Abstract and Introduction
Dietary supplements are commonly used by patients in an ophthalmology practice. Many of these agents have direct toxic effects on the eye and visual system or may interfere with elective surgery. A high index of suspicion should be maintained. The authors review common preparations and discuss them in three contexts: direct ocular effects (beneficial and deleterious); bleeding effects that may affect ocular surgery; and effects on medications.
The actions of dietary supplements are diverse and may be adverse. Their prevalence and their potential toxicity are underappreciated among ophthalmologists. With a high index of suspicion, both vision-threatening and life-threatening interactions may be avoided.
The ocular toxicity of pharmaceutical preparations is well documented.[1] In contrast, the ocular effects of dietary supplements are less well described, although recognition of their potential toxicity is increasing.[2,3] In the literature, the terms "herbal," "supplement," and "complementary and alternative medicines (CAM)" are all used, which may lead the reader to confusion. They refer to a heterogeneous group that may include minerals, nutrients, botanical supplements, or ingredients or extracts of plant or animal origin.
We will use the broader term "dietary supplements" in this manuscript, although the regulation of each classification of medication varies, depending on the labeling and on the disease treatment claims made by each agent. The distinction between a "drug" and a supplement may be difficult. For example, cardiac glycosides are derived from foxglove (Digitalis purpurea), and cyclosporine (Sandimmune®; Novartis, Basel, Switzerland) is derived from the fungus Tolypocladium inflatum Gams (later renamed Beauveria nivea).
The 1938 Food, Drug, and Cosmetic Act regulates any substance that claims to diagnose, prevent, treat, cure, or mitigate any disease ("disease claims"). The 1994 Dietary Supplement Health and Education Act (DSHEA, revised in 2000) regulates any substance that claims to affect the structure or function of any organ or system ("structure/function" claims) without specifically claiming efficacy against any particular disease. For example, a substance that makes no medicinal claims is not regulated; a substance that claims to "maintain healthy eyes" would be regulated by DSHEA; and a substance that claims to treat age-related macular degeneration (AMD) would be regulated by the Food, Drug, and Cosmetic Act. Enforcement of these acts is carried out by two federal agencies. The Food and Drug Administration (FDA) controls claims made on the bottle and package insert. The Interstate Commerce Commission (ICC) oversees claims made through advertisements.
The net effect is that most dietary supplements are brought to market with less regulation, and in most cases less rigorous scientific investigation, than pharmaceuticals. Thus, the ophthalmologist should have a working knowledge of these preparations, which are in common use among the general public.
Compr Ophthalmol Update. 2005;6(3):153-159. © 2005 Comprehensive Ophthalmology Update, LLC
Cite this: Dietary Supplements and the Ophthalmologist - Medscape - May 01, 2005.
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