54.6.1 General Considerations

¥Unlike with PPV, the VR traction is not eliminated.

¥To state, as many surgeons do, that pneumatic retinopexy does not address the VR traction, is erroneous. Much like SB, it weakens the traction that caused the retinal break, but, unlike SB, it also creates traction elsewhere.

Pearl

Injecting an expanding gas bubble into an eye that still has gel vitreous has two consequences. The VR traction in the area of the break weakens, much like a rubber band will lose some of its elasticity when held in an expanded state for extended periods. Conversely, the gas compresses the gel throughout the vitreous cavity, accelerating the syneresis process and yielding more room for gel movement once the gas bubble disappears. This result is more VR traction postoperatively, explaining the high incidence of re-RD due to a (Ònew or previously undiagnosedÓ) break.

54.6.2 Patient Selection

The failure of pneumatic retinopexy to properly deal with VR traction limits the type of cases in which it can be employed. The following are good candidates for the procedure:79

¥A patient who understands that positioning is crucial and failure to do so80 will have a major negative impact on the success of the operation.

¥Minimal VR traction as detected on careful biomicroscopy.

¥An RD of only one quadrant.

¥A break that is superior.81

¥A break that is small.

¥Single break or if multiple breaks are present, they are clustered within 1 oÕclock.

54.6.3 Surgical Options

54.6.3.1 Cryopexy, Followed by Gas Injection

¥A paracentesis prior to gas injection helps prevent the rise in IOP.

¥The most commonly used gas is 0.5 ml SF6.

79Those advocating this procedure gradually increase the list of potential candidates.

80Positioning and positioning as long as the gas bubble is present or the surgeon says he should. In this case the tamponade is truly that.

81Between 10 and 2 oÕclock.