Questions & Answers
Reprinted from Our Newsletters
What is the time frame for the progression of vision loss in normal tension glaucoma when there was considerable nerve damage (~75%) at the time of diagnosis?
We can’t estimate time to vision loss. Each patient progresses at their own rate although it’s a good sign when there is no progression over the years. Treatment will help maintain vision and slow progressive vision loss in most cases. The Normal Tension Glaucoma Study shows a 30% lowering of eye pressure slows the worsening of glaucoma.
I have been diagnosed with early stage glaucoma. Can you advise me if using a computer all day worsens the condition? What about stress?
Working on a computer all day will have no impact on the worsening of your glaucoma. No studies have shown that stress worsens glaucoma, but many ophthalmologists have found that eye pressure may be elevated during periods of stress. This may be due to poor compliance with eye drops use. The best way to minimize worsening of glaucoma is to use your drops and attend your regular follow-up appointments.
My mother has glaucoma, what are my chances of getting it?
Although glaucoma tends to run in families, it does not affect all family members equally. Your overall risk increases with the more first degree relatives (parents, siblings) affected by glaucoma that you have. If you have family members with glaucoma, you should be screened regularly.
Do I have glaucoma?
Patients frequently ask their doctors the question “Do I have glaucoma?” To reply, I need to do a complete eye exam as well as visual field testing. Additional tests such as HRT (Heidelberg Retina Tomography) and OCT (Ocular Coherence Tomography) may help me answer. I often tell patients that to truly say one has glaucoma, we must document characteristic optic nerve head changes and/or visual field loss during the first exam or follow-up appointments. We must also see signs of worsening of the optic nerve or visual field over the follow-up period. It may take many years before changes are found.
Are there any new therapies?
Some new formulations of existing medications are now available including:
- Travatan Z with a different preservative
- Lumigan RC where a lower concentration of the drug provides the same IOP lowering effect
- Azarga which combines Timolol and Azopt in the same bottle.
These various medications may either reduce eye drop side effects or reduce the frequency of eye drop use.Surgically, new treatments include:
- the Express Shunt
All these surgeries aim to lower intraocular pressure and reduce eye drop use.
Can I use medical marijuana to lower my eye pressure?
Researchers have found Cannabinoid receptors in human eyes. Cannabinoids are the active ingredient in marijuana and help to lower eye pressure. Their action is short lived so you would have to smoke marijuana constantly to have any long-term effect in lowering eye pressure. This would result in a constant “high” which would be unsafe. Also smoking marijuana has significant health risks including lung cancer. Using marijuana to treat glaucoma is not recommended.
I have glaucoma and was told my vision is not good enough for me to drive. What are the requirements to keep my driver’s licence?
Patients with advanced glaucoma may not meet the legal requirements to drive. The current regulation is to maintain 20/50 or better vision in at least one eye and have at least 120 degrees of continuous visual field. Because glaucoma can affect peripheral vision, many patients with advanced glaucoma may have 20/50 or better vision but they do not have enough continuous visual field. In Ontario, physicians must report this by law. This may result in a suspension of your licence.
What is low tension glaucoma?
Normal tension or low tension glaucoma is a condition where there is damage to the optic nerve and/or the visual field in the setting of normal eye pressure (<22). More than 50% of normal tension glaucoma patients don’t worsen even without treatment so it is okay to watch.
Are there any possible causes for optic nerve damage other than glaucoma?
Other things can mimic glaucoma field loss. These include a “stroke” to the eye which can cause a similar visual field defect, previous eye trauma with damage to the retina, or, more rarely, a brain tumor.
Why would my vision loss be from the top and not the sides?
Not all glaucomatous visual field defects are from the sides. Quite commonly with low tension glaucoma, many defects may be top or bottom.
Are any other medical problems associated with glaucoma?
Raynauds Sx and migraine are commonly associated with normal tension glaucoma as is low blood pressure and major blood loss.
Can issues, such as blood pressure, weight, diet, and smoking affect my glaucoma?
There is more of an association of glaucoma worsening with low blood pressure than with high blood pressure. Certain blood pressure medications, such as diuretics (water pills) or calcium channel blockers have been associated with glaucoma worsening, but the data to support this is still limited.
Diet and weight loss do promote overall general well-being and obese people may have higher eye pressure readings.
Smoking has been shown to affect glaucoma surgical outcomes in a negative way and patients are encouraged not to smoke.
Can I lift weights if I have glaucoma?
No, weight lifting such as bench pressing has recently been reported to temporarily increase eye pressure.
Does wearing sunglasses help glaucoma?
A recent report suggests that certain wavelengths of light could be bad for the optic nerve. This hasn’t been proven yet but it would be wise to wear sunglasses and a hat on very bright days.
Does having a sibling with glaucoma increase my risk of getting it?
Yes, a recent study has shown that if you have a sibling with glaucoma you have a significant risk of developing optic nerve damage.
Do only elderly people get glaucoma?
No, not all glaucoma patients are elderly. In fact, 25 percent of patients are under 50 when they develop the disease.
What is the difference between glaucoma and ocular hypertension?
Glaucoma refers specifically to high pressure causing damage to the optic nerve and/or peripheral vision. Ocular hypertension refers to high pressure which does not damage the nerve or vision. Most patients with ocular hypertension do not develop glaucoma.
I see very well and do not wear glasses. How can I have glaucoma?
Glaucoma affects side vision first, and only affects central vision very late in the disease, so it has no effect on your need to wear glasses.
Can vision deteriorate despite treatment for glaucoma?
Yes, as part of the normal aging process, we lose cells in the optic nerve responsible for vision. Currently, there is very little that can be done about this change due to aging.
Patients with severe damage from glaucoma will be more aware of this progressive loss of vision. That’s why it’s essential to diagnose glaucoma early before damage occurs to the nerve cells.
Does emotional stress affect my intraocular pressure?
There is no scientific evidence suggesting that emotional stress affects intraocular pressure.
What does a hemorrhage on my nerve mean?
In glaucoma, a small hemorrhage on the rim of the optic nerve indicates that eye pressure is too high for the nerve. Your eye specialist will usually recommend lowering your pressure to a safer level with eye drops, laser treatment or surgery.
If my blood pressure is high will my eye pressure be high?
Not necessarily. Although there is an indirect relationship between high blood pressure and glaucoma in older patients, patients under stress or who experience a sudden increase in blood pressure do not usually have high eye pressure.
Does eye strain cause glaucoma?
I have noticed darkening of my eyelashes. Is this a side effect of my glaucoma medications?
Darker, thicker eyelashes are a common side effect of all Prostaglandin medications – Lumigan, Xalatan and Travatan. There is no way to avoid this. It does reverse itself once you stop the medication but it can take a few months to return to normal.
Some people also notice some darkening of the skin around their eyes. You can minimize this by avoiding skin contact. Put the drop in about an hour before you go to bed, gently wipe around the eye with a damp tissue and rinse your eyes just before bedtime.
The Canadian Medical Association recently published an article showing a higher incidence of inflammatory eye diseases – uveitis and scleritis – for users of osteoporosis drugs (oral bisphosphonates). Do these eye diseases worsen glaucoma?
Osteoporosis drugs have been linked with uveitis. Discontinuing osteoporosis drugs is usually the best management for uveitis.
The use of these medications does not directly cause glaucoma to develop or worsen. However, if someone develops uveitis, the treatment is topical or oral steroids. Long term use of steroid medications can cause eye pressure elevation and the development of glaucoma. This is less likely to occur if you are under the care of an eye specialist who monitors your condition.
Is anyone doing stem cell research on repairing eyes damaged by glaucoma?
Stem cell research is currently an active area of interest for ophthalmology and for glaucoma treatment. Promising and ongoing research involves trying to regain function of the trabecular meshwork (internal drain of the eye) as well as regrowth/repair of retinal ganglion cells damaged due to glaucoma.
What about Glaucotab, a herbal treatment that I found on the Internet?
Do not use it. It has no scientific validity and should not be used until it is shown to work and not to be toxic.
What is HRT?
A fast scanning laser ophthalmoscope called a Heidelberg Retinal Tomograph (HRT) produces a 3-D image of the optic nerve so specialists can diagnose damage early on. HRT can also detect early progression of glaucoma caused by nerve damage.
My doctor has recommended an HRT test, what is this?
HRT (Heidelberg Retinal Tomography) is a diagnostic test that scans the optic nerve to generate a 3-D image. This image provides information about the size, shape and contour of your optic nerve, and may help in predicting if you have early glaucoma. The test may be repeated every six months or yearly and images are then compared to earlier images to see if the glaucoma is worsening. This information helps your doctor determine if you need treatment for glaucoma or an increase in therapy for better eye pressure control.
My doctor has asked me to stay in his office all day and evening to check my eye pressure. Why?
Your doctor is obtaining a diurnal intraocular tension curve which looks at your eye pressure over the course of the day. Eye pressure is dynamic and fluctuates throughout the day. Patients with glaucoma may have their eye pressures vary by up to ten units (mm Hg) in one day. One eye pressure reading may not accurately reflect your eye pressure control and may miss elevations at other times of the day. This full day pressure allows your doctor to alter your treatment for better eye pressure control.
I had cataracts removed from both eyes 30 years ago and several years later had an implant in one eye. In the other eye, I use a soft contact lens. I have had 3 Heidelberg tests over the last 3 years without good results. The technician has tried taking the Heidelberg – both with my contact lens in and with it out. Why is it difficult to get an image in this eye?
The test is probably difficult because you don ’t have a lens in the eye. Most diagnostic machines have a certain focal range and when you are aphakic (no lens in the eye), you fall out of the machine’s focal range. As well, your contact lens may blur the image.
Some attachment lenses for the HRT can extend the focal range and also correct for astigmatism. Another option is to try to get the image with your regular glasses on instead of a contact lens .
Because you are aphakic and have worn a contact lens for many years, issues with your cornea may block the image quality.
During my annual vision test, my eye doctor discovered that I have two different sized optic nerves and the pressures are high as well. I don’t think I did well on a subsequent field test. Any advice?
Diagnosing glaucoma can be difficult. Your doctor needs to consider a number of factors before making a diagnosis and starting treatment. He or she will take into account your eye pressure and its range over the day, what your optic nerves look like, how different the two of them are, and the visual field test result.
Don’t worry if you didn’t do well on the visual field test, as there is a learning curve and it may take three to four tests to get better at it.
Your doctor will also consider your past medical history, as major surgeries, blood loss, and previous medications such as oral steroids, may influence your IOP or the look of the optic nerves.
If you do have glaucoma, remember there is no cure. The majority of cases are managed with eye drops, laser treatment and surgery. Treatment is individually determined.
My sister has been told that her “temporal angles are narrow which could increase the risk for pupillary block”. Because her pressures have been low and stable for many years, she wants to stop her Timolol drops. Is this a good idea?
To manage the narrow temporal angle, she may benefit from either a laser iridotomy or else cataract extraction. This will open the angle and lower the risk for pupillary block. Cataract surgery is the more definitive treatment.
If she has definite glaucoma then she should not discontinue timolol. If she has mild elevated eye pressure (ocular hypertension) but no glaucoma damage, then she may be able to discontinue the drops once she has had the laser iridotomy or cataract surgery.
My night-time eye drops cause significant eye redness, skin discoloration and long eyelashes. How can I avoid the first two problems?
These are common side effects of prostaglandins (Xalatan, Travatan, Lumigan) which are used to control eye pressure. To avoid these effects, take the medicine shortly before you go to bed and use a damp tissue to remove the eye drop residue that can form on your eyes after you use drops. Removing this residue will minimize eye redness and skin discoloration.
Does Xalatan cause high blood pressure?
No clinical evidence indicates that Xalatan raises systemic blood pressure. It has been shown to have no effect on blood pressure control and is overall safe to use.
The prescribed drops for my glaucoma are causing problems with my eyelids. Can you tell me about implants that vent excess pressure in the eyeball?
Many new surgical devices are used to treat glaucoma. An iStent may reduce the need for glaucoma drops. An iStent is indicated for early glaucoma, and seems to have better results if combined with cataract surgery. The cost, about $800-$1000 for one, $1200-$1400 for two, may not be covered by provincial medical or private insurance.
Can using eye drops for an extended period result in loss of effectiveness and allergic reactions?
Most of the newer drugs do not wear off or lose their effect over time. Many studies with Prostaglandin meds, such as Xalatan, have shown long term effectiveness in stable patients. Beta blocker meds however, such as Timolol, do lose their effect over time.
Some drugs, such as Trusopt or Alphagan, have shown allergic effects of about 20-30% over time. We see less when the drug is used in combination with a beta blocker (Cosopt, Combigan).
With long term use, some preservatives in eye drops may cause red eyes with burning and irritation. Rather than an allergy, this has more to do with tolerability.
In spite of these issues, patients should continue to use eye drops as recommended by their doctors. Medications control glaucoma in more than 90% of patients.
I was given a generic medication. Is it the same as I was taking before?
Few studies compare a generic medication with its branded counterpart. Generic medications must contain the same quantity of active ingredient (drug amount) as brand name medications. Fillers however, do not have to be the same. This means generics may have different side effects including burning and allergic reactions. The bottles can also be different. This may cause confusion with each use. If you switch to a generic medication, I suggest you bring the bottle to your doctor on your next visit.
What if I forget to take my eye drops?
Take them as soon as you remember. Every time you forget to put an eye drop into your eye, your eye will have no medication to control the pressure. The pressure may increase, causing more damage to your sight. To control your glaucoma, you must apply drops regularly according to your doctor’s instructions.
Can I miss the occasional eye drop?
No. Your eye needs consistent medication to control the pressure and prevent blindness. Every time you miss an eye drop, eye pressure may increase, causing further damage to your sight.
How can I avoid side effects?
Two things will help. Keep your eyes closed for 3 minutes after putting in your drops. Apply pressure to the side of your nose (where your upper and lower eyelids meet) to prevent the drops from entering the nose from your tear ducts.
What about contamination?
Always wash your hands before applying eye drops. Do not touch the dropper tip or let it touch your eye, eyelashes or any other surface. Always close the bottle when finished.
I use 3 eye drops. Can I put them in all at once?
You should wait at least 3 to 5 minutes between drops. This prevents them from being diluted and lost in teardrops.
Does the order of the drops matter?
If you are taking TIMOPTIC-XE®, it should go in last.
Do eye drops cause cataracts?
Today’s eye drops probably don’t cause cataracts. Some of the older drops such as Phospholine Iodide may predispose patients to cataracts. Doctors tend not to use these very strong drops in patients with a normal lens.
How many times a day are Timolol eye drops recommended?
Generally, regular Timolol 0.5 % drops are recommended for twice daily use. The gel forming type is once daily, but because the drop is thicker in consistency, this may cause visual blur.
Over time research has shown that once daily T1/2 (non gel forming) can last up to 24 hours. Some ophthalmologists have therefore advocated using the drops once daily. If this is something you want to try, I recommend rechecking the eye pressure in the late evening after morning administration to ensure a prolonged effect of the drug.
What is the consequence if I mistakenly instilled two drops of the same type in an eye at five minutes apart?
If two drops go into the eye at the same time – either extra from squeezing the bottle or if you felt the first drop didn’t get in – the eye will naturally get rid of any excess drops. Normal absorption of drops is during the next five to fifteen minutes.
The minimum five minute window is recommended for eye closure to minimize systemic absorption of drops and to prevent one drug from washing out the second drug if two different medications are required at the same time.
Adding a second eye drop of the same type five minutes later may not further lower eye pressure but can increase systemic absorption through the nasal lacrimal duct increasing the drug’s side effects.
The big issue will be toxicity from the second eye drop – either allergy to the preservative or the medication, or eye surface irritation. There is also a greater chance of systemic side effects such as low blood pressure, low heart rate, and tiredness.
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.