Eye Care
2. Drainage Valve Devices Implantation
Glaucoma drainage devices, also known as tube shunts, are implanted devices that are designed to maintain an artificial drainage pathway for patients with glaucoma. This procedure is often chosen for patients at high risk of failure with a traditional glaucoma filter procedure (trabeculectomy). Such patients might include those with neovascular glaucoma, glaucoma associated with uveitis (iritis), prior history of failure with a filter procedure, and any patient with glaucoma under 30 years of age. All of these patients are at significant risk for failure of a routine glaucoma filter procedure due to greater inflammation and fibrosis (scarring), which might close off the drainage canal.
Tube Shunt Implantation
Prior to surgery, your ophthalmologist may have you take eye drop medications to prepare your eye for surgery. These may be started on the day of surgery, or even up to 3 days prior to surgery. Just prior to surgery, local anesthesia will typically be given to numb your eye for surgery. In young children, the procedure must be performed under general anesthesia.
Your eye will be prepped in the operating room and sterile drapes placed to maintain a sterile field. An operating microscope will be moved into place. The surgeon will place a small instrument to hold the lids apart during the surgery.
A small incision is made in the conjunctiva, usually towards the top of the eye. The surgeon will then make a tiny incision in the sclera of the eye and will fashion an opening for the drainage implant device. The drainage tube will be placed such that the opening of the tiny tube is inside the anterior chamber of the eye where it is bathed in aqueous fluid. The tube is sutured in place with the drainage device attached to the sclera of the eye. Most surgeons will place an absorbable suture around the tube at the time of surgery to prevent filtration through the device until a fibrous capsule has formed. As such, the device is not expected to function until about 3 to 8 weeks following the procedure. This technique is thought to prevent over-filtration. Once the tube shunt is securely sutured into the desired position, the conjunctiva over the device is closed with tiny sutures, which are considerably finer than human hair.
After Procedure
As previously stated, the tube shunt device is not expected to function until 3 to 8 weeks following surgery. In the meantime, the glaucoma may be even more difficult to control than before. Some surgeons, therefore, create a separate glaucoma filtration site, which is expected to fail at approximately the same time that the tube shunt begins to function.
You will be instructed to use antibiotics, anti-inflammatory medicines, and glaucoma medications following the procedure. The actual medicines and dosing schedules will be carefully planned and reviewed with you by your doctor. You may expect to use these additional medicines for up to two to three months after surgery to help prevent infection and control inflammation.
In general, you will likely be able to return to most activities within a day or two after surgery. Your eye may feel scratchy or have a foreign body sensation. This should usually resolve in the first one to two weeks.
Laser peripheral iridotomy involves creating a tiny opening in the peripheral iris, allowing aqueous fluid to flow from behind the iris directly to the anterior chamber of the eye. This typically results in resolution of the forwardly bowed iris and thereby an opening up of the angle of the eye. The narrow or closed angle thus becomes an open angle.
The laser peripheral iridotomy procedure is usually completed as a brief outpatient procedure. Prior to the procedure, the pupil is often constricted with an eye drop medication known as pilocarpine. The procedure itself is completed with the patient seated at the laser and requires no sedation. Usually, a lens is placed on the eye after topical anesthetic drops are applied to better control the laser beam. The entire procedure only takes a few minutes. The lens is then removed from the eye, and vision will quickly return to normal. After the procedure, your eye surgeon may recommend anti-inflammatory eye drop medications for the next few days.
4. Cyclodiode Photocoagulation
Transscleral cyclophotocoagulation is a procedure for glaucoma that is performed on an outpatient basis. In this procedure, the ciliary body of the eye, which creates aqueous fluid, is treated with laser to decrease production of aqueous. This in turn reduces pressure inside the eye. The technology has been available for nearly 30 years, but has only recently become available to glaucoma patients.
The cyclophotocoagulation procedure is usually performed with local anesthesia while seated at a slit-lamp delivery system. About 20 to 40 laser delivery applications are completed. After the procedure, the patient is usually started on both dilating and anti-inflammatory eye drop medications, and perhaps oral anti-inflammatory medications as well.
Cyclophotocoagulation is most often employed when other means of glaucoma treatment have failed to properly control high pressures. Many patients will require more than a single treatment.
5. Argon Laser Trabeculoplasty
Argon laser trabeculoplasty (ALT) is a procedure which has been proven to be effective for different types of glaucoma. ALT is often recommended when medical therapy alone is insufficient in controlling pressure and the progression of glaucoma.
In the ALT procedure, the eye surgeon directs a laser beam into the trabecular meshwork, which is the primary aqueous (fluid) drainage region of the eye. The trabecular meshwork is located in the angle of the eye, approximately where the cornea meets the iris. The effect of the procedure is increased drainage of aqueous fluid out of the eye, thereby lowering the intraocular pressure.
The ALT procedure can be completed as an outpatient procedure. It is completed with the patient seated at the laser, with topical (eye drop) anesthesia, and a lens applied to the surface of the eye to allow delivery of laser applications into the trabecular meshwork.
This procedure is typically painless or results in only minor discomfort. After the procedure, the patient is treated with anti-inflammatory eye drops for a few days, perhaps in association with their usual glaucoma medications. Vision is minimally, if at all, affected, even on the day of the procedure. There is generally no discomfort after the procedure.
Iridoplasty is a time tested laser treatment for closed angle glaucoma and plateau iris. By opening the drainage area in the eye, this procedure improves drainage of fluid in the eye and thus can help prevent the potentially blinding "angle closure attack."
In addition to protecting against angle closure attack, iridoplasty will occasionally result in a decreased intraocular pressure. This is considered a secondary benefit and is not seen in all cases. If the laser decreases the patient's intraocular pressure, the drops that would otherwise be needed to control the intraocular pressure can be decreased or possibly stopped. This saves the patient time and money.
The laser is performed in an exam room using a modified slit lamp. The procedure takes about 10 minutes and may be associated with slight discomfort but no severe pain. The person can drive themselves home after the procedure. Steroid drops are used for one week. There are no limitations on activity after the laser procedure.
This is the most common operation performed for retinal disorders. The operation involves removing the jelly of the eye (vitrectomy). This is performed through three small incisions in the eye which are stitched up at the end of the operation.
Pars plana vitrectomy uses small instruments are inserted into the eye through the pars plana. The pars plana is the part of the eye lying between the retina and the pars plicata. The pars plana has no known function in the post-fetal eye. It is thus a "safe" place through which one can insert instruments.
Generally, vitrectomy is an outpatient procedure and is done under intravenous sedation with local anesthesia. The operation takes approximately one hour to perform Postoperative pain varies in intensity but is usually well controlled with narcotics. If the surgeon places an intraocular gas bubble in the eye (to maintain retinal reattachment while the eye heals from surgery), the patient will have to maintain a face-down position postoperatively.
