The laser is used to stop abnormal retinal blood vessels from
leaking fluid into the retina. Vision does not usually improve
with laser, but laser can frequently stop further loss of vision.
When the swelling of the retina or amount of exudate in the
macula has reached a critical stage, laser should be done so that
vision does not deteriorate further. Your own doctor can help
you evaluate your chances with laser and discuss the options with
There are two types of laser surgery for NPDR: Focal (or
specific) surgery and Grid surgery. With focal laser surgery,
the specific leaking spots in the retina are found by a
fluorescein angiogram, which is then used as a guide for the
laser in an attempt to stop the leakage. In some patients, all
of the leaking spots may be properly treated. In some patients,
all of the leaking spots may be properly treated, but they may
continue to leak, or new ones may develop. In such cases,
further leakage causes more swelling and worsening of vision.
Additional laser surgery frequently needs to be done in order to
stop new leakage, but again, the vision is not likely to improve.
In other situations, further laser surgery is not helpful and
should not be done.
In some cases of NPDR, blood vessels appear
to be leaking everywhere in the macula and not just in a few
specific areas. In such cases, a scatter of laser in a grid
pattern is placed across the entire swollen macular area. Grid
laser surgery has a fair chance of drying the macula and holding
vision stable. Grid surgery, however, infrequently improves
vision. Again your doctor will help you evaluate whether
specific (focal) or grid surgery, or a combination of the two, is
After the laser surgery, the patient will often see the
many small spots caused by laser burns. With time, the spots
tend to shrink and fade, and the patient will be less bothered by
them, though they will always be there.
Even when laser surgery
has successfully sealed the leaking vessels, new areas of leakage
frequently appear later, causing more swelling and more loss of
vision. The patient who is treated with laser should continue to
check the vision in each eye daily and tell the doctor
immediately if there are new changes, such as a return of
distortion or blurriness. Vision does not usually improve with
laser surgery, but if NPDR is discovered early enough, laser surgery may
stop further loss.