RETINAL DETACHMENT 401

closed by the surface tension from the gas bubble, the retinal pigment epithelium can pump the subretinal fluid back into the choroid and allow retinal reattachment. The break is sealed either with cryotherapy at the time of gas injection or with laser photocoagulation after the retina is flattened. The ideal candidates are patients with a detachment caused by a single retinal break in the superior 8 clock hours or multiple breaks if all of the tears are within 1–2 clock hours of each other. Obviously the patient must not have a systemic disease or mechanical problem that precludes the positioning requirements. Phakic patients tend to fare slightly better than patients with a history of cataract surgery.

12.Which patients are poor candidates for pneumatic retinopexy?

Patients with RDs caused by multiple tears in several locations are poor candidates, as well as patients with a detachment resulting from a single tear but with tears in other areas of attached retina. Proliferative vitreoretinopathy, especially if fixed folds are present, lessens the chances for reattachment with pneumatic retinopexy. And, as previously stated, patients with rheumatoid arthritis or other systemic conditions who are unable to obey the strict postoperative positioning requirements are poor candidates.

KEY POINTS: FACTORS THAT INFLUENCE THE

DECISION TO TREAT RETINAL BREAKS

PROPHYLACTICALLY

1.Type of break.

2.Presence of symptoms of vitreoretinal traction.

3.Horseshoe tears are usually treated. All symptomatic horseshoe tears should be treated.

4.Operculated tears are generally not treated unless symptomatic.

5.History of retinal detachment in the fellow eye.

6.Family history of retinal detachment.

7.Anticipated prolonged inaccessibility to care.

13.What are the advantages of scleral buckling and pars plana vitrectomy?

Scleral buckling and pars plana vitrectomy reduce vitreous traction mechanically. Scleral buckling involves the surgical placement of a silicone band or sponge, either sewn to the sclera as an exoplant or implanted in the sclera after a partial-thickness scleral bed is surgically created (Fig. 48-6). Scleral buckles provide smooth, broad relief of vitreous traction. Subretinal fluid may be drained at the time of placement of the scleral buckle via an external sclerostomy,

and intraocular gas may be injected into the vitreous cavity as an adjunct to aid in retinal reattachment. Scleral buckles are especially effective in anterior retinal breaks. This is the most common site for postcataract retinal breaks. Another advantage of scleral buckling is the opportunity to repair the RD from a purely external approach with no intraocular invasion.

With vitrectomy, it is possible to relieve vitreous traction directly with the vitrectomy cutter. This technique is especially useful in cases with very posterior breaks. Vitrectomy is advantageous in cases of RD with vitreous hemorrhage or vitreous opacities that obscure a view of the retinal breaks. Vitrectomy also allows the surgeon to remove epiretinal membranes when proliferative vitreoretinopathy is present. When vitrectomy is performed, the vitreous cavity must be filled with gas to reattach the retina. The presence of intravitreal gas hastens the development of cataract in phakic patients.