A common problem after LASIK is the need to enhance the operation due to residual
spherical or astigmatic error. Recutting the flap is difficult because the centration
might not be the same, resulting in a possibility of small corneal losses along the
edge of the flap. Similarly, the depth might be different, resulting in a “double
cut” in the base and the potential for even more problems. Sometimes a recut is unavoidable
if the original flap intersects corneal scars or previous corneal incisions. Examples
would include a previous radial keratotomy or a previous corneal transplant. In these
cases the pre-existing incisions intersect with the flap incision causing increased
healing in the areas of intersection and the necessity to recut with the microkeratome.
For the cases with a simple flap on a “virgin” cornea, this technique allows a flap
lift up to 5 years after the original surgery.
The technique begins with the patient seated at the slit lamp. Place anaesthetic
eye drops in the eye. While the edge of the flap may not be visible in the operating
room under the operative microscope, At the slit lamp, the beam may be narrowed to
a slit and the edge of the flap is almost always visible. Using a 18 guage needle,
place the tip of the needle on the edge of the flap as seen in figure A. Press slightly
to indent the cornea (the needle is actually relatively dull and will not penetrate
the cornea without a lot of pressure). Move laterally toward the pupil as seen in
figure B. Be sure to make a large enough section of flap to be grasped in the OR.
As seen in figure C this will result in a portion of the graft edge which has been
dislodged. If, in the occasional patient, the edge of the flap is not visible, the
general area of the flap is known and the technique may be used to “explore” for
the edge since an area close to the margin, on the flap, may slide with pressure.
In the operating room I mark with an 8 zone RK marker and grasp the edge of the flap
with a 0.12 forceps very gently as seen in figure D. A blunt cyclodialysis spatula
is inserted into the “pocket” (figure C), in the plane of the previous microkeratome
incision, and gently inserted forward. Move the spatula back and forth while going
forward, then weep to the right and left across the bed as seen in figure E. It should
be relatively simple to dissect the bed however the edges will have a more firm attachment.
If the flap was made relatively recently, grasp the flap with the forceps and open
as seen in figure F. Otherwise, open the edge with the side of the spatula.
Click on any figure to see a larger picture.
Febbraro J-L, Buzard KA, Friedlander MH: "Reoperations after myopic laser in-situ
keratomileusis," Journal of Cataract and Refractive Surgery, Vol. 26, January 2000,