currently being done into treatments for slowing or stopping myopia progression in children. Here are some of the treatment options currently being offered:

Orthokeratology (Ortho-k)

Ortho-k is a process that uses specially designed rigid gas permeable contact lenses worn at night to gently reshape the cornea, eventually allowing clear vision during the day. The lenses are worn every night or every couple of nights depending on the results of the individual. Ideal for mild to moderate myopia, ortho-k usually takes a few weeks to show results, during which time the patient may need to temporarily continue wearing glasses or contact lenses.

Studies show that the use of ortho-k can permanently reduce the progressive lengthening of the cornea which is responsible for nearsightedness and can therefore slow or stop the childhood progression of the condition. Therefore, in addition to being used for myopia correction, it is now also being offered as a therapeutic treatment to halt myopia progression in children.

Multifocal Eyeglasses or Contact Lenses

Bifocal or multifocal soft contact lenses or glasses have been shown in some studies to slow myopia progression. This therapy is based on the idea that the eye is strained from accommodating to see close up and that by providing multiple focusing powers, this allows the eye to relax when doing near work, which reduces the progression of the refractive error. This treatment has been shown to delay or slow the advancement of myopia in some children.

Atropine Drops

Treatment with atropine drops is another therapy that is used to relax the eye from “focusing fatigue” which may be a culprit in myopia progression. Research is still being done but some studies show that daily use of low doses of atropine drops do slow the progression of myopia. Atropine drops dilate the pupil which temporarily prevents the eye from being able to focus, thereby allowing this mechanism to relax. Research is still being done to determine dosages, but the results are promising.

If your child has progressive myopia, seek out a pediatric optometrist who is knowledgeable about the options available. Finding the right treatment could give your child the gift of better eyesight for life.

Corrective Eye Surgery Basics

In recent years there have been tremendous advances in the field of vision correcting eye surgery which is also known as refractive or laser surgery. Corrective eye surgery offers patients clear vision without the use of glasses and contact lenses. There are a number of types of refractive surgeries that are able to correct different vision problems, so if you are considering surgery here are some of the options you should know about.

LASIK

LASIK (laser-assisted in situ keratomileusis) surgery is perhaps the most well-known refractive surgery today. LASIK can help patients with myopia (nearsightedness), hyperopia (farsightedness) and astigmatism. During the procedure, the doctor makes a flap in the outer layer of the corner to reach the underlying tissue and then uses a laser to reshape the tissue which allows the cornea to then focus light properly. The procedure is usually painless and vision is usually clear within a few hours.

Recent advances in the field have developed subcategories of LASIK surgery such as Bladeless LASIK, which uses a laser rather than a mechanical tool to make the initial flap or Wavefront (custom) LASIK which uses computer mapping to guide the reshaping of the cornea and is able to create a much more precise visual correction for very subtle optical imperfections. There is also a procedure called Epi-LASIK in which following the procedure, the doctor applies a soft contact lens to protect the surgical area, holding the flap in place while it heals.

PRK

PRK (photorefractive keratectomy) also uses a laser to correct mild to moderate myopia, hyperopia and astigmatism. PRK was a precursor to LASIK which eliminated many of the complications of prior surgeries such as glare, seeing halos around lights, blurred vision and regression of vision. Unlike LASIK, the procedure only reshapes the surface of the cornea and not the underlying tissue. Consequently, there is often some discomfort for a couple of weeks until the outer layer of the cornea heals. Additionally, the patient may experience blurred vision during this period of healing. PRK does offer an advantage over LASIK in that there is less risk of certain complications. Wavefront technology is also available for PRK surgeries.

Due to the increased comfort of LASIK there was a period that PRK saw a decline. Recent studies show however that LASIK and PRK have similar long-term success for improved visual acuity and with the assistance of newly developed effective pain medications, PRK has become more popular again as an option.

LASEK

In LASEK or laser-assisted sub-epithelial keratomileusis, the doctor creates a flap smaller but similar but to LASIK, and then uses an alcohol solution to loosen the tissue around the cornea which is pushed aside, and then a laser is used to reshape the cornea itself. In an Epi-LASEK procedure, the doctor may apply a soft contact lens to hold the flap in place to assist in reattaching to the cornea as the eye heals. Patients that undergo LASEK generally experience less discomfort and quicker vision recovery than PRK patients. LASEK may be preferred over LASIK as a safer option for patients with a thin cornea.

Cataract Surgery

Cataract Surgery is a very common refractive surgery that removes the clouded natural lens of the eye and replaces it with an artificial lens called an IOL (intraocular lens). Many patients these days will receive a lens that also corrects any refractive error they have such as nearsightedness, farsightedness or presbyopia.

RLE

RLE or refractive lens exchange is a non-laser procedure the replaces the natural lens of the eye. This is the same as the surgery that is used to treat cataracts, ,yet for non-cataract patients, RLE is used to correct severe nearsightedness or farsightedness. The procedure involves the doctor making a small cut in the cornea, removing the natural lens and replacing it with usually a silicon or plastic lens. It is particularly useful for patients with minor corneal problems such as thin corneas or dry eyes.

RLE is more risky than the other procedures mentioned and can affect the patient’s ability to focus on close objects, possibly requiring reading glasses following the procedure. However, in cases of severe vision correction it is often the preferred method.

PRELEX

PRELEX or presbyopic lens exchange is for patients with presbyopia, the age-related condition in which you lose the flexibility of your lens and can no longer focus on close objects. Patients that prefer not to wear reading glasses or multifocals, can opt for a procedure in which the doctor removes the natural lens of your eye and replaces it with a multifocal artificial lens. This procedure is often done in conjunction with cataract surgery.

Phakic Intraocular Lens Implants

Phakic IOLs are implants that are used for individuals with very high nearsightedness who do not qualify for LASIK or PRK. The implant is attached to your iris or inserted behind your pupil, while the natural lens remains intact. Because this is a procedure that involves the inner eye, it is more risky than LASIK or PRK and is therefore also typically more expensive.

Conductive Keratoplasty (CK)

CK uses a hand-held radio wave device to shrink tissue on the cornea to reshape it. The procedure is typically used to treat mild farsightedness and presbyopia, particularly for patients who have already undergone LASIK.

Any surgical procedure has risks and may have some side effects or complications that you should research before you decide to go ahead with the surgery. Nevertheless, as technology advances these complications are being significantly reduced making refractive surgery a great option for vision correction in many patients.

LASIK

LASIK or laser-assisted in situ keratomileusis is a refractive surgery that is used to correct myopia (nearsightedness), hyperopia (farsightedness) and astigmatism as an alternative to eyeglasses or contact lenses. LASIK is currently the most common of the refractive eye surgeries, largely because of the relatively low risk and the quick recovery and improvement in eyesight.

Also known as laser eye surgery or laser vision correction, LASIK uses a laser to reshape the cornea which is responsible for clear vision. The procedure is quick and relatively painless and eyesight is usually improved to 20/20 vision within one day of the surgery.

How Does LASIK Work?

LASIK is an outpatient procedure, which takes about 15 minutes for the actual surgery on both eyes and an hour total with recovery. A topical anesthetic drop is used and there is no need for bandaging or stitches following the procedure. The doctor will start by stabilizing the eye and then making a small flap in the outer layer of the cornea. Then with access to the underlying tissue, he uses a laser to reshape the corneal tissue and re-closes the flap, which will heal on its own. The nature of the corneal reshaping depends on the type of refractive error.

Wavefront LASIK

Wavefront LASIK uses computer mapping technology to guide the laser treatment based on the precise shape of the cornea. This can correct very precise issues, provide much sharper vision than non-wavefront LASIK and can reduce complications such as halos, glare and problems seeing at night.

What to Expect During and After LASIK?

During the procedure you may feel some pressure on your eye while the laser is working. Immediately following you will likely experience some blurriness and may feel burning or itching (be sure not to rub your eyes!). For your journey home you will be given protective shields to guard your eyes and will need someone to drive you. You will also be prescribed medicated eye drops for a week or so to aid in healing and prevent infection. Your doctor may also recommend artificial tears to moisten the eyes and keep them comfortable in the days following the procedure.

The day after the surgery you will be asked to visit your eye doctor (or the surgeon) for a checkup and to evaluate whether you are able to drive. Most people experience an improvement in vision by then, although for some it can take a few days or even a week. Your eyes may be sensitive to light for a day or two as well. You will likely be advised to rest for a day or two and to refrain from strenuous physical activity for about a week until further healing has taken place.

Most people achieve at least 20/20 vision following the surgery, although this can vary and there are cases where 20/40 vision is obtained or where people continue to wear glasses or contacts with a much lesser prescription. Some patients have light sensitivity, particularly when driving at night, also suffering from seeing halos around lights or glare. There are glasses and lenses available to reduce this glare and assist with night driving.

For some, it can take weeks or even months until the vision completely stabilizes. Occasionally, after a few months, patients who do not experience perfect results will schedule an enhancement or touch up surgery to correct the vision even further.

Am I a Candidate for LASIK?

The ideal LASIK candidate is a patient over 18 with generally healthy eyes. Since the procedure involves shaping the cornea by removing some of the tissue, it is not ideal for individuals with a thin cornea or any sort of corneal condition or disease. Patients with chronic dry eyes might also be disqualified as LASIK can often exacerbate these symptoms.

During a comprehensive eye exam your eye doctor will assess your eligibility by looking at the general health of your eye including your cornea, your pupil, the moisture in your eye, the type of refractive error you have and whether you have any other eye conditions of concern.

For the right candidate, LASIK can offer a lifestyle improvement in giving clear vision without the need for glasses or contact lenses, however, the results are not guaranteed. You and your eye doctor need to weigh the benefits and the potential risks based on your personal needs.

LASIK Risks and Complications

LASIK is the most common refractive eye surgery, partially due to the fact that the risks and complications are low. The majority of patients don’t experience any long term complications as a result of the surgery. Nevertheless, as with any surgical procedure there are some risks, however rare they are and it is important to know them and to discuss them with your eye doctor or surgeon prior to undergoing the surgery.

Side effects of LASIK

There are a number of side effects that are somewhat common immediately post-op and in some instances can last longer – sometimes indefinitely. Those include:

Dry Eyes

About half of LASIK patients experience dry eyes, which are usually a temporary side effect that resolves within 3-6 months after the surgery. Your doctor will likely prescribe artificial tears in the days and weeks following the surgery which should be continued as long as the symptoms persist. Because of this, it is usually recommended that patients with a history of chronic dry eyes opt for another type of refractive surgery such as PRK, another style of laser refractive surgery with reduced risk.

Eye Infection or Irritation

While not common due to the eye drops and checkups prescribed post surgery, there is a chance of developing an eye infection. If this does occur, it can be treated with antibiotic eye drops, anti-inflammatories or sometimes may require other treatment such as oral antibiotics. If you are experiencing symptoms of an eye infection such as redness, pain, discomfort, discharge or any change in vision, see your eye doctor immediately. As a precaution, it is imperative to follow your surgeon’s instructions for your post-operative care including prescription medications and doctor’s visits.

Vision Issues

Following surgery, you may experience certain vision issues such as such as poor night vision, double vision, halos around lights or glare. These side effects are common and can last up to a few weeks, but typically go away. Some patients report a lasting reduction in vision in low light conditions and may require vision aids for seeing better at night.

Other risks of LASIK include surgical errors, many of which can be corrected by a follow-up surgery. These include:

Overcorrection or Undercorrection

The key to vision improvement in LASIK is accurate reshaping of the corneal tissue. If too much is removed or not enough is removed, your vision will remain imperfect and when possible may require a follow up procedure to obtain the clear vision being sought.

Flap Complications

Perhaps the greatest risk involved in LASIK is the accurate creation and healing of the flap of the cornea that is lifted to reshape the underlying tissue and replaced after. If the flap in the cornea is not made accurately, cut too thick or too thin and not carefully replaced back on the eye, it can cause complications in the shape of the eye surface and therefore clear vision. Studies indicate that these complications occur usually in under 6% of cases and the experience and skill of the surgeon play a large role.

There can also be complications in the healing process of the flap which include infection or excessive eye tearing.

Vision Loss

There is a chance, albeit small that the surgery can result in a loss of vision or reduction in visual clarity due to complications with the surgery.

It is quite rare for any permanent damage or vision loss to occur as a result of LASIK and usually any vision problems can be corrected by a follow-up procedure. However, as with any surgical procedure, there are risks, so it is important to reduce your risks by finding an experienced surgeon and carefully considering your suitability for the surgery in the first place.

LASIK – How to Measure Success or Applicability

Is laser eye surgery for everyone?

Below are some guidelines to help you decide if LASIK is a good choice for you.

  • Vision stability: Young adults often experience annual changes in their prescription for eyeglasses or contact lenses. A 12-month period of maintaining the same prescription is highly recommended prior to LASIK. Otherwise there is a considerable risk of requiring repeated LASIK surgery in the future.
  • Healthy Eyes: Problems, diseases or conditions related to your eyes could cause increased risks to both the actual surgery and the healing process. If you have a condition that can be treated such as dry eyes, pink eye (conjunctivitis) or any eye injury speak to your doctor. It is probably best to wait until the condition is resolved to schedule your LASIK surgery. Conditions like cataracts, glaucoma, and other more serious conditions may disqualify you from LASIK altogether.
  • Age: 21 is the minimum age of consent for LASIK. Younger patients may be able to get special exemptions based on certain circumstances.
  • Vision prescription range: A very high degree of myopia may require removal of too much corneal tissue. This may exclude your candidacy for LASIK or make another refractive surgery a better option. For example, many surgeons conclude that a phakic IOL procedure provides better results and possesses less risk than LASIK for nearsighted prescriptions higher than -9.00 diopters.
  • Pregnancy: Normal hormonal changes of pregnancy may cause swelling of the cornea which can alter vision. Dry eye is also common during pregnancy. Additionally, medications (antibiotics or steroids) which are administered for LASIK could cause risk to the embryo or nursing infant. It is recommended to delay LASIK for several months after childbirth until the eyes stabilize and risks are reduced.
  • Systemic and autoimmune diseases such as rheumatoid arthritis, type 1 diabetes, HIV or AIDS may disqualify or delay candidacy for LASIK. If your body has trouble healing, your cornea may not heal properly after LASIK surgery. Opinions vary among professionals as far as which diseases automatically disqualify and which ones pose acceptable risks. Discuss this in depth with your doctor if applicable.