I have been to 4 different Lasik consultations to try and find a common ground to all of my questions. At each of these places, depending on the tool they use, my pupil size has varied from 6.8 to 8.2. This is a big difference. One of the four doctors told me that he recommended waiting for better technology but also said he would perform the surgery if I still desired. The other three said I was a good candidate.

I have high myopia - around -7 for both eyes in contacts. No or very little astigmatism. And my corneal thickness is 625 for both eyes. In your opinion am I a good candidate?

What is the largest amount of area that I can get lasered with the amount of cornea that I have? Two of the four doctors (both of them were NOT the two that found me to have the 8mm pupils) did not suggest going out the full 8mm on the laser. They thought it would be using up too much tissue. What is the largest/safest amount of tissue I can get lasered? My concern is that even if my pupils only open up to 7-7.2mm during normal dark activty the fact still remains that in complete darkness (as measured in one facility) they do open up to 8mm. One doctor argued, "Well who sits in compete darkness?" We all do, when we drive at night, especially in a rural area.

Pupil size issues are complicated - and it would be great if one could perfectly predict the exact amount of the ablation diameter required to avoid any night time vision problems. But that is not the case, since some patients with large pupils do not have any night time vision problems when treated with a smaller ablation zone (such as a 6.5mm ablation zone for an 8.0mm pupil size), while others have severe night time vision problems. As well, some patients with smaller pupil sizes at night can still have bothersome night time vision problems.
So what is the solution. I personally think that one major issue is that the LASIK flap itself induces some aberrations (according to work by Dr. Durrie from Kansas City) - while surface ablation does not seem to induce aberrations.
A second issue is: what is the perfect ablation size? The wider the ablation size, the deeper the ablation. For example - a 6.0mm ablation diameter removes 12 microns per diopter. On the other hand, and 8.0mm ablation diameter removes 21 microns per diopter. So for a 7 diopter myope, approximately 147 microns would be removed (versus just 84 microns for a 6.0mm ablation).
A major issue with increased ablation depth is that the risk of corneal haze is increased with increasing depth of the ablation. So a very wide ablation can increase the risk of corneal haze after PRK. Similarly, the risk of ectasia increase with increasing depth of the ablation.
One method to try to reduce the risk of night time aberrations is to add a transition zone. The transition zone feathers out the treatment. Recent studies by Steve Schallhorn in San Diego, John Doane in Kansas City, and Dick Lindstrom in Minnesota found that the risk of night time vision problems was reduced when the VISX 6.5mm optical zone along with the transition zone was used. I have not personally seen the details of these studies, so there may be some issues with these studies.
So what to do.

Option 1: Wait for Wavefront - which will allow the wavescan unit to image a person's eye and then the laser will be programmed to treat the aberrations of the eye. The VISX system allows the ablation zone to be expanded to any width, so this may be one option for you.

Option 2: Faced with a similar situation, I treated a -7.0 myope with 8.0mm pupils on the Autonomous laser with the 7.0mm optical zone along with a 1.0mm transition zone. It has been more than 2 years since her PRK, and she reports excellent night time vision and she has no corneal haze. If you were to consider PRK, remember the importance of haze prophylaxis - which includes avoiding significant UV exposure, oral vitamin C, and possibly even intraoperative mitomycin C.
I should also point out that every person is different, and we carefully discussed the issues of a wider and deeper ablation versus the ablation we chose.
I hope this helps provide some general information.

Best regards

Bill Trattler, MD
Miami, FL

Thank you for taking the time to respond. I am torn between my impatience of not being able to see without contacts and my hesitance of not wanting to mess up my corrected 20/20 vision. I can only hope that my impatience does not get the best of me before Wavefront advances enough technologically for me to utilize it. Thank you again for your time and your advice.

I was considered moderate myopic (-4.5) and a good candidate, had my surgery performed one year ago on the Visx Star S3 laser (6.5mm with a blend to 8.2mm) and now suffer with severe starbursting and halos at night.
Alphagan P, used to constrict my pupils at night provides relief.
My pupils were measured at 7mm in darkness.
I've also corrected my mild residual refractive error (-.5) with contacts with no improvement.
Proceed with caution...

I was considered moderate myopic (-4.5) and a good candidate, had my surgery performed one year ago on the Visx Star S3 laser (6.5mm with a blend to 8.2mm) and now suffer with severe starbursting and halos at night.
Alphagan P, used to constrict my pupils at night provides relief.
My pupils were measured at 7mm in darkness.
I've also corrected my mild residual refractive error (-.5) with contacts with no improvement.
Proceed with caution...

...of whether or not your pupil is 6.8mm or 8.2mm or anywhere in between, you should not have RS. They are just plain too big, given your scrip of -7, to escape night vision problems. You've got some hellaciously thick corneas, tho, so they could zap you over and over to try and get it right.

You can hear about Laser XYZ doing this ablation zone X and transition/blend zone Y, yadda yadda yadda, and all that neat tweaky stuff, but the bottom line is that you are at a higher risk level for post-op vision problems due to pupil size.

Spend some more time on the web. Do a search with the parameters "LASIK Complications" and the like and you will see what I mean.

I had consultations with 5 different doctors in my area until I finally felt comfortable with one of them. The doctor I utimately decided on was willing to go out to a full 8 millimeters (no transition zone) after measuring my pupils to be at 7.9. It has been almost one month since my surgery and I currently have no glare or halos to deal with. Just wanted to share my experience for anyone interested.

Thanks.

I am glad to hear that things have gone well.

Best regards

Bill Trattler, MD
Miami, FL