Lens-Induced Glaucoma

Phacolytic glaucoma

Phacolytic glaucoma is an inflammatory glaucoma caused by the leakage of lens protein through the capsule of a mature or hypermature cataract (Fig 4-10). As the lens ages, its protein composition becomes altered, with an increased concentration of high-molecular-weight lens protein. In a mature or hypermature cataract, these proteins are released through microscopic openings in the lens capsule. The proteins precipitate a secondary glaucoma as they, along with phagocytizing macrophages and other inflammatory debris, obstruct the trabecular meshwork.

Figure 4-10 Characteristic appearance of hypermature cataract with wrinkling of the anterior lens capsule, which results from loss of cortical volume. Extensive posterior synechiae are present, and they confirm the presence of previous inflammation.

(Courtesy of Steven T. Simmons, MD.)

The clinical picture usually involves an elderly patient with a history of poor vision who has sudden onset of pain, conjunctival hyperemia, and worsening vision. Examination reveals a markedly elevated IOP, microcystic corneal edema, prominent cell and flare reaction without keratic precipitates (KP), and an open anterior chamber angle (Fig 4-11). The lack of KP helps distinguish phacolytic glaucoma from phacoantigenic glaucoma. Cellular debris may be seen layered in the anterior chamber angle, and a pseudohypopyon may be present. Large white particles (clumps of lens protein) may also be seen in the anterior chamber. A mature or hypermature (morgagnian) cataract is present, often with wrinkling of the anterior lens capsule representing loss of volume and the release of lens material (see Fig 4-10). Although medications to control the IOP should be used immediately, definitive therapy requires cataract extraction.

Figure 4-11 Phacolytic glaucoma. The typical presentation of phacolytic glaucoma is conjunctival hyperemia, microcystic corneal edema, mature cataract, and prominent anterior chamber reaction, as demonstrated in this photograph. Note lens protein deposits on endothelium and layering in the angle, creating a pseudohypopyon. (Courtesy of George A. Cioffi, MD.)

Figure 4-12 Lens particle glaucoma. Despite the large amount of lens cortex remaining in the anterior chamber following cataract surgery, this eye is relatively quiet; the IOP remained normal. (Courtesy of the Wills Eye Hospital slide collection, 1986.)

Lens particle glaucoma

Lens particle glaucoma occurs when lens cortex particles obstruct the trabecular meshwork following cataract extraction, capsulotomy, or ocular trauma. The severity of IOP elevation depends on the quantity of lens material released, the degree of inflammation, the ability of the trabecular meshwork to clear the lens material, and the functional status of the ciliary body, which is often altered following surgery or trauma.

Lens particle glaucoma usually occurs within weeks of the initial surgery or trauma, but it may occur months or years later (Fig 4-12). Clinical findings include free cortical material in the anterior chamber, elevated IOP, moderate anterior chamber reaction, microcystic corneal edema, and, with time, the development of posterior synechiae and peripheral anterior synechiae.

If possible, medical therapy should be initiated to control the IOP while the residual lens material resorbs. Appropriate therapy includes medications to decrease aqueous formation, mydriatics to inhibit posterior synechiae formation, and topical corticosteroids to reduce inflammation. If the IOP cannot be controlled, surgical removal of the lens material is necessary.

Phacoantigenic glaucoma

Phacoantigenic glaucoma (previously known as phacoanaphylaxis) is a rare entity in which patients become sensitized to their own lens protein following surgery or penetrating trauma, resulting in a granulomatous inflammation. The clinical picture is quite variable, but most patients present with a moderate anterior chamber reaction with KP on both the corneal endothelium and the anterior lens surface. In addition, a low-grade vitritis, synechial formation, and residual lens material in the anterior chamber may be found. Glaucomatous optic neuropathy, although it may occur, is not common in eyes with phacoantigenic glaucoma. Phacoantigenic glaucoma is treated medically with corticosteroids and aqueous suppressants, which are used to reduce inflammation and IOP. If medical treatment is unsuccessful, residual lens material should be removed.

Intraocular Tumors

A variety of tumors can cause unilateral chronic glaucoma. Many of the tumors described in this section are discussed in greater detail in BCSC Section 4, Ophthalmic Pathology and Intraocular Tumors. The glaucoma can result from several different mechanisms, depending on the size, type, and

location of the tumor:

direct tumor invasion of the anterior chamber angle

angle closure by rotation of the ciliary body or by anterior displacement of the lens–iris interface (see Chapter 5)

intraocular hemorrhage neovascularization of the angle

deposition of tumor cells, inflammatory cells, and cellular debris within the trabecular meshwork

Choroidal melanomas and other choroidal and retinal tumors tend to cause secondary angle-closure glaucoma as the result of a forward shift in the lens–iris interface and closure of the anterior chamber angle. Inflammation caused by necrotic tumors may cause posterior synechiae, which can exacerbate this angle closure through a pupillary block mechanism. Choroidal melanomas, medulloepitheliomas, and retinoblastomas can also cause anterior segment neovascularization, which can result in angle closure.

The most common cause of glaucoma in primary or metastatic tumors of the ciliary body is direct invasion of the anterior chamber angle. This glaucoma can be exacerbated by anterior segment hemorrhage and inflammation, which further obstruct outflow. Necrotic tumor and tumor-filled macrophages may cause obstruction of the trabecular meshwork and result in a secondary OAG. Tumors causing glaucoma in adults include uveal melanoma, metastatic carcinoma, lymphomas, and leukemia. Glaucoma in children is associated with retinoblastoma, juvenile xanthogranuloma, and medulloepithelioma.

Grostern RJ, Brown SVL. Glaucoma associated with intraocular tumors. In: Higginbotham E, Lee D, eds. Management of Difficult Glaucomas. Boston: Butterworth Heinemann; 2004:343–351.

Shields CL, Materin MA, Shields JA, Gershenbaum E, Singh AD, Smith A. Factors associated with elevated intraocular pressure in eyes with iris melanoma. Br J Ophthalmol. 2001;85(6):666–669.

Ocular Inflammation and Secondary Glaucoma

Inflammatory glaucoma is a secondary glaucoma that often combines components of open-angle and angle-closure disease. In uveitis, elevated IOP occurs when the trabecular dysfunction exceeds the ciliary body hyposecretion seen with acute inflammation. Often the ocular inflammation is nonspecific. When the inflammation is accompanied by increased IOP, the physician’s dilemma is whether the cause of the increased IOP is the active inflammation and insufficient anti-inflammatory therapy, chronic structural damage to the outflow pathway related to the underlying inflammation, or corticosteroid therapy.

Inflammatory glaucoma may be caused by a variety of mechanisms:

edema of the trabecular meshwork

trabecular meshwork endothelial cell dysfunction

blockage of the trabecular meshwork by fibrin and inflammatory cells prostaglandin-mediated breakdown of the blood–aqueous barrier

the presence of peripheral anterior synechiae blockage of the Schlemm canal by inflammatory cells

steroid-induced reduction in aqueous outflow through the trabecular meshwork

Most cases of anterior uveitis are idiopathic, but uveitides commonly associated with open-angle

inflammatory glaucoma include Fuchs heterochromic iridocyclitis, herpes zoster iridocyclitis, herpes simplex keratouveitis, toxoplasmosis, juvenile idiopathic arthritis, and pars planitis. See also BCSC Section 9, Intraocular Inflammation and Uveitis.

The presence of KP suggests iritis as the cause of IOP elevation. Gonioscopic evaluation may reveal subtle trabecular meshwork precipitates. Sometimes, peripheral anterior synechiae (PAS) or posterior synechiae with iris bombé may develop, resulting in angle closure. The treatment of inflammatory glaucoma is complicated by the fact that corticosteroid therapy may increase IOP, either by reducing inflammation and improving aqueous production or by decreasing outflow. Miotic agents should be avoided in patients with iritis, because they may aggravate the inflammation and cause posterior synechiae. Prostaglandin analogues may exacerbate inflammation in some eyes with uveitis and herpetic keratitis; however, studies have demonstrated their ocular hypotensive efficacy in eyes with anterior uveitis. In uveitic glaucomas, inadequately controlled inflammation with elevated IOP is often mistaken for steroid-induced glaucoma. In the face of active inflammation, elevated IOP should be presumed to be inflammation-related rather than steroid-induced.

Glaucomatocyclitic crisis

Glaucomatocyclitic crisis (Posner-Schlossman syndrome), an uncommon form of open-angle inflammatory glaucoma, is characterized by recurrent bouts of markedly increased IOP and lowgrade anterior chamber inflammation. First described by Posner and Schlossman in 1948, the condition most frequently affects middle-aged patients and usually presents with unilateral blurred vision and mild eye pain. The iritis is mild, with few KP that are small, discrete, and round in nature and that usually resolve spontaneously within a few weeks. KP may be seen on the trabecular meshwork on gonioscopy, suggesting a “trabeculitis.” The IOP is usually markedly elevated, in the 40–50 mm Hg range, and corneal edema may be present. In between bouts, the IOP usually returns to normal, but, with increasing numbers of attacks, a chronic secondary glaucoma may develop, resulting in vision loss. The etiology of the disease remains unknown, but infection with herpes simplex virus has been implicated. There is no evidence that long-term suppressive therapy with topical nonsteroidal anti-inflammatory agents or mild steroids is effective in preventing attacks. Recurrent attacks of acute angle-closure glaucoma have been mistaken for this condition. In some cases in which glaucomatocyclitic crisis was initially diagnosed, cytomegalovirus DNA was subsequently detected in the aqueous humor by polymerase chain reaction (see BCSC Section 9, Intraocular Inflammation and Uveitis). Distinguishing glaucomatocyclitic crisis from cytomegalovirus is important, because specific antiviral therapy for cytomegalovirus is available.

Fuchs heterochromic iridocyclitis

Fuchs heterochromic iridocyclitis, a relatively rare, chronic form of iridocyclitis, is characterized by iris heterochromia with loss of iris pigment in the affected eye; low-grade anterior chamber reaction with small, stellate, pancorneal KP; posterior subcapsular cataracts; and secondary OAG. The condition is insidious and unilateral, affecting the hypochromic eye (in patients with blue irides, the affected eye may appear hyperchromic), and presents equally in middle-aged men and women. The secondary OAG occurs in approximately 15% of the cases. Gonioscopy reveals multiple fine vessels that cross the trabecular meshwork (Fig 4-13). These vessels, unlike those in iris neovascularization, do not appear to be associated with a fibrous membrane and usually do not lead to PAS and secondary angle closure, although in rare cases the neovascularization may be progressive. These vessels are fragile and may cause an anterior chamber hemorrhage, either spontaneously or with trauma, including cataract or glaucoma surgery.