HOW DO YOU OBTAIN A GLAUCOMA DIAGNOSIS?You can find important information here on how a doctor arrives at a glaucoma diagnosis along with steps that you should take if you are diagnosed with glaucoma. WHY IS A GLAUCOMA DIAGNOSIS IMPORTANT? The other day, a patient came to my office complaining of headaches. She described the pain as most severe around her eyes and asked if I thought that she might have glaucoma. Before I could answer her, she started crying. After getting her calmed, I explained that although having a family history of glaucoma does place her in a higher risk category, it does not guarantee that she will develop the disease, and, even if she does, there are steps that she can take to prevent blindness. I further explained that while it was possible that her pain could be caused by elevated pressure inside the eye, which is a symptom of glaucoma, other more common factors might just as easily be responsible for her headaches. After performing an examination, I concluded that she neither had glaucoma nor was she in the process of developing it. Her headaches appeared to have been caused by a sinus infection. We discussed a plan for treatment and a few days later her headaches had disappeared. This patient recognized that she had a problem and this problem brought her to me. She made a good decision. We were able to clear up her headaches quickly and lower her anxiety about having a glaucoma diagnosis. However, she also engaged in a process of
self-diagnosis
before seeing me, which most of the time is not a good decision.
How do I, as an ophthalmologist, determine if a patient either has, or is showing signs of developing glaucoma? Glaucoma diagnosis can be a relatively simple task. But there are situations where it is difficult and may not lead to a clear conclusion. You may be a person in the process of determining if you have glaucoma, a person newly diagnosed, or one that has had the condition for many years. In each case, I must consider the following three elements to arrive at a responsible glaucoma diagnosis and to monitor progression of the disease.
INCREASED INTRAOCULAR PRESSURE Intraocular pressure is measured by a test called tonometry. Tonometry is part of the standard examination that I perform in my practice. It is short and simple, but gives me some very important information about glaucoma diagnosis.
The Goldmann tonometer is very precise and is considered the gold standard in clinical practice for a glaucoma diagnosis. Glaucoma is a stealth destroyer. This means that it causes irreversible damage to the optic nerve often without the patient being aware that they even have a problem. In more than half of the glaucoma cases, there are no outward symptoms at all. In fact, increased intraocular pressure determined by an eye-care professional may be the only symptom that suggests glaucoma or that a patient is at an early stage of the disease, known as pre-glaucoma or glaucoma suspects. These terms may be a bit confusing, but what they imply is that a person must participate in regular checkups and treatment to identify glaucoma disease and to prevent its progression. But I cannot rely on a tonometer reading alone to arrive at a glaucoma diagnosis. A tonometer reading is simply one tool that can indicate a need for further assessment and follow-up. For example, there is one type of glaucoma called
normal tension glaucoma
that does not present with ocular hypertension. Instead, the pressure is normal. Approximately 15-25% of patients have this type of glaucoma.
A fundamental step in glaucoma assessment is visualization of the optic nerve through an ophthalmoscope. This test also is very simple. The ophthalmoscope has a special light that I use to see inside your eye and allows me to examine your optic nerve.
OCT obtains images that are cross-sections of the optic nerve. A cross-section is a perspective that cuts across something, instead of cutting down its length. For example, chopping a carrot into disks creates cross-sections of the carrot.
A person’s visual field is the scope or coverage of a scene that is observable at any given moment. For humans, this is a little more than 180° or half of a circle. But let me simplify this technical explanation. Extend your arms out at your sides at about eye level. Got it? Great! Now focus forward on a point in front of you. Even though you are looking straight ahead, you still should be able to see your hands. This commonly is known as peripheral vision or seeing out of the corner of your eye.
Visual field damage can be caused by retinal diseases, other structures of the eye, or due to damage to the optic nerve. Thus, a common symptom of glaucoma is a decreased field of view, also known as tunnel vision. Tonometry, visualization of the optic nerve and perimetry not only are important tools for a glaucoma diagnosis, I also use them as essential tools to monitor disease progression and treatment in patients with glaucoma.
I have had patients that have visited my office with other needs, such as complaints of dry eyes, allergies, or simply because they wanted to be evaluated for a new prescription for their glasses. Nevertheless, my examination revealed increased intraocular pressure or changes in the optic nerve, suggesting that the patient might have glaucoma. Most of these patients had no symptoms. Many even had excellent visual acuity. During my consultation with them about their glaucoma diagnosis and the need for treatment and further monitoring, some reacted with surprise, others in disbelief. I recognize that it can be hard to accept a glaucoma diagnosis when you do not have any symptoms and your vision is good. But as I said previously, glaucoma often acts as a silent disease in its early stages. Unfortunately, this sometimes leads people to ignore advice from their ophthalmologist and fail to participate in, or adhere to the glaucoma treatment regimen prescribed. However, this is an unwise decision. It is precisely at the early stages of glaucoma that treatment can have its best outcomes for patients. If you have received a glaucoma diagnosis from your doctor, it is important that you take it seriously. Adhering to treatment and participating in regular checkups of your intraocular pressure, field of vision, and optic nerve can help to ensure that you will not develop blindness from glaucoma.
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In between sobs, she indicated that her uncle had glaucoma and was blind. She was afraid of being diagnosed with glaucoma too.
There are several types of tonometers or instruments that measure pressure inside the eye. Among the most used are the Goldmann applanation tonometer, the non-contact tonometer or pneumotonometry, the electronic indentation tonometer, and the manual indentation tonometer or Shiotz. 
In essence, glaucoma is a disease of the optic nerve. All people with glaucoma have optic nerve damage to some extent. Sometimes this damage can be very mild. In fact, it can be so mild that the optic nerve may appear normal when I look at it through an ophthalmoscope during a regular eye examination. It then becomes necessary to look at the optic nerve and its fibers using more precise tests, such as Optical Coherence Tomography or OCT to arrive at a glaucoma diagnosis. 
Nerves, such as the optic nerve, are actually bundles of fibers. These fibers are like the groups of small wires that you would find inside the cord to an electrical appliance, such as a lamp. OCT uses ultrasound technology to view cross-sectional images of the bundles of fibers that make up the optic nerve. This enables me to determine if the number of fibers in your optic nerve is within a normal or below normal range. A loss of nerve fibers suggests glaucoma.
To obtain a glaucoma diagnosis, I measure a patient’s visual field using a perimetry test, sometimes also called campimetry.
