Laser settings

[golgi]

Was wondering if any of you had a good list of general laser settings for things such as PRP,focal,YAG capsulotomy/PI (YAG and argon), ALT, SLT, etc...Would be greatly appreciated!

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[rubensan]

along this same topic, does anyone argon before they YAG when performing a laser PI? some say is decreases the liklihood of bleeding.

Was wondering if any of you had a good list of general laser settings for things such as PRP,focal,YAG capsulotomy/PI (YAG and argon), ALT, SLT, etc...Would be greatly appreciated!

 

[idoc]

Yes, I always pre-treat with argon prior to doing a Yag. You need to have a small spot size (~50microns) with a relatively high power (500 or so). Place about 10-15 spots in a flower petal type pattern in a iris crypt in the supero-nasal quadrant in the far peripheral iris. This hopefully coagulates any iris stromal vessels and prevents bleeding when doing the Yag portion. I usually will start my Yag power at about 3 to 4 mJ, and it should only take about 5 - 10 shots to get that wonderfully rewarding gush of pigment and fluid. Hope that helps. Remember to check IOP about 1 hour post op, warn them about signs/symptoms of IOP spike and keep on pred forte qid for about a week to prevent inflammation.

 

[Visionary]

Varies depending on the equipment you have. We have an Argon/Krypton (514 nm green, 647 nm red), YAG (1064 nm), double-frequency YAG (532 nm). Here are the settings I use for the bread-and-butter laser procedures. Hope you find it helpful!

Suture lysis:
Argon, 300-800 mW, 50 um, 0.1 sec

ALT (don't do SLT):
Argon, 300-700 mW, 50 um, 0.1 sec, 50 spots @ ant TM

YAG capsulotomy:
YAG, 1.2-3 mJ, 1 pulse, offset 100

LPI:
for dark irides, pretreat Argon 400-800 mW, 50 um, 0.02 sec
treat YAG, 4-6 mJ, 1 pulse, no offset

PRP/retinopexy:
double-frequency YAG
indirect - start at 180 mW, 0.1 sec pulse, 0.25 sec repeat interval
direct - Rodenstock lens, 200-300 spot size, start at 180 mW, 0.1 sec pulse

 

[shredhog65]

I think you mean Argon for PRP/ Retinopexy? I like LIO better than the quad/superqaud.

I dont think pretreatment with argon is necessary for PI's. You should be able to get through with the YAG in a few shots. If too much pigment gets kicked up you can just let the patient sit for 10 minutes and try again (rarely happens). That being said, agron pretreatment may help in an iris that's thick, juicy, and dark (hispanics mostly).

SLT supposedly works just as well as ALT, can be repeated if necessary (ALT can't), and is a much quicker proceedure.

 

[Wolverine98]

There are lots of ways to do a PI. For blue eyes, I just go straight to YAG on high power.

If you're laying down an argon bed, it doesn't matter how many spots you make; it matters how deep you get.
For dark brown, cryptless irides, I start with a 200 micron spot size with the power between 300-400. I like to start low on the power and then titrate up based on the response. If you start too high, you get bubbles which can make the rest of the procedure more difficult. I lay a shallow bed with this, then I decrease the spot size to 50 microns (sometimes I'll also increase the power to around 500 for this) and pound away at the center of the bed I originally created. I usually go onto a high repetition rate, and sometimes it will take a couple of hundred shots before you're really deep.
Then I switch over to the YAG; I usually do around 4mJ, repeat 2; I like no offset, but that's really a personal preference issue. I aim deep, and then pull back to where I want to minimize the chances of hitting the cornea.

If they have nice deep crypts, I'll usually skip the first step of the 200 micron spot size argon and go straight to the 50.

For suture lysis I use 400mW, 50 micron, red laser, 0.07-0.1s. I like to use the red to minimize any effect on any blood vessels.

Dave

 

[Wolverine98]

I think you mean Argon for PRP/ Retinopexy? I like LIO better than the quad/superqaud.

I dont think pretreatment with argon is necessary for PI's. You should be able to get through with the YAG in a few shots. If too much pigment gets kicked up you can just let the patient sit for 10 minutes and try again (rarely happens). That being said, agron pretreatment may help in an iris that's thick, juicy, and dark (hispanics mostly).

You're forgetting comfort. Yes, you can get through a dark cryptless iris with just the YAG, but it's much less comfortable for the patient. In addition to that, as you mentioned, you have to take the extra time to let them sit if you stir up a lot of pigment, so it often takes longer when everything is added together. IME, you get a lot more inflammation afterwards, you're much, much more likely to get bleeding, and it's more likely to close (I try to make my PIs as small as possible while still getting the necessary flow through); the argon will remove some of the bloodflow to the area, and it also retracts some of the tissues away from the PI, so they can't pull back over your opening as easily.

SLT supposedly works just as well as ALT, can be repeated if necessary (ALT can't), and is a much quicker proceedure.

There's still significant debate over whether or not SLT works as well as ALT (or as long).

 

[ckyuen]

I always pretreat argon then yag, a lot of the time don't even use the yag, makes a lot nicer opening. My patients all have dark eyes so if you don't pretreat success rate will be a lot lower. I have a lot of asian hyperopes so it seems like I always doing pi's. in my white patients with light eyes pretreatment not necessary, plus they dont have a lot of pigment to absorb. Usually i go with 800-900 mw, 0.05 to 0.07 s, 50 um spot, and always go for crypt if available. then yag 3.4 mj to 4 mj 1-10 spots 25 -50 um post offset
yag cap 2 mj
slt 1.0 mj
prp 200 um superquad lens 0.07 to 0.15s 200-400 mw. with the pigmentation of my patients dont need a lot of power to do prp. good for retina but bad for cataracts as the red reflex is terrible in asians. Did not encounter that in hispanics or blacks, and whites it seems like they have a tapetum there is so much reflection. I had a doc visiting watch me do phaco and wonder how i was doing the rhexis b/c he couldn't see a red reflex, he though it was the video and asked to look through the scope then said that's a pretty crappy red reflex. It does make you good at doing the rhexis as I have done mature cataracts without t blue or icg.

 

[PDT4CNV]

I think you mean Argon for PRP/ Retinopexy? I like LIO better than the quad/superqaud.

Remember that other lasers can be used for retinal photocoagulation. Argon green is probably most common, but also krypton red, dye lasers, diode lasers, and the frequency-doubled YAG laser. The frequency doubled YAG laser converts the infrared wavelength at 1064nm to the green wavelength at 532 nm. Sometimes it is called a KTP laser because of the potassium titanyl phosphate crystal.

 

[Visionary]

I think you mean Argon for PRP/ Retinopexy? I like LIO better than the quad/superqaud.

No, as PDT4CNV correctly noted, dfYAG can be used for PRP. Works quite well, in fact. I always start with the BIO, but use a direct approach (our old Rodenstock works fine, but I've used Superquad) to work closer in or for macular laser. Have found that most patients prefer the BIO. I sure do, as it gives a better view (I use a 2.2 lens). I can also lay 1000 burns in 15 min with the repeater.

SLT supposedly works just as well as ALT, can be repeated if necessary (ALT can't), and is a much quicker proceedure.

None of our attendings perform SLT, and we have found ALT to work sporadically at best. Usually is our last gamble before trab.

You're forgetting comfort. Yes, you can get through a dark cryptless iris with just the YAG, but it's much less comfortable for the patient. In addition to that, as you mentioned, you have to take the extra time to let them sit if you stir up a lot of pigment, so it often takes longer when everything is added together. IME, you get a lot more inflammation afterwards, you're much, much more likely to get bleeding, and it's more likely to close (I try to make my PIs as small as possible while still getting the necessary flow through); the argon will remove some of the bloodflow to the area, and it also retracts some of the tissues away from the PI, so they can't pull back over your opening as easily.

Completely agree. If I am working with blue irides, YAG is pretty quick and easy, so I don't bother with pretreatment. Dark irides, however, respond better with pretreatment, and it's definitely more comfortable for the patient.

BTW, put the wrong Argon settings down for pretreatment. Have made the change above.

 

[BTS]

For an alternative view... we've had SLT for several years and don't do ALT at all - the results seem to be pretty much the same and re-treatment seems to be possible with SLT after 360 rx.

My SLT settings: 0.6-0.9 mJ (looking for "champagne bubbles") and 80-100 spots for 360 degree treatment

 

[Mirror Form]

None of our attendings perform SLT, and we have found ALT to work sporadically at best. Usually is our last gamble before trab.

Supposedly SLT/ALT work much better for some types of secondary glaucoma than they do for POAG (although you can still use them in poag).

 

[Wolverine98]

Supposedly SLT/ALT work much better for some types of secondary glaucoma than they do for POAG (although you can still use them in poag).

Often PXF and pigmentary glaucoma respond very well.

Dave