Ask an Expert about Glaucoma

This is an excellent question. This depends on the type of glaucoma that you have and if you have already had glaucoma surgeries in the past. There are classically two types of glaucoma that have the potential to make cataract surgery more difficult: pseudoexfoliative glaucoma and sometimes pigment dispersion glaucoma. In both of these cases, the small "zonules" or suspension cables that suspend the lens in the middle of the eye can become weakened. In this case, the surgery can be a bit more difficult. If the zonules are weakened, there is a higher risk that they will be too weak to hold the lens up during the surgery and the lens can fall into the back of the eye. If the lens does fall, we work with retina specialists who are trained to take the lens out of the eye in a slightly different manner. If you have had glaucoma surgery in the past, there are a few things that we do consider. First, if you have had a glaucoma implant, this can pose a minor difficulty if there is a tube in the front of the eye. In most cases we can work around the tube, but the worst case scenario is that we would trim the tube slightly and shorten it. This does not affect ability of the tube or the shunt to work; it is just an extra step in the surgical procedure.

Secondly, if you have had a trabeculectomy, there is a minor risk that the "filter" will not work as well after the surgery because of the inflammation that is created during the surgery. We often increase the amount of steroids that our trabeculectomy patients receive to help counteract this. Except for these rare occurrences, cataract surgery in a patient with glaucoma is not any more difficult than any other routine patient. Secondly, you may actually see a benefit and a lowering of your intraocular pressure after cataract surgery. There is a great deal of evidence that suggests cataract surgery can lower intraocular pressure by 1-2 mmHg, and that some glaucoma patients may be able to reduce or stop their glaucoma medications for some time. The reason for the decrease in eye pressure after cataract surgery is not yet known, but there are several studies trying to find the answer. Some people have proposed that the cataract, which is a portion of the natural lens in the eye that has become cloudy, may be at fault.

Over our lifetime, the natural lens in the eye continues to grow similar to an onion adding layers. As the lens gets bigger, it may crowd the drainage system in the eye causing the pressure to increase (like a sink backing up when the drain gets clogged). Removing the lens may allow the drainage system to expand again and begin to flow better. Other people have proposed that the inflammation caused after the surgery may in fact be of benefit and cause the drainage system to start working better. Finally, some people feel that some of the techniques that we currently use to remove the cataract (e.g., phacoemulsification) may have steps that cause the drainage system to be cleaned and begin flowing better. The true answer is that we don't know; however, we do know it is a real phenomenon. There are some lucky patients (like my grandmother) who used glaucoma drops for years prior to cataract surgery and have never had to restart them again. However, on average, we tend to see the eye pressure staying lower for about 1-2 years, and then it often increases again over time. It is important that you continue to see your eye doctor for routine exams to check the intraocular pressure, vision, visual fields and optic nerves because we cannot predict who will need to restart their medications or when this need will occur. Best of luck with your cataract surgery.

Thank you for your question. The answer to that question depends on the type of glaucoma that you have. Medications such as antihistamines used for the treatment of seasonal allergies can dilate the pupil, and this can lead to an episode of “angle closure” in glaucoma in patients that are predisposed to angle closure and have narrow angles. There are some anxiety and depression medications that can also precipitate episodes of angle closure in patients with either angle closure glaucoma or narrow angle glaucoma but this is also a relatively rare occurrence. In patients with open angle glaucoma, the use of allergy medication, anxiety medication or depression medication is not likely to cause angle closure, and it is not contraindicated in patients with open angles. It is important that you make sure that your eye doctor has completed a “gonioscopy” to ensure that the drainage angle is open before you use these types of medications. There is no evidence to suggest that any of these medications can cause or exacerbate open angle glaucoma.

Secondly, a change in pressure from 14 to 16 between visits is not all that unusual. The intraocular pressure fluctuates throughout the day even in patients without glaucoma. This is called a diurnal rhythm or circadian rhythm. We do not yet know the exact mechanism that controls this diurnal fluctuation, but some people are studying it to determine why this occurs. In most people, but not all, intraocular pressure is highest in the morning. The peak is often shortly after someone wakes up. We also know that, even in patients without glaucoma, the intraocular pressure can vary approximately 4 to 6 mmHg throughout the day. In patients with glaucoma or glaucoma suspects, this amount of variation can increase. In these cases, it is not uncommon to see variations over 6 mmHg throughout the day and the highest pressure may occur at a time other than the morning. As glaucoma specialists we will often set a target or goal intraocular pressure for each eye of our glaucoma patients. We understand that there will be some fluctuation of the intraocular pressure, but as long as the pressure does not go above the goal pressure, we are not concerned. If the pressure ever goes above the target that your doctor has set or your doctor notices any progression of your glaucoma, they will add more medications, or use laser treatment or surgery to help lower the intraocular pressure further. If you have specific concerns about your intraocular pressure, I recommend that you discuss what goal intraocular pressure your doctor would like for your eyes. This may help alleviate some of your concerns as well.

Thank you for your question. Xalatan is a prostaglandin analog, similar to Lumigan and Travatan. The medication works by increasing the drainage of fluid out of the eye through a secondary pathway called the "uveoscleral outflow" pathway rather than the primary “trabecular meshwork” drainage. In essence, instead of draining fluid out of the natural drainage system in the front of the eye, the fluid gets reabsorbed by the structures under the white part of the eye. This is very beneficial and works quite well. There are several side effects that can occur with prostaglandin analogs including the darkening of the color of the eye, darkening of the eyelids, redness of the eyes and longer eyelashes. Another side effect of the medication is that it slightly increases the risk of swelling. So called, “cystoid macular edema” is a form of swelling that may occur in the retina after cataract surgery. Although the risk is only slightly increased, we often ask our patients to stop taking the prostaglandin for a short time after the surgery to be safe. After the initial healing process occurs we often restart the prostaglandin analogs again to help control the glaucoma. In your case, when you were taken off of the medication, your eye pressure increased, and the risk of losing sight from the increased pressure is much greater than the small risk of having swelling in the retina. In addition, if there is any swelling that does occur in the retina we do have medications to treat that. In short, it is not unusual for your doctor to stop a prostaglandin analog after cataract surgery for a little while and then restart the medication after the initial healing process is complete. While I do not have your whole medical history to review, in general terms I agree with your doctor and would also restart the prostaglandin analog.

Antihistamines do have ocular side effects and the warning label in most antihistamines warn patients with glaucoma to avoid their use. Antihistamines can dilate the pupil and in patients and this can lead to an episode of angle-closure in glaucoma in patients that are predisposed and have narrow angles. In patients with open-angle glaucoma, the use of antihistamines is not likely to cause angle closure, and it is not contraindicated in patients with open angles. It is important that you make sure that your eye doctor has completed a gonioscopy to ensure that the drainage angle is open before you use these types of medications. In addition, there is no evidence that the use of antihistamines interacts with any of the medications used to treat glaucoma.

Thank you for your question. I am sorry to hear that you now have to make this decision. Unfortunately, I am not likely to be of any help in this particular situation (i.e., I cannot make this decision for you). As you are probably aware because of your mother's history, glaucoma is classically defined as a stereotypical pattern of damage to the optic nerve and certain layers of the retina. Elevated intraocular pressure is a risk factor for glaucoma, but just because the pressure is elevated this does not mean you have glaucoma. Often people with elevated intraocular pressure alone, and no other signs of glaucoma, are given the diagnosis of ocular hypertension. Similarly, just because the intraocular pressure is normal, this does not mean that someone cannot have glaucoma. We often see patients with glaucoma that have never had increased intraocular pressure, and we call this "normal-tension glaucoma."

Your eye doctor will likely follow the intraocular pressure, vision, visual fields, and the appearance of the optic nerves to see if there is any evidence of glaucoma that presents in the future. Given your family history and the data that was collected, there are ways to now calculate the risk of developing glaucoma (just as your doctor has apparently done). Unfortunately, we cannot look into the future to find out if you will be one of the fortunate people with ocular hypertension that never develops glaucoma, or if you will be one of the patients that eventually progresses to get glaucoma. I often give my patients the exact same options that you have been given. You can either start a medication now, or you can wait. Unfortunately, no one except you can make the decision as to what route is best for you.

When I tell patients that we are considering changing or recommending a new therapy, I always discuss the risks, benefits, and alternatives. First your doctor needs to discuss what medication he would consider starting you on. If it is a prostaglandin, then he will likely discuss the fact that it can make your eyes red, it can change the color of the eyes, it can change the color of the skin around the eyes, etc. If he were to choose a beta blocker, he would likely discuss the fact that you could have symptoms of feeling lightheaded or have a drop in your blood pressure. Also, he would need to know if you have asthma or any other pulmonary issues, etc. The benefit of starting therapy is that the intraocular pressure will likely be lowered. Lowering eye pressure is the only way we have of possibly preventing or slowing the onset of glaucoma. The alternative is to do nothing and continue to examine the eye to see if it continues to progress to the point that you can be definitively diagnosed with glaucoma. The real question is whether you want to start taking medications now and risk possible side effects from the medicine even though we don't necessarily have a diagnosis of glaucoma, or would you rather wait until we can definitively say that you have glaucoma before starting treatment. That is something that only you can decide. I have some patients that say that they would rather know they are trying to do something to prevent any loss of vision even though they may not have glaucoma. Others say that they want to avoid using medications as long as possible and want more definitive proof that they have glaucoma before using drops.

Both routes are fine, and that is why the doctor gave you the two choices. If the doctor felt strongly that you needed to start medications, he/she would not have given you the choice of staying off medications but having more frequent exams. There is really no correct or incorrect answer, you simply have to decide which would make you feel better. Best of luck with making this decision and I encourage you to discuss the risks, benefits and alternatives with your eye doctor.

Thank you for your question. Absolutely, glaucoma can and often does impact one eye more than the other. It is not uncommon for glaucoma to be diagnosed in one eye and the second eye is either normal or not as badly damaged at the time of the initial diagnosis. The rate of progression can also be different in each eye. We do not yet know the reason for this, but there are a lot of eye doctors doing research to determine why this happens.

To my knowledge, low-tension glaucoma (also known as normal-tension glaucoma) should have no bearing on lens replacement surgery. In fact, removal of a cataract often helps glaucoma patients see slightly better because the view is no longer clouded by the cataract. In some open-angle glaucoma patients, the intraocular pressure actually decreases for some time after surgery. I do caution my patients that have glaucoma that they are not eligible for certain "premium" lenses. There are new lenses on the market that help correct for both near and distance vision. One type of lens is called a multifocal lens and it uses concentric rings of different lens strengths to correct for near, then far, then near, then far, etc. This allows patients to see both close-up and at a distance without the use of reading glasses. The problem with this lens for glaucoma patients is that it splits the light into two paths (one for allowing the patient to see near objects, and one allowing the patient to see objects at a distance). That causes the amount of light hitting the retina at any one time to be decreased and lowers the ability to see contrast (think of contrast as being able to distinguish very similar shades of grey). Glaucoma also damages the optic nerve and decreases a patient’s ability to see contrast as well, so eye doctors avoid any increased contrast loss by avoiding multifocal lenses in glaucoma patients.

As for macular pucker, this is simply a sheet of tissue that is on the retina that is beginning to contract and wrinkle or "pucker" the retina. This epiretinal membrane is not related to glaucoma either, but can get worse over time. If necessary, a retinal specialist can peal that membrane off of the retina if the vision gets bad enough. Finally, glaucoma is definitely a genetic condition, but the genetics are complicated. Just because you have glaucoma does not mean that your parents had it or your children will get it. It is a very complicated puzzle and genetic researchers are working hard to find out what the exact genetic links are. While some types of cataracts are related to genetics, most are simply a matter of aging. Finally, I am unaware of any genetic predisposition to epiretinal membranes or macular puckering.

Thank you for your question. Floaters are simply pieces of debris or condensed vitreous that are elevated slightly above the retina and cast a shadow on the retina as light passes through the eye. If you think of your retina like the grass in your yard, the blades of grass are like the photoreceptors in the retina that detect light. If you held a piece of string over the grass in the sunlight, the shadow of the string would be cast onto the blades of grass. This is how you end up seeing floaters. Floaters are relatively common in most people. They can come as a natural process of aging and are most often seen between the ages of 60-65. This is usually related to a process in which the vitreous or gel inside the eye begins to condense and pull away from the attachments to the back of the eye along the retina, retinal vessels, optic nerve, and the front part of the eye called the vitreous base. This is known as a posterior vitreal detachment and is often associated with flashes of light and onset of seeing new floaters. Any time new flashes of lights or new floaters are seen, you should have a dilated eye exam to make sure there is no evidence of a retinal tear. While retinal tears are rare in these cases, they are important to diagnose and treat appropriately. This process can occur at a younger age in people for a lot of different reasons. It can often be seen early in patients that have myopia (near sightedness). It can be seen in patients after they have had surgery as well.

I had a surgery on my eye when I was 10 and I have had floaters ever since. It can occur after hitting your head or your eye. To my knowledge, Xalatan and other prostaglandin analogs have not been associated with an increased number of floaters in the eye. The floaters may or may not go away. As I noted, I first noticed my floater after my surgery as a child, and I still notice it every once in a while, especially on bright sunny days when I am looking at a blue sky. The floaters will often settle to the bottom of the eye and will not be noticeable for quite some time. They may get stirred up and become noticeable again for no apparent reason. If you notice new floaters, new flashes of light, or feel like there is a curtain coming over your vision call your doctor immediately and discuss it with them. They will likely do a dilated exam to make sure that it is simply new floaters and not a retinal tear.