Ocular Inflammation and Secondary Glaucoma
Inflammatory, or uveitic, glaucoma is a secondary glaucoma that often combines components of open-angle and angle-closure disease. In individuals with uveitis, elevated IOP may be caused by a variety of mechanisms, and appropriate therapy depends on the etiology:
edema of the trabecular meshwork
endothelial cell dysfunction of the trabecular meshwork
Figure 8-11 Goniophotograph of a ciliary body melanoma in the anterior chamber angle.
Figure 8-12 Goniophotograph of a ciliary body melanocytoma in the anterior chamber angle.
fibrin and inflammatory cells blocking outflow through the trabecular meshwork or Schlemm canal
corticosteroid-induced reduction in outflow through the trabecular meshwork
Peripheral anterior synechiae blocking outflow
prostaglandin-mediated breakdown of the blood–aqueous barrier
Most cases of anterior uveitis are idiopathic, but uveitides commonly associated with open-angle inflammatory glaucoma include Fuchs uveitis syndrome, herpes zoster iridocyclitis, herpes simplex keratouveitis, toxoplasmosis, juvenile idiopathic arthritis, and pars planitis. See also BCSC Section 9, Uveitis and Ocular Inflammation.
The presence of KPs suggests anterior uveitis may be the cause of IOP elevation. Gonioscopic evaluation may reveal subtle trabecular meshwork precipitates. Occasionally, 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, likely by increasing outflow resistance, but also possibly by improving aqueous production, which can be decreased in eyes with intraocular inflammation. Miotic agents are not recommended in patients with anterior uveitis because they may exacerbate the inflammation and result in formation of more central posterior synechiae. Prostaglandin analogues may exacerbate inflammation in some eyes with uveitis and herpetic keratitis; however, this relationship is not clear, and some patients may benefit from their IOP-lowering effects without increased inflammation.
Some uveitis patients may have low IOP. The etiology is unclear but may be related to a prostaglandin-mediated increase in uveoscleral outflow. Hyposecretion of aqueous humor (particularly if ciliary body detachment is present) has often been assumed to be the etiology for low IOP but has not been confirmed, because aqueous flow currently cannot be measured in the presence of uveitis.
First described by Posner and Schlossman in 1948, glaucomatocyclitic crisis (also known as Posner-Schlossman syndrome) is an uncommon form of open-angle inflammatory glaucoma characterized by acute, unilateral episodes of markedly elevated IOP accompanied by low-grade anterior chamber inflammation. This condition most frequently affects middle-aged persons, who usually present with unilateral blurred vision and mild ocular pain. The anterior uveitis is mild, with few KPs, which are small, discrete, and round and which usually resolve spontaneously within a few weeks. On gonioscopy, KPs may be seen on the trabecular meshwork, suggesting a “trabeculitis.” The elevated IOP may range between 40 and 50 mm Hg, and corneal edema may be present. In between episodes, the IOP usually returns to normal, but with increasing numbers of episodes, chronic secondary glaucoma may develop.
The etiology of this condition is unknown; theories include infections (eg, herpes simplex virus, cytomegalovirus [CMV], Helicobacter pylori) and autoimmune disease. Recurrent attacks of acute primary angle closure have been mistaken for this condition. In some cases in which glaucomatocyclitic crisis was initially diagnosed, CMV DNA was subsequently detected in the aqueous humor by polymerase chain reaction (see BCSC Section 9, Uveitis and Ocular Inflammation, for more on CMV). Distinguishing glaucomatocyclitic crisis from CMV is important, as specific antiviral therapy for CMV is available.
During a glaucomatocyclitic crisis, treatment should be initiated to control IOP and may be considered to reduce inflammation. Topical and often oral ocular hypotensive medications are used to reduce IOP. Prostaglandin analogues may exacerbate the condition but can be used in some patients. Topical corticosteroids and topical and/or oral nonsteroidal anti-inflammatory drugs (NSAIDs; eg, indomethacin) may be of benefit. There is no evidence that long-term suppressive therapy with topical NSAIDs or corticosteroids is effective in preventing attacks. In some cases, filtering surgery is performed to prevent IOP spikes in eyes with advanced optic nerve damage or in those undergoing frequent attacks.
Fuchs uveitis syndrome
Fuchs uveitis syndrome (formerly Fuchs heterochromic iridocyclitis) is a relatively rare, insidious, and chronic form of uveitis that is typically unilateral. There is no race or sex predilection, and it often manifests in young to middle adulthood. It is characterized by iris heterochromia, low-grade anterior chamber inflammation, posterior subcapsular cataracts, and IOP elevation. The heterochromia is caused by loss of iris pigment in the affected eye, which is usually hypochromic in dark irides and hyperchromic in light irides. The low-grade inflammation is often accompanied by small, stellate, pancorneal KPs. Despite the low-grade inflammation, these patients are classically asymptomatic and present with a nonhyperemic eye. Fuchs uveitis syndrome has variously been associated with toxoplasmosis, CMV, herpes simplex, and rubella, although these links are difficult to prove given the frequency of those infectious agents in the population.
Figure 8-13 Fuchs uveitis syndrome. The goniophotograph shows fine vessels (arrows) crossing the trabecular meshwork. This neovascularization is not accompanied by a fibrovascular membrane and does not result in peripheral anterior synechiae formation or secondary angle closure.
(Courtesy of Steven T. Simmons, MD.)
Secondary OAG occurs in approximately 15% of patients with this disease. Gonioscopic examination reveals multiple fine vessels that cross the trabecular meshwork (Fig 13-8). These vessels are usually not accompanied by a fibrous membrane and typically do not result in PAS formation and secondary angle closure, although in rare cases the neovascularization may be progressive. The vessels are fragile and may cause an anterior chamber hemorrhage, either spontaneously or resulting from trauma. A classic finding is anterior chamber hemorrhage after a paracentesis during intraocular surgery (Amsler sign).
Treatment of Fuchs uveitis syndrome is directed at controlling the IOP with topical ocular hypotensive medications. IOP control may be difficult, and the IOP does not necessarily correlate with the degree of inflammation. Corticosteroids are generally not effective in treating the low-grade chronic inflammation, and their use can elevate the IOP.
Birnbaum AD, Tessler HH, Schultz KL, et al. Epidemiologic relationship between Fuchs heterochromic iridocyclitis and the United States rubella vaccination program. Am J Ophthalmol. 2007;144(3):424–428.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.