Ocular Drug Toxicity

Retinal Drug Toxicity: When Systemic Drugs Poison the Retina

The retina is a piece of the brain pushed out to the surface of the eye, and it pays for that exposure. Drugs swallowed for lupus, for schizophrenia, for breast cancer, for hepatitis — drugs that never come near the eye on purpose — can quietly accumulate in the retina and destroy the very cells you read these words with. The damage is often painless, sometimes irreversible, and frequently preventable if you know to look. This chapter is about the drug history that explains an unexplained loss of vision.

Optic-Nerve and Corneal Drug Toxicity

If the retinal-toxicity chapter was about drugs poisoning the film at the back of the camera, this one is about two other places a drug can strike: the cable that carries the picture to the brain — the optic nerve — and the clear front window it comes through — the cornea. One of these is a quiet emergency: a patient on a tuberculosis drug whose colours are fading and whose central vision is dimming, symmetrically, painlessly, in both eyes at once. The other is usually a harmless clue: a whorl of deposits in the cornea that spoils nothing but tells you exactly what the patient has been taking. Telling the dangerous one from the trivial one is the whole point of this chapter.

Steroid-Induced Glaucoma and Cataract: The Price of Corticosteroids

Corticosteroids are among the most useful drugs in all of medicine — and among the most quietly dangerous to the eye. Give them long enough, by almost any route, and two complications follow like a shadow: a slow, painless rise in pressure that can steal sight before the patient ever notices, and a cataract that clouds the very back of the lens. Neither hurts. Both can blind. The whole discipline of using steroids around the eye is really the discipline of respecting that hidden bill — and paying as little of it as possible.