I read that disposable contact lenses are actually worse for your eyes than the normal one-year ones because they allow less oxygen to go to your eyes, and the only advantage is that there are less cleansing problems. Also, it is claimed that inadequate oxygen to your eyes (possibly caused by prolonged wearing of contact lenses) leads to a condition when extra blood vessels sprout around the iris, which leads to sight problems at old age. Is that true?

I am very concerned because I normally wear (one-year) contact lenses from 8am to 8pm, and maybe to 12am during reading periods. I don't feel very comfortable with glasses because they give distorted visions and fatigue. I thought switching to disposable contact lenses would do my eyes good. My current lenses contain 38 percent water. Is this good enough?

1) I often have a bad taste in my mouth, and bad breath as well, I assume. This doesn't stem from poor hygiene: I brush my teeth at least three times a day, and usually more. I'm wondering if there is anything I can do about this. Could this be a symptom of some sort of nutritional deficiency? I think my diet is pretty bad, although I'm working pretty hard on getting more protein and eating less fat. I've also been nauseous a lot lately, and vomiting some. Could that be related?

2) Like many people, I often have an embarrassing bad breath. Listerine and other mouthwashes won't be of any help for this chronic problem. There are lots of products available to get rid of "volatile sulfur compounds (VSC)" - that supposedly cause this — and I just don't know which one I should try. Also, what's your opinion on tongue-brushing?

1) Which is better for you, tap or bottled water?

2) How bad is the water here in New York City? Do you recommend drinking filtered water, or does it really make a difference?

What is the significant difference between a product that is antiseptic and one that is antibacterial? All of the antiseptic mouthwashes I find have a great amount of alcohol in them. This can be very irritating to the mouth. I have found one that is alcohol free, but it says it is antibacterial.

Thanks for your help.

So far I have been extremely impressed by your service. I trust you with a question which I know many people share: Are whitening toothpastes detrimental to the longevity of one's teeth?

I was told by my dentist that my teeth eroded, due to consumption of too much acidic food. I would like to know what kind of food causes tooth erosion. Do you have a list of these foods?

Do you know anything about the safety of eyelash extensions?

I was having a conversation with my roommates about pop and coffee and we were wondering which is worse for your teeth, the pop or the coffee? And what do they do to your teeth when you drink them?

For the last year or so, I haven't been able to cry anymore. And when I do, absolutely no tears come out. My eyes just water up, but there are no tears. Is this normal? Should I be worried?

What causes fever blisters on lips and how should they be treated? Also, what is the difference between fever blisters and shingles?