Common Retinal Procedures

Imaging of the retina can show incredible detail, however it cannot show blood flow in the retinal tissue. It can document conditions such as bleeding inside the eye, but rarely will show the source of the bleeding. This is where a circulation test called fluorescein angiography is extremely helpful. Similar to fundus photography, fluorescein angiography consists of capturing rapid-sequence images of the back of the eye after injecting a special dye intravenously. A vein in the patient’s hand or arm is used for the injection. The resulting images show the physician the circulation in the retina, and will reveal any abnormalities. Patients may notice a discoloration of their skin for up to twelve hours and urine discoloration for up to thirty-six hours after the test.

Optical Coherence Tomography (OCT) is a relatively new technology that is used to create cross-sectional images of the retina and optic nerve head. A special light beam is directed at the tissue and scanned across the surface in a linear fashion. The light that is directly reflected is interpreted by the instrument to form an image. The portion of the light that is scattered is filtered out. OCT gives the surgeon a “side-view” or cross section image of the retina, as opposed to a front view obtained with standard imaging.

 Some diseases such as glaucoma and optic nerve problems can lead to loss of peripheral, or side vision. Visual Field analysis consists of “mapping” a patient’s visual field. Using a special instrument called a visual field analyser, the patient stares at a central point and is presented with small points of light at various locations throughout the peripheral areas of vision. The patient depresses a handheld button when the light is seen. The lights vary in intensity and the instrument frequently checks to make sure the patient is fixating properly.

Vitrectomy is a surgical procedure in which the vitreous gel inside the eye is removed, and then replaced with a special saline solution. The procedure is actually called the trans-pars plana vitrectomy, because small, needle-like devices are inserted through the wall of the eye in an area known as the pars plana.

Vitrectomy is performed for many different diagnoses, including retinal detachment, vitreous hemorrhage, and macular pucker. Vitrectomy is an outpatient procedure done under local anesthetic with intravenous sedation. Most patients experience little or no post-operative discomfort, and usually return to normal activities in a few days.

Vitrectomy is sometimes accompanied by secondary procedures such as endophotocoagulation, gas-fluid exchange or membrane peeling.

Endophotocoagulation is laser performed inside the eye during vitrectomy. A special needle-sized laser probe is inserted through the wall of the eye, and the surgeon can photocoagulate, or laser areas of the retina that require treatment.

The gas-fluid exchange may be performed after the vitrectomy portion of surgery is complete. A bubble of a special gas is introduced into the eye in place of some of the saline solution used during vitrectomy. Some retinal conditions require pressure be put on the retina to hold it in place while healing, such as retinal detachment and macular hole. The gas bubble floats against the retina, providing the pressure, or tamponade. Because the gas bubble floats up, against gravity, special positioning may be required of the patient to ensure the bubble contacts the proper area of the retina. The gas is slowly absorbed by the body over several days to two weeks.

Occasionally a patient who has been diagnosed with retinal detachment or macular hole may be physically incapable of postoperative positioning after vitrectomy and gas-fluid exchange. An alternative procedure involves filling the eye with special silicone oil. The oil acts like a cast with a broken bone and holds the retina in place. The oil remains in the eye usually for several months or longer, but requires a second procedure to remove it.

The membrane peel is exactly what it sounds like; a membrane, such as described with macular pucker is physically peeled off of the retinal surface. The surgeon uses a needle-sized instrument with tiny jawed forceps on the tip. After vitrectomy, the membrane is peeled from the retina, and then sometimes an anti-inflammatory medicine is used inside the eye to quiet swelling.

Scleral buckling is performed to repair some retinal detachments. A silicone and plastic band is placed around the eye, and tightened like a belt. This brings the wall of the eye inward, toward the detached retina. The fluid behind the retina is then drained. The surgeon then uses cryotherapy or freezing treatment to seal any retinal tears. The scleral buckle acts as a support structure for the retina and usually remains in place for the patient’s lifetime. The buckle is not visible from an observer’s standpoint.

Some diseases such as Wet AMD (Age-related Macular Degeneration) may require special medications to be injected into the eye. These medications usually remain effective inside the eye for several weeks, providing long-term thereapy. Intraocular injections are routinely performed in the office.