Glaucoma is a generally painless eye disease that damages your eye’s optic nerve, causing vision loss. It usually occurs when fluid builds up in the front part of your eye. This extra fluid increases the pressure in your eye, damaging the optic nerve. The optic nerve is located at the back of the eye and connects the eye to the brain. It contains nerve cells that transmit images, allowing us to see. In glaucoma, the optic nerve cells slowly die, causing changes in vision.
Patients may not know they have glaucoma until the disease is quite advanced. This is why glaucoma is sometimes called the “silent thief of sight” because symptoms are often not apparent until the condition has damaged most of the optic nerve fibers. Glaucoma can cause total blindness within a few years if not treated. Every year, many Canadians needlessly go blind because their glaucoma was detected too late. Ophthalmologists and optometrists can easily diagnose glaucoma through routine eye examinations. Early detection and treatment are key to preventing vision loss.
Symptoms include blurred vision, loss of peripheral vision, halo effects around lights and painful or reddened eyes. Risk factors include family history, high myopia (nearsightedness), diabetes, thyroid disease, previous trauma to the eye and ocular hypertension, which is when the pressure inside the eye is above it’s normal level.
What is the treatment for Glaucoma?
The treatment for glaucoma is aimed at achieving a target intraocular pressure for your eye. There are four options available to decrease the intraocular pressure: eye drops, oral medication, laser, and surgery. If the laser or medications fail to lower the IOP to the target pressure level and nerve damage continues to occur, your target pressure will be lowered and further medication, laser treatment, or surgery may be required.
There are many types of medications now available to safely and effectively reduce intraocular pressure. They work either by 1) Reducing the production of fluid inside the eye or 2) Increasing the drainage of the fluid out of the eye.
Oral medication can also be used temporarily prior to surgery to treat glaucoma when the pressure is difficult to manage. In cases of emergencies, such as acute angle-closure glaucoma, intravenous medications may be used. The different groups of glaucoma medications are presented below. Speak to your doctor or pharmacist if you have any questions or concerns and ask your doctor about possible side effects.
Selective Laser Trabeculoplasty (SLT):
SLT is a common laser procedure used to decrease intraocular pressure. In this procedure, the laser light is focused on the drainage angle of the eye (the trabecular meshwork) to increase the drainage of the fluid out of the eye. During the procedure, you will see brief flashes of light and feel little, if any, discomfort. Either 360 degrees (full) or 180 degrees (half) of the eye will be completed. The procedure usually takes less than 10 minutes. 30-40 minutes after the treatment, your eye pressure will be measured again. If you just had 180 degrees laser, you will have a second SLT appointment to have the other 180 degrees lasered. This will be in approximately 6-8 weeks’ time. You will also be given drops after the procedure. You may not plan to drive after this treatment as your vision may be blurry for several hours. Your doctor may recommend anti-inflammatory drops that increase your IOP, lowering the effect of the laser and increases the success rate of the laser.
What are the risks of SLT?
Your vision will probably be blurred and you may experience a mild ache for the next few hours, but it should clear. Most people still need to take glaucoma drops after the procedure. Several days or weeks after the procedure, the flow of fluid from your eyes should improve. In 50% of people, the effect of this treatment stops working in about 5 years, however, it can be repeated up to two or three times.
Laser Peripheral Iridotomy (LPI):
LPI is a procedure to treat narrow angles by using a laser to create an opening in the iris so that the flow of fluid can leave the eye more easily. It is performed for patients with narrow angles that may be prone to closure. Narrow angles may predispose one to an episode of angle-closure glaucoma, in which pressure in the eye can rapidly increase, threatening vision and even causing blindness. The procedure normally takes less than 5 minutes. Your vision will be clear in 1-2 hours. After the procedure, please keep taking your usual drops along with the new drop prescription given by your surgeon for this procedure.
What are the risks of LPI?
The risks are rare but include pain, blurred vision, pressure spiking in the eye, and inflammation. The risk of having more serious complications with LPI such as retinal swelling or a retinal tear is very, very rare.
In North America, glaucoma surgery is generally not done unless medical and laser therapy has been inadequate to control the IOP. The purpose of the operation is to control the pressure and preserve your vision; any vision lost to glaucoma cannot be restored. There are two main types of glaucoma surgery:
Minimally Invasive Glaucoma Surgery
Minimally Invasive Glaucoma Surgery, or MIGS, includes three main types of surgery:
- iStent Trabecular Micro By-Pass Surgery
- Kahook Dual Blade Goniotomy
- XEN Implantation
These surgeries involve the incision and removal of one wall of the drainage channel or insertion of very small implants that allow for better drainage of aqueous fluid out of the eye. These procedures are performed faster than traditional glaucoma surgery.
Traditional Glaucoma Surgery
Traditional glaucoma surgery includes the two following types:
- Trabeculectomy
- Glaucoma Tube Shunt Implantation
Traditional Glaucoma surgery involves creating a flap or drainage channel into the anterior chamber of the eye.
iStent® Trabecular Micro-Bypass Stent Surgery: iStent® is the smallest medical device approved by the FDA to date. The iStent is inserted into the drainage area of the eye (trabecular meshwork), where it allows fluid to drain into Schlemm’s Canal. The goal of the procedure is to improve the flow of fluid out of your eyes. The iStent® helps to control the pressure in the eye and reduces the risk of future vision loss to glaucoma. After implantation, many patients are able to better control their eye pressure with fewer medications. This procedure takes about 15 minutes and is often performed at the same time as cataract surgery.
What are the risks of iStent®?
The iStent® may not necessarily stabilize your glaucoma. The most common complication of iStent is microscopic bleeding in the eye that may cause temporary blurred vision. You may need further treatment or surgery to treat complications, however, the complications of iStent are no more severe than that of stand-alone cataract surgery.
Kahook Dual Blade Goniotomy (KDB) is a surgical therapy for patients who have mild to moderate open-angle glaucoma and may have tried medications and laser surgery. In KDB surgery, a section of the trabecular meshwork, the drainage tissue of the eye, is removed to allow for better drainage of fluid out of the eye. As your surgeon has discussed, the KDB is potentially beneficial in helping to reduce the number of glaucoma medications you take. This procedure takes 15 minutes and is often performed at the same time as cataract surgery.
What are the risks of Kahook?
There is the possibility that KDB surgery will not help to control your glaucoma and further surgery will be needed. Transient hyphema is the most common complication of KDB. The complications of Kahook surgery are no more severe than that of stand-alone cataract surgery.
XEN Implantation: XEN gel stent is a very small tube (about the length of an eyelash) that is inserted into the eye to create a channel for fluid from the eye to flow into a filtering area called a bleb, which is a raised section of the eye, located just beneath the eyelid, where fluid from the eye is stored. The procedure takes about 15 minutes. When successful, this procedure will decrease the pressure in the eye, minimizing the risk of further vision loss from glaucoma. The purpose of the operation is to control the pressure and preserve vision as vision lost to glaucoma cannot be restored.
What are the risks of XEN?
As with any surgical procedure, there are risks associated with XEN gel stent implantation. For instance, there is always the possibility that the surgery you have will not help to control the eye pressure. Eye drops or further adjustments may be needed. Careful follow-up is required after surgery. After your eye heals, you will still need regular eye exams to monitor the pressure and to watch for other eye problems. Occasionally, a bleb adjustment or XEN repositioning is needed to help the surgery work.
Trabeculectomy
Trabeculectomy is used if medications and laser surgery have not effectively lowered intraocular pressure. In this surgery, an incision is made in the sclera, which is the white part of the eye, to allow for fluid to drain more easily out of the eye. A flap is made in the sclera near the cornea. A channel into the anterior chamber of the eye is then created. The scleral flap is then secured with sutures that are loose enough to allow for some aqueous drainage but are still tight enough to maintain the shape of the anterior chamber.
What are the risks of Trabeculectomy?
After the surgery, the intraocular pressure may go too high or too low and needs to be carefully monitored. After your eye heals you will still need regular eye exams to monitor your pressure and to watch for other eye problems. You will have post-operative check-in appointments once a week for one month following your surgery. Infection may happen at any time after surgery, and you need to contact your eye caregiver immediately after any sign of infection, such as red-eye, burning sensation, discharge, or pain.
Glaucoma Tube shunt implantation – Ahmed Valve
This procedure allows your ophthalmologist to create a new drainage channel for the eye. Your doctor will insert a tube into the anterior chamber that connects to a plate. The plate will be placed on the outside of the eye just beneath the upper eyelid. The tube shunt implantation will allow fluid from the eye to flow into a plate and from there into a filtering area called a bleb. When successful, this procedure will lower the pressure in your eye, minimizing the risk of further vision loss from glaucoma.
What are the risks of the Ahmed Valve?
As with any surgical procedure, there are risks associated with Tube shunt implantation. For instance, there is always the possibility that the surgery you have will not help control the eye pressure and further adjustment will be needed. Careful follow-up is required after surgery. After your eye heals you will still need regular eye exams to monitor your pressure and to watch for other eye problems. It is important that you do not rub your eyes post-surgery as the valve may migrate in the eye and further adjustment will be needed. Within 2-3 weeks, to a few months after the tube, the intraocular pressure may increase and remain high for 3-6 months. You will need to restart your glaucoma drops based on your doctor’s recommendation.
What is Intraocular pressure?
Intraocular pressure, referred to as IOP, is the measurement of fluid pressure inside your eyes. Within the normal eye, there is constant production and drainage of fluid called aqueous humor. This fluid nourishes the lens and the cornea. The aqueous humor helps maintain a stable pressure in the eye. If the eye pressure is too high, it can cause damage to the optic nerve. If the pressure is too low, the eye may not function normally.
The average eye pressure tends to change slightly during the course of a day and from one day to the next. It also varies with ethnic origin. In most cases of glaucoma, the intraocular pressure is elevated. This is a key risk factor in developing glaucoma.
Eye pressure is the only modifiable risk factor of open angle glaucoma. You may ask what a normal eye pressure will be. The answer is that there is no normal or abnormal eye pressure. Each individual or each eye can tolerate a certain amount of pressure, which can be defined as normal pressure for that eye or that individual.
Risk factors for Glaucoma
Other risk factors for open angle glaucoma are family history of glaucoma, age, African-Caribbean descent, thin cornea, and myopia. Myopia is also known as nearsightedness, which is a vision condition in which objects that are near to you are seen clearly, but those that are far away appear blurry. There is also a high prevalence of open angle glaucoma in diabetic patients.
There are two major types of glaucoma; open-angle glaucoma and angle-closure glaucoma. Open-angle glaucoma is the most common type of glaucoma in Canada. A person has open-angle glaucoma if the drainage system is open, but does not function as well as it should. The fluid within the eye cannot drain properly, thus increasing the pressure in the eye. Continued elevated pressure within the eye will damage the optic nerve. An eye examination will show the changes to the optic nerve. As the disease progresses, blind spots occur in your peripheral (side) vision. Angle-closure glaucoma, also called closed-angle glaucoma, is a less common type of glaucoma. A closed-angle occurs when the colored part of the eye (the iris) is pushed forward, so it closes the angle where fluid drainage takes place. This causes a build-up of fluid within the eye as the drainage becomes blocked. It can be chronic or acute. If this occurs, the pressure can increase suddenly causing a combination of blurred vision, a red eye, a headache as well as nausea and vomiting. This may lead to permanent blindness.
OPEN-ANGLE GLAUCOMA
CLOSED-ANGLE GLAUCOMA
Glaucoma Research Foundation. (2017). Retrieved from https://www.glaucoma.org/glaucoma/types-of-glaucoma.php
Here are the signs of an acute attack:
- Sudden blurry vision
- Severe eye pain
- Headache
- Nausea
- Vomiting
- Seeing rainbow-coloured rings or halos around lights
You may also ask if you are going to go blind. The answer is no. However, if you ignore your condition and do not follow the instruction and treatment plan, there is high risk of vision loss. Unfortunately, visual loss from glaucoma is irreversible, hence prevention is critical to prevent glaucoma blindness. We recommend that you check your eye with your primary eye care giver and follow the recommended plan.
Diagnosis of glaucoma needs combination of eye exam, visual field test and optic nerve imaging (OCT). These diagnostic tests should be repeated regularly based on your stage of glaucoma, between every 3-4 months to every year.
The treatment will be defined for each individual based on the severity of glaucoma and eye pressure. The treatment can begin with eye drops or laser. In case of failure of these measures or in severely damaged eyes, surgery will be required. Based on severity of your glaucoma, there are different surgical options that your doctor will discuss with you, which range from minimally invasive glaucoma surgery (MIGS) to incisional surgeries such as trabeculectomy or tube insertion.
Common questions
What can I expect after glaucoma surgery?
After surgery, a registered nurse will instruct you and your family regarding activity level, putting drops, and/or using an eye shield. You will be given written instructions as well. Depending on the type of glaucoma surgery, you will be instructed to stop or continue your glaucoma drops.
You must seek medical attention immediately if:
- You have severe pain anytime after the operation;
- Your vision drops suddenly;
- Your eye (or eyelid) swells up;
- You have increased discharge;
- You have uncontrolled nausea and vomiting
Call your surgeon or call the Eye Institute or go to the nearest Emergency Department.
What can I do to keep my glaucoma under control?
Patient compliance is the most important factor to prevent an increase in intraocular pressure. Medications must be taken as prescribed because glaucoma is painless unless it is acute. You may not feel like you need to take your medications, but you must take them regularly even if you feel fine or experience temporary eye redness. It is the best way to manage glaucoma and prevent or delay any further vision loss.
Remembering to take your eye drops is easier if you make it part of your daily routine. Medication should be taken around the same time every day. If you must take your eye drops twice a day, consider noon and bedtime for your schedule, or breakfast and dinner. If you have to take drops 4 times a day, you might want to take them with your meals and at bedtime.
Take note of any side effects that persist and discuss them with your ophthalmologist at your next visit or contact the ophthalmologist or the ophthalmology nurse by telephone.
Regular follow-ups with your ophthalmologist and optometrist are crucial in controlling your glaucoma.
Can I exercise? Are there any changes I need to make to my diet?
Continue your sporting activities and eat well. We put all the chances on our side when we lead a healthy life. There are no special diets or foods to avoid. The consumption of alcohol, wine or beer, and caffeine in reasonable quantities is not restricted. Tobacco, on the other hand, is not good for health in any quantity. Avoid doing any activity in which your head is staying below your waist for long periods of time, such as a headstand in yoga.
Do I have glaucoma?
The only way to diagnose glaucoma is with a complete eye exam. A glaucoma screening that only checks your eye pressure is not enough to find out if you have glaucoma. During a glaucoma eye exam, your ophthalmologist will: measure your eye pressure, inspect your eye’s drainage angle, examine your optic nerve for damage, test your peripheral (side) vision, examine or take a picture of your optic nerve, and measure the thickness of your cornea.
Will I go blind?
You will not go blind if you follow your ophthalmologist’s instructions and stay on top of your treatment daily; however, if you choose to ignore your ophthalmologist’s instructions you may go blind as glaucoma damage is permanent – it cannot be reserved. Without treatment for glaucoma, your vision will continue to worsen, which can eventually lead to blindness. Oral medication, eye drops, and laser surgery can help to stop further damage to your eyes. This is why it is very important to follow your ophthalmologist’s instructions.
What is eye pressure? Is my eye pressure normal?
Intraocular eye pressure, referred to as IOP, is the measurement of fluid pressure inside your eyes. Within the normal eye, there is constant production and drainage of fluid called aqueous humor. This fluid nourishes the lens and the cornea. The aqueous humor helps maintain stable pressure in the eye. If the eye pressure is too high, it can cause damage to the optic nerve. If the pressure is too low, the eye may not function normally.
The average eye pressure tends to change slightly during the course of a day and from one day to the next. It also varies with ethnic origin. In most cases of glaucoma, the intraocular pressure is elevated. Everyone’s IOP is different and what is normal for you may be different for someone else.
Is my glaucoma stable?
With a visual fields test, an OCT test, and an IOP measurement your ophthalmologist can comment on the stability of your glaucoma. Glaucoma medication, eye drops, and laser surgery can help stop or slow down further damage to your eyes. Glaucoma damage is permanent – it cannot be reserved. This is why it is very important to follow your ophthalmologist’s instructions.
Is my glaucoma laser surgery covered by OHIP?
Yes, glaucoma laser surgery is covered by OHIP.
Does my eye glass prescription change after surgery?
No. Your eyeglass prescription will not change after surgery. You will continue to wear your current eyeglass prescription.
What can I do to help my glaucoma? What should I avoid?
To help your glaucoma the best thing you can do is follow your ophthalmologist’s instructions. Patient compliance is the most important factor to prevent an increase in intraocular pressure. Medications must be taken as prescribed as glaucoma is painless unless it is acute. Medication is the best way to manage glaucoma and prevention delay any further vision loss. Things to avoid when you have glaucoma include smoking, exercises where your head is below your waist such as a headstand in yoga.
If any patient is interested to share their experiences or participating in our glaucoma group- support please let Dr. Abtahi or the management team know. Email us at general@icarecentre.org
Your doctor will be happy to answer your questions during your visit.
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