This is a cartoon video showing how a cataract surgery is done from start to finish! The first half is all cartoon animation, and in the second half, I show an actual surgery using the same steps.
length: 8:42 minutes
SCREEN SHOTS FROM THIS VIDEO LECTURE:
Cataract surgery is the main operation of the ophthalmologist. There are MANY
individual steps during this surgery, however, and this can be overwhelming
at first. To help you understand the technique, I’ve created an animated step-by-step
video of a cataract surgery from start to finish. The first half of the lecture
involves a cartoon animation of a cataract surgery. The last half shows an actual
live surgery. I’ve kept the orientation the same between the cartoon and the
live surgery to make this easier to understand. Hope you find this useful:
The first step is to create a paracentesis … a small incision through the
clear cornea. This is done with a side-port blade (there are many types). The
key here is to create a small incision that is big enough to get your instruments
and canula through, but no so large that it will leak.
Most of the anesthesia with modern cataract surgery is obtained with
topical lidocaine drops (or jelly). However, the inside of the eye can be sensitive
as well, particularly the iris muscle itself. Intracameral (in the eye) lidocaine
is injected into the anterior chamber to anesthetize the iris and decrease pain
Viscoelastic is then injected into the anterior chamber. This gel protects the
inner surface of the cornea and keeps the eye from deflating when we make our
main incision. There are several types of viscoelastic that can be used, with
dispersive and cohesive properties. I typically use VisCoat during this step
… the mnemonic I use is "VisCoat Coats the Cornea" … which is
exactly what I want at this stage in order to protect that delicate corneal
The main incision is made with a keratome through the clear cornea. I perform
my surgeries temporally, so I come in from the ear and point my instrument toward
the middle of the pupil. You are supposed to make a "tri-planner"
incision with this instrument … the idea here being that a stepped incision
will be more watertight and less prone to leak. To do this, you angle the blade-tip
upwards when contacting the corneal surface, angle it downward as you pass through
the stroma, then level out as you enter the anterior chamber. Does this really
work? Hard to tell, but certainly good practice to enter in this fashion.
The capsulorhexis is created starting with a cystitome … essentially a bent
noodle that "rips a hole" through the anterior capsule. Remember,
the cataract has three layers (like a peanut M&M candy). We are trying to
make a round hole through the anterior capsule (the front of the "hard
candy shell") so that we can access the inner two layers of the cataract
for subsequent removal. Its easy to start this hole with the cystitome needle,
but some people just use their utrata forceps to start this rip.
The capsule rent is then extended using utrata forceps. You have to be very
careful as you create this round hole, and peel the thin capsule in a tangential
manner. If you aren’t careful, the rip may "run out" into the peripheral
lens can cause major problems. The rip might even extend around the back of
the cataract during surgery and cause complications with dropped nuclear fragments
(and difficulty with placement of the implant). Thus, this is an important step
for making the rest of the case go smoothly.
Hydrodissection is performed next. This is when you inject BSS (basic salt solution)
fluid between the outer capsule and the middle cortex. This mechanically separates
the inner layers of the cataract from the outer capsule, facilitating the removal
of the inner cataract. When you perform hydrodissection, angle the canulla immediately
under the lip of the capsulorhexis and push your plunger slowly. As the fluid
cleaves a plane in the cortex, you will often see a "fluid wave" as
the fluid rushes across the back portion of the cataract. This is a good sign.
Tap down on the central nucleus occasionally to push the water out and further
help with dissection.
You want to make sure that the inner nucleus layer is truly dissected from the
outer capsule at this point. To do this, try spinning the nucleus with an instrument
(the blunt-tipped Connor wand is my instrument of choice). Carefully rotate
the nucleus … if it spins, you can proceed. If the nucleus won’t spin, then
you should probably repeat hydrodissection.
With a clear-cornea surgery like this, you can’t "eat up" the entire
central nucleus in one giant piece. Instead, it is better to physically break
it into smaller pieces and remove each individual "pie-slice" one
at a time. There are many ways to break up the nucleus. Most surgeons begin
by using the classic devide-and-conquer technique. This involves splitting the
lens into four quadrants, then using phacoemulsification to remove each piece.
I show this method with the animated portion of the video. With the live surgery,
however, I show a different method called a "horizontal chop" which
After dividing up the nuclear fragments, each one is removed with phaco energy.
Care is made to run the phaco machine such that the tip of the instrument is
roughly level with the iris. If you apply that vibration energy too close to
the inner cornea, it can cause damage to the delicate corneal endothelial cells
and create corneal swelling (that might not recover). If you run the instrument
too deep, you risk breaking through the posterior capsule. These "capsular
ruptures" really suck, because pieces of the nucleus can fall through into
the back of the retina and cause retinal edema post-operatively. These ruptures
also make it hard to place your implant securely at the end.
Careful manipulation pushes each of the fragments to the phaco tip. As you remove
the nucleus pieces, it becomes more and more important to utilize your second
instrument (in this case my trusty conner wand) to protect the posterior capsule.
By keeping your hand deep and under the fragment pieces, you hold the posterior
capsule back and keep if from jumping up into your phaco instrument.
After the inner nucleus is removed, there is still a lot of clear material hanging
out inside your capsular bag. This is residual cortical material (the middle
layer of the cataract). This cortex is removed with the IA handpiece which vacuums
it out. This is done carefully, as you want to peel that cortex off without
ripping your supporting capsule bag. The material under your incision site is
usually the hardest to get out, because you have to turn your IA instrument
over (an awkward rotation of the wrist) and pull that material out without causing
damage to your capsule.
Inflate the capsule
The cataract is out and the implant is ready to go in. However, you can’t just
inject that implant forthwith! It is better to reinflate that capsular bag with
some more viscoelastic. This will make the implant slide in better, and minimizes
the chance of it snagging or causing a rip in the capsule. We use a different
viscoelastic at this point … something called ProVisc. This is a cohesive
viscoelastic that doesn’t spread or stick too much, making it easier to vacuum
out at the end of the case.
Insert the Implant:
Finally, we get to insert the lens implant. The inserter we use is like an injector,
but you screw the plunger and it pushes the implant out (there are different
kinds of injectors). The implant is folded up inside the clear cartridge (like
a folded burrito) and unfolds like a flower into the capsular bag. As you inject,
you angle the leading edge of the implant through the capsulorhexis hole, so
that it goes inside the capsule.
The leading portion of the lens is already in the capsular bag, but you have
to push the trailing edge of the implant through the capsulorhexis so that the
entire implant unfolds properly. The haptic arms spring out at this point, and
secure and help center the central optic. You want the haptic arms to form a
backward-S configuration (like this graphic). Otherwise, the implant has been
put in upside-down and you have to fix this.
Now that our implant is in good position, you need to clean things up. The Irrigation/Aspiration
handpiece (the same one used during cortex removal) is used to remove residual
viscoelastic. Because we used cohesive ProVisc, the viscoelastic comes out pretty
easily. You’ll notice that the implant wobbles quite a bit during this step
… this is a good sign. It means that the viscoelastic underneath the lens
has rushed around the edge of the implant and into your instrument. We try to
get as much of that stuff out as possible, as it can clog the trabecular meshwork
and cause problems with pressure spikes the next day.
Hydrate the Incisions:
The final step is to secure our incisions. Sure, you could put sutures in them
(and sometimes we do) but if you have well constructed incisions … they are
small enough that they are practically watertight already. Instead, we hydrate
the edges of the incisions with BSS solution and a canulla. This swells the
surrounding tissue and keeps it from leaking. I also check the pressure at this
point by pushing on the eye with a q-tip to make sure it is reasonably normal.
At the end of the case, we remove the speculum, take the drapes off, apply
antibiotic and steroid eye drops, take a clear eye-shield over the eye, and
bring the patient to the postoperative area. While there are a lot of steps,
with time this surgery will become second nature and the surgery becomes a well-choreographed
surgery involving the surgeon, scrub tech, and circulating nurses each doing
their part. Fun!
You are a LIFESAVER, sir!
-from a medical student
Comment by N — July 19, 2013