I'm 78 and have had conjunctivitis, on and off, for a year. Endless courses of antibiotics have failed to clear it up - what would you advise?

Repeated conjunctivitis - red eye - may be caused by infections (for which antibiotics are appropriate) or allergies (which respond to steroid drops or ointments). Repeated bouts suggest you are being exposed to either one or the other. Or you may have dry eyes - not producing enough tears - for which artificial tears may be useful. Is the main symptom pain or itch on the eye surface, or do you also have pain inside the eye? Are you having trouble seeing - is your vision blurred? You need a full examination to find the solution. So see your doctor again.

I am in an almost constant state of fatigue. I can sleep up to 16 hours a night and still wake up tired. I exercise regularly and have a balanced diet. What would you suggest?

You have classic 'tired all the time' syndrome. You say that you sleep for 16 hours, which is not normal and suggests you may have a sleep disorder. Your doctor needs to know about it. Paradoxically, over-sleeping may make you tired. I would also have to consider depression as a cause. Do you have a disturbed appetite? Do you wake up very early some mornings unable to get back to sleep? Do you feel you don't want the company of friends or family? You need to ask for a longer than usual appointment with your doctor, so you can get to the bottom of this problem.

Do you have a question for Dr Smith? Email doctordoctor@theguardian.com