Primary Retinal Detachment

Technique 61
solution; however,these need to be started 24–48 h prior to the procedure
with frequent use to substantially affect the ocular flora,
limiting their usefulness as a true prophylactic method in this setting.
A wire-lid speculum is used to open the lids, avert the lashes
from the field, and protect the lid margin from cryopexy damage.
If the patient is to undergo a one-step procedure, then cryopexy is
performed prior to gas injection, as small breaks may be difficult
to visualize following gas injection. Cryopexy is the preferred
method in cases where media opacities limit the view, when the
break(s) are located in the far periphery, or when there is underlying
pigment epithelial atrophy. Laser, via a two-step method, is
preferred with bullous superior detachments with large retinal
breaks, when breaks occur over a previously placed buckle element,
and with posteriorly located tears. Some surgeons feel that there
is a lower incidence of PVR with laser retinopexy compared with
cryopexy. Laser can be difficult to perform through or around the
gas bubble and will not provide adequate adhesion if there is still a
small amount of fluid present near the tear site. Small breaks may
be difficult to find with the laser once the retina is reattached. Laser
might form a chorioretinal adhesion faster than cryopexy, which
decreases the critical duration of required post-operation positioning.
Multiple rows of confluent laser are placed around each
tear with careful attention to carry the treatment anterior to the
ora serrata. It should be noted that the two methods are not
mutually exclusive, and many instances are best managed by a
combination of both modalities.
Preparation of the chosen gas is performed by withdrawing gas
from a cylinder via a valve system through a Millipore filter into a
1-ml or 3-ml syringe. The valve, tubing, filter, and syringe are
flushed with gas once, and the process is repeated to eliminate
room air from the system. High pressures may damage Millipore
filters, so care must be taken to maintain lower pressures during
gas filtration. The filter is replaced with a 30-gauge needle, and
excess gas is pushed out of the syringe until the desired amount for
injection remains behind.