Ocular Side Effects of Systemic Drugs (Anterior Segment)
Professor of Ophthalmology
Shahid Beheshti University of Medical Sciences
Torfeh Eye Hospital
Commonly reported ocular side effects of systemic drugs include abnormal vision, blurred vision, poor focusing ability, Dry/Irritated eye, color perception change and altered pupil Size.
The eye, because of its blood supply and relatively small mass, exhibits an unusually high to toxic substances. Drug molecules present in circulation can reach the ocular structures by way of the uveal or retinal vasculature. The choroid, sclera and ciliary body have thin, fenestrated walls for drug molecules to pass. Small, lipid soluble molecules pass freely into the aqueous humor, and can further diffuse into avascular structures such as the lens, cornea and trabecular meshwork
Drug molecules that enter by means of the uveal circulation exit the eye from the Canal of Schlemm, ciliary body or may diffuse into adjacent anatomical structures. Drugs from the retinal circulation can re-enter the systemic circulation, diffuse into the vitreous and anatomical structures, or get actively transported out.
Determination of drug reactions depends on amount of drug administration, nature of Drug, route of administration, pathophysiologic variables, age and gender, multiple drug therapy, drug interaction and history of allergies to drugs
Many systemic drugs are associated with: Dry-eye related sign and symptoms, conjunctivitis, corneal problems and the lens including: beta blockers, oral diuretics (change the tear film), oral contraceptives, antipsychotics (phenothiazine, thioridazine, chlorpromazine,), tricyclic antidepressant, anticholinergics (atropine, scopolamine),
Isotretinoin(decreased meibomian gland function- deficiency of normal lipid layer in tear film) , antihistamine, corticosteroids, amiodarone (Cordarone),Chemotherapy drugs, Immunosuppressive medications and topiramate
Conclusion: Many systemic drugs can produce ocular and visual side effect which range from mild to severe and can be even vision threatening. A careful and detailed case history is necessary to be aware of patient's medical history. It is very important that these ocular side effects from systemic drug use be reported and addressed timely. These visual side effects should be recognized at the earliest to minimize serious complications and to plan appropriate intervention by modification of dosage or use of alternative drugs