DEAR DR. DONOHUE: I need help. I am a diabetic on pills only. I have what’s called a Charcot joint. Can I get a drug to help me? Sometimes I can barely walk. – J.C.

ANSWER: When people sit or stand for a long time, they unconsciously move slightly all the time. Their brains know that a perfectly still joint suffers damage if it doesn’t move. The movement need not be huge, just a slight change in the joint position. Without those all-but-undetectable movements, joint cartilage begins to crumble. With the passage of time, a severe, destructive arthritis results. The joint becomes unstable, and the joint is often dislocated. That’s a Charcot joint.

It happens because something has gone wrong with the nerves that signal the brain to move the joint. That condition is a special kind of neuropathy – nerve disease. It often happens to diabetics, but it can happen to others with different causes for nerve malfunction.

Other than keeping your blood sugar as close to normal as possible all the time, there isn’t anything you can do to restore the joint. But maintaining normal blood sugar stops the process from happening to other joints. There is no medicine for this.

However, braces and splints can stabilize the joint and make it more functional, helping you move around. Fusing the joint surgically is another way to make it less wobbly and more dependable.

DEAR DR. DONOHUE: I have glaucoma. I use eyedrops daily. Does caffeine cause eye pressure to rise? – A.G.

ANSWER: Glaucoma comes about from a rise of fluid pressure in the eye and from damage to the optic nerve at the back of the eye. Lowering fluid pressure – often with eyedrops – preserves the optic nerve and vision.

Caffeine can slightly raise eye-fluid pressure for a limited amount of time. I would stop using it until I saw my doctor again. Then I would question the doctor, who can determine if the rise of pressure would be significant for you.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www .rbmamall.com