Halo sign in keratoconus: a case report.

BACKGROUND

There are several clinical signs that may contribute to the diagnosis of keratoconus. Their appearance is associated with the evolution of keratoconus. In this case, the formation of a halo on the iris in a patient with stage IV keratoconus was reported. This halo sigh is a novel one and has not been reported earlier.

CASE PRESENTATION: A 30-year-old woman presented to the ophthalmology clinic with one year history of vision deterioration to finger counting in her left eye. A diagnosis of keratoconus was made due to the inferior-central corneal steepening and thinning. When the slit-lamp light projects onto the cone, a halo forms on the iris and shifts its shape and location as the irradiation angle changes.

CONCLUSION

A halo sign was observed on the iris of a patient with stage IV keratoconus (Amsler-Krumeich classification) when the slit-lamp beam was projected onto the corneal cone.