Vitamin D and its Relationship to Ocular Diseases: A Systematic Review

Introduction Vitamin D plays a vital role in the proper functioning of various systems of the human body. Conventionally, it is known that its deficiency can impair, among other factors, calcium homeostasis, bone metabolism, and immune system regulation. Besides having anti-inflammatory and antiangiogenic properties, 25(OH)D also acts in maintaining the integrity of the human retina, favoring the idea of it being a protective factor for certain ocular diseases. Objective Therefore, the purpose of this review was to collect data from the literature which support the importance of vitamin D for ocular health. Methods Through the Scientific Electronic Library Online and the National Library of Medicine databases, a compendium was created on the subject. Results In total, 31 articles in English published between 2016 and 2020 were found. These articles were reviewed and categorized by diseases in order to study each disorder thoroughly. It is noticed that 25(OH) D is, in fact, a potential protective factor against such diseases, including diseases that affect both the surface of the cornea and the ocular tissues that have vitamin D receptors. Conclusion Vitamin D is a protective hormone in the eye, and its deficiency is related to a variety of ocular diseases. Therefore, the supplementation of 25(OH)D can be considered as a complementary treatment for patients with these diseases, since it brings relevant benefits.