Glaucoma is an eye disease that causes damage to the optic nerve. Most people who get this condition do not know they have it until they develop vision problems. There is no cure for glaucoma. People with this condition may need surgery or medicine to control pressure inside the eye.
Ocular injuries are very common among young people. Some of them are minor and do not need hospitalization. But there are some injuries that are severe and can lead to blindness if not treated properly.
Injuries such as corneal abrasion, cataract, retinal detachment, optic nerve damage, open globe injury, closed globe injury, and traumatic glaucoma are extremely dangerous. Blunt trauma or penetrating injuries can cause these injuries. The severity of these injuries depends on the type of injury.
What Causes Traumatic Glaucoma?
Glaucoma Caused by Block in Drainage
Traumatic glaucoma is an elevated intraocular pressure (IOP) caused by damage to the trabecular area of the eye. This area is present in the angle between the cornea and iris.
The pressure inside the eye is maintained with a balance between formation of a fluid (aqueous) and its drainage out of the eye through the trabecular meshwork in the angle of the eye.
When trabecular area is damaged, the outflow of this fluid is blocked. This causes an increase in the amount of fluid in the eyes. This then leads to an increase in the pressure in the eyes.
Hyphema (caused by trauma in this case) is the collection of blood within the anterior chamber of the eye. Blood blocks outflow of aqueous and therefore high eye pressure. It is more common in children than adults. The incidence of hyphema varies from 2% to 5% after blunt ocular injury.
The most common causes of hyphema are direct trauma (penetrating) or indirect trauma (non-penetrating).
Peripheral anterior synechiae (PAS) is a condition that prevents the flow of aqueous humor through the trabecular outflow system. Peripheral anterior synechiae (PAS) are bands of scar tissue that connect the iris to the cornea. This causes the iris to stick to the cornea.
PAS are formed in some people after blunt injury and is one of the mechanisms which causes secondary glaucoma.
Any type of injury followed by scarring can block the angles and high eye pressure consequently.
Glaucoma Caused by Lens Subluxation or Dislocation
In some cases, a mechanical problem may cause an intraocular pressure (IOP) increase, such as a dislocated crystalline lens (natural lens of the eye which is situated just behind the iris).
If an anteriorly luxated lens becomes lodged in the anterior chamber, it can lead to acute angle closure because of secondary pupillary block or raise intraocular pressure by blocking the drainage route for fluid out of the eye.
Posterior dislocation (also known as posterior luxation) may not increase your risk of developing secondary glaucoma.
If the lens capsule ruptures, protein from the lens will leak into the eye, causing inflammation. Inflammatory cells release chemicals which increase intraocular pressure.
These two conditions can lead to an acute rise in eye pressure and blindness because of secondary glaucoma.
Early Onset Traumatic Glaucoma Pathophysiology
Trauma can cause trabecular meshwork disruption. A procedure called gonioscopy shows where tears lie within the eye.
These changes may cause a temporary rise in intraocular pressure (IOP). This rise in pressure may last until the injured tissues heal. In some cases, the healing process leads to scarring and permanent damage to the outflow system.
Hyphema is caused by rupturing of blood vessels in the eye. This happens when there is a blow or injury to the eye. When the blood vessel breaks, it bleeds into the anterior chamber of the eye.
A person who has hyphema often feels pain in the eye. Sometimes, people with hyphema do not notice any symptoms.
Traumatic hyphema is caused by bleeding into the eye. Blood clots form inside the eye and block the flow of fluid in the eye. This causes swelling, pain, redness, and blurred vision.
A traumatic hyphema should be treated immediately because it can cause blindness if untreated.
Late Onset Traumatic Glaucoma Pathophysiology
Ghost cells are abnormal cells found in the trabecular meshwork of the eye. These cells are believed to be derived from the iris. When the trabecular space is filled with ghost cells, the pressure builds up within the eyes, causing glaucoma.
eye globe trauma may lead to lens dislocation. Posterior dislocation of the lens causes vitreous prolapse in the anterior chamber. This results in pupil block glaucoma. Most cases of glaucoma because of lens subluxations are of the open angle variety. Glaucoma may also be caused by vitreous prolapse, causing occlusion of the trabecular meshwork.
Trauma to natural lens of the eye causes leaking of proteins into the eye. This leads to inflammation and blockage of the trabecular network. Inflammation causes glaucoma. Cataract surgery resolves the problem.
Penetrating eye injuries can cause traumatic glaucoma. Injury to the lens may cause inflammation of the anterior segment, leading to glaucoma. Anterior iris bowing and acute angle-closure glaucoma can occur after traumatic cataract.
Penetrating trauma might create a pathway for epithelial cells of cornea and conjunctiva to enter the anterior chamber. Epithelial cell sheets could block out the meshwork, causing angle closure glaucomatous changes. Iron foreign body retained in the eye could cause siderotic glaucoma. Multiple mechanisms may lead to glaucoma from penetrating trauma.
Incidence and Prevalence of Traumatic Glaucoma
Glaucoma is a disease that causes damage to the optic nerve because of high pressure inside the eyeball. Penetrating injury leads to higher incidence of glaucoma than blunt trauma. The risk of developing glaucoma after penetrating injury is estimated as 2.67% and that after blunt trauma is 3.39% according to American Academy of Ophthalmology.
Traumatic injuries are more common among males than females. This causes more traumatic glaucoma in males.
How Is Traumatic Glaucoma Diagnosed?
Doctors usually carry out an eye exam to check if there’s any damage or rupture of the eye globe. They then examine the IOP and the angles of the eyes. An imaging test is used to measure the thickness of the nerve fibers, which are part of optic nerves. These tests are usually done after other preliminary tests have been completed.
How Is Traumatic Glaucoma Treated?
Glaucoma is an eye disease that causes damage to the optic nerve. Treatment goals for glaucoma include lowering IOP to less than 21 mm Hg. To lower IOP, a patient may take beta blockers, prostaglandins, alpha-adrenergic agonists, or carbonic anhydrase inhibitor eye drops.
Beta blockers reduce the amount of fluid (aqueous) forming in the eye. Prostaglandins relax the eye muscles and allow fluid to flow out of the eyes. Alpha-adrenergic agonists inhibit the production of fluid. Carbonic anhydrase inhibitors slow down the production of fluid.
Steroids can help treat inflammation in the eye.
We consider surgery when maximally tolerable medical therapy has failed. Laser trabeculoplasty, alternative laser procedures, or filtration surgery are potential surgical options. If left untreated, traumatic glaucoma can cause permanent, irreversible damages to vision. Therefore, a regular eye exam should be performed after an injury.
Is Follow-Up Treatment Necessary?
Follow-up visits are essential after initiating the treatment. Your doctor will monitor the response to the treatment, and may adjust the dosage of the medication if needed.
What Is the Prognosis?
Glaucoma is a condition that causes damage to the optic nerve and eventual blindness. Constant medical treatment is required to keep the disease in check. Most patients will eventually go blind in the affected eyes if medical treatment is not provided.
Visual outcome is generally good for people who seek medical attention immediately after the injury and follow the treatment advice as prescribed by their doctor.