Three levels of surgery may be used, pneumoretinopexy, scleral buckling, or vitreous surgery. The judgment for this is made by the surgeon.

A gas bubble is injected into the vitreous cavity which acts as an internal splint to hold the elevated retina against the outer wall of the eye (Fig. 5). The injection is carried out in the "safe zone" of the wall of the eye that lies between the anterior limits of the retina and posterior limits of the lens. This is the least intrusive, but can be used only in well-selected cases. The size and location of the retinal breaks, the extent of retinal detachment, the lack of traction by the vitreous gel on the retina, plus the cooperation of the patient are important considerations in choosing this treatment. For successful treatment by this technique, the retinal breaks should be relatively small, located in the upper half of the retina, and be spread within an arc of 60 degrees. The permanent closure of the retinal breaks is obtained by placing the freezing probe over the external surface of the eye in the area of the breaks. This is done under direct visualization with the ophthalmoscope. Then a long-lasting gas is injected in the vitreous cavity. As the gas bubble swells, it keeps the retina against the upper wall of the eye. To assure constant contact between the retina and the outer wall of the eye, the patient’s head must be properly positioned. The head is usually kept erect or tilted to one side, over 90% of the time, for a week to ten days. With this regimen, a vast majority of eyes treated at the SRA Foundation have been reattached with no further treatment necessary.

Fig. 5 Pneumoretinopexy. A needle is introduced into the vitreous cavity, between the crystalline lens and the peripheral retina. The air injected acts like a balloon and pushes the detached retina back in place, provided that the air bubble is over the break in the retina. To accomplish this, the patient may have to rest in a special position.

Most eyes having a detached retina are treated with a scleral buckle. The operation is carried out in three steps. Step one consists in creating an adhesion between the area that surrounds the retinal tears and the RPE. Such adhesion is obtained either by burning or by freezing the external wall of the eye in the correct location. Step two creates a permanent reduction of internal traction by the vitreous on the retina, by indenting the outer wall of the eye. This is carried out by placing a silicone rubber implant on the external wall of the eye, over the location of the retinal tears (Fig. 6). This area is located over the burn (or freeze). Once the pretreated area and site of buckle has been chosen, step three consists of releasing the fluid located between the detached retina and RPE by making a drainage hole in the "outer wall" of the eye. When this fluid is removed, the sutures that hold the silicone rubber implant in place are tightened and a permanent indentation of the globe results (Fig. 7).

Fig. 6 Scleral buckle. The buckling under the retinal tears is obtained by indenting the external wall of the eye with a silicone implant.

Fig. 7 (not available yet)

Fig. 7 Cross section of the eye after the scleral buckle is in place and subretinal fluid continues to escape. The suture on the buckle is tightened when all subretinal fluid has escaped.

This type of operation consists essentially in removing the shrinking vitreous gel from the eye and peeling the new formed tissue that may be present on both surfaces of the retina. This new formed tissue is prone to occur in long standing retinal detachments, and in cases operated upon unsuccessfully. The vitreous gel represents about 80% of the volume of a normal eye. In spite of this, it can be removed without causing major disturbances in the eye. Its removal often causes a cataract and probably affects the immunity of the eye and other functions, but our knowledge in this area is still incomplete.

At operation one introduces a vitrectomy instrument into the eye in such a fashion that it does not damage either the anterior edge of the retina or the patient’s crystalline lens (Fig. 8). This instrument works like a rotor rooter, by slowly grinding vitreous gel and sucking it out of the eye. As the sucking goes on, a gradual injection of replacement fluid is carried on, in order to maintain the eye pressure normal. Next, the peeling of vitreous and abnormal tissue from the retina is carried on as indicated. It is an indispensable but very delicate step that should be exclusively carried out by expert retinal specialists. In some cases, tissue also has to be removed from the underside of the retina. This difficult step is carried out after making an incision in the retina. This incision is repaired later. When the retina is free from all adhesions to abnormal tissue, the fluid that keeps the retina elevated is sucked out through the tears in the retina, and air is injected into the vitreous cavity to push the retina toward the eye wall. Then laser is used around the retinal tears in order to create an adhesion between the retina and the RPE. Finally a long-lasting gas is injected to replace the air. This is a gas that attracts other gases dissolved in the blood, so that the bubble of gas in the eye expands to some degree and does not absorb fully for about three weeks. When long-lasting gas is injected, the patient should generally avoid to travel by plane for three weeks or longer postoperatively. The reason is that the bubble will expand further as the plane flies in altitude and this will create glaucoma.

Fig. 8 Vitreous surgery. The vitrectomy instrument penetrates into the eye between the crystalline lens and the retinal periphery. Another perforation is used to illuminate the area. Replacement fluid is constantly injected through a third perforation of the eye, which is not shown in the figure.

The various steps of vitreous surgery are extremely delicate and should be carried out by well trained specialists. Modern vitreoretinal surgery is very successful in retinal detachment in general. However, it may not be successful in difficult cases of retinal detachment. For instance, retinal detachment with multiple tears, giant tears, detachment associated with significant vitreous hemorrhage, and a very soft eye just to mention a few. Such cases often develop proliferative vitreoretinopathy or PVR.