Some washing powder manufacturers are starting to recommend that we wash our clothes at 30 degrees centigrade instead of 40 degrees centigrade. I can see the energy benefits of that, but is 30 degrees hot enough to kill bacteria in the wash?

What's glaucoma?

I'm very short sighted, but over the years I've started to suffer from a stigmatism. I'd like to know what it is and what causes it.

I've got diabetic retinopathy in both eyes and I was wondering if there was any evidence that if you get your sugar levels just right, the blood vessels will repair themselves?

Why can't I recognise a face that I've known for many years upside down?

Why is it that we're perfectly comfortable with black and white movies and photographs when we know that the world is in colour, but the same picture in reds, green or any single shade of colour doesn't seem to have the same satisfying effect? It's ok to substitute a colour with a grey tone, but not shades of other colours.

My eyes often become watery for no apparent reason. Why do you think this is?

We all know that when we open our eyes under water we see blurry images. I believe that this is because water has a different index of refraction in air, where our eyes have been designed to work properly. Is it possible for someone to have such poor eyesight in air that they could see clearly under water?

I have neovascular macular degeneration of the right eye, which means that I haven't any sight left in that eye. I went to see if I could have laser treatment to cure it but nothing happened. The bad news is that I've been told that there is a 40% chance that I'll get it in the other eye. What is macular degeneration and what are the chances?

My husband has recently developed a squint overnight. Why is that?

Can bulls see red?

Do birds that hunt in water or below water have polarised vision, as it would be a good advantage for them to be able to see through the water?

Why are the cones in our eyes red, green and blue? Why not red, yellow and blue? How can we see yellow?