Figure 5-21 Inflammatory glaucoma. PAS in uveitis occur preferentially in the inferior anterior chamber angle and are nonuniform in height and shape, as shown in this photograph. (Courtesy of Joseph Krug, MD.)

Ocular inflammation can lead to the shallowing and closure of the anterior chamber angle by uveal effusion, resulting in anterior rotation of the ciliary body. Significant posterior uveitis causing massive exudative retinal detachment or choroidal effusions may lead to ACG through forward displacement of the lens–iris interface. Treatment is primarily directed at the underlying cause of the uveitis. Aqueous suppressants and corticosteroids are the primary agents for reducing elevated IOP and preventing synechial angle closure.

Interstitial keratitis may be associated with OAG or ACG. The angle closure may be caused by chronic inflammation and PAS formation or by multiple cysts of the iris pigment epithelium.

Samples JR. Management of glaucoma secondary to uveitis. Focal Points: Clinical Modules for Ophthalmologists. San Francisco: American Academy of Ophthalmology; 1995, module 5.

Aqueous Misdirection

Aqueous misdirection is also known as malignant glaucoma, ciliary block glaucoma, and posterior aqueous diversion syndrome. This rare but potentially devastating form of glaucoma usually presents following ocular surgery in patients with a history of angle closure or PAS. It may also occur spontaneously in eyes with an open angle following cataract surgery or various laser procedures. The disease presents with uniform flattening of both the central and peripheral anterior chamber, which is typically markedly asymmetrical to the fellow eye (Fig 5-22). This is in contrast to acute PACG, which presents with iris bombé and a shallow peripheral anterior chamber (Fig 5-23). Classically, the

condition is thought to result from anterior rotation of the ciliary body and posterior misdirection of the aqueous, in association with a relative block to aqueous movement at the level of the lens equator, vitreous face, and ciliary processes. More recently, some have proposed that primary angle closure and malignant glaucoma may result from the simultaneous presence of several factors, including a small eye, a propensity for choroidal expansion, and reduced vitreous fluid conductivity.

Figure 5-22 Aqueous misdirection seen by UBM. Expansion of the vitreous pushes the lens and ciliary body forward, causing a uniform shallowing of the anterior chamber. The central portion of the anterior lens capsule (LC) is nearly in contact with the cornea (C). PC = posterior chamber; CB = ciliary body; I = iris; S = sclera. (From Lundy DC. Ciliary block glaucoma.

Focal Points: Clinical Modules for Ophthalmologists. San Francisco: American Academy of Ophthalmology; 1999, module 3. Courtesy of Jeffrey M. Liebmann, MD.)

Figure 5-23 Acute angle closure seen by UBM. Pupillary block leads to forward bowing of the peripheral iris. The peripheral chamber is shallow, whereas the central chamber is relatively deeper by comparison. C = cornea; AC = anterior chamber; PC = posterior chamber; LC = lens capsule; CB = ciliary body; I = iris; S = sclera. (From Lundy DC. Ciliary block glaucoma. Focal

Points: Clinical Modules for Ophthalmologists. San Francisco: American Academy of Ophthalmology; 1999, module 3. Courtesy of Jeffrey M. Liebmann, MD.)

Clinically, the anterior chamber is shallow or flat with anterior displacement of the lens, pseudophakos, or vitreous face. Optically clear “aqueous” zones may be seen in the vitreous, highlighting the underlying pathology. In the early postoperative setting, aqueous misdirection is often difficult to distinguish from choroidal effusion, pupillary block, or suprachoroidal hemorrhage. Often the level of IOP, time frame following surgery, patency of an iridectomy, or presence of a choroidal effusion or suprachoroidal hemorrhage helps the clinician make the appropriate diagnosis and initiate treatment. In some cases, unfortunately, the clinical picture is difficult to interpret and surgical intervention may be required to make the diagnosis.

Medical management includes the triad of intensive cycloplegic therapy; aggressive aqueous suppression with β-adrenergic antagonists, α2-adrenergic agonists, and carbonic anhydrase inhibitors; and shrinking of the vitreous with hyperosmotic agents. Miotics should not be used and can make aqueous misdirection worse. In aphakic and pseudophakic eyes, the anterior vitreous can be disrupted with the Nd:YAG laser. Argon laser photocoagulation of the ciliary processes has reportedly been helpful in treating this condition; this procedure may alter the adjacent vitreous face.

Approximately 50% of patients can be controlled with laser hyaloidotomy and medical management, whereas the other half will require surgical intervention alone. The definitive surgical treatment is pars plana vitrectomy with anterior hyaloido-zonulectomy combined with an anterior chamber deepening procedure. BCSC Section 12, Retina and Vitreous, discusses vitrectomy in greater detail.

Lundy DC. Ciliary block glaucoma. Focal Points: Clinical Modules for Ophthalmologists. San Francisco: American Academy of Ophthalmology; 1999, module 3.

Quigley HA, Friedman DS, Congdon NG. Possible mechanisms of primary angle-closure and malignant glaucoma. J Glaucoma. 2003;12(2):167–180.

Nonrhegmatogenous Retinal Detachment and Uveal Effusions

A nonrhegmatogenous retinal detachment occurs as a result of subretinal fluid in which no retinal break is present. A suprachoroidal effusion or hemorrhage refers to blood or fluid in the potential space between the choroid and the sclera. Retinoblastoma, Coats disease, metastatic carcinoma, choroidal melanoma, suprachoroidal hemorrhage, choroidal effusion/detachment, infections (HIV), and subretinal neovascularization in age-related macular degeneration with extensive effusion or hemorrhage can cause nonrhegmatogenous retinal detachments or suprachoroidal mass effect that may result in secondary angle closure related to forward displacement of the lens–iris interface. See BCSC Section 12, Retina and Vitreous, for further discussion.

In a rhegmatogenous retinal detachment, the subretinal fluid can escape through the retinal tear and equalize the hydraulic pressure on both sides of the retina. In a nonrhegmatogenous retinal detachment, by contrast, the subretinal fluid accumulates and becomes a space-occupying lesion in the vitreous, which may progressively push the retina forward against the lens like a hydraulic press. The fluid or hemorrhage may accumulate rapidly, and as it pushes the retina forward to a retrolenticular position, in severe cases it can flatten the anterior chamber completely. The retina may be dramatically visible behind the lens on slit-lamp examination.

Epithelial and Fibrous Ingrowth

Epithelial and fibrous proliferation are rare surgical complications that can cause severe secondary glaucomas. Epithelial and fibrous ingrowth occur when epithelium and/or connective tissue invades the anterior chamber through a defect in a wound site. Fortunately, improved surgical and wound closure techniques have greatly reduced the incidence of these entities. Fibrous ingrowth is more prevalent than epithelial ingrowth. Risk factors for the development of these entities include prolonged inflammation, wound dehiscence, delayed wound closure, or a Descemet membrane tear. Epithelial ingrowth has also been reported following Descemet-stripping automated endothelial keratoplasty.

Epithelial ingrowth presents as a grayish, sheetlike growth on the trabecular meshwork, iris, ciliary body, and posterior surface of the cornea. It is often associated with vitreous incarceration, wound gape, ocular inflammation, hypotony secondary to choroidal effusions, and corneal edema (Figs 5-24, 5-25). The epithelial ingrowth consists of nonkeratinized stratified squamous epithelium with an avascular subepithelial connective tissue layer.

Figure 5-24 Epithelial ingrowth appears as a grayish, sheetlike growth on the endothelial surface of the cornea, usually originating from a surgical incision or traumatic wound. The epithelial ingrowth shown here originated from a cataract surgery incision.

Figure 5-25 Epithelial ingrowth. The precipitating causes of epithelial ingrowth include vitreous incarceration in corneal and scleral wounds, as seen in this photograph, as well as wound gape, ocular inflammation, and hypotony secondary to

choroidal effusions. (Courtesy of Steven T. Simmons, MD.)

The argon laser produces characteristic white burns on the epithelial membrane on the iris surface, which help to confirm the diagnosis of epithelial ingrowth and to determine the extent of involvement. If the diagnosis remains in question, a cytologic examination of an aqueous aspirate can be performed. Radical surgery is sometimes necessary to remove the intraocular epithelial membrane and the affected tissues and to repair the fistula, but the prognosis remains poor; thus the decision to intervene is made based on the extent of disease, the visual potential, the status of the fellow eye, and social-medical circumstances relevant to the affected individual.

Fibrovascular tissue may also proliferate into an eye from a penetrating wound. Unlike epithelial proliferation, fibrous ingrowth progresses slowly and is often self-limited. A common cause of corneal graft failure, fibrous ingrowth appears as a thick, gray-white, vascular retrocorneal membrane with an irregular border. The ingrowth often involves the angle, resulting in PAS and the destruction of the trabecular meshwork (Fig 5-26). The resultant secondary ACG is often difficult to control. Medication is the preferred treatment of the secondary glaucomas that present without a pupillary block mechanism, although surgical intervention may be required. See Chapters 7 and 8 for further discussion.