Ask an Expert about Glaucoma

Unfortunately, the answer is not as easy as telling you a single number. While the "average" eye pressure is approximately 15, the range of "normal" eye pressure is much larger. About 9 out of 10 people (about 90%) will fall somewhere between a pressure of 10 and 21. Even knowing this, it does not mean that if you have a pressure of 22 or higher it is "abnormal." Every individual and every eye is different. There are many patients with pressures in the mid-20s who do not have glaucoma and they can simply be followed with routine eye examinations by their eye care specialist. There are also patients who have been diagnosed with glaucoma and even though treatment may decrease their pressure below 22, they still experience worsening of their glaucoma. It is important that you see an eye care specialist so that they can do a thorough examination and determine if your your eye pressure is problematic.

Thank you for your question. I am sorry that you have had to endure so many problems with your eyes recently. In general, I would tell you that there is minimal to no association between the functioning of your tear drainage system and your glaucoma. The tear drainage system normally drains the tears from the front surface of the eye down into the nose and into the back of the throat. The fluid created inside the eye (aqueous humor) drains back into the body through an entirely different pathway. Mohs surgery for basal cell carcinoma on the eyelid often requires a plastic surgeon on hand to reconstruct the eyelid after the cancer is removed. In many cases, when the surgery involves the inner parts of the eyelid, the tear drainage system cannot be salvaged. In some cases, after surgery, patients can continue to have some eyelid positioning problems as well as disruption of the normal surface tears. A decrease in the tear production and dry eyes can often result in the burning sensation and tearing that you are describing. In response, the eyes will then create too many tears as a reflex reaction. This usually results in tears running down your cheek. Often our first line of therapy in treating dry eyes is artificial tear eye drops or ointment to help soothe the eyes and re-establish a normal tear film layer. If this does not help and the patient still is not making enough tears, we often will plug the tear drainage system on purpose. In your case, I would suggest seeing an occuloplastic surgeon and they can determine whether or not you are experiencing dry eyes or tearing related to the damage to your tear ducts. In either case, fixing the tear drainage system or leaving it alone will have absolutely no impact on your eye pressure or progression of glaucoma.

As for the glaucoma diagnosis in the same eye, I would again think that the chance of a connection between the two is highly unlikely; however as doctors we never say "never." I suggest that you consider a second opinion from a glaucoma specialist considering you have these findings in the setting of recent surgery and a normal eye pressure. It may not be a bad idea to possibly repeat the visual field test after the cornea irritation is under control. Severe dry eyes, eyelid malposition, and several other things can give you a false positive visual field test. While this does not explain the "optic nerve damage," I think it warrants a second look. Until then, I would suggest continuing your Timoptic XE and follow up with your eye doctor as scheduled. Best of luck and it sounds as though you deserve to have a little good luck coming your way!

Individuals at high risk for glaucoma should have a dilated pupil eye examination at least every two years. Eye doctors use several tests to detect glaucoma; these tests include:

• Tonometry measures the pressure inside the eye. Examples of tonometers include: 1) The air puff or noncontact tonometer emits a puff of air. Eye pressure is measured by the eye’s resistance to the air. 2) The applanation tonometer touches the eye’s surface after the eye has been numbed, and measures the amount of pressure necessary to flatten the cornea. This is the most sensitive tonometer, but a clear, regularly-shaped cornea is needed for it to function properly. 3) The electronic indentation method measures pressure by directly contacting anesthetized eyes with a digital pen-like instrument.
  
  
• In pupil dilation, special drops temporarily enlarge the pupil so that the doctor can better view the inside of the eye.
  
  
• Visual field testing measures the entire area seen by the forward-looking eye to document straight-ahead (central) and/or side (peripheral) vision. It measures the dimmest light seen at each spot tested. Each time a flash of light is perceived, the patient responds by pressing a button.
  
  
• A visual acuity test measures sight at various distances. While seated 20 feet from an eye chart, the patient is asked to read standardized visual charts with each eye, with and without corrective lenses.
  
  
• Pachymetry uses an ultrasonic wave instrument to help determine the thickness of the cornea and better evaluate eye pressure.
  
  
• Ophthalmoscopy allows the doctor to examine the interior of the eye by looking through the pupil with a special instrument. This can help detect damage to the optic nerve caused by glaucoma.
  
  
• Gonioscopy allows the doctor to view the front part of the eye (anterior chamber) to determine if the iris is closer than normal to the back of the cornea. This test can help diagnose closed-angle glaucoma.
  
  
• Optic nerve imaging helps document optic nerve changes over time. An eye doctor may choose to use one or more of the four available scanning techniques, all of which are painless and non-invasive.

New research is focused on lowering pressure inside the eye, and finding medications to protect and preserve the optic nerve from the damage that causes vision loss. Scientists are also investigating the role of genetics in glaucoma, and over the last few years their understanding of this factor has progressed. Researchers have discovered genes associated with congenital glaucoma, juvenile glaucoma, normal-tension glaucoma, adult-onset open-angle glaucoma, pigmentary glaucoma and other conditions related to secondary glaucoma.

Thank you for your question. Depending on the severity and location of the blow to your head, you could be at risk for one type of glaucoma. We will often ask our patients if they have ever had head trauma, black eyes, been knocked out, etc. to determine if they are at risk for angle recession. The fluid that is made inside the eye (aqueous humor) flows around the pupil into the drainage system where the colored part of the eye (iris) meets the white part of the eye (sclera). The fluid must drain through the trabecular meshwork into Schlemm's canal before it returns to the blood stream and is reabsorbed by the body. If the eye receives direct or indirect trauma in this location, there can be damage near the drainage system. If this damage is present, you can be at risk for developing glaucoma in that eye at any time in the future. This could even be years or decades after the trauma. If you are concerned about possibly having glaucoma as a result of trauma to the head or eye (i.e., angle recession glaucoma), I would highly recommend that you see a glaucoma specialist that is comfortable doing a complete eye exam that includes gonioscopy. This is a special exam that is done so that the eye doctor can look at the drainage angle to determine whether or not there is any damage. Once the exam is complete, they can tell you if you are at increased risk for glaucoma in the future.

Thank you for your question. I am sorry that you have had some difficulty with your right eye, but unfortunately an excellent functioning bleb can sometimes be quite large and cause the problems you are describing. It sounds as though the surgery was successful in lowering the pressure, but you are now dealing with one of the known side effects of this surgery. The pain that you describe is known as bleb dysesthesia (bleb discomfort). Often because the bleb is so large it will disrupt the tear film and prevent the eyelids from dispersing the tears evenly over the surface of the cornea. This often leads to dry eye syndrome as well as an excavation of the cornea near the edge of the bleb where the tear film is disrupted. This excavated area is known as a dellen. Often we try drops or ointments as the first line therapy. However, if this is not sufficient, we will resort to using a bandage contact lens. I typically try not to use the bandage contact lens as a long-term solution, but that is my personal preference. I worry about bacteria growing on the contact lens and causing a corneal ulcer. If I choose to use a bandage contact lens, I will often keep my patients on a low level of antibiotic drops the entire time that they are using the lens to help prevent ulcers. Many cornea specialists says that this is not always necessary and I do know many doctors that do use bandage contact lenses long-term in their patients without too much trouble. Again, this is only my personal preference. I think this treatment path is fine as long as there are no other side effects that emerge. Otherwise, you may need to consider doing a bleb revision surgery. This is a difficult decision considering the pressure is now well controlled and your vision is stable. Often, blebs do not function as well after revision. I recommend that you and your doctor have a discussion regarding the risks, benefits and alternatives of continuing the current treatment vs. considering bleb revision surgery. After you know your alternatives, you can make a decision on how long you would like to continue using the bandage contact lens.

Thank you for your questions. Because I have not examined your daughter's eye or seen the results of the test myself it is very difficult to give fully accurate advice in this complex case. I will take the information that you have given but will have to make some general assumptions to fill in the remainder. Let's take each of your questions individually:

• Do you think it is acceptable to wait 6 weeks for the eye clinic appointment?

  Given that your daughter is considered a glaucoma suspect and the pressures are only mildly elevated at this time, 6 weeks is not an unreasonable wait. There are patients with pressures that remain above 21 for nearly their entire life and never progress to glaucoma. We often describe them as "ocular hypertensives."

• What kind of ophthalmologist should we go to?

  Keep your appointment with your pediatric neuro-ophthalmologist. After they have seen your daughter they will be able to make a more clear recommendation as to whether or not a glaucoma specialist is needed. It sounds as though your daughter has need of a pediatric specialist, possibly a neuro-opthalmology specialist, and possibly a glaucoma specialist. Starting with a pediatric-neuro-ophthalmologist is an excellent beginning and they will be able to assess whether or not she needs to see a glaucoma specialist. Because you are in a University Hospital setting, the pediatric-neuro-ophthalmologist probably has a glaucoma specialist partner that can easily be consulted. I do suggest that you try to use a single practice for your sub-speciality care and not see a pediatric specialist in one practice, a neuro-ophthalmologist in another practice, and a glaucoma specialist in a third practice. It is better for patient continuity and care to have all of the specialty care in one practice, if possible.

• Our new appointment is with a pediatric neuro-ophthalmologist. Should we see a glaucoma doctor?

  See the answer above.

• The new doctor ordered a full spectrum visual field test. What other tests should they order?

  This is difficult to determine because I did not personally examine the visual field test results and I did not examine your daughter's eyes. In general, if I am concerned about glaucoma I would typically like to see the visual fields, gonioscopy, central corneal thickness, stereo disc photos (for baseline comparison in the future), and possibly an OCT of the optic nerve head and a couple of other general exam findings. Again, this all may change if the visual field and the optic nerves look relatively healthy and the only issue is slightly increased pressure. Let the neuro-ophthalmologist examine her first and they will have a better idea of which tests to order.

• Can my daughter go on roller coasters, play sports, swim, hike, or fly in an airplane without treatment? Is that safe?

  This is an interesting question. In our patients with pigment dispersion syndrome and pigmentary glaucoma, we do know that they can have increased pigment dispersion with exercise and this can lead to occasional bouts of elevated eye pressure. While your daughter's angle appears to be relatively wide open, it might not be a bad idea to restrict her intense exercise for a couple of weeks until she sees the specialist. This being said, roller coasters are fine if they do not jar her head around. Mild exercise with sports/swimming/hiking is fine (and encouraged considering her age, height, and current weight). Flying should also be fine.

• My daughter is 5’3” and very over weight (170 pounds). Could her weight have an impact on her eye problems?

  First, at the age of 13, a girl that is 5'3'' and 170 pounds is likely considered morbidly obese. This has ramifications on her health way beyond just her eyes. She is at risk for early diabetes, hypertension, heart trouble, and a lot of other health problems. As her parent, it is important for you to provide guidance. I highly recommend that you find a pediatrician that can help you plan a good diet and exercise routine to help your daughter lose some weight and become healthier overall. As for her eyes specifically, this is nearly impossible to determine without examining her eyes myself. Young women that are obese can have certain eye problems that are also accompanied by headaches and swelling of the optic nerves; however, by what you have told me about her exam, this does not appear to be the case. Again, overall, making a lifestyle modification that includes a better diet and an exercise program is the best advice for her long-term health.

Thank you for your question. This is something that many of our readers inquire about. Essentially, your question relates to the long-term effectiveness of drops. This simplest and most straight forward answer is that every patient with glaucoma progresses at a different rate and patients often react to medications differently over time. Unfortunately, neither I nor any other glaucoma specialist can predict how long a certain treatment will continue to work in an individual patient. In many of our patients, a drop will continue to work for their entire life; however, we also have many patients that have used a drop for years and have done well, but suddenly the drop no longer maintains their intraocular pressure at the target level. The exact reason for this is not always clear, and researchers are exploring why this happens.

Glaucoma is a progressive disease, and it may just be that the resistance to the flow of aqueous through the trabecular meshwork continues to get worse over time. It is possible that one drop may be adequate initially, but as the glaucoma progresses, it eventually becomes insufficient. It is also possible that the body may begin to respond less well to the same medication over time. More research is required to find the exact mechanism(s). Continue to use your eye drops as prescribed by your eye doctor and visit him/her routinely. Your doctor will examine your eyes and watch for any signs of progression. If there is any evidence that the current treatment regimen is not working, they will change it quickly and hopefully prevent any further damage to your eyes.