Ganciclovir gel (Zirgan) is used to treat eye ulcers caused by the herpes simplex virus. Ganciclovir is not a cure for CMV or herpes. This medication will not treat symptoms of these infections in any other part of the body.Ganciclovir may also be used for purposes not listed in this medication guide.You should not use this medication if you are allergic to ganciclovir or acyclovir (Zovirax). Ganciclovir implant (Vitrasert) is used to treat cytomegalovirus (CMV) infection of the eye.e the first to review this Drug. Ganciclovir is an antiviral drug. It slows the growth and spread of the cytomegalovirus. Ganciclovir ophthalmic (for the eyes) is used to treat certain viral infections affecting the eyes. Ganciclovir implant (Vitrasert) is used to treat cytomegalovirus (CMV) infection of the eye.