If your pet has red eyes, the pressure should always be measured from the red eyes. Redness of the eye sometimes can signal a more serious eye condition or disease, such as uveitis or glaucoma. The best way to assess IOP(intraocular pressure) is with rebounce tonometry. The Icare® TONOVET tonometer will accurately measures the IOP on our animal patients. It is painless and therefore creates no anxiety.