Oxidative stress, free radicals, antioxidants - when it comes to our health, this topic is taking up more and more attention. But what is oxidative stress, how does it arise and what effects does it have on the most sensitive area of our body: the neuronal tissue or the retina. Many neurological diseases affecting the brain or the retina are associated with elevated levels of reactive oxygen species (ROS). High levels of ROS can cause damage to proteins, nucleic acids, lipids, membranes, and organelles such as mitochondria, and can be caused not only by external stimuli but also by aging. Most theories on the aging scenario assume that cumulative oxidative stress leads to mitochondrial changes, mitochondrial dysfunction, and oxidative damage. Therefore, it is not surprising that excess ROS is among others associated with the development of a variety of age-related neuronal diseases, including Alzheimer's and Parkinson's disease, as well as retinal diseases diabetic retinopathy, glaucoma, and age-related macular (AMD) degeneration. The aim of this Research Topic is to answer open questions, to combine already gained knowledge, to close the gaps between ophthalmology and neurology when it comes to oxidative stress in order to understand the underlying pathways and derive innovative therapies. It searches for the updates and new findings in both fields that answer the central question: are the same cell types affected by oxidative stress in the same way in the brain and retina? Experimental studies or patient studies that provide new insights are welcome, as well as studies that investigate antioxidant therapies.