The title is just a fancy way of saying that some women seem to have four colour receptors in their eyes rather than the usual three. Actually some people also have a different set of three and this was known for some time before the discovery that quite a few women see extra colours than the rest of the population. Of course some men are missing a receptor and have only two and as a result are called colour blind. Compared to tetrachromats we are all colour blind. Join discussion...

Italian researchers looked at the coffee drinking and smoking habits of 166 people with blepharospasm. Sufferers have uncontrollable twitching of the eyelid which, in extreme cases, stops them being able to see. One or two cups of coffee a day seemed to reduce the risk of the condition, the team reported in the Journal of Neurology, Neurosurgery and Psychiatry. Join discussion...