Imavir is a prescription medication used to treat the symptoms of acute herpetic keratitis. Imavir can be used alone or with other medications. Imavir belongs to a class of medications called antiviral, antimicrobial eye medications. How To Use aciclovir: • The recommended dosing regimen is to apply a thin layer of Imavir 1 cm in the lower part of the affected eye 5 times a day (about every 4 hours). • It is recommended to continue treatment for a period of not less than three days after healing.