LENS INDUCED GLAUCOMAS

SIGNS AND SYMPTOMS
The lens induced glaucoma patient is typically elderly, with a history of cataracts. There are four types of glaucomas associated with lens complications (excluding cases of lens displacement in ectopia lentis):

phacolytic glaucoma
lens particle glaucoma
phacoanaphylactic uveitis
phacomorphic glaucoma

In all of these cases, the glaucoma is typically very symptomatic with pain and redness in the involved eye, and cells and flare in the anterior chamber. Frequently, an advanced cataract in the involved eye severely reduces vision.

PATHOPHYSIOLOGY
Phacolytic glaucoma This condition involves a hypermature cataract with severe visual reduction (typically light perception). It's characterized by acute onset of pain and redness and IOPs often of 35mm Hg or greater. There is liquefaction of the lens nucleus and cortex, and attenuation of the capsule with the release of lens proteins into the anterior chamber. Macrophages engulf the lens proteins, become bloated, and block trabecular outflow. The angle remains open, though in some cases peripheral anterior synechiae may develop.

Lens particle glaucoma The mechanism of lens particle glaucoma resembles that of phacolytic glaucoma, except that there is a history of surgery or trauma that releases the lens proteins into the anterior chamber and initiates a macrophage-driven inflammatory reaction. The angle remains open.

Phacoanaphylactic uveitis This is a chronic uveitis that occurs one to 14 days following cataract extraction or lens trauma. This mechanism is similar to the previous two types of glaucoma, except that inflammatory cells are not limited to macrophages. Also, there is considerable flare and mutton-fat keratic precipitates, and a propensity for synechiae formation. The angle may be open or closed.

Phacomorphic glaucoma In this case, an increase of lens thickness from an advancing cataract leads to a relative pupil block, posterior bombé and angle closure. The intumescence often develops quickly. Typically, the cataract reduces vision severely. The angle in this glaucoma is closed.

MANAGEMENT
Employ topical beta blockers, carbonic anhydrase inhibitors and alpha adrenergic agonists to temporize the IOP. Avoid miotics and prostaglandin analogs in cases where inflammation is present. In cases where there is significant anterior segment inflammation, use topical steroids to quell the inflammation. In cases where the lens precipitates a secondary glaucoma, the best management is surgical lens removal.

CLINICAL PEARLS

In cases of severe granulomatous uveitis with IOP rise following cataract extraction, consider phacoanaphylactic uveitis.
In patients with hypermature cataracts and shallow anterior chambers with angle closure, consider phacomorphic glaucoma, especially if the fellow lens has less intumescence and there is a deeper chamber.
Phacomorphic and phacolytic glaucoma develop only in eyes with hypermature cataracts. Vision typically ranges from 20/400 to light perception. If vision is better than 20/400, consider another cause for the glaucoma.
In cases where there is phacomorphic glaucoma in a nanophthalmic eye, surgical excision of the cataract is associated with severe complications of choroidal detachment and hemorrhage. In these cases, you may prefer medical therapy and laser iridotomy rather than surgical management.