Iris freckles, nevi, and melanosis do not require treatment. The presence—or lack—of ophthalmologic changes (eg, iris thickening, dyscoria, invasion of the pigment to the iridocorneal drainage angle, changes to the iris architecture, pigment dispersion, involvement of the ciliary body, increased intraocular pressure) may be associated with malignant pigmentary tumors and can aid the decision to enucleate an eye. Thus, patients with iris hyperpigmentation should be closely monitored, ideally by a veterinary ophthalmologist, with advanced diagnostic techniques such as slit lamp biomicroscopy, gonioscopy, and tonometry. The potential malignancy of iridal pigmentary lesions should be discussed with the owner. The decision to enucleate an eye with diffuse pigmentary changes can be difficult, as lesions may be benign and focal areas of hyperpigmentation may exist for months to years before irregular iris masses develop.9
Laser treatment for suspected diffuse iris melanoma in cats has recently been suggested to effectively delay tumor progression10 but remains controversial due to a lack of controlled studies and the difficulty in differentiating benign diffuse iris melanosis from melanoma.
In dogs and other species with iris melanosis due to chronic uveitis,7 uveitis should be treated, and a complete diagnostic investigation should be performed to identify and treat the underlying cause.