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- From: grants@research.canon.com.au (Grant Sayer)
- Newsgroups: sci.med.vision,sci.med,sci.answers,news.answers
- Subject: sci.med.vision: Frequently Asked Questions (FAQ), Part 4/5
- Supersedes: <faq-part4_843777040@research.canon.com.au>
- Followup-To: sci.med.vision
- Date: 19 Feb 1997 08:32:00 +1100
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- Summary: This posting contains a list of Frequently Asked Questions concerning
- vision and eyecare.
- Xref: senator-bedfellow.mit.edu sci.med.vision:22075 sci.med:202853 sci.answers:5925 news.answers:95062
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- Version: $Id: faq-part4.txt,v 1.18 1996/03/13 00:40:28 grants Exp grants $
-
- +============================================================================+
- 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
-