Ask an Expert about Glaucoma

Thank you for your question. It is difficult to answer it without being able to examine your eyes and review your complete history, but there can be different causes for fluctuations in your eye pressure after surgery. If the intraocular pressure is currently 5 mmHg, your vision is stable, and your trabeculectomy is working well, then I would consider that a success. With regards to your tearing, I would be sure to mention this to your surgeon because given your low eye pressure, your surgeon would want to make sure that your trabeculectomy site is not intermittently leaking. If that is not the case, the tearing may be caused by irritation, and some artificial tears may help. Also, if you are still using any drops in your right eye that might be causing irritation, you should talk with your doctor about this.

Thank you for your question. This is an interesting subject and while it is not something that we encounter daily, it is not incredibly rare. There have been a few scientific studies that have focused on examining the association between acquired optic nerve pits and glaucoma. It appears that optic nerve pits are an increased risk factor for progression of glaucoma (i.e., those that have optic nerve pits are at an increased risk of progressing compared to open-angle glaucoma patients without pits). In addition, it appears that optic nerve pits are more prevalent in low-tension glaucoma (i.e., glaucomatous optic nerve damage in patients that have never had a recorded intraocular pressure above 21 mmHg) compared to patients that have open-angle glaucoma with increased pressure.

There are no known treatments specifically for optic nerve pits at this time other than simply reducing the eye pressure (as would be done for the treatment of glaucoma). In your case specifically, I would recommend that you have routine eye examinations that include intraocular pressure checks, dilated exams of the optic nerve (including photos if possible), visual fields, and possibly OCT studies. If you have any evidence of visual field defects, I would suggest discussing the possibility of treating your case as normal-tension glaucoma even if your pressures are never above 21 mmHg. This could include a discussion of initiating the use of pressure lowering drops versus watching for any evidence of advancement in the visual field defects prior to starting treatment. I wish you the best of luck.

Thank you for your question. In general, you should be somewhat cautious about swimming in open water especially if you have had a trabeculectomy surgery (with or without an EX-PRESS™ mini-shunt). Swimming and diving will likely expose the eye and bleb to open water in which bacteria could be growing. If you are thinking of doing any scuba diving or snorkeling, you should discuss these types of dives with your eye doctor. There are no good data showing exact intraocular pressures during the dives, but changes in pressure because of the mask or goggles may alter eye pressure transiently depending on the type of mask, the depth of the dive, and the duration of the dive.

There are dive techniques (equalizing mask pressure) that can alleviate this, but should be taught by a dive master. I would consider discussing your desire to go diving with your eye doctor and discuss whether or not they feel that precautionary use of an antibiotic eye drop may be useful prior to and after the dive. Several of my patients do dive and have not had any problems, but we do discuss the risks of bleb-related infections because of exposure to open water. I hope this is helpful.

I am a steroid responder, so I am on Lotemax, which I tolerate well, but I'm concerned because my pressure is going down so slowly. Could I now have inflammatory glaucoma in my right eye in addition to the pigmentary glaucoma? I was under the impression that the cataract surgery might lower my eye pressure; is this still possible?

Thank you for your question. Without having examined your eyes or having seen the results of previous tests and exams, it is nearly impossible for me to give a completely accurate recommendation. Pigmentary glaucoma is caused by the release of pigment from the back of the iris. This is usually caused by the zonules that hold the natural lens in place rubbing on the back of the iris and releasing the pigment. It is not uncommon to have spikes of pressure in pigmentary glaucoma and it can often be associated with increased physical activity that might jar the eyes (exercise, for example). This releases additional pigment that gets trapped in the trabecular meshwork (the natural drainage system) and causes a spike in pressure.

It is possible that during your cataract surgery, additional pigment was released simply because of the process of trying to remove the lens. This would not be uncommon. There is a significant amount of saline that is flushed through the eye to help wash the lens through the phacoemulsification hand piece during the surgery. This fluid flow or the ultrasound could cause pigment to be released from the iris. Your doctor should be able to do a gonioscopy to determine if there is now increased pigment in the angle.

It is also possible that there is some residual inflammation that could be causing a trabeculitis, which can influence the resistance to outflow of eye fluid, and subsequently increase the pressure. Your doctor should be able to tell if there are still some inflammatory cells floating around in the front of the eye.

If you are still on steroids to help reduce inflammation, it is also quite possible that you are a steroid responder. It does not have to be a large dose of steroids; it can simply be a low dose of steroids over a long time frame (five months would be a relatively long time to be on steroids). The only way to find out if you are a steroid responder is to stop the steroids under the direction of your eye doctor and to check the pressure again after you are off the steroids.

If the eye doctor believes that pigment is still being released, you might consider having an ultrasound biomicroscopy (UBM). This is an ultrasound of the eye that will allow the doctor to look at the location of the “arms” holding the lens in place. Those “arms” should be secured within the original bag that held the natural lens. If there is evidence that they are outside the bag, they could be rubbing on the iris and releasing additional pigment and cause inflammation of the iris. I wish you the best of luck.

Thank you for your question. The answer to this question may not be as straight forward as you might think. Let me try to answer your question as directly as I can first. When you say “I am 42 years old and totally blind…,” I have to assume that you mean that you cannot even perceive a bright light when it shines directly in your eye. In that case, high pressure in a totally blind eye is not harmful to the nervous system or any other part of your body. However, this does not preclude the fact that the increase in pressure can cause pain or headaches if the pressure gets high enough. If, on the other hand, you mean that you are “legally blind” (i.e., your vision is worse than 20/200 or you have less than 20 degrees of vision but still have ability to see some objects or at least light), then the high eye pressure can continue to cause further optic nerve damage and eventually lead to absolute blindness (i.e., inability to even see light). If you have any vision remaining (even just the ability to detect light) I would suggest attempting to maintain that level of vision as long as possible by controlling the intraocular pressure. I hope this helps.

Yes, UBM (ultrasound biomicroscopy) is used by glaucoma specialists to examine the angle, including the angle anatomy and positioning of various structures. Often it is used to diagnose plateau iris syndrome in patients who still have narrow angles after laser iridotomy. Ophthalmologists can also see the position of the lens relative to the pupil and angle structures. The clear scan cover is used where I see patients and they do find it comfortable during the exam.

Yes, your frustration with the visual field test is shared among many of my patients. Having taken it myself, I can see how patients would feel that the test is inaccurate. But one thing that I have observed is that patients usually get better at taking the test over time because they understand how to take the test and are less anxious about it. I do believe that it is important for you to be relaxed during the test, which is easier said than done! Alternatively, there are other algorithms for testing that are often faster, which sometimes helps if patients become inattentive during the test (although that does not seem to be your issue). Other types of visual field testing require a person to “map” out your visual field defect, and most ophthalmologists will not have that type of equipment (although academic centers often will). My advice to you is to try to relax and realize that visual field testing, while important, is only one part of your glaucoma management, and that your physician will be taking into consideration many factors when treating you.

Thank you for submitting your question. First, you should know that this happens to many of our patients at one time or another, so you are not alone. There may be two possible ways to interpret your question, so let me answer both.

If you squeeze the bottle hard enough that more than one drop comes out and a couple of drops get into your eye, there is no problem medically when this happens. The eye only holds so much fluid (tears, medications, etc.) at one time and if there is too much fluid in the eye, when you blink, it will push out the excess and you will feel it run down your cheek. The drawback is that if you put more than one drop in at a time and you are blinking out the extra, it is a waste of medication and it can cost you money because you will need to refill your medications more frequently. In these cases, sometimes we suggest having someone assist you in putting in the medication, if that is possible.

On the other hand, if you are supposed to take Combigan two times, and sometimes you put in an extra drop because you think that you previously forgot to put the correct number of drops in, that means that you might occasionally put in three drops of Combigan throughout the day instead of two. This is a slightly different issue. If it only happens once in a great while, there is a pretty good chance that nothing bad will happen. It is best to avoid doing this because there is a very small chance you could get some additional side effects from taking too much of the medication. It is similar to taking an extra dose of any oral medications that you might take. If you notice that you are taking extra drops, I would suggest using a tally system on a piece of paper. As soon as you put a drop in, put a mark on piece of paper that reminds you that you took the drop. If you forget, you can always go back and look at your tally sheet. I hope this helps, and I wish you the best of luck.