Table 2: Anesthesia options for trabeculectomy, with main advantages and disadvantages

Technique		Main advantages-any surgery		Main disadvantages-any surgery		Main advantages-trabeculectomy		Main disadvantages-trabeculectomy		Special considerations for trabeculectomy
General anesthesia		Patient asleep and unaware May be the only option for uncooperative patient		Time Expense Personnel Needs hospital facilities Life-threatening complications		Good operating conditions; no chemosis or hemorrhage		Stay suture needed		Avoid systemic hypotension (ischemia may worsen visual field defect) Avoid postoperative nausea and vomiting (may cause choroidal hemorrhage)
Retrobulbar		Good analgesia and akinesia		Sight-threatening complications Globe perforation needle damage to optic nerve retrobulbar hemorrhage “wipe-out”, etc. Life-threatening complications brainstem anesthesia		Good operating conditions		Stay suture needed Risk of “wipe-out” May cause subconjunctival hemorrhage and chemosis May cause bulgy eye		Care with LA mixture (Table 3) Ensure intraorbital pressure is back to normal before commencing surgery (but avoid over-use of compression)
Peribulbar		Good analgesia and akinesia		Sight-threatening complications Globe perforation needle damage to optic nerve retrobulbar hemorrhage “wipe-out”, etc Life-threatening complications brainstem anesthesia		Good operating conditions		Stay suture needed Risk of “wipe-out” May cause subconjunctival hemorrhage and chemosis May cause bulgy eye		Care with LA mixture (Table 3) Ensure intraorbital pressure is back to normal before commencing surgery (but avoid over-use of compression)
Posterior sub-Tenon’s with blunt cannula (e.g., via inferonasal snip)		Good analgesia and akinesia Lower risk of sight-threatening or life-threatening complications, compared to peribulbar, retrobulbar		Sight-threatening complications Globe perforation needle damage to optic nerve retrobulbar hemorrhage “wipe-out” etc. Life-threatening complications brainstem anesthesia		Good operating conditions		Stay suture needed Risk of “wipe-out” More likely to cause subconjunctival hemorrhage and chemosis		Care with LA mixture (Table 3) Ensure intraorbital pressure is back to normal before commencing surgery (but avoid over-use of compression)
Anterior sub-Tenon’s with blunt cannula (e.g., by surgeon, during surgery)		“No risk” of life-threatening or sight-threatening complications Good analgesia		Potentially mobile eye		Good operating conditions No stay suture needed “Mobile eye” makes surgery quicker, easier Surgeon can give LA during surgery (start with topical)		Potentially mobile eye, need to ensure patient can cooperate subconjunctival hemorrhage and chemosis		In literature, some subconjunctival LA injections by surgeon are described as “anterior sub-Tenon’s”. Some surgeons prefer to use a stay suture, to stop eye movement Could convert to posterior sub-Tenon’s “on the table”, if needed
Subconjunctival		“No risk” of life-threatening or sight-threatening complications Good analgesia		Potentially mobile eye		Good operating conditions No stay suture needed “Mobile eye” makes surgery quicker, easier Surgeon can give LA during surgery (start with topical)		Potentially mobile eye, need to ensure patient can cooperate subconjunctival hemorrhage and chemosis Previously thought to be risk factor for bleb failure or leaky bleb		Best to give LA under operating microscope, to avoid vessels and minimize risk of hemorrhage or globe perforation Some surgeons prefer to use a stay suture, to stop eye movement Could convert to posterior sub-Tenon’s “on the table”, if needed Previous concerns about bleb failure or leaky bleb appear to be refuted by recent evidence
Topical and intracameral		“No risk” of life-threatening or sight-threatening complications		Potentially mobile eye Needs careful technique for good analgesia (e.g., time for LA to work, use gel LA or sponges or cocaine drops)		Good operating conditions No stay suture needed “Mobile eye” makes surgery quicker, easier		Higher risk of patient discomfort? Potentially mobile eye, need to ensure patient can cooperate Special drops/gel may not be readily available		Some surgeons prefer to use a stay suture, to stop eye movement Could convert to posterior sub-Tenon’s “on the table”, if needed