Glaucoma is a disease that can cause serious vision loss through damage of the optic nerve of the eye. The optic nerve acts like a video cable that sends images from the eye to the brain. As glaucoma worsens, damage to the optic nerve increases. Vision loss starts out in the peripheral or side vision, but if untreated can progress to blindness. Because it usually progresses slowly, most people have had serious vision loss by the time they notice symptoms on their own.
Vision loss in glaucoma is primarily caused by an increase in the internal pressure of the eye, known as intraocular pressure (IOP). The goal of glaucoma treatment is to lower the intraocular pressure to a safe level. This can be achieved either with eye drops, laser procedures, or surgery. Although glaucoma cannot be cured, with modern therapies nearly every case of glaucoma is treatable and vision loss can be prevented.
What Causes High Intraocular Pressure?
IOP is a measure of the internal pressure of the eye. Like a tire or basketball, the eye must have internal pressure to work correctly. Instead of air like a tire, the eye’s internal pressure comes from a fluid called aqueous humor. This clear fluid is constantly being produced inside the eye and then drains out through a complex drainage structure inside the eye.
An increase in IOP usually results from production of too much fluid or poor drainage of the aqueous. The eye’s drainage structures slowly become less effective with age, causing IOP to slowly rise. Rarely, the drainage structures can suddenly stop working completely and cause a rapid rise in pressure that can lead to serious vision loss in a short time.
Different Types of Glaucoma
Glaucoma is a group of diseases that share similar features. However, most people have one of the two most common types: open angle glaucoma or narrow angle glaucoma
Open angle glaucoma is the most common form of glaucoma in the U.S. In this type of glaucoma the eye either produces too much aqueous or the drain slowly becomes less efficient over time. Both problems cause aqueous to build up in the eye, leading to a rise in IOP. Over 90% of adult glaucoma patients have open angle glaucoma, which is typically treated with eye drop medications.
Narrow angle or angle closure glaucoma is caused by an abnormality in the drainage structures inside the eye. In most cases the drain slowly narrows over time. When the drain becomes too narrow, it is susceptible to becoming completely blocked or closed. When the aqueous outflow becomes completely blocked there is a sharp rise in IOP called an acute angle closure attack. Symptoms may include blurred vision, rainbows and halos around lights, severe eye pain, headache, nausea and vomiting. Vision loss can happen within hours to days.
How is Glaucoma Detected?
Glaucoma is often called the “sneak thief of sight” because it is most often painless and can lead to severe permanent damage to vision before a patient is aware. Glaucoma can only be detected during a complete eye exam by an eye care professional. There is no one test that can consistently detect all types of glaucoma. Therefore, your doctor will commonly use several tests to determine if you have it.
These tests include:
- Measurement of IOP
- Peripheral vision testing
- Quick, painless scans of optic nerve health
- Corneal thickness measurements
- Gonioscopy which is an inspection of the drainage structures of the eye
- Thorough examination of the optic nerve and overall eye health
Glaucoma Treatment Options
Unfortunately, damage from glaucoma cannot be reversed. This means prevention of further damage and vision loss is the aim of treatment. While glaucoma can’t be cured, it can be controlled. Most patients with open angle glaucoma are treated with daily eye drops to lower the eye pressure to safe levels. Some patients with aggressive or advanced cases may require laser or eye surgery to preserve their vision.
Patients with angle closure glaucoma typically only require a single laser treatment to control their glaucoma. However, some patients with angle closure glaucoma also develop open angle glaucoma and need eye drops as well.
A new generation of surgical devices and procedures have been developed for the control of glaucoma. Some of these procedures can be performed in the office and others can be combined with routine cataract surgery with minimal side effects.
Laser peripheral iridotomy or LPI is an in-office laser procedure which is frequently used to treat narrow angle or angle closure glaucoma to prevent glaucoma attacks in patients with anatomically narrow angles. In a normal eye, aqueous fluid drains out through structures in the angle between the cornea and iris. As the eye ages, the angle narrows and can become blocked, leading to a rapid rise in pressure and potentially serious vision loss. In this case, a laser is used to make a small drainage hole in the eye that forms a shunt to improve aqueous drainage and lower IOP.
Selective laser trabeculoplasty or SLT is an in-office laser procedure designed as a treatment option for patients with open angle glaucoma. Approved by the FDA in 2001, SLT is a “cold laser” which causes no scar tissue and improves the eye’s ability to drain away excess pressure. It can be used for many patient to reduce the need for expensive eye drop medications. Unlike previous laser treatments SLT does not cause scarring or damage to surrounding tissue.
SLT offers the following benefits:
- Takes only minutes to perform in the office
- Very few patients experience any discomfort with the procedure
- There are no restrictions or limitations after the treatment
- successful for the majority of patients
- Just one treatment may reduce the daily use of expensive glaucoma drops
- Virtually all insurance plans covers SLT, including Medicare & Medicare Advantage plans
Minimally invasive glaucoma surgery or MIGS is the latest advance in surgical treatment for glaucoma. It is a collective term for a variety of surgeries that use microscopic shunts or tubes to help control intraocular pressure in those with mild to moderate glaucoma. Most of these procedures are performed in conjunction with cataract surgery. Our surgeons use the IStent injectTM for its effectiveness and safety. The IStent inject TM improves the eye’s natural fluid outflow to safely lower eye pressure through a tiny incision. Proven safe and effective, the IStent inject TM is implanted into the trabecular meshwork during routine cataract surgery. It spares important eye tissue that is often damaged by more invasive traditional glaucoma procedures.
Trabeculectomy is a surgical procedure that can be performed when glaucoma is more severe at time of diagnosis or when the disease continues to progress despite the use of medication and/or laser treatments. During the procedure a filter, often referred to as a “bleb”, is created in the tissue that lines the outside wall of the eye. The bleb provides an alternate passage for aqueous fluid to flow out of the eye, thus lowering the intraocular pressure.