Fuchs’ Heterochromic Iridocyclitis
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Fuchs’ Heterochromic Iridocyclitis
Fuchs’ Heterochromic Iridocyclitis, also known as Fuchs’ heterochromic cyclitis, presents as a chronic unilateral uveitis in young to middle aged people with no race or sex predilection.
Clinical Findings
On examination, typical findings include Iris heterochromia (resulting from a decrease in the number of stromal melanocytes--with dark irides becoming lighter and light irides becoming darker), low grade anterior chamber cell, posterior subcapsular cataract and small stellate pan-corneal keratic precipitates (Figure 1). Intraocular pressure (IOP) is often high. Inflammatory iris nodules may also be noted (~20% of effected patients) with Koeppe nodules on the pupillary margin (Koeppe found on the “Kliff” of the iris) and Busacca nodules found on the surface of the iris (Busacca on Body of the iris). Complicating presentation for care is the fact that the disease process is often asymptomatic and without red eye. Gonioscopy often reveals fine vessels crossing the trabecular meshwork (~6-22% of patients) and are not accompanied by PAS/fibrosis but may progress and may bleed spontaneously causing a hyphema. The Amsler Sign is the name for bleeding in anterior chamber after acute change in pressure in the eye (paracentesis at time of cataract surgery or sometimes spontaneous). Open angle glaucoma develops in 15% of effected patients and controlling IOP is difficult to manage with topical therapeutics. Glaucoma may also result from trabeculitis, chronic steroid treatment and neovascularization. It is important to note that IOP rise does not correlated with degree of inflammation. Unfortunately, use of steroids is ineffective. Studies point to rubella as a causative factor although this is not definitive and, regardless, does not alter treatment. Other studies, although with less rigor than those pointing to rubella, have also implicated ocular toxoplasmosis, herpes simplex virus and cytomegalovirus. The diagnosis is one of exclusion and viral causes, such as HSV and CMV, represent the most important etiologies to exclude through PCR testing since specific antivirals may be used in such cases and may mitigate disease sequela. Fortunately, most patients maintain excellent vision despite chronic issues and the most important take home message is to have high suspicion for this disease process when appropriate so that patient expectations are addressed and follow up schedules are maintained.
Treatment
Treatment is centered on lowering intraocular pressure with topical therapeutics and appropriate use of steroids which are marginally effective in addressing inflammation but may provide some symptomatic relief. Care should be taken to recognize steroid induced intraocular pressure spikes. Surgical intervention is occasionally required and can include trabeculectomy and glaucoma drainage device implantation. There is a dearth of data on using minimally invasive glaucoma surgery (angle surgery) and laser endocyclophotocoagulation to treat this disease.
Further Reading:
1. Quentin CD, Reiber H. Fuchs heterochromic cyclitis: rubella virus antibodies and genome in aqueous humor. Am J Ophthalmol. 2004 Jul;138(1):46-54. 2. Kimura SJ, Hogan MJ, Thygeson P. Fuchs’ syndrome of heterochromic cyclitis. AMA Arch Ophthalmol 1955; 54:179-186.
