Angle Recession Flashcards
Things to watch out for in someone with history of eye trauma
It’s usually in OS
- corneal scar
- iris tear
- angle recession (damage to TM
- RD
- blowout fracture
- optic atrophy
- ptosis
- vossius ring
- glaucoma
Things to consider with a larger pupil
CN 3 palsy
Adies
Sphincter tear
Pharmacological
APD: efferent or affernet?
Afferent
- ON damage
- retina damage
Aniso: efferent or afferent
Efferent
Diff for miotic pupil
Horners
ARP
Secondary glaucoma’s that affect the angle
- PAS from narrow angles closing (emergency to prevent CRAOs) or uveitis (also plateau iris can look like narrow angle)
- NVA-CRVO/DM
- toxic material damages TM (PXF, PDS)
What is sometimes the only way to differentiate plateau iris vs narrow angle
A PI will not fix the plateau iris
Angle recession glaucoma
History of blunt trauma, unilateral elevated IOP associated with optic nerve damage, iris sphincter tear, and vossius ring
Vossius ring
Circular deposition of pigment on the anterior capsule of the lens due to iris-lens contact during trauma
Gonioscopy and angle recession
Must be performed in order to definitively diagnose angle recession glaucoma. Angle recession is characterized by a very deep angle with an uneven iris insertion, a recessed iris, and a widened CB band. The recession may occur for any number of clock hours. Bc recession is unilateral, the other eye can be used as comparison on gonioscopy to continue recession. Although the angle appears open, the trauma causes damage to the TM; the greater the extent of damage, the greater the risk of developing elevated IOP and glaucoma
Chance of glaucoma in angle recession
10% of patients with angle recession involving at least 2/3 of the angle will develop glaucoma
Uveitic glaucoma
Often caused by posterior synechiae and/or PAS (can only be viewed through gonio) causing angle closure glaucoma. Recall that during active episodes of uveitis, the iris thickens and becomes sticky (due to inflammation) and may become stuck to the lens (posterior synechiae) or the TM (PAS). 360 degrees of PS are required in order for the IOP to become elevated due to the peripheral iris moving forward into apposition with the TM. The number of clock hours of pAS required to obstruct enough TM to cause IOP elevation is dependent on each patient; however in most patients, 6 or more clock hours is associated with a increase in IOP.
Rubeotic glaucoma
Caused by NVA. Fibrous tissue always accompanies neo, and can obstruct AH outflow by physically blocking the TM, or by pulling the iris into contact with the TM, resulting in secondary angle closure glaucoma.
Intermittent angle closure glaucoma
Associated with narrow AC angles
Iridodialysis
Separation of the iris root from the attament to the CB due to ocular trauma. It often has a similar appearance as a PI. Patients may also have a traumatic cataract and an iris sphincter tear
Why does IOP increase in angle recession
TM damage
Primary angle closure glaucoma
Occurs in patients with narrow angles due to the posterior pressure gradient. Recall that the pressure in the posterior chamber is higher than in the anterior chamber to allow AH to flow from the posterior to the anterior chamber and through the TM. In patients with narrow angles, the posterior pressure gradient can move the peripheral iris forward into apposition with the TM, resulting in obstruction of AH outflow and elevated IOP. Pupillary block may or may not be present
Pupillary block
Occurs when the AH cannot flow from the posterior to the anterior chamber due to iris bombe (360 PS), iris-lens apposition, or pupil block from the vitreous or an IOL. Primary angle closure can occur without pupillary block in patients with plateau iris syndrome (characterized by anterior insertion of the ciliary processes, which can push the iris forward into the TM)
Acute angle closure
Characterized by an acute and symptomatic elevation in IOP
- hyperopes, the elderly (advancing cataracts), asians, eskimos, and patients with lens subluxation are at risk for acute angle closure glaucoma
- symptoms include blurred vision, halos around lights, eye pain, nausea, and vomitting
- clinical signs include a closed angle on gonio (no visible structures), IOP >50, corneal edema, mid dilated pupil, cells in the AC, and conjunctival injection
Percentage of occludable angle over age 60
5%, but only 0.5% will develop angle closure glaucoma
Most immediate threat to vision in acute angle closure glaucoma
CRAO if the IOP is higher than the perfusion pressure in the CRA.
Management of acute angle closure glaucoma
Aggressive and quick lowering of IOP via the following
- topical ocular hypotensives. Note that pilocarpine is contraindicated as it will worsen the contact between the iris and the lens and increase the degree of angle closure
- oral CAIs (diamox two 250mg tablets), DO NOT give slow release 500mg tablets
- hyperosmotic agents (IV mannitol or oral glycerin). These agents increase the osmotic gradient, resulting in a significant decrease in the volume of the vitreous and IOP
Hyperosmotic agents and DM
Glycerin is contraindicated in DM
-elevates the blood glucose levels, patients should receive isosorbide instead. These should be used in caution in patients with CHF as well
Chronic (sub-acute) angle closure
Asymptomatic mild elevations in IPO. Chronic angle closure should be suspected in patients with occludable angles and PAS, pigment splotches on the TM (indicated aborted PAS), and progressive optic nerve damage and visual field loss despite low IOP
Treatment for angle closure glaucoma
PI (most often done by laser) is the ultimate treatment for acute and chronic angle closure glaucoma. The fellow eye will likely require a prophylactic PI as well due to the presence of similar iris-TM anatomy
What are angle closure glaucoma patients at risk of once they are treated
Open angle component due to previous damage to TM and the optic nerve. The open angle glaucoma component may develop concurrently or years after the treatment of the narrow angle. conversely, patients with open angle glaucoma may develop an angle closure components as the lens thickens with increased age. Glaucoma characterized by both open and closed angle component is termed mixed mechanism glaucoma
What causes hyphema
Leaking neo
Trauma
Blebitis
Infection of the filtering bleb that is created during trab. An infection can occur anytime after the surgery.
- associated with redness, photophobia, pain, decreased vision, and cells in the AC and vitreous. Although hypopyon may be present, it is not associatd with blebitis
- treatment depends on severity and can range from intensive tropical abx to hospitilazation for IV abx
Symptoms look a lot like uveitits
Steroids and IOP elevation
-PF and durezol are assocaited with the greatest risk of an elevation IOP.
Lotemax, FML, and alrex are soft steroids and are associated with less risk of IOP elevations
