SCLEROSTOMY GLAUCOMA SURGERY 3

Aftercare : Patients can use their eyes after filtering surgery, although they should have a friend or relative to drive them home after the procedure. They can go to work the next day, although they will probably notice some blurring of vision in the operated eye for about a month. Patients can carry out their normal activities with the exception of heavy lifting, although they should not drive until their vision has completely cleared. Most ophthalmologists recommend that patients wear their eyeglasses during the day and tape an eye shield over the operated eye at night. They should apply eye drops prescribed by the ophthalmologist to prevent infection, manage pain, and reduce swelling. They should also avoid rubbing, bumping, or getting water into the operated eye. Complete recovery after filtering surgery usually takes about six weeks. Long-term aftercare includes avoiding damage to or infection of the bleb. It is important for patients recovering from filtering surgery to see their doctor for frequent checkups in the first few weeks following surgery. In most cases the ophthalmologist will check the patient’s eye the day after surgery and about once a week for the next several weeks.

Risks
The risks of a sclerostomy include the following:
• Infection.
Infections may develop in the bleb (blebitis), but may spread to the interior of the eye (endophthalmitis). The symptoms of an infection include pain and redness in the eye, blurred vision, teariness, and a discharge. Infections must be treated promptly, as they can lead to loss of vision.

• Hyphema.
Hyphema refers to the presence of blood inside the anterior chamber of the eye. Hyphemas are most common within the first two to three days after surgery and are usually treated with corticosteroid medications to reduce inflammation.

• Suprachoroidal hemorrhage.
A suprachoroidal hemorrhage, or massive bleeding behind the retina, is a serious complication that can occur during as well as after eye surgery.

• Cataract formation.

• Hypotony (low IOP).
If hypotony is not corrected, it can lead to failure of the bleb and eventual cataract formation.

• Loss of central vision.
This is a very rare complication.

• Bleb leak or failure. Blebs can develop leaks at any time from several days after surgery to years later. Bleb failure usually results from inadequate control of the intraocular pressure and a new obstruction of aqueous humor outflow.

• Closing of the opening in the sclera by new tissue growth. A sclerostomy can be repeated if necessary.

Normal results
According to the National Eye Institute, sclerostomy is 80–90% effective in lowering intraocular pressure. The success rate is highest in patients who have not had previous eye surgery.

Morbidity and mortality rates
Mortality following a sclerostomy is very low because the majority of procedures are performed under local anesthesia. The most common complications of filtering surgery are cataract formation (30% of patients develop cataracts within five years of a sclerostomy) and closure of the drainage opening requiring additional surgery (10–15% of patients). Bleeding or infection occur in less than 1% of patients.

Alternatives
Nonpenetrating deep sclerectomy
There are two surgical alternatives to sclerostomy that are called nonpenetrating deep sclerectomies because they do not involve entering the anterior chamber of the eye. The first alternative, viscocanalostomy, is a procedure that involves creating a window in Descemet’s membrane (a layer of tissue in the cornea) to allow aqueous humor to leave the anterior chamber; and injecting a viscoelastic substance into Schlemm’s canal, which is the main pathway for aqueous humor to leave the eye. The viscoelastic helps to keep the canal from scarring shut following surgery.

The second type of nonpenetrating surgery involves implanting a device called the Aquaflow® collagen wick about 0.8 in (2 cm) long under the sclera. The wick keeps open a space created by the surgeon to allow drainage of the aqueous humor. The wick is made of a material that is absorbed by the body within six to nine months, but the drainage pathway remains open after the wick is absorbed. The Aquaflow wick was approved by the Food and Drug Administration (FDA) in July 2001. Both types of nonpenetrating deep sclerectomies allow patients to recover faster, with fewer complications than traditional sclerostomies. Their drawbacks include a lower success rate and the need for additional procedures to control the patient’s IOP. Viscocanalostomy in particular is not as effective in reducing IOP levels as traditional filtering surgery.

Complementary and alternative (CAM) approaches
Bilberry (European blueberry) extract has been recommended as improving night vision; it was given to RAF pilots during World War II for this reason. There is evidence that 80–160 mg of bilberry extract taken three times a day does improve night vision temporarily. The plant does not have any serious side effects, but it should not be used in place of regular eye examinations or other treatments for glaucoma.

People who support the medicinal use of marijuana have argued that cannabinoids, the active chemical compounds found in the plant, lower intraocular pressure in patients with glaucoma. According to the Glaucoma Research Foundation, however, very high doses of marijuana are required to produce any significant effect on IOP. A Canadian researcher has concluded that the effects of cannabinoids on IOP “....are not sufficiently strong, long lasting or reliable to provide a valid basis for therapeutic use [of marijuana].”