 |
 |
IU Optometry Clinics & Patient Care: Patient Education Angle on Glaucoma: Types |
||||
 |
||||||
|
|
|
Post-Traumatic Glaucoma If a blunt trauma occurs to the eye, the force can be transferred to all of the structures in the eye. The sheer force of the blow can cause a hyphema, lens dislocation, angle recession, inflammation, and/or penetrating injury to the eye. Most traumas to the globe are to males in their 20s to 30s. When the ciliary body is damaged, there may be an angle recession or tearing of the ciliary muscle fibers from each other. The tear may cause bleeding from the major arterial circle of the iris into the anterior chamber and lead to a hyphema immediately or within about seven days. Depending on the obstruction of the drainage angle, the blood in the chamber may cause an extreme increase in the intraocular pressure (IOP).
Angle recession may be the initial cause of bleeding into the anterior chamber, but usually is a cause of late onset post-traumatic glaucoma. Only a small number of patients will develop this type of glaucoma. Those who do have had extensive damage to the trabeculum, ciliary muscles, and a large recession of the angle. Initially, there is a low IOP because of the direct access to drainage due to the large tear in the angle. As the recession begins to heal, scar tissue is laid down which causes the IOP to rise dramatically as the aqueous outflow is being obstructed. Penetrating injuries can also cause a late onset glaucoma. There are several mechanisms that can cause glaucoma after a penetrating injury. The first is the formation of a peripheral anterior synechia (PAS). This can occur due to the inflammatory response causing the cornea and iris to come into contact for a period of time and sealing off the drainage angle. Due to the perforation of the eye, aqueous may be able to leak out and allow the cornea and iris to be in contact with one another for a period of time. Epithethial ingrowth of the posterior cornea may also cause obstruction of the trabeculum as well as foreign bodies such as copper and iron that are trapped there after the trauma. What Is Glaucoma? | Types of Glaucoma | Diagnosing Glaucoma | Treatments | Research & Links | Glaucoma Home 
| ||||
Additionally, the trabecular meshwork may be damaged and lead to a decrease of aqueous outflow. This can occur early after the trauma due to swelling of the meshwork and blockage by liberated iris pigment and red blood cells associated with a hyphema. Trabecular injury can cause late onset glaucoma years after the initial injury. This is due to the continual scarring of the trabeculum after the initial healing of the ciliary body.