DSAEK is a new corneal graft transplant technique
where the unhealthy, diseased, posterior portion of
a patient's cornea is removed and replaced with healthy
donor tissue obtained from the eye bank. Unlike conventional
corneal transplant surgery known as penetrating keratoplasty
(PKP), the DSAEK procedure utilises a much smaller
surgical incision and requires fewer corneal sutures.
This usually results in more rapid visual rehabilitation
for the DSAEK patient and also better post-operative
visual acuity.
Who is a candidate?
DSAEK is indicated for those patients who have corneal
pathology located on the posterior aspect of their
cornea known as the endothelial layer. When endothelial
cells are healthy, they function as a "pump-leak system"
to provide nourishment for the cornea. In other words,
these cells allow nourishing fluid from inside the
eye (aqueous humor) to leak into the cornea. After
the corneal cells have been nourished, the cells pump
the fluid out of the cornea. If the endothelial pump
is compromised for any reason the cornea will over
hydrate and become cloudy. This most commonly occurs
in patients who have sustained trauma to the endothelial
layer during complicated cataract surgery or patients
who have an inherited disease of the corneal endothelium
known as Fuchs' Endothelial Dystrophy. Such patients
are good candidates for the DSAEK procedure. It is
also indicated for patients with endothelial rejection
and bullous keratopathy.
The DSAEK Corneal Transplantation Procedure
The first part of the DSAEK procedure includes removal
of the unhealthy, compromised endothelial cells and
attached Descemet's membrane. The second part of the
procedure involves replacing this unhealthy tissue
with healthy cells from a donor cornea. The entire
intra-operative procedure is performed in about 20
to 30 minutes.
Approximately 30 minutes before the DSAEK procedure
the patient is sedated. The DSAEK procedure can be
performed under local or topical anaesthetic. DSAEK
is a microsurgical technique that is performed under
a special operating microscope.
Preparation of the donor tissue has been greatly facilitated
by the use of the microkeratome. The microkeratome
has been used for decades in refractive surgery and
is most commonly used today to cut the flap in LASIK
surgery. The donor tissue for the corneal graft is
machine cut rather than hand cut and has a smooth
surface which enhances visual recovery.
When the procedure is completed, the small incision
site is closed with two or three sutures (much less
than with Penetrating Keratoplasty procedures) and
the patient is sent home to return the next day for
follow-up.
Post-op visual recovery varies depending on the severity
of the corneal cloudiness prior to surgery, but is
much faster than with Penetrating Keratoplasty (PKP)
procedures. Most patients notice improvement in their
vision during the first two weeks after surgery with
continued improvement during the next four to six
weeks. This recovery represents a dramatic improvement
over the time required following conventional corneal
transplant surgery (PKP), which usually takes six
to twelve months.
