13 March 2011

Lay down face up with anesthetized, paralyzed eye.
Your lids will be held back. The surgeon keeps the eye irrigated.

Surgeon works through microscope. He works by sight, there can't
be much physical feedback from such delicate surgery. Its rather
amazing because he's operating on transparent structures.

Puts small incision through cornea into aqueus humor front chamber,
then a larger tunnel at 90 degrees to that.

Some docs use a ring to hold the cornea, and also draw markers on the cornea with
the same blue color used to mark meat. Sometimes the knives are
diamond blades, transparent.

Then reach in through bigger tunnel and tear a circle in the front of the capsular sac that encloses the lens.
Pull torn pieces out. Keep eye inflated with saline or a viscoelastic collegen fill.

Then use ultrasonic tool to destroy lens, and mild vacuum to suck it out.
All while infusing saline to keep the chamber (between the vitreous, back of the sac,
and cornea) inflated.

Then he folds up a soft plastic lens and inserts it into the now empty bag through
a tube passed through the tunnel in the cornea.
Little arms on the lens hold it in place.

Then you're done. 5 minutes. Next patient. Apparently on most patients you don't need
diathermy (electrosurgury, cautery) to stop bleeding or leaking cornea. They
can use sutures too, done manually with forceps and a needle.

But when they're cutting the tunnels in the periphery of the cornea, they shape it such
that internal corneal pressure closes the corneal flaps. Self-sealing flaps.

The machines that do this ultrasonic & suction are $100,000 with $5,000 handpieces. They use an IV
bottle on a pole for pressure and mild pumps for suction. The handpieces have
a hollow ultrasonic tip and tubes for water in, water and gunk out. The gunk goes into
a plastic bag attached to the machine. Otherwise they use tiny diamond or
metal knives --daggerlike, some of them, not just single edged.

Apparently certain drugs (flomax) messses with your irises and they become floppy
and can puff out. Surgeons can use hooks to keep the iris in place during surgery

Best not to need surgery, but if you do, it apparently works great. Nowadays the lenses
are trick, progressive or toroidal or tinted..

Amazingly this stuff only started mid last century. Now they're working on 3D computer
stereo optics for the doc, so he doesn't have to lean over a scope.