Questions & Answers Reprinted from Our Newsletters
My doctor recommends Selective Laser Trabeculoplasty (SLT) for my narrow-angle glaucoma. I read that this treatment is usually used for patients with open-angle glaucoma. Has it proved effective in treating narrow-angle glaucoma?
If the angle is narrowed, you might need a YAG laser iridotomy prior to SLT to open the angle. Once open, SLT can be used to “clean” the internal trabecular meshwork (TM) of the eye to lower eye pressure. It can be done in any type of glaucoma as long as the angle is open wide enough for angle laser surgery to be performed.
Since undergoing a laser iridotomy, I’m seeing double when looking at lights. My doctor recommended a corneal tattoo. Is this a normal procedure?
A ghosting or streak of light occurs when light strikes your tear miniscus at the eye lid margin, then goes through the small laser opening. The location of the iridotomy is linked to this side effect. Corneal tattoo is the best option to resolve this. It involves tattooing the cornea over the spot of the iridotomy, so less light can penetrate the small opening.
My father has glaucoma and can't drive. Could laser surgery help his vision?
A certain amount of peripheral (side) vision is needed in order to drive. This may be specific to the jurisdiction you reside in.
Advanced glaucoma causes a restricted visual field. Other eye conditions that may make driving difficult include cataracts, macular degeneration or stroke.
Treatments for glaucoma include eye drops, laser and surgery. Although controlling eye pressure can slow the worsening of glaucoma, there is no cure nor any means of bringing back lost vision.
Are there any specialists in southwestern Ontario experienced in performing trabectome surgery?
There is currently no one in southern Ontario who does trabectome surgery. Other surgical options, including iStent and Xen/Aquesys implants, may be available in London and Kitchener.
How is the success of ALT and SLT measured?
Recent studies show both ALT (Argon Laser Trabeculoplasty) and SLT (Selective Laser Trabeculoplasty) to be similarly effective. We have been doing ALT for more than 20 years and SLT for about 15. ALT is a more universal laser. SLT is a stand-alone laser without any other application, so it is less available.
Both require applying laser treatment to the internal drain of the eye. The way they work is different. ALT makes a burn mark with shrinkage, opening up the area in between the burn marks to create more drainage. SLT incites inflammation in the drain, recruiting cells to help clean up debris in the drain, so it works better.
Once 360 degrees of the drain is treated with ALT - essentially two treatments - no more can be done. SLT may have more repeatability but this is still controversial. Side effects are the same for both treatments.
How successful is a trabeculectomy and how long does it take to determine if the surgery was a success?
The rate of success for a trabeculectomy is 80% at 5 years. Anytime during the post-operative period, the surgery may stop working. Post-op care, with frequent visits to the surgeon, is critical for success.
The rate of complications is less than 2%. Common complications include bleeding, infection, or loss of vision. Long term complications include failure - elevated eye pressure, too low eye pressure, or infection.
What is an iStent? How does it work?
An iStent is a small titanium device that can be implanted in the eye’s internal drain to help it drain more. Some glaucoma patients may be candidates for iStents during cataract surgery.
iStents are indicated for early, mild to moderate, open angle glaucoma. They may eliminate one or more glaucoma drugs. Their main limitations are cost and the lack of long-term studies.
How long does it take for vision to return after a trabeculectomy? If it doesn’t totally return, can the lens be replaced as with cataract surgery?
It is not uncommon for vision to be blurry for 8 to 10 weeks after surgery, especially if you are still taking steroid eye drops such as prednisolone or Maxidex.
Also if your eye pressure is a little on the low side that can cause the blurry vision.
Once the lens of the eye is replaced after cataract surgery, it is rarely ever replaced again. Later on you may benefit from a YAG Capsulotomy laser to polish the lens.
What should the normal eye pressure be a year after surgery for glaucoma?
There is no such thing as normal pressure.
To treat glaucoma, doctors set individualized targets where they hope no further glaucoma damage to the optic nerve or visual field will occur. The more glaucoma damage, the lower the target.
CTV reported on a new technique – placing a small stent in the eye to relieve pressure build-up. How do I go about getting my mother evaluated for this new treatment by a surgeon experienced in this procedure?
Talk to your mother’s doctor for a referral to a surgeon doing iStents. Your mother needs to be evaluated to see if she is a candidate for the surgery. The evaluation will examine the status of the internal eye drain, whether it is open or closed, and the amount of glaucoma present – mild, moderate, severe.
iStent is a new procedure with no proven track record beyond two years. It may eliminate the need for some eye drops. iStent works best in mild to moderate glaucoma.
It is best to combine iStent insertion with cataract surgery. The biggest issue is the cost of $500/stent. OHIP does not cover this cost so it may not be available in some hospitals and there may be patient pay models.
CTV recently reported a cutting edge procedure that involves implanting a tiny stent into the eye to give glaucoma patients new hope. Is this a process that glaucoma patients should consider when facing cataract surgery?
Some patients may be candidates for iStent during cataract surgery. It is indicated for early, mild to moderate glaucoma and may eliminate one or more glaucoma medications. Its main limitations are cost and lack of long term studies.
I have had glaucoma for 15 years and controlling it with drops. Is laser surgery safe or I should keep using drops?
If eye drops are working well to control your eye pressure, I would not recommend surgery at this point.
If your ophthalmologist is concerned about your eye pressure or you are having side effects from your present medications, then surgery may be an alternative treatment. Its effectiveness is the same as adding another eye drop, but it doesn’t always work or its effect may not last.
I have moderate to advanced glaucoma. My doctor is recommending surgery. Is it harmful to smoke marijuana? Will it help eye pressure control or affect future surgery?
Avoid smoking marijuana. It lowers eye pressure but only for a short period of time. You would have to constantly smoke in order to keep your eye pressure low and then the health risks, especially of lung cancer, are great. Smoking marijuana post surgery can jeopardize the surgical outcome — you may be at higher risk of failure due to scarring.
Is there anything I should do after eye surgery?
After laser treatment, make sure you understand and follow your doctor’s instructions for using eye drops. Recovery time after a trabeculectomy can be six to eight weeks or longer. During recovery, you should avoid any bending, heavy lifting, or strenuous physical activity. Also avoid swimming until your doctor advises that you can.
My father was diagnosed with glaucoma more than 5 years ago and has been treated with eye drops. What are the benefits of having surgery rather than continuing with eye drops?
The standard glaucoma surgery is a trabeculectomy with Mitimycin C. It’s a 45 minute procedure with recovery of about 6 to 8 weeks.
Benefits of surgery are lower eye pressure, less eye pressure variability and possible discontinuation of eye drops. Risks include bleeding, loss of vision, infection and failure of about 20% over 5 years.
Some newer operations are less invasive with faster recovery (Trabectome, iStent, Canaloplasty) but they do not lower eye pressure as well as trabeculectomy, so patients may still need to take eye drops or may need more surgery.
I was diagnosed with glaucoma and had trabeculectomy surgery two weeks ago. I have been told that I might need another surgery, is this common?
It is uncommon to need a second surgery so quickly after a trabeculectomy which lowers eye pressure by making a window on the eye to bypass the eye’s internal drain. After surgery this window may be “too open” or “too closed” resulting in very low or very high eye pressure. If this persists, another surgery may be required to correct this.
Do you know why an eye will not freeze?
It is uncommon for freezing (topical anaesthesia) not to fully take. However, in some patients topical anaesthetics don’t work that well. This may be because the eye is hypersensitized from medications or previous surgeries. Also eyes that tear excessively may wash out the anaesthetic drops.
An injection around the eye is sometimes necessary to control any discomfort, and for surgery, a general anaesthetic may be better.
Should I have LASIK surgery if there is glaucoma in my extended family or will this make treatment of glaucoma more difficult if needed in the future?
Glaucoma runs in families with highest risk when parents or siblings have it. If it’s in the extended family, the overall risk of getting glaucoma is low. It can skip generations.
LASIK thins the cornea. Your doctor may underestimate eye pressure in a thinner cornea and miss a glaucoma diagnosis. To get a specific correction factor for eye pressure for the future, get a series of eye pressures measured over the course of the day before and after LASIK.
My doctor has recommended laser treatment for glaucoma, how well does it work?
Because it can be difficult for patients to use multiple eye drop medications and because of less damaging side effects with current laser treatment, we are using laser treatment earlier.
Selective Laser Trabeculoplasty (SLT) has a pressure lowering effect of about 20% – comparable to adding another medication. Laser however, is not a “cure” for glaucoma – it doesn’t always work, its effect may not last, and your ophthalmologist must still continue to monitor your eye pressure.
I need glaucoma surgery, what are my options?
The surgery of choice for glaucoma is a trabeculectomy. This procedure has been used for more than 30 years and has a proven track record. Recently, a study has shown that a tube shunt operation (Seton) has similar efficacy to the trabeculectomy and possibly less side effects. The tube shunt was traditionally reserved for complicated glaucoma cases or cases that had previously failed a trabeculectomy.
Why can’t the eye grow new nerve cells to replace the ones damaged by glaucoma?
The eye is made up of sophisticated nerve cells that are an extension of the brain and are incapable of regenerating when they are damaged. Currently, we are only able to regenerate certain neural cells in laboratory conditions. We are looking at medications that may help damaged cells survive longer or prevent the damage altogether.
Do you give sedation when performing a laser treatment?
Generally, we don’t give a sedative for a laser procedure. We need the patient to be co-operative and not move. With a sedative, you may become drowsy and your head may fall back from the laser causing injury. Talk it over with your surgeon.
How long does the eye take to properly heal after Trabeculectomy surgery?
The recovery process for a trabeculectomy is about eight to ten weeks. (There really is no “healing” process involved as “healing” would indicate that the operation has stopped working and wasn’t a success.)
Does the healing process differ depending on the age of the patient?
Age can affect recovery. Younger patients tend to recover faster than older patients. Other issues such as previous eye medication use, quantity of medications and duration of use, and smoking can also affect recovery rates.
If further surgeries are required within a short period of time what concerns should the patient be aware of?
Usually, a second surgery in the short term after trabeculectomy is not necessary. Your ophthalmologist may, however, need to cut a stitch or “needle” the surgery site to keep it functioning.