DEAR DR. GOTT: I am a 48-year-old woman with green eyes, black edged and dark lines toward the centres. My siblings and children have the same green eyes. That was until two weeks ago, when I woke up to beautiful blue eyes.

We are all amazed. I look in the mirror now and someone else's eyes look back. The colour and patterns are completely different.

I have very good health. I have worn clear contact lenses for many years with no significant changes in vision.

DEAR READER> I don't have a ready explanation for your sudden change in eye colour, but I certainly advise you to check with your ophthalmologist just to make sure that your eyes are otherwise normal.

DEAR DR. GOTB> As a veteran of WWII, I was instructed all through basic training and beyond to take my "salt tablets." There were salt-tablet dispensers in the barracks, in the mess hall and at our workstations. We were told that the reason was to replace the salt in our systems that was lost due to excessive sweating during our daily routine of drilling, marching, etc. In today's world, the population has been told to avoid salt as much as possible. Do salt tablets have any beneficial value at all, or are they harmful to our health?

DEAR READ Salt supplements are appropriate if the body is actively sweating out dietary salt, as can happen during strenuous exercise in a hot, muggy environment. Salt tablets are not necessary for normal, inactive people in temperate climates. In fact, a heavy load of salt supplements can lead to serious consequences, such as high blood pressure, if the salt doesn't leave the body in perspiration.

DEAR DR. G: I second your reader's approval of the soap-bar method of preventing leg cramps. However, I have found the method works well for about three months, but after that, the cramps return. And it now happens on awakening rather than in the middle of the night. Perhaps the answer after three months is to provide a new bar of soap, preferably one of different shape than used previously. Or one could supplement the treatment with a good swig of tonic water before retiring to bed. At any rate, I have informed several of my specialist doctors of the viability of this approach, which prevents the pain of leg cramps rather than merely alleviating the pain once it is under way, as most remedies do. They, of course, remain skeptical at best. The family dog has also realised there is some benefit to this new intrusion into the bed and has to be removed forcibly from it for anyone else to gain any benefit from the treatment.

DEAR RER: The reason the soap therapy works remains a mystery. But perhaps you are right that the soap changes in some manner after three months of use. Try changing the soap periodically.