Fuchs’ heterochromic cyclitis (FHC)
With this virus, 20% to 100% of patients with FHC are positive for intraocular antibodies to rubella, according to Dr. Margolis.
“This suggests a localized immune response,” he said. Furthermore, 8% to 17% of these patients are positive for rubella RNA.
Interestingly, FHC develops less often in patients who were vaccinated for rubella, indicating that rubella may cause FHC, he noted.
However, some investigators have identified that 8% to 42% of those with FHC have cytomegalovirus (CMV) DNA in the anterior chamber, suggesting that both CMV and rubella may be causative agents of FHC.
CMV iritis in immune-competent patients is real. Physicians have probably seen it and misdiagnosed it, according to Dr. Margolis.
CMV iritis is characterized by unilaterality, masquerades as FHC or Possner-Schlossman syndrome, small corrals of keratoprecipitates, elevated IOP, or iris atrophy, and may be present with/without endothelitis with corneal edema. CMV DNA can be present in the aqueous. The virus responds to ganciclovir and valganciclovir, but not to acyclovir.
Over an 8-year span from 2007 to 2015, Dr. Margolis saw 9 men and 6 women (7 Asian, 8 Caucasians) with CMV iritis. Six of 10 patients who underwent vitreous taps were positive for CMV by polymerase chain-reaction assay. Valganciclovir was effective, whereas topical ganciclovir was not. IOP elevations, corneal edema, and anterior chamber reaction were achieved in a mean of 28 days with treatment. When medication was decreased, the CMV recurred in 9 of 10 patients; some were treated for up to 6 years.