What is the success of a trabeculectomy?
The success of surgery depends upon keeping this drainage channel open. The body’s normal healing response will usually close the drainage channel unless the healing response is modulated. Young age, increased skin pigmentation, previous eye surgery, and complicated glaucoma increase the likelihood of scarring and surgical failure. There are 2 drugs, mitomycin C and 5-fluorouracil, which have been widely studied and have been shown to successfully block the healing response after glaucoma surgery and help keep the drainage channel open. When applied during trabeculectomy surgery, these drugs have been shown to significantly improve the long-term success of glaucoma surgery.
Studies have shown that after 1 year 85-90% of operated eyes achieve significantly improved pressure control and after 5 years about 35-50% of eyes that have undergone trabeculectomy surgery continue to have controlled eye pressure without the need for additional surgical intervention. Although these anti-scarring agents improve the success of glaucoma surgery they also may increase the likelihood of development of certain post-operative complications. Often anti-scarring medicines are administered not only during, but also after surgery to further suppress the healing response. These are usually administered in the form of injections underneath the conjunctiva or “skin” of the eyeball during the post-operative period.
Steroid eye drops, which suppress inflammation, have also been shown to improve the success rate of surgery and will be prescribed for about 3 months on a tapering schedule. Continued healing leading to scarring and closure of the drainage channel may necessitate reinstitution of glaucoma medicines, revision procedures, or repeat glaucoma surgery.
What changes will occur on my eye after a trabeculectomy?
You may notice a mound or bubble-like elevation after surgery on the white of the eye. This is called a “filtering bleb”. Sometimes the “bleb” is subtle and not noticeable. Although most of the time you won’t notice the bleb, occasionally you may feel irritation or a sandy or gritty feeling. Artificial tear lubricants, in most cases, relieve the discomfort.
After a trabeculectomy do I still have to use my eye-drops?
In many cases glaucoma medications may be completely discontinued in the operated eye and the eye pressure stabilizes to a more desirable range. However, you may still need 1 or more glaucoma medications after surgery to achieve the desired level of pressure control.
What are the risks or complications from a trabeculectomy?
Although most patients following glaucoma surgery will benefit from improved pressure control, as with all surgical procedures there are potential risks in addition to benefits. Most problems following surgery can be successfully treated in the office. However, sometimes additional surgery may be necessary for persistent post-operative problems or new problems that may develop later. Complications occurring during or following trabeculectomy surgery include but are not limited to; early infection (days to weeks after surgery), late infection (months to years after trabeculectomy surgery), choroidal hemorrhage (sudden bleeding behind the retina), choroidal effusion (fluid accumulation behind the retina), macular edema (swelling of the central part of the retina), cataract formation or progression, excessively low eye pressure, chronic leakage of internal eye fluid, dry eye syndrome, chronic inflammation, chronic discomfort, and droopy lid.
The most common cause of a reduction in vision in patients undergoing glaucoma surgery is due to development of or worsening of an existing cataract. This is not an issue in patients who have already had cataract surgery or will undergo cataract surgery on the same day as trabeculectomy surgery. The risk of cataract development or progression may be up to 50%. Visual loss due to cataract varies from patient to patient and can range from little to no change in vision to a severe reduction in vision. Mild visual loss that is not reversible occurs on the average in about 5% of patients and severe visual loss including total and irreversible visual loss usually occurs in less than 1% of operated eyes.
Pre-operative Instructions
- Glaucoma medications need to be instilled in the eye up to the morning of glaucoma surgery. Patients who are taking glaucoma pills (diamox/acetazolamide or neptazane/methazolamide), unless instructed otherwise should take the morning dose with a small sip of water.
- Unless instructed otherwise, discontinue xalatan, travatan, travatan Z, or lumigan 5 days before surgery only in the eye undergoing surgery.
- Beginning 5 days before surgery start Pred forte, Econopred plus, or prednisolone acetate in operative eye one drop 4 times a day.
- Scrub lashes with baby shampoo mixed with water (1 part shampoo 3 parts water) using a cotton swab and then rinse with warm water beginning 5 days prior to surgery. Alternatively, an over the counter eyewash such may be used instead of baby shampoo. Your doctor may suggest different eyewash brands.
- You may need antibiotics pills, drops, or ointment before surgery. You doctor will advise you if these are necessary.
- Food and drink are permitted only until midnight the day before surgery. Afterwards you must not eat or drink anything except for your heart and blood pressure medications. They should be taken the morning of surgery with a small sip of water. If you are taking blood thinners such as aspirin, plavix, or coumadin only your family physician or cardiologist can tell you if it is safe to stop them prior to surgery. Your family physician will instruct you regarding the use of your non-eye medications prior to surgery.
Post-Operative Instructions and Expectations
Expect to be seen the first day after surgery and then weekly for the first month. Close follow-up is extremely important in order to observe and control the healing response and increase the likelihood of surgical success.
A separate handout with detailed post-operative instructions will be given to you at the time of surgery.