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Wednesday, November 2, 2011

ANGLE RECESSION GLAUCOMA

SIGNS AND SYMPTOMS
Angle recession glaucoma may affect patients of any age. The patient remains asymptomatic, and will report a history of blunt trauma to the involved eye, often years earlier. There may be an associated traumatic cataract.

Expect a rise in IOP, which may be substantial. An unexplained IOP rise in the fellow eye often occurs in unilateral cases. There may be an associated iridodyalysis in severe cases. Gonioscopy will reveal a deepening of the angle recess and the appearance of excessive gray tissue (ciliary body) posterior to the scleral spur.

PATHOPHYSIOLOGY
In angle recession, blunt trauma to the eye tears the ciliary body between the longitudinal and meridional muscles. Frequently, there is hyphema at the time of trauma.

Intraocular pressure does not rise until long after the initial injury. Approximately 20 percent of patients with angle recession develop secondary glaucoma, depending on the extent of angle recession. Typically, two-thirds of the angle must be compromised in order for glaucoma to develop.

Controversy surrounds the etiology of IOP rise in traumatic angle recession. One theory involves direct traumatic damage to the trabecular meshwork. Another theory contends that particulate matter such as pigment and hemosiderin released at the initial trauma damages the trabecular meshwork, causing scarring and poor filtration. Yet another thought suggests that endothelial cells migrate and proliferate over the trabecular meshwork in response to trauma, forming a Descemet's-like membrane that blocks filtration. Interestingly, there seems to be a higher than expected incidence of POAG in the non-traumatized fellow eye, leading some to speculate that these angle recession eyes have a predisposition to IOP elevation.

MANAGEMENT
Miotics, prostaglandin analogs and argon laser trabeculoplasty are rather ineffective in managing angle recession glaucoma since the outflow structures have likely been compromised. More appropriate topical medications include aqueous suppressants such as beta blockers, carbonic anhydrase inhibitors and alpha adrenergic agonists. If medical therapy fails to control IOP, filtering surgery remains an excellent option.

CLINICAL PEARLS

In cases of unilateral glaucoma, look for a history of trauma.

In many cases of angle recession glaucoma, the angle appears relatively normal, except that it shows more of the posterior angle structures than typical. By examining only the suspect eye, you may misread the diagnosis. In unilateral cases, compare the suspect eye with the normal fellow eye to reveal asymmetry between the angles.

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