Ask an Expert about Glaucoma

Thanks for your interesting question. I just started swimming myself, and I do wear goggles. Prolonged exposure to chlorinated water can definitely irritate your eyes; however, I do not know of any association between swimming with your eyes open in a chlorinated swimming pool and elevated eye pressure. Obviously, you do not want to apply your eye drops prior to diving into the pool!

Decreased tear production does not cause glaucoma nor is it associated with the disease. However, the treatments sometimes used to treat dry eye can cause glaucoma, and the treatments used to treat glaucoma can cause dry eye! For example, sometimes patients with dry eye who have an underlying inflammatory component to their symptoms may be prescribed topical steroid drops. In some patients, topical steroids can cause elevated intraocular pressure and eventually glaucoma. On the other hand, glaucoma drops, particularly ones that contain preservatives, can exacerbate dry eyes. I hope this answers your question.

Latanoprost is one of three prostaglandin analogues that are commonly used in glaucoma treatment. It is also now available in a generic formulation. The other prostaglandin analogs available in the United States are Travatan-Z and Lumigan. You did not mention if latanoprost has been effective in lowering your eye pressure, but if it has, it may be worth considering switching to one of the alternative prostaglandin analogs, as you may better tolerate a different formulation. If you cannot tolerate the prostaglandin analogs, then your doctor can also consider prescribing medications of another class. One example is a topical beta blocker, such as timolol. Beta blockers are also very effective at lowering eye pressure. They typically do not cause side effects in the eye, but can have systemic effects such as a decrease in heart rate and blood pressure, and an increase in fatigue; although, the majority of patients tolerate beta blockers fairly well. If you have asthma or other lung diseases, most doctors will avoid prescribing this class of medication, however. It is worth having a chat with your doctor about your medication options and preservative-free formulations that might work very well for you.

Thanks for your question. As you observed, during a yawn, tearing and tear turnover increases. The volume of a drop or two of your typical eye medication actually exceeds the volume that your eye can handle by ten times. So, in some sense, pharmaceutical companies have taken into account the fact that a good proportion of medication is flushed away by normal tearing, drainage, tear evaporation, binding by other proteins in the tears, etc. Ideally, if you can avoid yawning right after you instill the eye medication, you will enhance its effectiveness.

Thank you for your question. I believe that you are referring to asymmetric cupping of the optic discs when you ask about your “uneven optic nerves.” This is one of the physical signs on eye exam that alerts doctors to the possibility of glaucoma, but does not mean that you actually have this eye disease. Most patients have relatively symmetric “cupping” of the optic disc, which is a description of the appearance of the optic nerve tissue and blood vessels as they converge at the back of the eye and go towards the brain, where visual processing occurs. Therefore, when patients have asymmetric cupping, it is a red “red flag” for your doctor because this finding can be associated with glaucoma. You should undergo a comprehensive ophthalmic examination including but not limited to eye pressure measurement, corneal thickness measurement, examination of your drainage system, visual field testing, optic nerve exam, and optic nerve imaging. This can be performed by a general ophthalmologist, but you can also see a glaucoma fellowship-trained ophthalmologist. Sometimes patients who have asymmetric cupping are monitored as “glaucoma suspects” and examined over time on a less frequent basis than patients who definitely have glaucoma.

Thank you for an interesting and challenging question. This a challenging question because of the limited information I have and because I have not examined you. I am assuming your eye pressure must be quite high; however, eye pressure is only a risk factor for glaucoma, and there are patients with elevated eye pressure (ocular hypertension) who do not have evidence of optic nerve damage. However, the tools that eye doctors use for detecting optic nerve damage are not perfect. Doctors examine your optic nerve in the clinic, as well as obtain quantitative measurements of your nerve. They also perform visual field testing, which is not a perfectly precise test. So, the tools used to assess whether an optic nerve is healthy are not perfect. Therefore, it is possible that if you have very high eye pressures and a high likelihood of optic nerve damage (although it may not yet be detectable using our current tools), it is not unreasonable to require glaucoma surgery. However, glaucoma surgery has its own set of risks, and therefore you need to have a frank discussion with your ophthalmologist about the risks and benefits of surgery versus your current treatment regimen, which I am assuming includes medications. Lastly, you could also obtain a second opinion from a glaucoma specialist before undergoing glaucoma surgery.

Thank you for this interesting question. I will answer the easier part (the second question) first. The broken blood vessels in the whites of your eyes you describe are common, especially in patients who are taking blood thinners such as aspirin. They are benign and I sometimes describe them to patients as “bruises” that will take several weeks to go away. These are not related to glaucoma. Usually they do not cause any visual or physical symptoms, although sometimes patients experience eye irritation for which I recommend artificial tears.

To address the second part of your question, it has been demonstrated in large population-based studies that low diastolic blood pressure (the lower number in a typical blood pressure reading) is associated with glaucoma and its progression. Ocular blood flow may also be decreased in those with low diastolic blood pressure. There is some evidence to suggest that decreased ocular blood flow may play a role in glaucoma, especially low-tension glaucoma. There is currently no consensus, however, as to the best test to measure ocular blood flow, nor how the measurement should impact glaucoma treatment.

One intervention an ophthalmologist may consider is whether a patient taking blood pressure medications might have too low blood pressure. For example, patients with decreased ocular blood flow might be especially vulnerable to aggressive blood pressure lowering. In summary, ocular blood flow measurement is not a standard nor is it a necessary part of glaucoma care, but it may give your ophthalmologist information that could be helpful in your treatment.

Thank you for submitting a question. Because I have not personally examined you, it's difficult for me to address your question as accurately as your physician. However, I can help answer the question of whether a low eye pressure of 1 – 2 mmHg is harmful to the eye. First of all, your problem of having a low eye pressure after mini-express shunt surgery (trabeculectomy) is not uncommon, especially if there was a leak. More often the surgical site scars down and heals “too much” and the trabeculectomy fails (and the low pressure that is desired is not achieved), whereas sometimes there is leaking or too much fluid flowing out of the trabeculectomy site, and the pressure is too low. There is a delicate balance that glaucoma surgeons strive to achieve.

It is a good sign that your vision is improving. The situation you describe in which the eye pressure is 1 - 2 mmHg after surgery is most likely hypotony of the eye. This condition can cause changes in the retina (a condition called hypotony maculopathy), which can make your vision blurry. When there is a leak causing the eye pressure to be too low and the leak does not stop in response to conservative treatment, then eye doctors recommend revision surgery, which you had. However, the eye pressure can still remain low if the trabeculectomy is “overfiltering.” In these cases it is reasonable to try conservative treatments first to allow the body's natural healing to occur and for the eye to increase its pressure. In-office procedures or surgical strategies are available to your ophthalmologist that can increase the pressure, but these also come with risks. Therefore, it is reasonable to wait and try conservative treatment first, and while there is no definite time period as to when you should have more aggressive treatment, I would recommend waiting much longer than 3 - 4 months, especially if vision is impaired. I hope this helps clarify your situation.