NEFL and ischemia: Based on this, we can hypothesize that injury, inflammation, or ischemia, from conditions such as glaucoma or optic neuritis which are known to degrade axons in the nerve fiber layer of the retina, results in the local release of NfL from the axons that may diffuse into the vitreous humor through the internal limiting membrane of the retina, leading to elevated NfL in the vitreous.