Search the FAQ Archives

3 - A - B - C - D - E - F - G - H - I - J - K - L - M
N - O - P - Q - R - S - T - U - V - W - X - Y - Z
faqs.org - Internet FAQ Archives

sci.med.vision: Frequently Asked Questions (FAQ), Part 4/5

( Part1 - Part2 - Part3 - Part4 - Part5 )
[ Usenet FAQs | Web FAQs | Documents | RFC Index | Counties ]
Archive-name: vision-faq/part4
Posting-Frequency: monthly
Version: $Id: faq-part4.txt,v 1.18 1996/03/13 00:40:28 grants Exp grants $

See reader questions & answers on this topic! - Help others by sharing your knowledge
+============================================================================+
                  FREQUENTLY ASKED QUESTION: Vision and EyeCare
                                  Part 4/5
                          (Copyright(C), Grant Sayer)
                         (grants@research.canon.oz.au)
+============================================================================+

+============================================================================+
+ Section 8:  Refractive Surgery and Non Surgical Refractive Corrections     +
+============================================================================+

8.0 WWW Resources on Refractive Surgery:
---------------------------------------
URL: http://www.eyenet.org/public/faq/refractive_surgery_faq.html
(American Academy of Ophthalmology refractive surgery FAQ)

URL: http://eyesite.ucsd.edu/
(UCSD Eye Center - providing information on refractive surgery including
 corneal topography maps of patients).

URL: http://www.ascrs.org/
(American Society of Cataract & Refractive Surgery 

URL: http://www-or.stanford.edu/~mob/RK
(Personal account of RK with FAQ information, surgery information
 Also contains index of all surgery centres that are on the net)

URL: http://hinet.medlib.arizona.edu/.opa/crnap/rk.htm
(Information on RK surgery from Univeristy of Arizona Health Services Centre)

URL: http://hawaii-shopping.com/eyes
(personal account of LASIK procedure on a patient)


URL: http://www.synapse.net/~hurleyp
( personal account of PRK procedure )

URL: http://www.southwind.net/~resiman/index.html
(private ophthalmology practice providing information on RK and PRK)`

URL: http://www.promote.com/rklaser/index.html
(Ellise Eye & Laser Centre - includes FAQ on RK and patient guide on 
 refractive surgery)

URL: http://www.the-wire.com/TLC/
(TLC Laser Centre offering information on vision correction)

URL: http://www.ozarksol.com/medsource/prk.htm
( Information about PRK, RK, AK, LASIK )

URL: http://www.direct.ca/excel/
(Information on procedures from Excel)

URL: http://www.iac.net/~lca/index.html
(Information on procedures and conveniently lists Eye centers which
 happen to perform procedures)

URL: http://www.polymer.com/rksurg.html
(Information on RK, vision and eyecare)

URL: http://pages.prodigy.com/LA/rkmaster/rkmaster.html
(Information on RK Software - commercial advertisement)

URL: http://www.synapse.net/~hurleyp/
(Personal page on experience with PRK)

URL: http://www.rli.com/rk.html
(Information on refractive surgery techniques with a number of detailed
 pictures, eg histological sections, cornea photographs, etc.)

8.1   Types of Refractive Surgery
---------------------------------
There are basically 4 main operations performed for correction of refractive
errors:
		+ Radial Keratotomy (RK)
		+ Photo-Refractive Keratectomy (PRK)
		+ Automated Lamellar Keratoplasty (ALK)
		+ Laser Assisted Intrastromal Keratomileusis (LASIK)

8.2 Description of the Procedures:
----------------------------------

RK involves making 4 or 8 radial cuts in the surface of the cornea.  
Previously 16 cuts were used  but this was found to give too much refractive 
instability and glare. As the incisions heal the resulting scar tissue 
flattens the cornea.  

PRK uses an excimer laser to photo-ablate or resculpt the surface of the
cornea.  The excimer laser is a charged beam of argon and fluoride gases in
a mirrored tube to produce a beam of ultraviolet light.  The beam is unique
because it possesses the ability to vaporize living tissue, a microscopic
layer at the time without destroying or burning the surrounding tissue.
The energy from the laser breaks the bonds between molecules, with each
pulse taking off about 0.4 microns of tissue (a human hair is between 50-100
microns thick).  A person with -5 correction would require 200 pulses.

The LASIK and ALK procedure has 4 steps (in myopia) and 3 for hyperopia
        - A gentle suction ring places an instrument known as a Corneal
          Shaper over the cornea.

        - A blade in the Cornea Shaper is then passed over the cornea and
          removes a paper-thin film of tissue (the corneal surface).  
		  The tissue is not completely removed, but is left attached to 
		  the eye on one side, and is folded out of the way.

        - A second cutting pass removes the amount of tissue needed to put
          the prescription of the eye into the cornea.

        - The surface layer is replaced, and air dried slightly to allow it
          to stay in place.


8.2.1 Suitability for each procedure
------------------------------------
PRK
ALK
RK
LASIK : -4.00 to -8.00 more stable


8.3 Comparison of RK, PRK and ALK and LASIK:
----------------------------------
PRK: involves less than 5% the depth of the cornea, typically.  Some
	 likelihood of infection due to use of post-op bandage lenses for
	 post-op pain control.  There is a possibility of infectious keratitis
	 which will almost always resolve, without side-effects, if treated 
	 early.
RK:  can involve up to 95% the depth of the cornea, and eye penetration
     has occurred (which can cause blindness in the long term). The risk of
     infection is about 1/1000 operations and is treatable.  Minute
	 perforations ("microperforation") are relatively common (5%) and 
	 are harmless; larger ("macroperforations") are very rare and require
	 sutures. Blindness will only occur if there is an associated infection.


PRK: repeatable, so for high corrections (-6 to -10) if the first procedure
     doesn't give 100% correction, the second can.
     From study of 298 patients.  Severe scarring or under-correction
     requiring repeated treatment occurs in a small percentage of patients.
     Scarring occurred in 1.8% of patients with an original correction of
     up to and including -6.0 dioptres and 8.8% of patients with > -6.0 D.
     Under-correction occurred in 2.7% of patients with <= -6.0 D and
     30 to 40% of > -6.0 D.  30 eyes were redone (11 due to scarring and
     27 to under-correction).  After 6 months 63% of the re-treated group
     (19 eyes) were within +/- 1 D of a zero correction.  Only 1 eye still
     had scarring. 
     (Arch Ophthalmol 1992 Sep 110(9) pp 1230-3).

     Another study examined 17 eyes retreated due to undercorrection.  After
     6 months 64.7% (11 eyes) had uncorrected visual acuity at least as good
     as 20/40 and 58.8% (10) were within 1.0 dioptre of emmetropia (ie 0 D
     correction). (Am. J. Ophthalmol. 1994 Apr 117(4) pp 456-61)

RK:  not repeatable in general (but it is possible to do PRK after RK).
     91 eyes of 71 patients who had RK but still were myopic were treated
     with PRK.  Prior to PRK their corrections ranged from -1.5 to -8.0 D.
     Twelve months after PRK uncorrected visual acuity was 20/40 or better
     in 90% of patients, and 76% of patients were within +/- 1.0 D of
     intended correction.  (J. Refract. Corneal Surg. 1994 Mar-Apr
     10(2 Suppl) pp 235-8).
	 procedure can be repeated - called enhancement surgery - with rate
	 of repeating as high as 30% (Werlibin, Archives of Ophthalmology, 1994,
	 95% achieve 20/40 or better).


PRK: High accuracy.
    A study of 98 eyes 6 months after PRK reported the following results.

         original correction       % within +/- 0.5 D of
                                   attempted correction after PRK
              < -3.0 D                  100.0%
            -3.1 to -6.0 D               92.3%
            -6.1 to -9.0 D               77.8%
              > -9.0 D                  100.0% (attempted correction
                                                not necessarily 0 D in
                                                this group)
     2 eyes lost 2 lines, while 4 eyes gained 2 or more lines of best
     corrected visual acuity. (J. Refract. Corneal Surg. 1994 Mar-Apr
     10(2 Suppl) pp 231-4)

     From a study of 18 patients (23 eyes) with high degrees of myopia
     (-8.0 D to -19.50 D).  After approximately 6 months, 39% (9 eyes)
     were within +/- 1 D and 65% (15 eyes) were within +/- 2D.
     (Arch. Ophthalmol. 1993 Dec 111(12) pp 1627-34)

RK:  Not terribly predictable accuracy.
     "undercorrection occurs commonly" and "amount of correction cannot
      be predicted accurately for an individual patient" 
     (Ophthalmology 1993 July 100(7) pp 1103-15)
 
     From the PERK study (prospective evaluation of RK) involving 435
     patients in the US.  Follow-up after 4 years (91% still involved).
     Results:
         55% within +/- 1 dioptre of desired result
         28% under-corrected by > 1 D
         17% over-corrected by > 1 D
     90% prediction interval width 4.42 D "indicating lack of
     predictability".  Refractive error not stable in some eyes.  23%
     had change of greater than 1 D between 6 months and 4 years after
     surgery.  64% of 323 patients who had both eyes treated no longer
     needed glasses or contacts.
     (JAMA 1990 Feb 23 263(8) pp 1083-91)

	 A better indication of predicatability of RK is documented in 
	 Werblin, Archives of Ophthalmology [ full details to follow ]

PRK: Structural integrity of the eye essentially unaltered.
     J. Cataract Refract. Surg. 1994 Jan-Feb 10(1) pp 36-7 reports two
     cases of PRK patients who sustained blunt trauma to the eye.
     "Corneal abrasion following trauma in two patients who had undergone
     PRK healed as expected in a normal cornea."

RK:  Structural integrity of the eye is compromised.  RK incisions may
     remain incompletely healed and can re-open years later.
     1 patient had incisions re-open 9 years after RK during surgery
     on the cornea.  (J. Cataract Refract. Surg. 1993 July 19(4) pp 542-3)
     1 patient had traumatic rupture of the cornea 4 years after RK due
     to an athletic injury.  (Vestn. Oftalmol 1990 Mar-Apr 106(2) pp 64-5).

PRK: There is an occasional side effect of a buildup of collagen fibres
     while the eye heals - "plaques". They don't manifest themselves
     visually, but the doctor can see them examining the eye minutely.
     It happens in about 25% of the cases during healing, though
     most they go away in time.  Halos are also reported with PRK - 
	 references; Dan Epstein and John Marshall [ details to follow ].

RK:  Halos around objects and distorted refractions around point sources 
     of light. 

ALK: can cure myopia up to -30.0 dioptres. Although accuracy of within
	 1D in 20-40% of operations.

ALK: instrument is accurate, and procedures are performed quickly with corneal
	 surface left intact and unaltered so minimising healing problems, eg
	 scar tissue, as in PRK and RK

ALK: hyperopia can also be improvied with this procedure

8.4 Complications of the Procedures
-----------------------------------
PRK Side Effects -
1. Overcorrection - so you ended up long-sighted and need glasses for
   reading.  Initially the eye is over-corrected as the cornea has a
   tendency to regress to its original state.  The regression generally
   stabilises after 1-3 months and it is uncommon to end up permanently
   over-corrected.  If you are you'll need glasses for reading and any
   close up work.

2. Undercorrection - so you are still a little short-sighted.  You may
   regress so much you end up still myopic.  If it is severe the procedure 
   can be repeated.  Steroid drops are believed to control regression and
   are used for several weeks after the procedure to avoid under-correction.
   There is considerable debate in the literature over the benefits of
   steroid drops but they seem to be widely used.

3. Decentration - the treated zone isn't centred properly, usually because 
   the patient didn't focus on the right point during the procedure.
   "Measures are undertaken to ensure this doesn't occur" (according to my
   brochure). 
   A study of 97 eyes reported 
     37% centred within < 0.25mm of pupillary centre
     48% within 0.25 to 0.50 mm
     13% within 0.50 to 1.00 mm
      2% > 1 mm
   The largest deviation was 1.5 mm and the average was 0.36 mm.  The
   higher the attempted correction the higher the degree of decentration.
   (J. Cataract. Refract. Surg. 1993 19(2 Suppl) pp 149-54)
  
4. Post-operative Pain - varies in intensity and duration.  The procedure
   itself is painless.  From conversations with people the opinion varied
   from it was painful for: 
          8 hours;
          48 hours;
          3 days; and
          4-5 days
   and varied from 
          painful but not too bad;
          agonising on the first day, painful on the second, uncomfortable
            on the third; to
          as bad as child birth!
   The "typical" experience seems to be that it is very painful on the
   first day, not nearly so bad on the second and merely uncomfortable on
   the third and then painless after that.

5. Delayed Epithelial Healing - this is the outer layer of the eye.  It 
   usually heals in 2 to 4 days but can take longer (generally uncommon).
   appears to be very uncommon.

6. Corneal Haze - this gradually gets worse after the procedure and is at
   its maximum severity around 6 weeks.  It settles by 3 to 6 months and at
   this point is generally not detectable by the patient but only by 
   an ophthalmologist using magnification.  If it is severe it can impair
   your ability to determine fine detail.  The steroid drops are believed
   to also control the degree of haze as well as the amount of regression.
   If the scarring is severe the laser can be used to remove it and for
   reasons which aren't known yet it doesn't re-occur.

   From a study of 1821 patients (2920 eyes) corneal haze of grade 2 or
   more occurred in 0.38% (11 eyes).  Three of these patients (4 eyes)
   were re-treated.  Grade 2 or higher haze can cause myopia as the scar
   tissue reduces the flexibility of the cornea.
   (J. Refract. Corneal Surg 1994 Mar-Apr 10(2 Suppl) pp 226-30)

7. Halo effect - this can occur when the pupil enlarges beyond the
   treated area at nighttime.  They use larger treatment zones these days
   (6mm instead of 5 or 4mm) so this is less common.  It is also less
   noticeable when the second eye is done.

8. Sensitivity to Glare - both eyes often become very sensitive to bright
   light after PRK.  Treatment - wear sunglasses.  This goes away after 
   the first few months.

9. Other complications - theoretically possible but extremely unlikely
   (ie listed to cover their arse (US: ass)).
   corneal infection, intra-ocular infection, failure of healing, 
   corneal decompensation, persistent corneal oedema, corneal perforation, 
   corneal or anterior ocular neoplasia and cataract.

10. Damage to Bowman's layer - The sculpting burns away Bowman's Membrane,
    the 2nd layer of the cornea. This layer is the one implicated in
    keratoconus, a genetic disease whereby the cornea becomes irregular.
    Keratoconus is treated with specialized rigid contact lenses. The
    question here is: will PRK result in a keratoconus-like syndrome over
    the long term? Keratoconus takes years and years to really get rolling.
	Opinions from Ophthalmologists indicate that this issue is not a concern.

    However a histological study (the original work is cited in a review by
    Trokl, 1989, J. Cataract Refract. Surg. 15 : 373-782). This work
    demonstrated, using both light and transmission electron microscopy,
    the presence of a "pseudomembrane" covering surfaces which had been
    laser ablated. This membrane apparently exhibits ultrastructural
    properties characteristic of true membranes and also some of funtional
    properties of true membranes, for example, it acts as a template for
    re-epithelialization. 

    Another observation which suggests that destruction of Bowmans layer as
    a result of PRK may not have negative implications in the long term, is
    the fact that destruction of this layer as a result of trauma to the
    cornea apparently does not result in Keratoconus or other disorders.

11. From a study of 615 PRK procedures with a follow-up of up to 2 years:- 
    "intraoperative complications with experienced surgeons extremely
     rare"
    gross eccentricities of ablative zone (of 1.0 to 1.5 mm) occurred
     in 2 eyes (0.3%)
    "epithelial disorders rare"
    "recurrent erosions did not occur"
    increased intraoculur pressure due to steroid treatment (of either
     0.1% dexamethasone or 1% prednisolone) occurred in 30% of patients
     with initial corrections of <= -9.0 D and 50% in patients with
     > -9.0 D.
    increased intraoculur pressure was correlated with increased risk 
     of over-correction
    scarring severe enough to interfere with vision occurred in 0.5%
     of patients with <= -6.0 D and 10% of patients with > -10 D.
    scarring correlated with degree of attempted correction
    most serious complication - noninfectious corneal ulcer in patient
     with systemic lupus erythematosus
    (Klin. Monatsbl. Augenheilkd. 1992 Jun 200(6) pp 648-53).

RK:
    Major risks include; glare at night, fluctutations in vision from
	morning to night, loss of BCVA (best-corrected Visual Acuity) - rarer
	with RK than PRK, over/undercorrection, trauma (v. rare), infection
	(rare).  See Survey of Ophthalmology article by Rashid and Waring on
	complications of keratotomy surgery ~1989 [ reference details to follow].


LASIK/ALK:
	Risks basically the same as with PRK except no corneal haze occurs, but
	you can get irregular astigmatism from an irregular cut.  Perhaps 5%
	of eyes done by experienced surgeons lose BCVA of 2 lines or more. Also
	possible epithelial ingrowth between cornea and outerlayer which needs
	to be removed.
	
8.6 Criteria for Suitability of Procedures
-------------------------------------------
PRK: The following guidelines are suggested for those individuals suitable 
	 for the procedure

1. no significant change in prescription in the last 12 months (ie more
   than 0.5 dioptre);
2. prescription of up to -16 dioptres;
3. astigmatism of up to 6 dioptres;
4. superficial corneal scars or dystrophies of less than 200 microns
	  (ie nice, flat corneas); and
5. can afford to pay  (see below for costs)
6. best for young people ( 30 and under) with higher corrections (-4.5 to
   -9.0) who don't mind greater pain and are willing to wait longer for 
   sharp vision.

RK: The following guidelines are suggested for those individuals 
	suitable  for the procedure

1. Best for over 35yr old; ideal refraction -4 and under

ALK: The following guidelines are suggested for those individuals 
	suitable  for the procedure

1. Best for people with refraction/conditions which unable to meet
   requirements for RK/PRK.

8.7 Personal Experiences of Refractive Surgery
----------------------------------------------
The following information details the personal experiences that some 
Internet readers have found having undergone some of the procedures

PRK (Barbara la Scala bfls@ee.mu.oz.au)

Prior to treatment:

Surgeons have become more experienced with correcting high degrees of
myopia over the past few years and so the chances of success for even
myopes with a high degree of correction have improved over the statistics
quoted above.  My correction was -10 D in my right eye and -9.5 D in the
left.  I was told I had a 95% chance of never needing glasses again, a 2-3%
chance of needing them for driving and a 2-3% chance of still needing
glasses all the time but far less strong ones.

I saw Dr Unger and discussed at length the operation, the side effects,
complications and success rate.  My eyes were tested to determine my
current prescription and curvature of my corneas (I wasn't allowed to wear
contact lenses for a week beforehand).  My eyes were topographically mapped
using a laser to produce a surface plot of my corneas.  I also had to bring
in a old prescription so they could see how rapidly my correction was
changing.  For corrections of over -10 dioptres they generally measure the
thickness of the cornea using ultrasound but since I was a borderline case
they decided not to.  

The operation itself:

In the morning I went into Dr Unger's surgery and had all the tests I had
before repeated.  I wasn't allowed to wear contact lenses for 2 weeks
beforehand to allow my corneas to revert to their natural shape.  I also
had the degree of haze in my corneas measured using yet another laser.
This wasn't necessary for the surgery but for their research records.

I had the surgery itself that afternoon at the Royal Eye and Ear Hospital
in Melbourne as an outpatient.  I had 4 lots of cocaine drops put in my
right eye to anaesthetise it over a period of about 1/2 an hour.  I was
then taken into the surgery and a cap was put over my hair and my face
wiped with antiseptic.  A cover was put over my left eye so I wouldn't be
distracted by the sight of anything on my left.  I sat in a dentist-type
chair which was reclined and I was moved under the laser machine.  

At this point I panicked :-) I didn't run screaming down the corridor but I
wanted to.  Up until then I hadn't really thought about what the surgery
itself would involve - just the risks and benefits.  Suddenly I realised I
was going to let someone mess around and *touch* my eye.  I really didn't
expect such a strong emotional reaction.  I believe some doctors will give
their patients a little Valium beforehand to reduce the stress but my
doctor doesn't.  He found that if the patient was too relaxed it was hard
to convince them to stare a point and not let their gaze wander about as
the laser was doing it stuff.  Terrified patients concentrated better on
getting it right :-).

An instrument was put in my eye to hold my eyelids open.  It was rather
like the reverse of a pair of tongs - you had to squeeze the handles to
keep the ends together.  Surprisingly I couldn't feel this at all -
probably due to the topical anaesthetic.  A blow-up pillow, like those you
have for travelling in planes, was inflated around my neck so I couldn't
move my head from side to side.  The doctor then laid a circular instrument
with cross hairs rather like a gun sight on my eye to mark out the
treatment area.  He then used some sort of scalpel (I couldn't see what -
it was too close) to scrape off the outer layer of my eye and uncover the
cornea while I lay there trying very hard not to blink.  I could see the
knife moving back and forward over my eye and the tissue coming off but
could only feel a little pressure.  He would stop every once in a while to
rinse of dislodged tissue and give me a break.  It took about 5 minutes
altogether and was the longest 5 minutes of my life.

Then came the laser surgery itself.  The laser equipment consisted of a
small, bright red flashing light in a dark field with a ring of white light
around it to illuminate my eye.  I had to stare fixedly at the red dot and
not move my eye or try to blink while the laser operated.  The moment it
started to work I could no longer see clearly out of my eye - everything
disappeared into a bright white blur.  I could still see a pulsating spot
in the middle though so I stared at it for all I was worth.  The laser made
a clicking sound.  Because my correction was so strong the laser was used
twice.  The first time lasted for 1 minute and the second for 35 seconds.
The average time is more like 30-40 seconds.

After that it was all over.  More drops were put in my eye - anaesthetic
ones I think but I forgot to ask.  Then antibiotic ointment was put inside
my lower eyelid and they patched my eye closed.  My left eye was uncovered
and I got to watch it all on video before being taken home.

They recommend going home and going to sleep immediately after the
procedure because if you move your eyes the ulcerated portion of the
treated eye rubs against the inside of the eyelid and is very painful.  I
found that bright light hurt my untreated eye and I had to wear sunglasses
on the way home.  When I got home I took one of the sleeping tablets they
gave me and went to bed.  They also gave me Panadeine Forte tablets (these
are a mixture of paracetamol and codeine - the strongest mixture you can
get without a prescription in this country).  I took one of these also but
I don't know if it made any difference.  My eye had started to sting around
10 minutes after the procedure but wasn't too bad.  

After the treatment:

The morning after the surgery my eye was painful but not so bad I couldn't
be distracted from it.  It was extremely painful if I moved my eyes though.
My eye was checked and around 1/3 of the epithelial layer had grown back.
My eye became increasingly less painful over the next 2 days until it was
merely uncomfortable if I moved my eye.  The epithelial layer completely
regrew in 3 days.  Once it had regrown the pain was gone.

After 4 days I removed the eye patch and started using FML eye drops to
reduce inflammation.  These are made by Allergan and contain the
corticosteriod fluorometholone.  I was originally long-sighted but this
improved and after 10 days the vision in my treated eye was good enough
that I was able to rely on it alone and not bother using a contact lens in
my untreated eye.  I did notice fine details becoming slightly fuzzy as
time wore on due to haze developing.

After 3 months the correction in my treated eye was -0.25 D which is
virtually perfect and I had little scarring or haze.  However over the next
two months a great deal of scar tissue developed (level 2 I believe).  One
month later (4 months after surgery) I had regressed to -5 D but the rate
slowed and I was only at -5.75 D one month later.  After discussion with
several other eye specialists I was put on new stronger, steroidal eye
drops.  (Maxidex by Alcon which contain a 0.1% solution of dexamethasone).
This was successful in reducing scarring significantly in another patient.
I'm only the 5th patient of my surgeon to get scarring sufficiently severe
to interfere with sight.  The new drops had a noticeable effect after only
one week and my myopia reduced from -5.75 D to -1.75 D in 4 months.

An unfortunate side effect of the Maxidex drops is that it can make the
pressure in the eye increase causing a form of glaucoma.  If untreated this
can eventually kill retinal cells and send you blind.  After 4 months of
using the Maxidex drops two hourly my pressure started to increased.  This
also caused my myopia to worsen.  I was put on beta-blocker eye drops for a
month to reduce this pressure build up.  These were Timoptol by Merck which
contain a 0.5% solution of timolol maleate. However they weren't effective
so the Maxidex was reduced from every two hours to twice a day.  In the
following month the pressure did drop and my myopia improved.  

Now, 15 months after the inital treatment the scar tissue has gone away and
my correction has stabilised to -1.75D due to regression.  Ten days ago I
had my eye retreated with the new Summit Laser (the only one to gain FDA
approval so far).  This operates twice as fast as the Visx laser I had
orignally been treated with.  In addition, my doctor now uses the laser to
remove the epithelial layer as it leaves a smoother surface.  This makes
the treatement faster and less unpleasant.  He has also started using a
contact lens bandage in addition to an eye patch.  This speeds up the
regrowth of the epithelium.  About 70% had grown back in 24 hours and it
was completely healed in 48.  This makes the recovery period shorter and
much less painful.  My uncorrected visual accuity is 20/30 and there is no
sign of scarring.

(bfls@ee.mu.oz.au)

RK:
---

The following information is details of experiences of patients who
have undergone refractive surgery for RK.

RK: Gayle Chidester (gaylec@corp.megatest.com)
---
Prior to treatment:
-------------------

My correction was -4.75D in both eyes with 1D of astigmatism in my left
eye and .75D in my right. This left me with vision of 20/400 (I could
see the big "E" on the chart but it was fuzzy). I had been wearing
corrective lenses for about 25yrs. I had always considered my eye
color to be one of my best features (bright steel blue) but they
couldn't be seen with glasses. I tried contacts, but with my job (dusty,
windy environment) they became impossible to deal with and my eyes began
to become intolerant of the cleaning solutions. I had given up on
contacts and have been wearing glasses exclusively for the last 5 years. 

I had heard of RK when it first came to the US in the late-70's but was
always squeemish about the idea of anyone touching my eyes (even the
thought of a glacoma test gives me the willies). Recently the barrage
of RK TV commercials had been catching my attention. After having a
3 week old pair of $350 glasses fall out of their case to go sliding
across asphalt and get all scratched up, I had decided I had had enough.
I then started to research RK.

I picked 2 doctors to "interview". The first one I saw for a "free
consultation", had claims of extensive experience, even performing
surgery with Dr. Feutrov (developer of RK in the former Soviet Union).
After meeting with him and asking him several questions about his success
rates (about 95% improvement, but I couldn't pinpoint him to define
"improvement"), and guarantees (ABSOLUTELY NONE -but I'll take your
money anyway). He charges $1500 per eye. I felt uncomfortable about
this guy (he actually gave me the creeps), and felt that I could not
trust him. When my "free" consultation wound up costing me $80, I knew
there was no way I was going to let this money grubber touch my eyes!

I then went to a free seminar/consultatation at Dr. Kawesch's office. There
were about 12 people at the seminar, Dr. Kawesch showed a video of himself
performing surgery and another about refractive surgery in general, had 
former patients give (uncompensated) testimony, provided a big packet of
info, and answered questions. Dr. Kawesch's success rate is over 98% for
corrections of 50% or better. He has a written guarantee for most patients
that vision will be at least 50% better than before surgery, or your money
back.  After reviewing my prescription, Dr. Kawesch was able to guarantee
me at least 20/40 or better (which will allow me to pass the DMV vision
test), or my money would be refunded. Dr. Kawesch charges $1300 per eye.

In my research, I wanted to find people that had RK done to talk to
them about their experiences. I found neighbors, fellow students and
co-workers that had gone through RK. Everyone that I talked to had
nothing but good things to say about RK. One of the students had RK done
12 years ago and still has no need for glasses. A co-worker had RK
performed by Dr. Kawesch. She was originally -9D. She had both eyes
operated on and needed enhancement procedures in both eyes due to the
severity of her myopia. She now functions without glasses and uses a
mild perscription for night driving (she doesn't need to since she
passes the DMV exam, but feels more comfortable driving at night with
glasses). Talking to her is what clinched it for me and I called Dr.
Kawesch to schedule an appointment.

The operation itself:
---------------------

I went into the Dr. Kawesch's office the morning before my surgery was 
scheduled to have a comprehensive eye exam done which included a glaucoma
test and extensive examination of my eyes. After the exam, I was given
eye drops to constrict my pupil (the exam required my eyes be dialated,
but surgery can't be performed on a dialated eye). The drops that I was
given (4 doses, one every half hour) gave me a sinus type headache of
almost migraine perportion, but went away after I took an Advil. I was
given 4 perscriptions to fill: 1)an antibiotic drop 2) a drop for 
light sensitivity and scratchyness 3)a pain killer (with codeine) and
4) a pill to help me sleep. I filled those while waiting for my surgery
appointment.

I returned to the office a few hours later and they gave me a small dose
of Valium to relax me and reduce the chance of me flinching as my eye
is being worked on. Since my right eye is dominant, they decided to
operate on my left eye first. I was gowned up with a disposable surgery
gown with a cap over my hair and booties over my shoes. They put a little
green sticker on the cap over my left eye so there would be no confusion
as to which eye is receiving the procedure. They then gave me 4 doses of
cocaine drops in my left eye to anaesthetise it over a period of about
1/2 an hour. I was then walked into surgery and helped up onto the
operating table (floor is slick with booties on). After laying down, my
face was wiped with antiseptic.  A patch was put over my right eye so I
wouldn't be distracted by the sight of anything on my right. My face was
then covered by a sterile cloth.

An instrument was put in my eye to hold my eyelids open. It was like a
reversed pair of tongs - handles were squeezed to keep the ends together.
I couldn't feel anything in my eye but could tell that someone was
touching around the eye area. The doctor was working on me from the top
of my head as I lay on the table. The microscope (which had a video
camera attached) was then placed above my eye. All I could see was a
bright curly filament of the light in the microscope. I was instructed
to look at the filament and if during the procedure it appears as though
the filament is moving, to look at the point where the filament was
originally. The depth of my cornea was measured using an ultrasound at
several points around my eye. The treatment area was then marked using
two small rings with sterile dye on them, the smallest one in the very
center of the eye and a larger one around the smaller one, giving the
appearance of concentric circles around the pupil. Then a ring that had
spokes going inward like a wagon wheel was used to mark my eye, with
the center of the spokes touching the small inner ring mark that was
previously marked on my eye. A large ring was then held on my eye to
hold it still while the incisions were being made.

The first incision was to correct the astigmatism. An incision was made
along the outer ring mark between two of the spokes on the top side
of my eye. Antibiotic drops were placed in my eye and the cornia was
wiped with a small sponge (about the size of a Q-tip). Then the incisions
to correct the myopia were made along the eight "spokes" between the
inner and outer ring marks. (The doctor had to change hands as he worked
on my eye to go from the right side of the eye to the left side...I'm sure
glad he's ambidextrous!) Antibiotic drops were placed in the eye again
along with anaesthetic drops and something to remove the dye marks. The
drops made me flinch, and Dr. Kawesch asked me if I had taken the Valium.
I told him yes but it must not have taken effect until much later as I
was really relaxed on the way home. ;-) The "tongs" were removed from my
eye and the antiseptic was washed off my face. The whole procedure from
the time the "tongs" were put into my eye until they were removed was
about 10 minutes. They even gave me the video of my procedure!

I was again instructed on the use of the prescriptions and was sent home
(since I had opted for the Valium, it was strongly suggested that I have
my husband drive me home). My eye felt a little scratchy, so I put one
of the light sensitivity drops in. On the way home (we live an hour away)
I wore sunglasses and was able to look around a little since the eye was
not patched. I could already see much better in the operated eye even
though details were fuzzy because the drops that constricted my eye 
made it hard to focus. I could already see better in my left (operated)
eye whereas my right (unoperated) eye was of no use at all. When we got
home I put the antibiotic drops in my eye, took one of the sleeping pills
and went to bed.

I woke up the next morning, and for the first time in over 25 years,
I was able to see the alarm clock without glasses! I spent the day
doing the alternating "peek-a-boo", comparing the two eyes. I knew that
I was not quite 20/20, but I knew I was close. I had no pain but had
a dry/scratchy feeling and the eye was very sensitive to pressure. I
couldn't touch or pull on my eyelid, because I would get a strong
reminder from my eye that I had surgery. I had no problem sleeping
but had to watch how I held my head on the pillow to make sure it
didn't put pressure on the eyelid (I sleep on my left side). I wound
up not needing the painkiller at all and only used 2 of the sleeping
pills (one after each surgery). I used both of the drops 4 times a day.
I alternated the drops to get maximum effect (not dilute one with the
other) and to also provide my eye with moisture on a more regular basis.

The following day I was scheduled for the procedure to be repeated on
my right eye. Before surgery, they tested my left eye and it was 20/25!
I was then prepared for surgery. The procedure was the same as what was
done to the left eye except I took an Advil prior to the appointment (to
help prevent the sinus headache from the constricting drops), and I
asked that I be given a little more time to let the Valium take affect.
Since the amount of astigmatism in the right eye was less than 1D,
Dr. Kawesch decided not to do the incision for it. Everything else was
done the same, and since I was now familiar with the way things were
done, I was more relaxed.

On the way home, I could read the road signs as they approached and was
comparing with my husband at which points could we read a sign. I was
matching him for distance reading. I could already tell that my right
eye was better than my left. The following morning, I went down to the
DMV and had the corrective lens restriction taken off of my driver's
license! I could read the chart very clearly!

The next day (Saturday) my husband and I went for a drive in the hills.
I was able to spot three deer and two coyotes before my husband did 
(one of the coyotes my husband didn't see until it ran over the hill,
and we had been watching them for at least five minutes)! Everything
seems so much clearer. The contrast between colors is what I notice
the most (I was looking at a Mallard drake recently and was almost
overwhelmed by the irredecence of the head feathers.....it was as if
I had seen them for the first time!)

During my 4 week checkup, I was 20/20 in each eye (missed one character
on the line: was an "H", I thought it was an "M"). Better than 20/20
using both eyes and 20/20 night vision. The doctor examined the surface
of my eye and I am doing so well, my next appointment is in 6 months!

Eight weeks after the surgery, I went target practicing with my husband.
I was able to look through the scope without trouble, whereas before I
would get a tunnel vision effect with glasses, and was unable to line
the scope up correctly, causing me to miss most shots. This time all of
my shots were hits! 

Symptoms that I have experienced:
---------------------------------

Pain: Mild irritation associated with the dry/scratchy feeling. More 
   severe with pressure (I would tend to want to rub my eye/pull on the lid
   because of the scratchiness but that would cause discomfort, and make
   the eye water which would help with the dry feeling somewhat but wasn't
   worth the pain trade-off...I learned to keep my fingers away from my
   eyes!) Pressure sensitivity decreased until it was completely gone after
   3 weeks at which time I could rub my eyes vigorously without discomfort.
Dryness/scratchiness: Mild for about the first week, occasional during the
   second week decreasing until completely gone after 3 weeks.
Starburst: Varying depending on how tired I was. (I was working full time
   and going to school full time getting about 5 hrs of sleep per night.)
   I noticed more starburst later in the week, and it was more intense
   at around 11 pm than at 8pm. At 6am it was hardly noticable. Never at
   any time did it interfere with my driving. At eight weeks, starburst
   was most noticable in the peripheral vision but the central vision was
   mostly clear to somewhat fuzzy, with occasional return of starburst
   to central vision at times due to fatigue.
Light Sensativity: Noticable during really bright sunny days, but not to
   the point of being uncomfortable. Less light sensitive at night
   compared to wearing lenses. Can drive at night with someone following
   me and have the rear view mirror in the daylight position (in fact, it
   helps for the times when starburst is most noticable). Wouldn't even
   attempt to do that when I had glasses.
Vision fluctuation: Not often. Most noticable when I'm tired, decreases
   ability to make out fine detail. 
                        ==================

The following information was kindly contributed by Dr Robert Maloney M.D
(maloney@jsci.ucla.edu) from patients that have had RK performed.  Details
and experiences of the patients are given below

RK - Patient#1
RK - OD, ALK - OS, Before 20/800 O.U, Presently 20/20 OD, 20/30 OS
" The best part comes when you first realize that you are no longer 
conscious of the surgery and that good vision is now natural to you.

At age 47 I had no memory of ever having good vision without corrective
lenses. I had worn glasses full time since I was 6 years old and
probably should have had them sooner.  Glasses and even contacts have
an effect on your view of the world and your participation in it. (I
actually seem to be tripping over my feet less now when I go hiking).
"

						 ==============

RK - Patient#2
RK- OU, Before OD -5.75, OS -6.0 Presently: 20/20 OU
" My vision was to the point of not only being able to see the clock-radio
next to the bed but worse, I couldn't see if my husband was awake or
asleep!

I was in a shopping mall with my daughter when, during the process of
rearranging the shopping bags, my glasses fell off. I realized my eyesight
had dimished to the point of not being able to read the neon store 
names around me but more frightening was I couldn't read or find the 
exit signs.

This scared me because I travel a great deal and the idea of not 
finding an emergency exits or if my glasses were destroyed or lost 
during an emergency I wouldn't be able to find safety.  The 
surgery has been more successful than I imagined. I thought I'd still
be wearing glasses - just lighter ones !.  I'm doing well enough not
to require glasses for anything but night driving and movies.

Put me as one very happy person!
"

                        ==============

ALK: 
---
The following information is from Samuel L. Round II sround@crl.com

I am a 36 year-old male, systems engineer, who had -7.75 OU with some
astigmatism OD (yes, alas...the classic myopic math/computer NURD).
I had researched refractive surgery technology
for many years as I had very little luck wearing hard or soft contacts.
Then there were those Coke-bottle thick glasses: a full quarter
inch of bullett-proof CR39...those glasses that could jeopardize 
my life if I could not find them in an emergency.

Anyway, a year and a half ago I was evaluated at SurgiVision in Atlanta.
I had a bilateral ALK, a bilateral RK and AK, and a bilateral enhancement RK.

Relative to an RK or AK, the ALK is a very comfortable procedure.  
SurgiVision gives Valium for all procedures, so I'm pretty sure they
could of yanked out a couple of teeth too!  An ALK takes about 20
per eye, but again, with the Valium, it seemed like 5 minutes for
both.  After the surgery, I was driven home and I slept for the better
part of 24 hours.  The next day I returned to SurgiVision for an 
examination.  I was instructed to wear metal eye cups over my eyes
while sleeping for the next two weeks,  and use the antibiotic/cortizone
eye drops 4 times a day.  Within a few days after surgery, my vision
was 20/30.  For the next 6 months while my eyes healed I gradually 
became more myopic. I stopped around -4.00 diopters, which, of course,
put me in range of RK.  Needless to say, I'm a very happy camper!
I figured it would be worth it if they could get me to the point
where I would use glasses only for driving, but I had no idea they
could take me to 20/20.  
                         ==============

The following information was kindly contributed by Dr Robert Maloney M.D
(maloney@jsci.ucla.edu) from patients that have had RK performed.  Details
and experiences of the patients are given below:

ALK#1:
ALK OU- Hyperopic, Before OD +2.75, OS +1.25, Presently 20/20 O.U

"I think it's the best.  I would recommend this surgery to anyone with
not so great vision.  Trust me, do it!.  I took my glasses on a fishing
trip and threw them in the middle of the ocean."

8.7 Costs of Surgery:
-----------------------

Costs per eye (approximately)
	USA - US$1500
	NZ  - NZ$1650
	AUST-  A$2500


8.8 Further information on Procedures:
--------------------------------------
The supplement to volume 9 No. 2 (March - April 1993) of the Journal of
Refractive and Corneal Surgery has a great number of references to PRK and
RK. SLACK - the publisher - at USA 609-848-1000 to get a copy of the
issue that is exclusively concerned with the excimer laser manugactured
by Summit Technology.

Also in this supplement (pages 5121-2) is a report of an individual's
personal experience with PRK.



8.9 Location of Places Performing Surgery
-----------------------------------------
URL: http://www-or.stanford.edu/~mob/RK
(Also contains index of all surgery centres that are on the net)

In Australia
  Dr Unger of the Camberwell Eye Clinic who is associated with
  the Excimer Laser and Research Group, Dept of Ophthalmology,
  University of Melbourne.

  Sydney Refractive Surgery Centre
  Mater Misericordiae Hospital
  North Sydney, NSW.

  Lions Eye Institute
  2 Verdun Street
  Nedlands 6009
  Western Australia
  (09) 346 2801 Fax (09) 382 1171

In New Zealand
  LAZERSIGHT  
  Anglesea Clinic
  Anglesea St
  Hamilton
  New Zealand
  Ph. 00-64-7-839 4067
  Fax. 00-64-7-839 4071

  Dr Peter Ring 
  Eye Surgeon
  4/102 Remuera Rd
  Remuera
  Auckland 5


In Canada
  Dept of Ophthalmology 
  University of Toronto
  Ontario

  Dr Don Johnson
  London Place Eye Centre
  New Westminster, Vancouver B. C.

  Dr Peter Stockdill & Dr Murray McFadden
  20644 Easleigh Crescent, Suite 103
  Langley, B.C Canada
  Phone (604) 530-6838, 1-800-669-0616
  Fax (604) 535-6258

  The Chinook Laser Eyecentre
  Drs. Thad Demong, Don Parker, Ron Jans, and Ron Culver
  Suite 602, Chinook Professional Building
  6455 MacLeod Trail
  South Calgary, Alberta
  T2H 0K9 Canada

  Telephone: (403) 299-9811
  Fax: (403) 253-8608
  Toll Free (North America): 1-800-976-EYES (3937)
  E-mail: rickettn@cadvision.com


In USA
  FDA approval has been made for the Summit laser and a newer system, the
  Chiron Technalas is expecting approval in early 1997

  Dr Robert Maloney
  Jules Stein Eye Institute
  100 Stein Plaza, UCLA
  Los Angeles, CA 90024-7003
  UCLA
  rmaloney@jsei.ucla.edu

  Emory University Vision Correction Group
  404-321-0111

[This list is far from complete.  If you know of other places doing PRK
please let me know so I can add them to the list. Also there are an 
increasing number of WWW sites that are indicating refractive surgery]  


8.10   OrthoKeratology
---------------------
Fitting RGP contact lenses to change shape of cornea.
[ more details will be provided ]

-- 
Grant Sayer 
EMAIL: grants@research.canon.oz.au                PHONE: +61-2-805-2937
SNAIL: Canon Information Systems Research Australia
       1 Thomas Holt Drive, North Ryde, Australia 2113

User Contributions:

Comment about this article, ask questions, or add new information about this topic:

CAPTCHA




Part1 - Part2 - Part3 - Part4 - Part5

[ Usenet FAQs | Web FAQs | Documents | RFC Index ]

Send corrections/additions to the FAQ Maintainer:
grants@research.canon.oz.au





Last Update March 27 2014 @ 02:12 PM