The DMV gives medical authorizations to individuals seeking protection from the sun, so your local DMV may be a good starting point to obtain a form. The window tint law exemption in Michigan allows individuals with a medical exception to have darker window tints that would otherwise be illegal.Window tint medical exemptions allow you to install darker tint on car windows. See all requirements for medical waivers, certificates and exceptions. The information in this form must be based upon an examination within three months from the date of your physician's certification. 3.