Glaucoma is an eye condition that affects the connection between the brain and the eye called the optic nerve. When damage occurs at the optic nerve, it can lead to loss of vision and in later stages blindness. To detect glaucoma, your eye care provider will perform screening tests, a thorough assessment of the optic nerve, and next steps if you are diagnosed as a glaucoma suspect or glaucoma.
Like most diseases or conditions, early detection is very important in preventing vision loss and blindness. Although there is no cure for glaucoma, your eye doctor will recommend treatment and management options to slow the process of the advancement of glaucoma.
Depending on the type of glaucoma, there are different signs/symptoms of the disease. The most common form, primary-open angle glaucoma, does not have many symptoms for the patient to readily notice. This reinforces the need for regular eye health visits with your eye doctor.
- Gradual loss of peripheral or central vision (normal tension or primary-open angle glaucoma)
- Eye pain, halos, blurred vision, discomfort, redness, tearing, vomiting/nausea (narrow angle glaucoma)
In the front of the eye, there is a liquid known as aqueous humor that is produced by a structure called the ciliary body that travels from the back of the iris (colored part of the eye) to the anterior chamber (front compartment of the eye). Although well studied, the actual process leading to glaucoma is not totally elucidated.
The most accepted theory is that the outflow of aqueous humor (fluid inside of the eye) decreases. Therefore, an increase of fluid is maintained in the same area, which causes an increase in intraocular eye pressure (level of pressure inside the eye – not related to blood pressure). When this happens, the elevated intraocular pressure damages the optic nerve (connection between the eye and the brain). Long-term, this has significant consequences for vision.
Treatment Options for Glaucoma
There are many treatments available depending on the patient’s diagnosis. It is important to maintain a relationship with your eye doctor to discuss the best option for you. Some of the mainstays of treatment are as follows:
- Medications (eye drops): Eye drops are prescribed to reduce intraocular eye pressure. If your eye disease is worsening or changing, your eye doctor may prescribe one or more eye drops to manage your condition.
- Laser Surgery: Laser trabeculoplasty is a procedure where the eye doctor concentrates a high-energy laser beam toward the trabecular meshwork (drainage structure of the eye) to increase the outflow of the inner eye fluid. This often decreases the eye pressure of the inside of the eye, but it occasionally needs to be treated or has a limited effective period.
- Drainage Implants: This is when a small valve implant is placed inside the eye to help with uncontrolled glaucoma. Your eye doctor will discuss if this option is recommended for you.
- Conventional Surgery: There are several surgical options for patients that are not responding well to conventional therapies (eye drops, other procedures). Your eye doctor will discuss if or when this option is the most appropriate approach.
There are many specific tests completed to build a comprehensive eye health profile to show relative risk or existence of glaucoma for a patient. Some tests may include the following:
The physical examination of the back of the eye to assess the optic nerve by your eye doctor. Your eye doctor will look for risk factors that can be associated with glaucoma or other eye diseases.
- Visual Field
A test to assess light thresholds or how well your eye can detect light at differing levels for your central and peripheral vision.
- Fundus Photos
An image completed to monitor for subtle changes in size and other important characteristics for the back of the eye.
- Optical Coherence Tomography
An image taken to determine the thickness of the optic nerve. This allows your eye doctor to monitor for subtle changes that are not perceptible by your eye doctor to track for changes over time. This is like a magnetic resonance image (MRI) that allows your provider to detect and diagnosis diseases affecting the brain or other parts of the body. The OCT device is specific to the eye and uses light rays compared to MRI imaging that uses magnetic and sound waves.
- Intraocular Eye Pressure
Eye pressure is often a key sign for certain types of glaucoma and is checked at most eye visits.
- Corneal Pachymetry
A corneal pachymetry measurement is the thickness of the cornea (or thickness of the front surface of the eye). A thin versus thicker measurement indicate different findings to your eye doctor.
A tool that allows your eye doctor to check the drainage structure of the eye and to determine the presence or existence of problems blocking the flow of aqueous humor (inner fluid of the eye) from the eye.
- Visual Evoked Potential
A VEP instrument measures the electrical signal generated by or at the visual cortex in response to controlled visual stimulation. Your eye doctor may use this to help aid in the diagnosis of glaucoma.
Commonly Asked Questions
How is glaucoma diagnosed?
The diagnosis of glaucoma can sometimes take several tests in a short period of time or years depending on the stage of the condition. For example, a small puzzle with larger puzzle pieces may be easy to put together; however, a very complicated puzzle with small pieces may take weeks, months, or even years. Luckily, there have been many modern advances to allow your eye doctor to build a comprehensive eye health profile to make the determination whether a patient has glaucoma.
When are additional or repeat glaucoma tests recommended if I had already completed a glaucoma evaluation at a prior eye doctor office in the past?
It is not uncommon for patients to inform their eye doctor that tests have been completed in the past. Or patients informing their eye doctor that all the tests were “normal” and there was no sign of glaucoma. Unfortunately, we are dynamic or ever-changing and tests may need to be updated from time to time. Please check with your eye doctor for the next best steps.
Are there known risk factors for Glaucoma?
- Age: People over the age of 60 have an increased risk
- Refractive Error: Patients that are more nearsighted are more likely to be diagnosed with glaucoma or have an increase in risk.
- Race: Specific populations have a higher incidence such as African Americans, Indigenous People, Hispanic for Open Angle Glaucoma. However, narrow angle glaucoma is more common for Asian descent and Native Alaskan populations. While Japanese descent individuals are more likely to develop normal tension glaucoma.
- Family History of Glaucoma: Family inheritance is common in glaucoma.
- Systemic Diseases: Patients with hypertension, diabetes, and heart disease have an increased risk for developing glaucoma.
- Physical Injuries/Trauma: Injuries to the eye should always be closely followed by an eye doctor to rule out damage.
- Corticosteroid Use and other medications: Using corticosteroids for prolonged periods of time has been associated with an increased risk of developing glaucoma.
Are there different types of Glaucoma?
Yes, there are multiple types of glaucoma that have been identified.
- Primary Open-Angle Glaucoma (POAG): POAG is the most common type with a makeup of 90% of all types of glaucoma. The eye’s drainage structure is often the cause of increased eye pressure leading to vision loss if not detected, managed, and treated by your eye care provider.
- Angle-Closure Glaucoma: Angle-closure is when the drainage structure of the eye suddenly becomes blocked (between the cornea and the iris). This is considered a medical eye emergency and requires immediate diagnosis and treatment with both medical and surgical means. Symptoms often include: blurred vision, diffuse redness, eye pain, vomiting/nausea, and a throbbing sensation.
- Secondary Glaucoma: Secondary glaucoma develops when the eye’s intraocular pressure increases. Causes of secondary glaucoma can be as follows: an eye injury, eye inflammation, medications (systemic or eye drops), and other eye diseases that may lead to glaucoma. These eye conditions are often detected during an annual eye examination or emergent based upon circumstance.
- Normal Tension or Low-Tension Glaucoma: Normal tension glaucoma is often insidious, as eye pressures are within the “normal” accepted range. However, the optic nerve still becomes damaged even with “normal” eye pressures. This condition is not well understood but the working theories suggest that the optic nerve is more susceptible to damage or less blood supple to the optic nerve itself. Either way, this condition must be closely monitored for patients at risk for normal tension glaucoma.