On the other hand, surgeons who prefer no eye movement will likely opt for blocks,
as will surgeons performing longer or more complex cases. The speed at which the
surgeon works is also a consideration. A phacoemulsification with an intraocular lens
implant may take anywhere from 10 to 30 minutes.
Block types
Although other types of blocks are also used occasionally — including the Sub-
Tenon's (episcleral) block and the van Lint (lid) block — the blocks of choice for
cataract surgery remain the retrobulbar and the peribulbar.
• Retrobulbar blocks. They involve injecting local anesthetic inside the muscle
cone. They block the ciliary nerves, ciliary ganglion, and cranial nerves III, IV and VI.
They're usually deeper than peribulbar blocks and require less volume to attain the
goal of no movement and no pain.
• Peribulbar blocks. They're usually injected above or below the orbit. The anes-
thetic solution is deposited within the orbit, but doesn't enter the muscle cone, which
makes them safer overall than retrobulbar blocks.
Incidentally, general anesthesia should probably be used only as a last resort —
with pediatric patients and/or with patients who can't tolerate blocks, or who can't
hold still. More on that later.
Pros and cons of topical
With topical anesthesia, chemosis and periorbital hematoma are minimal, and sub-
conjunctival hemorrhage is rare. Patients may worry that they'll feel pain, but most
are amenable when the method is thoroughly explained. And generally, topical is sig-
nificantly less painful than the administration of blocks. When patients understand
that they won't be completely asleep, but that they'll feel very comfortable and
relaxed, both surgeons and patients benefit. As noted, supplementing with appropri-
ate sedation improves the topical experience. The risks associated with topical are
minimal and it provides rapid eye recovery immediately after surgery.
While topical is safe and comfortable, it requires a cooperative patient. Some
Anesthesia Alert
AA
3 2 • O U T PA T I E N T S U R G E R Y M A G A Z I N E • M A Y 2 0 1 6
