Diode Laser

This type of laser is reserved for cases when high eye pressure has already damaged the vision, and is now causing a lot of eye pain. This laser is used mainly to control pain, however it is sometimes used to save vision in patients with high eye pressure who are too high risk for surgery because of advanced disease or numerous medical problems.

A diode laser is done as an outpatient procedure in the hospital. First, freezing is applied with a needle (retrobulbar block). This will cause some pressure around the eye and some brief discomfort. The freezing will spread (a mixture of lidocaine 2% and Marcaine 0.5%) behind and around the eye, so that there is no pain during the procedure. A freezing gel (Xylocaine 2% gel) is also used to numb the surface of the eye. The freezing takes about 15 minutes to work. After this, the non-treatment eye is covered to protect it, while the eye to be treated is lasered. A clip is inserted to hold the lids back and the laser is applied with a pen-like "probe" to the surface of the eye. Usually, you cannot feel anything while this is done, because of the heavy freezing around the eye. Occasionally, however, there is a bit of discomfort. If there is a lot of discomfort, the procedure would be paused for more freezing to be applied, or the treatment may be shortened or postponed.

This entire procedure takes about 20-30 minutes, including the time it takes to freeze the eye (15 mins), and the time it takes to perform the laser and patch the eye before going home (5 minutes).

After the laser, the protective covering over your non-treated eye will be removed. Your lasered eye will be rinsed and patched with several different kinds of drops and ointment (to lower eye pressure, decrease inflammation and prevent infection). This patch needs to stay on your eye for 4-6 hours. It can be removed after this time, and the ointment prescribed, along with any other routine glaucoma drops, can be used the same evening.

The freezing usually lasts about 4-6 hours, sometimes longer, therefore most people only have some mild discomfort that improves with Tylenol®. It is not recommended to take ibuprofen or aspirin products right after this laser, since they may promote bleeding. If you were having a lot of pain prior to the laser, and think you will need more than plain Tylenol®, please let your doctor know.

Rarely, you may experience "sympathetic" inflammation in the untreated eye. This is a rare complication and can be treated. If you develop pain, irritation or decreased vision in your untreated eye, contact your doctor, or visit the Misericordia Health Centre or the nearest emergency department if this occurs after office hours or on holidays.

Your lasered eye will be patched with various eye drops and ointment to lower the pressure, risk of infection, and lower inflammation. This patch can be removed 4 to 6 hours after the laser. If you have any discomfort, you can use ice packs on top of the patch or around it. You can use plain or extra strength Tylenol®, however you should avoid ibuprofen or aspirin products. If you think you might need something stronger than Tylenol® (which is not typical), let your doctor know.

You will be given a prescription of a combined steroid and antibiotic ointment (eg. Maxitrol® or Tobradex®) that you need to use after any regular drops, once in the morning and one at night in the lasered eye for 3 weeks and then at night for 3 weeks. Continue all your regular glaucoma drops.

You will need to follow-up with your doctor in one month (unless otherwise specified) to check your eye pressure and see how you are doing. If you have excessive pain or decreased vision in either eye, contact your doctor immediately, or go to the Misericordia Health Centre or the nearest emergency department on evenings and weekends.

Usually, there is some discomfort in the lasered eye after this laser, which improves within a few days with Tylenol® (with or without codeine) and the eye ointment. If there was poor vision prior to the laser, this may be a bit worse right after the laser, or may be the same.

Excessive pain (worse than before the laser), tearing and marked decreased vision in either eye are unusual and rare problems that should be checked as soon as possible. Contact your doctor or go to the Misericordia Health Centre or the nearest emergency department on evenings and weekends.

The needle anaesthetic can cause some bleeding and bruising around the eye, which usually disappears within 10 days to 2 weeks. However, rarely, there can be a large amount of bleeding behind the eye that causes pressure behind the eye. If the bleeding is excessive, the pressure may have to be released by cutting the outer corner of the lids. This is a rare complication. The needle is directed under and to the side of the eyeball, but can sometimes puncture the eyeball or the optic nerve, especially in people with large eyes. Such a needle puncture is usually very tiny and does not need any stitching, but it can potentially cause bleeding, retinal tearing, retinal scarring or even infection. In cases where the optic nerve is punctured, some of the anaesthetic may travel to the brain and cause general anaesthesia which would be a medical emergency.

Despite these rare, potential risks, it is important to use a needle anaesthetic (retrobulbar block) since the diode laser can be very uncomfortable if the area is not properly frozen.

The diode laser can cause a lot of inflammation (which decreases with steroid ointment taken post laser). Sometimes the inflammation can actually "spread" to the good eye. This may cause pain and irritation of the good (non-lasered) eye. If this happens, it can be treated, but it is very important to see your doctor as soon as possible, or go to the Misericordia Health Centre or the nearest emergency department if it occurs on weekends or during holidays.

A diode laser may need to be repeated, if the effect was not strong enough to lower the eye pressure. In this case, over time, especially with repeat treatments, the eyeball that is being treated may shrink in size. It is also very possible to lose further vision over time, with repeated diode lasers, therefore this laser is usually only used in cases where pain control is the main concern. In situations where the treatment is being given to lower eye pressure to preserve vision, it is used sparingly and only when other procedures, like surgery, are considered higher risk for vision loss.