My four-year-old daughter has taken to blinking quite intensely (screwing up her face as she does so) and quite frequently. Could she be short-sighted, or is there another reason?

There are several possible causes for repeated blinking. The most common is that your daughter may have had a sticky eye recently, and is blinking to relieve the uncomfortable feeling in her eyelids. If so, it's harmless and will resolve itself in time. Or it may be a minor nervous tic - that's pretty common, too, in four-year-olds, and rarely needs treatment. However, screwing up her eyes in order to squeeze her eyeballs into shape can be a sign of short-sightedness. How close does she hold a book when she is reading? That may give you a clue. If you're not sure, you could take her along to your local optometrist.

My brother-in-law has just been diagnosed as having diabetes, and has to use insulin. He is still driving. What are the rules about this? Isn't it dangerous for him to drive?

He must tell the DVLA about his illness: he is breaking the law if he doesn't. Put simply, he should test for blood glucose before driving, and if it is below 4 mmol/litre he shouldn't drive. He should take his glucose meter with him in the car, test every two hours, and stop and snack if the glucose level drops below five. He should strictly observe these rules, as a dropping blood glucose level slows reaction times, increasing errors of judgment and his chances of causing an accident.

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