(In experienced hands, laser treatment of eye floaters is perhaps the safest procedure of intraocular eye surgery. The U. S. Food and Drug Administration when approving YAG lasers for this procedure, classified this as a non-significant risk procedure.)
The incidence of significant damage to the retina from treatment of floaters using a pulsed, YAG laser has been zero. This zero incidence includes all the cases in the world medical literature (see World Literature page of this web site) and all of Doctor Karickhoff's cases. Doctor Karickhoff has placed thousands of laser shots into the vitreous, has done this procedure on many patients who formerly had retinal tears, and has done the procedure in a few patients who have had retinal detachment surgery. Even in these patients with known retinal deterioration, the procedure has never caused significant retinal damage.
With the zero incidence noted above, patients should still realize that posterior vitreous detachments, retinal tears, and retinal detachments which are usually age related do occur regularly in patients who have never had eye surgery. Therefore, it is possible that these conditions could occur months or years after a patient has had laser treatment for floaters and be related or unrelated to the laser procedure.
The incidence of significant damage remains zero because the retina is protected in 8 different ways on each laser shot.
(The numbers on the drawing apply to the paragraphs below.)
1) The laser beam in this procedure is not a parallel beam that could miss the floater and then hit the retina with full power. Instead, the beam is converging at a 14 degree angle as it leaves my laser. It is converged more by the surgical contact lens, by the cornea, and then by the eye's lens, bringing the beam to a pin point focus on the floater. Behind the floater, the beam [if it is not all blocked by the floater and the plasma shield (see 5 below)] immediately diverges so that its power is greatly reduced, spread out, and defocused when it reaches the retina.
2) The laser beam is invisible. Because it is invisible, there is very little reaction with tissues anywhere along the beam except where it comes to a pin point focus on the floater.
3) A special surgical contact lens that focuses the beam away from the retina is used in every case. This contact lens reduces back scatter to the retina and holds the eye still. Dr. Karickhoff designed two surgical contacts lenses for treating floaters.
4) The phenomenon which obliterates the floater is called "optical breakdown". In optical breakdown electrons are stripped off atoms, heat is produced for a few nanoseconds, and destruction and vaporization of the floater occurs. This occurs only where the laser comes to a pin point focus (on the floater). There is no optical breakdown in front of the floater or behind it (near the retina).
5) Any time there is optical breakdown, a plasma shield also develops. In a plasma shield, which is located immediately behind the floater, the vitreous turns black for a microsecond, blocking the laser beam from going towards the retina.
6) Each time the laser is fired, it severs vitreous strands that can pull on the retina. This is helpful because one of the main causes of retinal tears and detachments is vitreous pulling on the retina.
7) There is a tiny shock wave created in the vitreous each time the laser is fired. Some of this shock wave is transmitted to the retina, compressing it against the underlying layer. However, in the history of this procedure there has never been retinal damage from this shock wave when using a modern, pulsed YAG laser. The strength of the shock wave is monitored on every shot since it is transmitted through eye to the contact lens, and then to the surgeon's fingertips holding the contact lens. If there is any significant shock wave felt, the surgeon reduces the laser power.
8) The light we use to see the floater is simultaneously illuminating the retina. So on every shot, the distance from the floater to the retina is monitored.