Fuchs Heterochromic Iridocyclitis
Fuchs' heterochromic iridocyclitis (FHI) is a chronic, low grade, usually unilateral, ocular inflammatory disease with a good visual prognosis.
- Fuchs’ heterochromic iridocyclitis 364.21
- Disease synonyms: Fuchs’ heterochromic cyclitis, Fuchs’ uveitis syndrome, Fuchs’ heterochromic uveitis
Fuchs’ heterochromic iridocyclitis is an unusual form of chronic, low grade anterior uveitis with variable clinical appearance. Clinical criteria for establishing the diagnosis of FHI has not yet been internationally accepted.
The precise etiology is not entirely known. However, there are associations with ocular toxoplasmosis, herpes simplex virus, rubella virus and cytomegalovirus infections. In a landmark paper, Quentin and Reiber were the first to provide firm evidence that rubella virus (RV) plays a pivotal role in the development of FHI. Their study reported intraocular synthesis of rubella antibodies in the aqueous humor of all affected eyes. Their finding of oligoclonal RV-specific antibodies in every FHI sample was soon confirmed by other investigators. Five case-control studies demonstrated increased rubella-specific antibodies in the aqueous humor (AH) of patients with clinical FHI diagnosis. Other associated diseases include ocular trauma, retinitis pigmentosa, Horner syndrome, Status disraphicus and hemifacial atrophy aka Parry-Romberg syndrome.
The iris shows a decrease in the number of stromal melanocytes with patchy depigmentation of the posterior layer. The ciliary body shows stromal fibrosis with muscular atrophy.
Clinical diagnosis of exclusion based on history and physical findings. Infectious etiologies should be ruled out when appropriate. For example, it is generally recommended that tuberculosis and syphilis be ruled out. Additionally, if there is a suspicion for a viral etiology (such as herpes simplex, cytomegalovirus, or rubella virus), an anterior chamber paracentesis may be performed with directed polymerase chain reaction testing or Goldmann-Witmer testing. In cases where herpes simplex or cytomegalovirus is detected, specific antiviral therapy can be used.
Floaters and visual deterioration.
- Heterochromia with typically the lighter iris indicating the eye of involvement. This generalization varies depending on the intensity of anterior stromal atrophy, iris color, and amount of pigment in the iris pigmented epithelium.
- Diffuse iris stromal atrophy with variable pigment epithelial layer atrophy
- Iris nodules occur in 20% of cases localized to either the pupillary margin (Koeppe) or on the surface of the iris (Busacca)
- Small white stellate keratic precipitates diffusely scattered over endothelium
- Anterior chamber inflammation with possible spill over into anterior vitreous (66%)
- Lack of anterior synechiae
Heterochromia, low grade anterior uveitis, cataract
Range from none to mild blurry vision, floaters and ocular discomfort
By history and clinical examination significant for the findings mentioned above.
Anterior chamber paracentesis is considered safe and aqueous humor antibody analysis is useful when the diagnosis cannot be determined based on clinical findings alone. Detection for rubella-specific antibodies in the aqueous humor of patients suspected to have Fuchs is not specific, but absence would make the diagnosis highly unlikely
There are no specific serological tests for FHI but other conditions, including sarcoidosis, syphilis and tuberculosis should be ruled out.
- Glaucomatocyclitic crisis (also known as the Posner-Schlossman syndrome)
- Phacolytic glaucoma
- Sympathetic heterochromia
- Heterochromia due to Duane’s syndrome or Waardenburg syndrome
- Neovascular glaucoma
- Herpetic keratouveitis
- Cytomegalovirus-associated anterior uveitis
- Few cases require therapy because the anterior chamber inflammation is low grade and minimally responsive to ocular corticosteroids.
- Occasional and short-term usage of topical corticosteroids may be indicated if a symptomatic exacerbation of uveitis occurs.
- Cycloplegics are seldom required
- Glaucoma associated with Fuchs’ is often responsive to medical therapy.
Medical follow up
Should be monitored at regular intervals for progression of cataract and development of glaucoma.
- Intraocular inflammation should be reasonably well controlled prior to cataract surgery but it is not necessary to achieve complete absence of cell and flare. A reasonable perioperative treatment might include topical corticosteroids six times daily for 7 days prior to surgery. If there is a history of herpes simplex virus in the eye, the patient should receive a systemic antiviral during the corticosteroid prophylaxis period. The surgical procedure of choice is phacoemulsification with implantation of an intraocular acrylic lens in the capsular bag. At the completion of surgery, a subconjunctival injection of corticosteroids and antibiotics should be given and intensive topical corticosteroid and mydriatic therapy initiated.
- Secondary glaucoma may require surgical intervention if unable to medically manage IOP.
- Trabeculectomy with intraoperative mitomycin C is a reasonable first choice . Combined cataract extraction and glaucoma surgery may lead to increased failure rate. If possible, the cataract surgery should be performed first. Glaucoma drainage devices may afford a better prognosis.
- Glaucoma, typically chronic open-angle glaucoma, complicates in 9-59% of cases. Mechanisms include trabeculitis, neovascularization of the iris stroma and angle, steroid treatment, and cataract surgery.
- Cataracts, most commonly posterior subcapsular, occur in 80% of patients and are often present at the time of initial diagnosis. They usually also form in the setting of corticosteroid therapy.
- Glaucoma as a result of cataract extraction and intraocular lens implementation occurring from 3-35%.
- Cystoid macular edema occurring after cataract surgery
- Vitreous debris resulting in symptomatic floaters in 12-50%.
- Significant vitreous opacification following uncomplicated cataract surgery may be corrected with pars plana vitrectomy.
- Post-operative hyphema due to abnormal blood vessels
Good with most patients maintaining a visual acuity of 20/40 or better in the affected eye.
- Turbert D, Lipsky SN. Heterochromia. American Academy of Ophthalmology. EyeSmart® Eye health. https://www.aao.org/eye-health/diseases/heterochromia-list. Accessed March 13, 2019.
- Basic and Clinical Science Course. Intraocular inflammation and Uveitis. p 132-134
- Quentin CD, Reiber H. Fuchs heterochromic cyclitis: rubella virus antibodies and genome in aqueous humor. Am J Ophthalmol. 2004 Jul;138(1):46-54.
- Bonifioli AA, Curi AL, Orefice F. Fuchs’ heterochromic cyclitis. Semin Ophthalmol 2005; Jul-Sep; 20(3): 143-6
- Velilla S, Dios E, Herreras JM, Calonge M. Fuchs’ heterochromic iridocyclitis: a review of 26 cases. Ocul Immunol Inflamm. 2001 Sep;9(3):169-75.
- Tejwani S, Murthy S, Sangwan VS. Cataract extraction outcomes in patients with Fuchs’ heterochromic cylitis. J Cataract Refract Surg. 2006 Oct;32(10):1678-82.
- Kimura SJ, Hogan MJ, Thygeson P. Fuchs’ syndrome of heterochromic cyclitis. AMA Arch Ophthalmol 1955; 54:179-186