Possibilities and prospects for antioxidant therapy in ocular diseases

Abstract

The eye is particularly vulnerable to oxidative stress due to its constant exposure to atmospheric oxygen, sunlight, ultraviolet and ionizing radiation, chemicals, pollutants, and microorganisms that may shift the physiological balance towards oxidation. Today, oxidative stress is considered a major pathogenetic feature of a wide spectrum of ocular conditions including diseases of the lens (cataract), anterior chamber (glaucoma), cornea (keratoconus, traumatic injuries, post-operative conditions), eye surface (pterygium, dry eye syndrome), retina (uveitis, retinopathies), and optic nerve (optic neuropathies, glaucoma). Potential strategies for pathogenetic therapy in conditions, associated with oxidative stress, include direct inhibition of lipid peroxidation, induction of Nrf2 transcription factor signaling, repression and sequestration of vascular endothelial growth factor (VEGF), and the use of agents with direct antioxidant effect. Methylethylpyridinol or 3-oxy-6-methyl-2-ethylpyridine hydrochloride, a potent free radical scavenger, is often regarded as a major antioxidant agent for ophthalmological purposes. Methylethylpyridinol is characterized by a possibility of being used in different types of dosage forms. In ophthalmology, it is given by injection, as well as by instillation in the form of eye drops. Methylethylpyridinol can be used for the treatment and prevention of inflammation and burn injuries of the cornea, hemorrhages into the anterior chamber of the eye and into the sclera, thrombosis of the central retinal vein and its branches, diabetic retinopathy and complications in myopia, as well as for the protection of the cornea when exposed to high intensity light and wearing contact lenses. This paper reviews the main features of oxidative stress as the leading pathogenetic factor in ocular diseases, and the possibilities of antioxidant therapy using methylethylpyridinol.