Comparison of laser vs non-laser glaucoma treatment?

Question:

I am having unstable IOP. In addition,the preservative BAK in my eye

drops appear to be giving me trouble. I finally decided that

surgery,trabeculectomy is the way to go. My left eye suffers severe

reduction of central vision because of a central retinal vein occlusion.

The trabeculectomy is to be done on my "good" rightey to preserve its

central vision. Needless to say, this makes me nervous.

I was surprised to find out that the surgery is planned to be true

cutting rather than laser based. I was under the impression--perhaps

incorrectly--that laser treatment avoided much of the risk associated

with actual cutting. Where can I get a good comparison of the pros and

cons of laser surgery as opposed to scalpel surgery? I want to be armed

with knowledge when I ask more questions.

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Answer:

I have a non-surgery bias. Just how unstable is the IOP? And could
other eye drops not using BAK be tried? I am a Xalatan user and "side
effects" don't seem to be a problem. Uses BAK as I understand. What
effects are you having?