What do you know about a laser called the LaserScan LSX? I have a high myopia (-10) and 6-7 mm pupils in dim light. My doctor yesterday suggested I mught want to wait a few weeks and have Lasik with this laser versus the VISX because it has a wider ablation zone and thus a lower risk of side effects due to pupil size. Please advise your comments. Thank you.

Is this laser FDA approved? Or are you going to be entered into a study? I am familiar with most lasers in the U.S. and I have not heard of this laser. It (to my knowledge) is not FDA approved. You may want to check further into this laser
As for the VISX laser- it currently can treat up to a diameter of 6.5 mm. The problem is that as you widen the diameter of the treatment, the depth of the treatment increases exponentially. For example, increasing the width of treatment from 6 mm to 7.0 mm will required the laser to remove 50% more cornea to achieve the same effect. For people who are very near-sighted, it is possible to remove too much cornea, so one's doctor must be cognizant of this issue.
i hope this helps answer some of your questions

Bill Trattler, MD
Miami,FL

Dr Trattler,

In you post you said the Visx can go to 6.5mm, then gave the example that if it went to 7mm it would take off more cornea?

So is it possible to go to say 7mm or more if you are a relativly low myopic with sufficent coreneal thickness? Do any Doctors ever do this?

Rob Fordham

The Laserscan LSX is FDA approved but only for a 5.5mm central optical zone. The one draw back to keep in mined concerning the Visx is if your Rx includes astigmatism the central optical zone is oval shaped with the narrow part of the oval being 5mm.

Excellent comment (and thank you Merlin as well). Please note that I answered this question in 1999 (so it is an old question and answer.
There are issues of optical zones and transition zones. I use the VISX laser, which can go to a max if 6.5 mm. Other lasers can potentially have a larger optical zone, but in doing so they consume more cornea. So this is onlyu appropriate for patients with lower degrees of myopia (obviously every case is different).
I hope this helps answer your question

Bill Trattler, MD
Miami, FL

I just went for a pre-op consultation, and was told my pupils are 6.4 and 6.5mm in dim light. The clinic I am considering uses the Lasersight LSX. If the LSX can only treat a 5.5mm optical zone, does that mean I am more likely to experience halo's in dim light? My prescription is quite low (-1.0 and -1.25 with a slight astygmatism in left). If this laser is not suited to my eye, can you recommend a laser that is?

If your pupil measures 6.5mm you could really cover a lot of bases by having a 7mm central optical zone created with a Bausch and Lomb Technolas 217. The 7mm central optical zone would be large enough to eliminate night vision problems associated with a small central optical zone. Dr. Jack Holliday a well know RS researher currently doing research for Lasersight beleives the shape of the transition area created by putting a 5.5mm central optical zone on a pupil measuring 6.5mm for example reduces contrast sensitivity at night. Dr. Horn at www.chicagolasercenter.com beleives by putting a 7mm central optical zone on a 6.5mm pupil eliminates the transition zone issue. This senario should be possible in your case because you have a low perscription and would likely easily have enough cornea thickness. I'm not a Dr. I have had lasik surgery and had a similar Rx as you had I known this info at the time of my surgery this is how I would have proceeded.

The LaserScan LSX in the US has an optical zone of 6.0mm and a total treatment zone of 7.0mm for treatments with a spherical equivalent of <-6.00 diopters. For -6.00 and above the zones decrease to 5.5mm and 6.5 mm, respectively. In the international version the zone sizes are variable and may go up to 10.0mm. Angela King, M.D., VP Medical Affairs, LaserSight Technologies, Inc.
>What do you know about a laser
>called the LaserScan LSX? I
>have a high myopia (-10) and
>6-7 mm pupils in dim light.
> My doctor yesterday suggested I
>mught want to wait a few
>weeks and have Lasik with this
>laser versus the VISX because it
>has a wider ablation zone and
>thus a lower risk of side
>effects due to pupil size.
>Please advise your comments. Thank
>you.

Dr. Gerald Horn at www.lasiksafety.com has listed the maximum FDA approved central optical zone for each laser currently approved in the U.S. The Laserscan LSX is listed at 5.5mm maximum FDA approved central optical zone.

I use a LADARVision laser with a laser eye tracking system. It is a small flying spot scanning laser similar to the Lasersight LSX and Bausch and Lomb Technolas 217. The LADARVision laser however has an FDA approved commercially available tracking system to keep the laser pulses on target in the face of a moving eye.

I can vary the treatment zones up to 8.0x10.0 mm. I routinely use the 7.0x9.0mm treatment zone for individuals with large pupils. It works great. I love the LADARVision system and like it because it incorporates features that no other FDA approved laser for LASIK has.

Shannon Wong, MD
Austin Eye Clinic
Austin, TX
www.austineye.com

Merlin,
I do not use the Lasersight laser, but I would think that the Vice President of Medical Affairs for LaserSight Technologies, Inc would not provide false information - unless that is what you are suggesting.
If you notice, Dr. Horn is highlighting the lasers that he uses as being superior to others based on the optical zone sizes. So he may have just taken the smaller optical zone size to help prove his point (which may be false) that he uses the better lasers.
Lasersight has a website - and they have a chart of the different lasers with their optical zones - this is the link:
http://www.lase.com/proinfo/laser.html
I have never used a lasersight laser, but again I think the company would know their own laser better than a doctor trying to promote his own lasers.

Bill Trattler, MD
Miami, FL

On the other hand, as I look at that chart produced by lasersight, I see that it is biased towards its own laser. For some reason, it says the VISX has a 5.5 mm optical zone when in fact the VISX laser has either a 6.0 or a 6.5 mm optical zone.
Again - it looks like it is very difficult to compare lasers.

Bill Trattler, MD
Miami, FL

DR. Horn claimed to have gathered this information from the FDA web site I don't know how to access the site but it would be the best source. I was not aware that the Lasersigh does not have an FDA approved eye tracker.

The chart leaves out some of the more recent lasers. Such as the Visx S3 upgrade or the MEL-70. This is marketing bullcrap. Of course today's technology is going to look better than last years. Don't believe the hype. This is like saying compact discs are the best music medium because they sound better than vinyl records, cassettes, and 8-tracks.