Angle Recession Glaucoma

Glaucoma is a group of eye diseases that develop due to elevated intra-ocular pressure (IOP) within the eye.

Angle recession glaucoma (also called angle-cleavage glaucoma) is a type of glaucoma that can develop following trauma to the eye.

Glaucoma is a potentially blinding condition in which the optic nerve (which transmits visual information from the eye to the brain) is damaged. This type of glaucomatous optic neuropathy is often associated with elevated eye pressure (intraocular pressure), though not all eyes with glaucomatous nerve damage have high eye pressure.

In angle recession glaucoma, the force of a traumatic blow to the eye damages the tissue in the eye's angle, resulting in elevated pressure within the eye. The elevated eye pressure eventually leads to glaucomatous optic nerve damage and vision loss if untreated.

To better understand how the blunt trauma results in elevated eye pressure and glaucoma, it is helpful to first understand what are the structures involved. The angle of the eye is the area where the peripheral iris and ciliary body (the colored ring-shaped muscle in the eye) meets the wall of the eye (the sclera). Within the angle is a ring-shaped sieve-like structure called the trabecular meshwork, which connects to a ring-shaped chamber called the canal of Schlemm.

• Normally, a clear liquid (aqueous humor) is constantly being produced within the eye by a structure called the ciliary body. The aqueous circulates within the eye and then drains into the eye's veins, passing through the trabecular meshwork and the canal of Schlemm on its way out.
• This constant fluid flow is important, as it brings vital nutrients to the inner eye and carries away waste products. However, if there is obstruction to the outflow of the aqueous fluid, pressure builds up in the eye.
• Following blunt trauma, the iris can be torn at its attachment to the sclera (iridodialysis of the iris root), the ciliary body can be torn (cyclodialysis), and/or the trabecular meshwork can be damaged.
• The outflow of fluid is affected in two ways: First, there may be an immediate rise in intraocular pressure due to the presence of blood and inflammatory cells that clog the trabecular meshwork. Second, the ocular trauma can cause permanent changes in the structure of the trabecular meshwork, making it more difficult for fluid to pass through. This results in chronically elevated eye pressure that may be subtle in some cases, but if left untreated, may eventually result in glaucomatous optic nerve damage.
• The onset of glaucomatous optic nerve damage can appear months or even years after the initial angle recession injury. Sometimes, angle recession and glaucomatous damage are found during a routine eye examination in patients who had long forgotten about a previous eye injury.
• The risk of developing glaucoma after an angle recession injury is related to the degree of eye pressure rise, the duration of the pressure rise, and the underlying health of the optic nerve.
• If the nerve was already partially damaged by another form of glaucoma (such as pseudoexfoliative glaucoma or primary open angle glaucoma), the angle recession injury may accelerate optic nerve damage.
• The optic nerve may also be more vulnerable to pressure-related damage in those with diabetes and in chronic smokers.
• Additional risk factors for the development of glaucoma include a thin cornea (which can be measured by the eye doctor), increased age, and family history of glaucoma.

Any direct blow to the eye can result in post-traumatic angle recession glaucoma. Often, the trauma is a result of high-speed or fast-moving blunt objects or projectiles, such as

• fists;
• stones (for example while trimming lawns with a weed whacker);
• balls (for example, paintball, racquetball);
• champagne corks;
• bungee cords; and
• air bags.

Immediately following the injury, there will likely be aching pain in the eye, light sensitivity, and blurred vision. The eye pressure may be very high in the initial phase when the trabecular meshwork is temporarily clogged with blood and inflammatory cells. The injury may be associated with blood in the angle and in the space between the cornea and iris (hyphema).

Once the blood and inflammation resolve, the pain subsides but the eye pressure may remain chronically elevated at a level that is painless yet still harmful to the optic nerve. The patient may not have any specific eye or visual complaints until the vision loss has progressed to an advanced stage.

Immediately following ocular injuries, a thorough examination by an ophthalmologist must be performed. In addition to looking for signs of angle recession, the ophthalmologist will look for other damage to the eye (for example, traumatic iritis, corneal abrasions, lacerations, retinal tears, and detachments, etc.). Initial medical care will depend on the extent of the injuries.

If an angle recession injury is found, repeat eye exams will be needed to screen for the development of glaucoma over time.

• Is my eye pressure elevated?
• Are there any signs of internal eye damage due to the injury?
• Are there any optic nerve abnormalities on my examination?
• Is treatment necessary?
• How often should I return for follow-up examinations?

• An eye doctor will perform a complete exam to assess the extent of the damage.
• Once it has been confirmed that the eye is not ruptured, the eye pressure is carefully measured and the angle structures are directly visualized.
• The eye's angle can be examined by the eye doctor with a slit lamp microscope and a gonioscope, a tool with small mirrors that works much like a periscope. This is called gonioscopy.
• The angle structures can also be evaluated with imaging devices such as ultrasound biomicroscopy and optical coherence tomography (OCT).
• Sometimes, a traumatic hyphema (blood in the angle) may temporarily block the view of the angle structures, so the gonioscopic exam would have to be repeated later.

The optic nerve is then carefully examined.

• The eye doctor can directly visualize the optic nerve at the slit lamp microscope.
• If the nerve appears to show signs of glaucoma, additional testing may include optic nerve thickness measurements (with OCT) and screening for early visual field loss (with visual field testing).

Close observation with repeat exams over several years is important to detect glaucoma at its earliest stages since prompt treatment may prevent permanent vision loss.

Although there are no home remedies for angle recession glaucoma, there are steps you can take at home that will help. The most important things to remember are to take your medications as instructed, keep the follow-up appointments, and report any changes in vision or development of new eye pain immediately.

One can also take measures to ensure that the optic nerves are in good health so they have the best chance of withstanding the elevated eye pressure. Stopping smoking, keeping blood sugars under control, and maintaining a healthy blood pressure go a long way toward keeping the nerves as healthy as possible.

The aim of all glaucoma treatments is to lower the eye pressure to a level at which the optic nerve is no longer being damaged. With angle recession, this might mean a combination of medicated eyedrops and/or surgery.

Medications

Initial therapy may require several different eyedrops.

• There are several categories of eye medications that are designed to lower eye pressure. Some reduce the aqueous fluid inflow (for example, beta-blockers), others facilitate the aqueous fluid outflow. Your ophthalmologist will select the appropriate drops based on your medical history.
• In some instances, an oral medication will also be necessary for eye pressure control.
• You may also need eyedrops to control swelling (for example, steroids) or drops to dilate the pupil (cycloplegics) initially.
• If the pressures remain elevated long after the injury, glaucoma drops may be continued indefinitely to adequately protect the nerve.

If the eye pressure is not sufficiently controlled with medication, surgery may be necessary.

The ophthalmologist will discuss the risks and benefits of each procedure with the patient.

Filtering surgery

If the trabecular network has been severely damaged, an ophthalmic surgeon can create an alternate outflow pathway for the aqueous humor that bypasses the damaged trabecular meshwork. This is known as filtering surgery. Examples include trabeculectomy with or without antimetabolite and placement of drainage implants (for example, Molteno valve) and stents.

Cyclodestructive procedures

Procedures that permanently decrease the production of aqueous by the ciliary body are called cyclodestructive procedures and are generally reserved as a last resort.

The success rate of these procedures varies from person to person. Your ophthalmologist will take your eye health, general health, and other factors into consideration when suggesting which treatment has the best chance of successfully controlling the eye pressure.

Ongoing follow-up with eye pressure checks and optic nerve evaluations are very important because the onset of glaucoma may not be evident until months or sometimes years after the initial injury.

Protective eyewear should be used for activities in which fast-flying objects could strike the eye, resulting in either blunt trauma (non-penetrating) or penetrating trauma (for example, weed whacking, racquetball paintball, etc.)

Following an angle recession trauma, it's possible to prevent or minimize glaucoma with adequate eye pressure control.

Angle recession glaucoma can cause progressive permanent, irreversible vision loss if not well controlled. Unfortunately, because a chronically elevated eye pressure may have no symptoms for years, there are instances in which the treatment is delayed, resulting in permanently blurred vision and even blindness.

The risk of vision loss depends on many factors, including

• the extent of the initial injury,
• the underlying health of the optic nerves, and
• the effectiveness of pressure-lowering treatments. For this reason, it cannot be emphasized enough that all people with angle recession trauma should continue to closely monitor their eye health.