getting ready for lasik...... help please Lasik Expert.

If you are thinking about having Lasik, IntraLasik, PRK, LASEK, Epi-Lasik, RLE, or P-IOL eye surgery, this is the forum to research your concerns or ask your questions.

getting ready for lasik...... help please Lasik Expert.

Postby heero124 » Fri May 02, 2008 5:03 am

Hi,

I've been to 2 doctors in the past 2 days and completed the extensive test.

1) Dr. M1 [redacted] of [redacted]
and
2) Dr. M2 of [redacted] vision institute.


here's my prescription to the best of my knowledge:
Eye: Left
Base Curve: 8.4
Diameter: 14.0
Power: -1.50
astigmatism: -.75

Eye: Right
Base Curve: 8.4
Diameter: 14.0
Power: -1.00
astigmatism: -.50

~~~~~~ M1 ~~~~~
After the extensive exam,
they said my pupil size is 5 in light and 7 in the dark, and that I would be an excellent candidate for Lasik. He said because of my very low correction there's generally never any problems in correcting my vision.

They read my Corneal thickness as 470 in the left eye and 475 in the right eye
They said they'd use intralase to cut a flap at 110 microns, and then the zapping would only take off around 20mm leaving me with 340mm


~~~~~ M2 ~~~~~

After the exam, they said my pupil size was 6.5 and 6.8 (i for get which eye) they didn't tell me whether it was light or dark. Said I was a good candidate. I asked about pupil size and how it affects the flap. He said they have one treatmeant zone. I asked how what about different pupils? They said custom vue basically takes care of the mapping and the laser can go up to 8mm in treatment area. My pupils don't get to 8mm in dark.

They read my corneas as 485 and 475.


My question is really, what does it mean one treatment size? Like one flap fits all?

They both recommended Lasik, not PRK. M2 has done Cameron Diaz, Dennis Richards, Angelina Jole, and many of the extreme make over people, so I feel pretty confidant.

I'd just like to fully understand the pupil size, I feel that i'm getting the reach around regarding it from both doc's...
Both, however, said the chances of me seeing better than 20/20 are 99%. The nurse even demonestrated to me how 'tough' the flap is by rubbing her own eye... pretty vigorously.

I'd like to understand what "Large pupil outside the treatment zone (spherical abberation)" means

Thank you so much in advance.

Note: Names of surgeons and clinics were redacted.
heero124
 
Posts: 1
Joined: Fri May 02, 2008 3:15 am

Re: getting ready for lasik...... help please Lasik Expert.

Postby LasikExpert » Wed May 07, 2008 10:56 pm

heero124 wrote:1) Dr. M1 [redacted] of [redacted]


I am generally familiar with this doctor, but I have no direct information regarding his patients' outcomes.

heero124 wrote:2) Dr. M2 of [redacted] vision institute.


I am very familiar with this doctor. His patient outcomes have been certified by our organization to be at or above the norm. With a greater knowledge of this surgeon and his certification by our organization I will naturally have a bias toward this Lasik doctor.

heero124 wrote:here's my prescription to the best of my knowledge:


You are mildly myopic (nearsighted, shortsighted) with a moderate amount of astigmatism.

re: M1

If you read our article about Lasik pupil size issues you will see that patients with very low myopia tend to be much less likely to have night vision problems after Lasik or similar laser vision correction surgery.

An area of concern is how the pupil size was measured. A Colvard pupilometer uses infrared light in otherwise total darkness. Since infrared light is invisible, the pupils do not constrict at all. Even in low light environments the pupils tend to constrict slightly. A pupil size measurement with a pupilometer tends to be about 1.0mm larger than it would be in low, but visible, light. Since you do not expect to be able to see in total darkness, the "in the dark" reading may be misleading. You need to check with doctors' offices to verify you pupil size in a low light environment or total darkness.

Your corneas are on the thin side. Research indicats that so long as 250 microns of tissue remains untouched in a healthy cornea (more is always better) the cornea will remain stable. A thinner flap will reduce the depth of the disturbed corneal tissue, however you may want to discuss whether or not a surface ablation technique like PRK, LASEK, or Epi-Lasik would be appropriate. These surface ablation techniques eliminate the Lasik flap, but have a slower vision recovery and more discomfort.

You would have 340 microns of untouched tissue if all goes as planned, not 340 millimeters.

re: M2

The pupil size measurement is essentially the same between M1 and M2, but the issue of total darkness measurement persists.


What is fortunate is that your myopia and astigmatism are relatively small. This makes the optical ablation zone size a issue less significant.

Although the laser can go up to 8.0mm in treatment zone, the optical zone which fully corrects the refractive error is limited to about 6.0mm. The remainder is a "blend zone". This is very important for someone with high refractive error such as over 6.00 diopters, but is less important for someone with very low myopia.

The size of the optical ablation zone for your myopia may be 6.0mm (or other, depending upon the laser and other issues), however the optical ablation zone is narrower on one axis for astigmatism correction. It would be likely that the optical zone for astigmatism treatment will be elliptical and about 5.0mm by 6.0mm (variable). This means that there will be a bit less treatment on the narrow axis. This law of physics applies to all lasers and for both Drs. M1 and M2.

heero124 wrote:My question is really, what does it mean one treatment size?


It means that if all goes as planned, 100% of your refractive error will be resolved within the 6.0mm to 5.0mm optical ablation zone. A blend zone of up to 8.0mm may be used to gradually go from fully corrected to no correction.

If you had a higher refractive error, then night vision degradation like slight fuzzy halos around light sources may occur, however many studies have shown that there is no direct pupil size = halos formula and pupil size alone is a very poor predictor of night vision problems. It is a combination of pupil size, size of optical ablation zone, curvature of cornea, amount of correction, and other factors.

heero124 wrote:Like one flap fits all?


That is a totally different issue. The flap only needs to be larger than the treatment area. It's not an area where patients usually need to be overly concerned.

heero124 wrote:They both recommended Lasik, not PRK.


It's good to see both have brought up the subject of surface ablation and made their recommendations known.

heero124 wrote:M2 has done Cameron Diaz, Dennis Richards, Angelina Jole, and many of the extreme make over people, so I feel pretty confidant.


Patient endorsements - no matter how well known the patient - are limited to the circumstances of that one individual. You probably would not expect to put in Angelina Jole's contacts and be able to see well. Neither should you put too much emphasis in the results of a few well known stars. While it may be cool to have your eyes done by the same doctor who did Cameron Diaz, such endorsements have limited value as a measurement of a surgeon's ability. I would put much more emphasis on the fact that Dr. M2 has had his patient outcomes independently evaluated, or the answers Dr. M1 gives to our 50 Tough Questions For Your Lasik Doctor.

heero124 wrote:I'd just like to fully understand the pupil size...


Everybody would like to fully understand the pupil size issue. That is what makes it so difficult. Night vision quality depends upon many, many factors and nobody has figured out a solid method of exclusion/inclusion. You have the advantage of a very low refractive error, but the disadvantage of (maybe) large pupils. The best you will get is the knowlegeable opinion of the doctors who have actually examined you.

heero124 wrote:Both, however, said the chances of me seeing better than 20/20 are 99%.


I admire both doctors' confidence and I'm delighted that they both believe you will be successful, but I personally hate predictions for any kind of surgery. Yes, we conduct studies on Lasik results, but even if accurate, a 99% probability of 20/20 sounds too much like a guarantee (I know they did not guarantee anything) and can lead some people to not take Lasik seriously. Lasik is microsurgery on your eyes and even if there is a very high probability of success, no surgery is perfect.

I recently heard a doctor describe these kinds of predictions in an irreverent way. “If 100 people drove across the railroad tracks with their eyes closed, 99 would probably be fine.” That is a bit over the top, but it makes patients think about the importance of their decision.

Research regarding your question about pupil size and treatment zone indicates that the increased probability of night vision problems because of a larger than normal pupil is undoubtedly mitigated by the very low prescription. You have been examined by two doctors, one I know has patient outcomes above the norm, and both have come to the same conclusion. I have a bias toward Dr. M2 because he is certified by our organization, but since both are saying about the same thing I guess bias is not so much of an issue.
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