Failure of phenylephrine to induce blanching of eye redness 2023-07-16T13:05:29Z Phenylephrine does not induce blanching of eye redness Instillation of 2.5% phenylephrine drops into the eye does not induce blanching of eye redness. Failure to blanch suggests redness caused by scleral vessel engorgement (e.g., scleritis) or extravascular cause (e.g., hemorrhage), not episcleritis or conjunctivitis. Inflammatory abnormality of the eye