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                                      Laser Surgery
Part 2

PRK Surgery
                                      Is it right for you?
                                                                 Primary Eye Care Centre
How the Eye Functions                                       Dr. R.M. McMorris & Dr. J.D. John
• The cornea provides 2/3 of                                     #205 – 52 High St. W.
   the eyes focusing power. The                                 Moose Jaw, Sask. S6H 1S3
   shape of the cornea, the                         306-693-8584 e-mail:
   power of the lens inside the
   eye, and the length of the         Our Mission
   eyeball are the three variable
   focusing elements.                 To provide the highest quality of care to every refractive surgery patient. This means
                                      providing both the safest and the most proven of technologies. It also means delivery
• Due to hereditary & develop-        of these services to the patient from an environment to which they will have timely
   mental factors, many eyes          access if needed. It means thorough examination, reporting and consultation with
   develop imperfectly, result-
                                      your surgeon. Our optometrists have developed a superior pre and post-operative
   ing in focusing problems.
                                      care protocol, and believe you should accept nothing less. As such, we offer co-
• Nearsightedness is the most         managed care with laser centres that share our standards of care. Although compli-
   common focusing problem.           cations are rare, they do occur, and we will not compromise where you and your eyes
   This occurs when light rays        are concerned.
   entering the eye are focused                                                          Sincerely ,
   in front of the retina instead
   of directly on it. By surgically
   altering the cornea’s shape                                                          Drs McMorris & John
   this can be corrected.

                                      What is PRK?
                                      PRK is a surgical procedure intended to reduce a person’s dependency on
                                      glasses or contact lenses. PRK stands for Photorefractive Keratectomy
                                      and is a procedure that permanently changes the shape of the cornea,
                                      the clear covering of the front of the eye. The surgeon uses a computer
Inside this issue:                    controlled instrument called an Excimer Laser to produce a cool beam of
                                      ultraviolet light. Pulses from the laser evapo-
Our Mission                      1    rates a pre-determined microscopic amount
What is PRK?                     1    of tissue to reshape the front surface of the
                                      cornea. After the procedure you will wear a
What are the Benefits & Risks?   2    contact lens, as a bandage for a few days, un-
When is PRK Not for me?          3
                                      til the surface layer of the cornea regener-
                                      ates. PRK is an outpatient surgery done un-
What Should I Expect ?           5    der local anesthesia.
Laser Surgery checklist
                                                                                            The Excimer Laser removes microscopic
                                                                                            amounts of tissue to reshape the cornea.
Informed Consent

What are the Benefits, Risks and Alternatives to PRK
This information is not intended to be a substitute for a thorough discussion with your eye doctor
about whether this treatment is right for you.
Please read this carefully and then talk to your eye doctor.
Advantages of PRK
•   This procedure has been successfully performed in Canada since 1990. Data regarding long
    term safety of PRK has been well documented since that time.

Risks and Complications
Transient complications: The following complications have been reported in the first month after
PRK. They are associated with the normal post-treatment healing process and include: post-
treatment pain (first 24 to 48 hours), corneal swelling, double vision, feeling something is in the
eye, shadow images, light sensitivity, tearing and pupil enlargement. These symptoms are tempo-
rary and occur in many patients during the early post-treatment period.
Long Term Post-treatment Adverse Events: The following is a list of adverse
events reported at Summit Technology’s PRK U. S. clinical trials.                    discuss with your
                                                                                     eye doctor whether
•   Anterior Stromal Reticular Haze 63%: Loss of perfect clarity of the cornea,      this treatment is
    usually not affecting vision.
                                                                                     right for you.”
•   Corneal Scarring 2-3%: Cloudiness or haze of the cornea, usually severe
    enough to affect vision.

•   Glare 10%: Glare, especially from bright lights may be seen particularly in the early months af-
    ter treatment.

• Halo 9.7%: Halo or hazy rings surrounding bright lights may be seen particularly at night after
• Induced Regular/Irregular Astigmatism: A change in astigmatism that may then distort vision
   and may or may not require patients to continue to wear glasses or contact lenses.
•   IOP Elevation 1.8%: An increase in the intraocular (inner eye) pressure due to usage of post-
    treatment medications may occur which
•   Loss of Best Spectacle Corrected Acuity 6-8%: A decrease in best corrected visual acuity with
•   Improper Correction 5%: It is possible that the treatment could result in undercorrection,
    where some degree of myopia (nearsightedness) may occur, requiring the use of glasses or

    contact lenses. Improper correction may also result in overcorrection or hyperopia, which may
    or may not require the use of glasses or contact lenses. It is possible that improper correction
    may increase dependence on reading glasses or require the use of reading glasses at an ear-
    lier age.
•   Night Vision Difficulties 1%: Tasks that are performed without difficulty during the day are per-
    formed with visual difficulty in low light or night time conditions.

The following adverse events occurred long term post-treatment in the PRK clini-
cal investigations in less than 1% of patients: blurred vision, cataract
(cloudiness of the lens), corneal epithelial defect, corneal scarring, corneal ul-   “The most common
ceration/infection, dryness of the eye, feeling something is in the eye, shadow      risks associated
images, corneal deposits, inflammation of the iris, irregular astigmatism, itch-     with PRK include
ing, double vision, patient discomfort, light sensitivity, drooping of the eyelid,
reading difficulty and corneal inflammation.                                         glare, halo, and
Alternative Procedures                                                               haze.”
Presently, alternatives to PRK surgery include the following:
• Continued use of glasses or contact lenses.
• LASIK– Laser-Assisted in Situ Keratomileusis.
• Astigmatic Keratotomy (AK) with a diamond blade.

When is PRK not for me?
• Lensectomy (with or without intraocular lens implant) - The natural crystalline lens is removed
  and may or may not be replaced with an intraocular lens implant in order to correct most of the
  refractive error.)
• Phakic IOL (Intraocular Lens) or ICL (Intraocular Contact Lens)-- insertion of an artificial lens
  without removing the crystalline lens.
• Intacs – crescent-shaped rings placed within the cornea. This procedure is reversible.

•   You are not a risk taker and expect perfection. PRK is a very low-risk procedure; but there is no
    such thing as a no-risk operation, and the same holds true for contact lenses.

•   It will jeopardize your career. Some jobs prohibit certain refractive procedures. Be sure to
    check with your employer/professional association/military service before undergoing any pro-

•   Cost is an issue. Most medical insurance will not pay for laser surgery. Although the cost has
    come down, it is still significant.
•   You have a disease or are on medications that may affect wound healing. Certain conditions,
    such as an immunodeficiency state, and some medication, such as retinoic acid and steroids,
    may prevent proper healing after a procedure.

•   The patient who will not accept the possibility of having to wear glasses or contact lenses part-
    time or even full-time following the PRK surgery.
•   The patient who cannot accept the presbyopic issue. Those who are at or above 40 years of
    age may have to use a correction for near vision following PRK. As we age the lens inside the
    eye loses its focusing ability, this is called presbyopia. Before PRK surgery, the patient who is
    presbyopic and nearsighted can take off glasses or contact lenses and see up close. It is impor-
    tant for the patient to understand that there is a trade-off, after PRK surgery has been per-
    formed, chances are that distance vision will be much better without glasses or contacts than
    it was before surgery, but reading without glasses will be much more difficult than before. If
    this would be unacceptable to you then you should not have the procedure. Monocular vision
    may be an option –i.e., one eye is corrected for distance and the other eye corrected for near

The safety and effectiveness of laser procedures has not been determined in patients with some
diseases and conditions. Beware of PRK surgery if you have a history of any of the following:
• Uncontrolled vascular disease or autoimmune diseases, because it is well known that these
   patients have difficulty in corneal healing and are more susceptible to corneal melting.
•   Women who are pregnant or nursing due to the potential for temporary fluctuation in vision
    (refraction) with pregnancy.
•   Signs of keratoconus since eyes with this condition may have unstable corneas.
•   Previous history of keloid formation because their corneal healing response is less predictable.
•   Herpes Simplex Virus or Herpes Zoster since cases of herpes reactivation have been reported
    after use of the excimer laser.
•   Uncontrolled glaucoma. The safety and effectiveness of PRK in patients with a history of glau-
    coma has not been established.
•   Long term insulin diabetics.
•   Thyroid eye disease.
•   Severe dry eyes.
•   Recurrent iritis/uveitis.
•   Patients who have previously undergone Radial Keratotomy have a higher incidence of best
    spectacle corrected visual acuity loss, glare and haze.
Other Risk Factors your Doctor will screen you for:
•   Large pupils – Younger patients and patients on certain medications may be prone to having

    large pupils under dim lighting conditions. This can cause symptoms such as glare, halos, star-
    bursts, and ghost images (double vision) after surgery. In some patients these symptoms may
    be debilitating. For example, a patient may no longer be able to drive a car at night or in cer-
    tain weather conditions, such as fog.

•   Thin Corneas – The cornea is the thin clear covering of the eye that is over the iris, the colored
    part of the eye. Most laser procedures change the eye’s focusing power, reshaping the cornea
    by removing tissue. Performing a laser procedure on a cornea that is too thin or has too few
    cells lining the back surface (endothelial cells) may result in blinding complications.
Birth Control Pills
In general, if a patient is taking birth control pills, this would not be considered a contraindication
to refractive surgery, especially if the patient has been taking the pills for a long period of time and
does not plan to stop taking them in the near future. It would be advisable for the individual who
undergoes refractive surgery, while on birth control pills, to stay on the pills for at least 3 to 6
months during the healing phase. This still may not cause significant problems, but there is an un-
known factor involved that could affect the healing process in some way during the critical healing
phase from 1 to 3 months. Also, there is a chance that if the individual went off the birth control
pills immediately after surgery and became pregnant, this could in turn possibly affect the healing
phase and outcome even more.

What Should I Expect Before, During, and After Surgery?
Before Surgery
Candidacy for PRK surgery is determined by an evaluation exam. This can be performed by your
own Optometrist. If you wear contact lenses, you must discontinue wearing the lenses prior to
your evaluation and also before the surgery (at least 2 weeks for soft lenses, 4 weeks for soft toric
lenses, gas permeable & extended wear soft contact lenses and 8 weeks for PMMA hard plastic
lenses). This is necessary in order to achieve the most accurate measurements of your natural cor-
neal curvature. You will be required to have measurements taken at the laser centre before PRK
surgery to be sure you are a suitable candidate.
You will be asked about:
•   your past and present medical and eye conditions
•   about all the medications you are taking, including over-the-counter medications
•   any medications you may be allergic to

Your Optometrist will perform a thorough eye exam and discuss:
• whether you are a good candidate
• what the risk, benefits, and alternatives of the surgery are
• what you should expect before, during and after surgery
• what your responsibilities will be before, during and after surgery

You should have the opportunity to ask questions during this discussion. This type of discussion is
called informed consent. Give yourself plenty of time to think about the informed consent discus-
sion, to review this package of information, and to have any additional questions answered before
deciding to go through with surgery and before signing the informed consent form. You should not
feel pressured by your doctor, family, friends, or anyone else to make a decision about having sur-

gery. Carefully consider the pros and cons.

If your evaluation exam proves that you qualify for surgery, your doctor will discuss surgical options
with you. In most cases, bilateral PRK is being performed. Patients are opting for both eyes to be
done on the same day for obvious reasons. However, if it is determined that you are not a good
candidate for the PRK surgery, you will be given an explanation as to the reasons why you are not a
good candidate. It may be recommended that you postpone your refractive surgery until further de-
velopments take place with PRK. You may want to consider an alternative method of refractive sur-
gery, or stay with your glasses or contacts.
Preparing for the Surgery
Note to ladies preparing for PRK surgery: please discontinue application of eye makeup, creams,
lotions and perfumes for at least one day prior to the date of surgery. These products as well as
debris along the eyelashes may increase the risk of infection during and after surgery. Your doctor
may ask you to scrub your eyelashes for a period of time before surgery to get rid of residues and
debris along the lashes.

Arrange for transportation to and from your surgery and your first follow-up visit. On the day of
surgery, your doctor may give you some medicine to make you relax and your vision may also be
blurry. Make sure someone can bring you home after surgery.

During the Surgery
Overall the surgery will take approximately 10-20 minutes. However the use of the laser beam
lasts only 15-40 seconds. You will lie on your back in a reclining chair in an exam room containing
the laser system. The laser system includes a large machine with a microscope attached to it and
a computer screen. Several numbing drops will be placed in your eye, the area around your eye will
be cleaned, and an instrument called a lid speculum will be used to hold your eyelids open.

The surgeon will ask you to look up through the bottom of the microscope. You will see colored
lights in the center of the microscope tube. The fixation light is very important in keeping your eye
positioned properly during the laser surgery. The surgeon will instruct you how and when to look at
these colored lights and will prepare you for what to expect during the actual treatment. Remem-
ber you and your surgeon are a team, cooperate with your surgeon to get the best possible result.
The treatment will begin with the surgeon using a surgical instrument to remove the outermost
layer of the cornea called the epithelium. Only after the surgeon has repositioned your head in the
chair, refocused the microscope and asked you to fixate on the colored lights will the laser treat-
ment be performed. The Excimer Laser has an eye tracker that is able to follow and compensate
for any eye movements during the procedure. After your treatment, the surgeon will place a soft
contact lens on your eye, this will act as a bandage and you may need to wear it for 2-3 days. The
treatment itself is painless because of the numbing drops. When these eye drops wear off, your eye
will likely hurt for one to two days. The doctor may recommend medicine to make you more com-
fortable during the immediate post-treatment period. It is important that you are able to take a few
days off work to rest and allow the eyes time to heal.

After Surgery
1st post-op visit: You will see the surgeon the day after surgery. At this visit the surgeon will test
your vision, and examine your eyes. You will be given one or more types of eye drops to take at
home to help prevent infection and/or inflammation. You will be advised to use artificial tears to

help lubricate the eyes and good quality sunglasses for UV protection when outdoors. You may be
sensitive to light and glare and have the feeling that something is in your eyes for the first few
weeks while the outer layer of your cornea grows back completely.
Do Not drive a car until your vision is good day and night. Do Not wash your hair until after your 1st
post-op appointment. Take extra care not to get water and soap in your eyes for one week. Keep
your eyes shut tight in the shower! Do not rub the eyes, especially the first 3 months following the
surgery. You will need to sleep with a protective shield over the eye while sleeping or napping for
at least 1 week. Be extremely cautious about deodorant spray, hair spray, paint, and any other
kinds of sprays. The mist from the spray can get on the cornea and cause irritation. . Generally, you
may resume eye lid makeup, preferably with new cosmetics, after 1 week . Be very gentle in apply-
ing your eye makeup and be sure not to bump your eye during the process. Avoid swimming, hot
tubs, saunas and gardening for 2 weeks. Do Not use any eye drops or eye washes other than those
given you. Do not start any new medications until consulting with your surgeon about how this
may affect the healing process. Keep your hands away from your face and wash your hands often.

It is imperative that you see your optometrist, for recommended post-op follow-up visits. In these
cases, we recommend that you be seen at 1 week, 1 month, 3 months, 6 months & 1 year. The la-
ser centre will receive follow-up forms from the optometrist so that they are able to follow your pro-
gress. If at any time the optometrist has a concern, the surgeon will be contacted immediately.

Initially your eye may be overcorrected making you hyperopic (farsighted) and objects up close may
be blurry. This is part of the normal healing process after PRK and it may take up to six months for
your vision to stabilize. All eyes get some degree of haze or cloudiness in the cornea following
treatment that may or may not interfere with vision. The haziness tends to decrease over time and
should eventually disappear completely.

                Informed Consent for the Use of the Excimer Laser for
                Performing Photorefractive Keratectomy (PRK) and/or
                     Laser-Assisted In Situ Keratomileusis (LASIK)

You are entitled to be informed about the proposed Photorefractive Keratectomy (PRK), and Laser-
Assisted In Situ Keratomileusis (LASIK), including the risks of the treatment and alternatives to it.
Please read this document thoroughly and discuss the content with your doctor so that all your ques-
tions are answered to your satisfaction.
This information is provided so that you can make an informed decision regarding the use of the exci-
mer laser to treat your refractive error (myopia-nearsightedness, astigmatism, or hyperopia– farsighted-
ness). A laser produces an intense beam of light which can be used to remove corneal (outer layer of the
eye) tissue. PRK and LASIK uses a computerized laser to reshape the surface of the cornea. Removal of
small amounts of tissue can produce the results you need to correct your myopia, astigmatism and/or
The alternatives to Photorefractive Keratectomy include eyeglasses, contact lenses or a refractive sur-
gery procedure called Radial Keratotomy (an operation in which a number of spoke-like incisions are
made with a surgical knife in the cornea).
Any questions that you have regarding PRK, LASIK or other alternative therapies of your case should be
directed to your doctor.
                                           Patient Statement
I have a refractive error (myopia, astigmatism, or hyperopia) which requires me to wear corrective
lenses in order to see clearly for my daily activities. I have been clearly informed of the alternatives in-
cluding eyeglasses and contact lenses. I have decided to undergo PRK/LASIK (PLEASE CIRCLE ONE)
with the excimer laser.
In giving my permission for the PRK or LASIK surgery, I declare that I understand the following informa-
1. The goal of the excimer laser treatment is to reduce or eliminate my refractive error, thereby reduc-
   ing my dependence or need for contact lenses and/or eyeglasses.
2. I understand that as with all forms of treatment, the results in my case cannot be guaranteed; there is
   no guarantee that I will completely eliminate my reliance on eyeglasses and/or contact lenses. It is
   possible that the treatment could result in undercorrection, overcorrection, and/or a change in my
   astigmatism where some degree of refractive error may remain requiring the use of glasses or con-
   tact lenses. It is possible that dependence on reading glasses may increase or reading glasses may
   be required at an earlier age. I understand further treatment may be necessary including a variety of
   eyedrops, the wearing of eyeglasses or contact lenses (hard or soft), or additional treatments.
3. I understand that if I currently need reading glasses I will likely still need reading glasses after this
   treatment. I also understand that if I do not currently need reading glasses, I need them at an earlier
4. (FEMALE ONLY) I am not pregnant or nursing. If it is possible that I am pregnant, then I will take a
   home pregnancy test to ascertain that I am not pregnant, since pregnancy could adversely affect my
   treatment result. If the results of the test are positive, I will not undergo treatment until the results
   are proven incorrect or I will reschedule the treatment for after the pregnancy. If I become pregnant
   in the 6 months following treatment, I will notify my eye doctor immediately.
5. I understand the treatment should not be performed on persons with uncontrolled vascular disease,
   autoimmune disease or keliod formation, who are immunocompromised or on drugs or therapy which
   suppress the immune system, if so I will tell the doctor if I have any of these or other medical condi-
6. I have been informed, and I understand, that certain complications have been reported in the long
   term post-treatment period by patients who have had PRK or LASIK including:
• Anterior Stromal Reticular Haze: Loss of perfect clarity of the cornea, usually not affecting vision,
  which resolves over time.
• Glare: Sensation produced by bright lights that is greater than normal and can cause discomfort and
• Halo: Hazy rings surrounding bright lights may be seen particularly at night.
• Loss of Best Spectacle Corrected Visual Acuity: A decrease in best corrected visual acuity with spec-
• IOP Elevation: An increase in the inner eye pressure due to post-treatment medications which is usu-
  ally resolved by drug therapy or discontinuation of post-treatment medications.
The following complications have been reported in less than 1 % of eyes which have had PRK or LASIK:
blurred vision, cataract (cloudiness of the lens), corneal epithelial defect (lesion in the outer layer of
the eye), corneal scarring (cloudiness of the cornea severe enough to affect vision), ulceration/
infection, dryness of the eye, feeling something is in the eye, shadow images, irregularities in cornea
(corneal deposits and microcysts), inflammation of the iris, irregular astigmatism (warped corneal sur-
face which causes distorted images), itching, lens opacity, double vision, patient discomfort, light sen-
sitivity, drooping of the eyelid, reading difficulty and corneal inflammation.
I understand that in addition to the above listed complications the following have been reported in the
short term post-treatment period by patients who have had PRK or LASIK and are associated with the
normal post-treatment healing process. These include: pain (first 24 to 48 hours), corneal swelling,
double vision, feeling something is in the eye, shadow images, light sensitivity, tearing and pupil

Since it is impossible to state every complication that may occur as a result of PRK or LASIK, I under-
stand that the above list of complications is not complete or exhaustive.
7. I understand that the doctor will prescribe certain medications as part of the treatment. The
  doctor is prepared to answer any questions I may have regarding the prescribed drugs and any side
  effects. I have informed my surgeon of any know allergies that pertain to me.
8. I understand that this is an elective treatment and that I do not have to have this treatment. I under-
  stand that the PRK or LASIK treatment is not reversible.
9. I understand that PRK or LASIK will require follow-up care at frequent intervals for one year after
  treatment and I agree to return for required examinations.

                               Primary Eye Care Centre
                            Dr. R.M. McMorris & Dr. J.D. John
                        #205 – 52 High St. W. Moose Jaw, Sask. S6H 1S3

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