That's a really good point and there are a few things to bear in mind with this. The smells that you get on clothes aren't actually the bacteria on your clothes per se. What happens is that your body create the ideal home for bacteria to live. They live on dead skin and sweat that you squirt out onto the body's surface. They produce trace elements and chemicals and metabolites, which soak up into your clothes like blotting paper, and they're a bit whiffy. So your clothes don't necessarily smell just because they're contaminated. When you wash your clothes you wash out those substances and that's why they have a nice smell. The excellent point you've made is whether these temperatures are hot enough to neutralise any bacteria that may be on the clothing. This could be important if you're working in a hospital, I suppose. The answer is that there are a lot of detergents in washing powder and it's very alkaline as well. It can cause caustic burns if you put it on the skin. It would take some pretty hardy bugs to survive it, but some can. Things like mycobacteria that cause TB can survive in those conditions. You maybe should consider washing at higher temperatures if you think there might be bugs loitering on there.

Glaucoma is another important condition of ageing. It causes a gradual loss of peripheral vision. The reason this happens is that the nerve is being gradually damaged and this usually happens because the pressure in the eye is too high. The treatment that we can give to try and prevent this from happening is treatment to lower the pressure either with drops or sometimes with operations.

The normal cornea, the bit at the front of the eye, is essentially spherical. But if it's not quite spherical, and is shaped like a rugby ball rather than a football, it creates a stigmatism. This means that the eye doesn't see perfectly in all planes. It's usually just the cornea that's shaped like a rugby ball, but it can sometimes be contributed to by the lens. This can run in families and there are certain diseases that cause it too.

I'm not sure whether they can repair themselves but what seems to be the case is that if you keep your blood sugar very well controlled, the chance that you will develop severe diabetic retinopathy is reduced. So it's well worth trying to keep your diabetes extremely well controlled. You can stop it getting worse rather than reversing the damage you already have. Once the blood vessels have started to proliferate in the retina, then we know that they can be lasered with a very high energy laser and they can be destroyed. This prevents them from causing the damage that they would otherwise have caused to the retinal function.

I'm afraid I don't have a clue! Although what I can say is that although we can't do it and other animals like sheep and cows can't recognise other sheep and cows when they're upside down, monkeys can actually do it. So it would seem to imply that if you habitually hang upside down then it's something you can do. They've not looked at bat face recognition as far as I know!

I can fairly say that I don't really know the answer to that. I suspect that it's just what we're used to. We're used to seeing colour photographs and we're used to seeing black and white photographs. But we're not really used to seeing red TV or green TV. I suspect that it's just what we're familiar with.

When you go out in the wind, it's a stimulus to tear production. Tears are quite useful because they keep the cornea, that's the front of the eye, moist. They keep the eye smooth and functional. But if you go out on a windy day, often you produce a few too many tears and they fill up the whole conjunctival sac and so you're looking through water. So I suspect that it's that: different conditions will bring it on.

The problem is that in air, light is focussed by both the cornea at the front of the eye and the lens within the eye, and actually most of the focusing is done by the cornea. The reason the cornea can focus is because the refractive index of air and water are different. But as soon as you put your head under water, the refractive index of the water and the liquid within the eye are the same and the cornea no longer focuses the light. The cornea is then lost as a refractive surface. In answer to the question, our eye is said to have a focusing power of 50 diopters. 45 diopters is due to the cornea. So about three quarters of the eye's focusing power is due to the cornea. When you go under the water you lose the cornea as a focusing surface. So you would have to be 45 diopters myopic, which means normally that you would be focussed at just over two centimetres. I've never met anyone who's minus 45 diopters.

I can't give you an exact chance really. This problem of neovascular degeneration of the retina, which is a devastating cause of visual loss is due, we think, to some sort of metabolic fault in the retina. This allows blood vessels to grow into the retina and then distort the retina. Up until very recently we haven't had very good treatment for it, because lasers can be quite destructive. If you laser a retina, you destroy the retina in the process. But there are some very exciting developments because there are now two new drugs that seem to be helpful in this condition. So it's possible that in the future we may be able to treat people like you with this condition.

It's probably because one of the muscles is not working properly. There are six muscles and it's probably because one or maybe two of them are not working very well. So it could be a nerve being pinched somewhere, but as it happened overnight, it's more likely that a blood vessel blocked. So the supply to the nerve is damaged and the nerve doesn't work very well. Usually it will tend to recover in a few weeks.

Yes, bulls can see red but they probably can't distinguish it from green. They only have one visual pigment in that part of the spectrum, which means that they can distinguish blue from other colours, but they can't distinguish red from green. They see the world like a red-green colour deficient person. So waving a red rag at a bull isn't a problem because it's red, but because it's moving. They're responding to the movement rather than the red, although they can still see the colour. They will just get confused between red and green rags.

A lot of animals have polarised vision, so that's actually a good suggestion. The other thing that I think is really interesting is birds that dive under the water. Earlier on we were talking about the way that humans become long sighted when they look under water; well birds that dive under water don't. They can actually accommodate up to 60 diopters, meaning that they can really change the shape of their lens. They do this by ramming their lens up against a very solid iris, and they form a great big bulge at the front of their lens.

They're not actually red, green and blue at all, although that's what we tend to call them. They're actually blue, green and yellow. The long wavelength cone absorbs mainly in the yellow and not in the red, so that's how we can see yellow.