Glaucoma Surgery (Trabeculectomy, Laser Trabeculoplasty, Drainage Device)
Updated On: July 23, 2026
Anesthetic Approaches
The globe is open partway through - once the anterior chamber is entered, a cough or a strain can expel the contents of the eye. That is a blinding complication, and preventing it is the anesthetic task rather than a courtesy.
Plan the emergence at the start - a smooth wake-up with no coughing or bucking has to be designed into the technique, not attempted at the end. Decide how you will achieve it before you induce.
Vomiting threatens the result - retching raises intraocular pressure against a fresh fistula or a new bleb. Give antiemesis prophylactically, because the consequence is a failed operation rather than discomfort.
Most of these are awake - a trabeculectomy is usually done under local anesthesia with sedation, and a laser trabeculoplasty needs only drops. A general anesthetic is a choice for the patient who cannot lie still, not the default.
Stillness is the requirement - the surgeon is working at high magnification on a structure a few millimetres across. Sedation that causes restlessness, disinhibition or snoring is worse than none at all.
The head is away from you - the table is turned so the surgeon can sit at the head, and the drapes cover the face. Secure the airway or the oxygen delivery for a position where you cannot reach the patient quickly.
Carbon dioxide under the drapes - a sedated patient under a sealed drape rebreathes, becomes hypercarbic and then moves at the worst moment. Run gas under the drape and monitor the carbon dioxide rather than assuming.
The oculocardiac reflex - traction on the globe or the muscles causes sudden bradycardia, and it is commoner in children having angle surgery. Have an antimuscarinic drawn up and ask the surgeon to stop when it happens.
Retrobulbar block has its own risks - it gives ideal conditions and can cause brainstem anesthesia, globe perforation or retrobulbar hemorrhage. Watch the patient properly for the first few minutes rather than turning away.
These patients are old and medicated - glaucoma surgery is largely an elderly population on systemic beta blockers absorbed from their own eye drops, with the bradycardia and bronchospasm that implies. Take the drop history as a drug history.
Congenital glaucoma is a different case - an infant having goniotomy needs a general anesthetic, has a syndrome often enough to matter, and may need repeated examinations under anesthesia over years. Plan for the series, not the single case.
Tucked Arms (general considerations): Consider a second IV – once the procedure has started, it's going to be VERY difficult to handle IV issues – especially if your only IV has problems. Ensure the IV is running and monitors are still functioning after tucking the patient's arms.
Glaucoma is a progressive optic neuropathy, and although it can occur at any pressure, lowering intraocular pressure is the only treatment that changes its course. Aqueous humor is made by the ciliary body and drains through the trabecular meshwork into Schlemm's canal; when that outflow fails, pressure rises and the optic nerve dies slowly and irreversibly. Surgery is offered when drops have stopped working. Laser trabeculoplasty treats the meshwork itself and is done in a clinic chair with drops alone. Trabeculectomy creates a deliberate fistula from the anterior chamber to a subconjunctival bleb, and because scarring is what makes it fail, an antimetabolite is applied to the site. A drainage device does the same thing through a silicone tube leading to a plate sutured to the sclera. In infants with congenital glaucoma the angle itself is malformed and is opened directly by goniotomy or trabeculotomy, which is the one version of this operation that always needs a general anesthetic.
Laser trabeculoplasty - the trabecular meshwork is treated through a contact lens in a clinic chair, with topical anesthesia and nothing else.
Conjunctival flap and scleral flap - for a trabeculectomy the conjunctiva is opened and a partial-thickness scleral flap raised at the limbus under the microscope.
Antimetabolite application - mitomycin or fluorouracil is applied to the flap bed to slow the fibroblast response that would otherwise close the fistula.
Creating the fistula - the anterior chamber is entered at the base of the flap and a block of tissue removed, so the eye is open at this point and aqueous begins to drain.
Drainage device or pediatric angle surgery - alternatively a silicone tube is passed into the anterior chamber and connected to a scleral plate, or in a child the malformed angle is opened directly from inside.
Topical glaucoma drops are systemic drugs that nobody lists as medication. Timolol absorbed through the nasolacrimal duct produces measurable beta blockade, and in an elderly patient it explains an unexpected bradycardia, a blunted response to a vasopressor, or wheeze in someone with airways disease. Brimonidine causes sedation and apnea in small children. Acetazolamide causes a metabolic acidosis and hypokalemia. Asking what drops a patient uses, and treating the answer as a drug history rather than an eye history, is the single most useful preoperative habit on this page.
The reason the whole page is about pressure is worth stating plainly. Everything that raises intraocular pressure - coughing, straining, vomiting, a tight mask, head-down positioning, a depolarizing relaxant, hypercarbia - works directly against an operation whose only purpose is to lower it, and at the moment the globe is open it can empty the eye. Choosing a technique for this list means choosing one that keeps the pressure low from induction through to the patient sitting up in recovery.