 In this presentation, we'll discuss glaucoma surgery and a few of the salient points regarding some of the more common surgical approaches. Again, I'm Charles Weber, and thank you for tuning into this lecture. We'll go over intraoperative gonioscopy and its steps, we'll go over trabeculectomy, its general overview, a very basic overview, and some of the goals that at the time of surgery and following that will produce the most successful outcomes, as well as the salient points regarding its postoperative care. Also go over laser trabecuoplasty in the review of this procedure and the different techniques. The steps to intraoperative gonioscopy include a temporal approach to reach the nasal angle. So for example, following cataract surgery and planning to insert a trabecular micro bypass stent, the patient can be left with their temporal orientation to the surgeon, and this allows for the surgeon to reach the nasal angle. The patient's head is tilted 30 to 40 degrees away, again, nasally for the patient. The microscope is rotated temporally to a similar amount, again, 30 to 40 degrees, to allow for the line of sight to the microscope and its microscope light to be roughly parallel to the iris plane. A Schwann Jacobs style gonioprism is generally what's used in these settings. So in the photographs depicted here, we can see that the microscope has been tilted. The patient's head has also been tilted, which is allowing for visualization of the nasal angle. Here is the gonioprism, and it's not fully applied to the patient's cornea, so we don't see the trabecular mesh work and angle structures in the image, but this shows the general orientation of the patient's head and the gonioprism's angle of approach. Moving on to trabeculectomy, the general steps for this procedure includes informed consent to the patient and setting appropriate expectations. The recovery time from trabeculectomy is different than, say, cataract surgery, and these patients should be made aware of the fact that their recovery is generally going to be on the order of weeks rather than hours or days. Anesthesia can be done either topically or retro bulbar. A conjunctival pyritomy is created after placing an attraction suture, and I prefer a fornic-based flap with the pyritomy started near the limbus. This is followed by cauterization of the episcleral blood vessels and dissection of the scleral flap. I like to pre-place flap sutures at the corners of the trabecular to be flap before creating my trabeculectomy punch. My punch is oriented in a way that's more anterior and generally only includes a section of corneal and decimates tissue rather than inclusion of any of the ankle structures. This prevents me from needing to perform a peripheral urodectomy. If a more posterior punch is performed and iris tissue enters into the punch space, a peripheral urodectomy should be performed. This is followed by tensioning of the flap sutures, and they should be tensioned in such a way to allow some initial flow through the trabeculectomy site, but also sufficiently tight to prevent hypotony. And then finally, a watertight conjunctival closure is performed to ensure that the patient forms a bleb of proper morphology. A link that I'd recommend to everyone view is provided by Ike Ahmed on YouTube, which is very similar to my own technique, and this particular link is to a combined cataract surgery and trabeculectomy. The general goals of trabeculectomy for the most optimal outcome include a wide application of an antifibrotic agent, such as mitomyosin C, using either a sponge or injection technique. I prefer an injection technique, which allows for a very broad area of treatment. I perform the injection of mitomyosin C preoperatively before the patient is prepped and draped for surgery, and then by the time I've begun the surgery, the mitomyosin C has been fully uptaked into the tissue. Flap dissection should be performed in such a way that allows for controlled posterior-directed flow, and this generally requires a flap of about three millimeters by three millimeters in size. This also should not be fully cut to the limbis, leaving the cut edges somewhat posterior to the limbis, again to direct flow posteriorly rather than anteriorly. The flap suture, again, should be tensioned in such a way to allow initial flow, but tight enough to prevent hypotony, and these can be done in an adjustable fashion or in a non-adjustable fashion in which case laser suture lysis can be performed postoperatively. A watertight conjunctival closure ensures that a diffuse blab is created, and early leak can prevent the development of proper blab. Postoperative medications include a topical antibiotic, generally four times a day for the first week, and then that antibiotic is stopped. A topical steroid should be used quite frequently. For example, I generally prescribe penicillin acetate 1% every two hours for patients in the immediate postoperative period, and I only prescribe psychoplegia when indicated. The first postoperative day is important to ensure that there is no wound leak at the conjunctival incision, and if a wound leak is present, a bandage contact lens can be placed and the patient may be placed on an aqueous suppressant. Assess the chamber depth, and a shallow chamber may require the patient to be placed on psychoplegia. This should also prompt closer examination for a leak at the conjunctival incision, as well as for any evidence of aqueous misdirection. Assess the blab morphology, and a flat blab can indicate a couple of different things. A limited flow would be associated with increased intraocular pressure, and a low flow may again indicate leak. Assess the posterior segment looking for crudal effusion and any evidence of crudal hemorrhage. Subsequent weeks, the blab morphology should again be assessed, and a limited flow or low flow through the tereclectomy flap and into the blab can be assessed through ocular massage and digital pressure. If the massage produces a raising of the blab and significant lowering of the pressure and may cause some hesitation in licing or releasing one of the flap sutures, if it does allow for greater flow and you assess that there is a limited risk of hypotony, the flap suture should be liced or released. Continue the topical corticosteroid very frequently for at least 6 to 8 weeks postoperatively and taper once stable. This is important as if it is tapered too early, then additional fibrosis and failure of the tereclectomy may occur. This is an example from one of my own patients where I was the surgeon for the right eye and the patient had a previous surgery for his left eye done elsewhere. With an injection technique we've achieved a low diffuse blab that has a moderate vascularity to it. We can see that it's non overriding and well covered by the patient's lid. This is in contrast to the patient's left eye which has a more focal, cystic and elevated blab that actually is visible when the patient is looking directly forward. Moving on to laser trabeculoplasty, again the general procedure includes informing the patient of what's to be done and what they can expect related to the procedure. Topical anesthetic is applied to the eye and then using a mirrored gonioscopy contact lens with a viscous coupling agent the laser is applied to the trabecular meshwork. This is done in non overlapping and adjacent laser applications including 180 degree or 360 degree treatment depending on their particular patient. Argon laser trabeculoplasty is a green laser in the 455 to 529 nanometer range. The spot size is set to 50 microns with a .1 second duration. The power ranges from 300 to 1000 milliwatts typically and is titrated depending on response. The left hand image depicts how the laser is applied to the trabecular meshwork by reflecting it off of the mirrored goniolens and then applied to the trabecular meshwork. The middle image is of a Latina SLT lens which could easily be used for ALT as well which is a single mirrored flange to goniomirred lens. The right hand image shows where the ALT spots should be applied to the trabecular meshwork where the pigmented and non pigmented trabecular meshwork meet. Selective laser of trabecular plastic is a 532 nanometer ND-EAG laser which has a 400 micron spot size which is non-adjustable. Generally takes .4 to 1.2 millijoule bursts of 3 nanosecond duration for the desired effect. This was first described in the 1990s by Latina in Park. We see in the image at the bottom part of the screen ALT has a wider spacing between spots and again is a smaller spot size. SLT is a more broad application with spots being adjacent but non overlapping to one another. This video depicts how SLT is performed and we see that in this case the laser energy is properly titrated to produce an alternating spots, champagne bubbles that are emitted from the trabecular meshwork indicating the proper setting of the power. Again it's a broad diffuse beam that's just generally applied to the trabecular meshwork not hitting iris and not hitting corneal endothelium. Selective laser of trabecular plastic produces a selective thermolysis and the fluence levels delivered to the trabecular meshwork are thousands of times lower than ALT which results in decreased thermal damage and this allows SLT to be repeated in subsequent years if needed. We can see in this electron microscopy image following ALT versus SLT the quail of necrosis of ALT in the left hand image and in the SLT image that there's really no change in the trabecular meshwork morphology even on electron microscopy. Again this is just a general overview of intraoperative gonioscopy trabeculectomy and laser trabecular plastic.