Nath Madhu & Prasad Hanuman Sharma
Ocular Pharmacology & Pharmacy Division, Dr. Rajendra Prasad Centre for Ophthalmic Sciences,
All India Institute of Medical Sciences, New Delhi, INDIA
Abstract
Systemic administration of therapeutic agents can adversely affect the structure and function of the eye. Notably, the quantity of drugs reaching ocular tissues may not be similar to the other tissue due to the eye's preferential uptake and efflux mechanism. As a result, these agents can cause several common and distinct adverse ophthalmic reactions, including temporary visual disturbances and permanent vision loss. For evaluating drug safety for the eye, both exposure concentration and time play a vital role. Still, the toxic effect may also be directly related to the transient drug distribution inside the vitreous body. In addition, the retina is subject to the risk of drug-induced toxicities owing to its rich blood supply and complex, well-organized neuro-retinal organization. Understanding these cellular and molecular principles is critical in elucidating the pathological pathways leading to drug-associated retino-toxicity. Due to the difficulties in evaluating the toxic effect of drugs in the human eye, animal data experiments are used by ophthalmologists/physicians as a guideline for designing an administration regime. Though the toxic level of the drug can be established by studying histological changes in ocular structure, adversity associated with color vision and excitotoxicity cannot be ruled out. Of note, electrophysiological recordings and the Gyro-DOT-optomotor response model can provide vital information for understanding the functional and behavioral changes associated with systemic drug exposure. Thus, these in-vivo techniques can provide important information at various stages for developing new drugs and optimizing an administration regime.