What's Up Doc 11-12-09

What is the difference between myopia and hyperopia?
Myopia is commonly called nearsightedness, and occurs when the curvature of the cornea is too steep, causing focus of the rays of light to form in front of the retina instead of directly on the retina. The result is a blurry view of distant objects. Hyperopia is commonly referred to as farsightedness, and occurs when an eye is too short for the cornea curvature, causing focus of the rays of light to form behind the retina instead of directly on the retina. As a result, a blurred image of close objects is produced.
Jeffrey Hankin, OD, Optometrist with The Eye Clinic

I got an email that said it was not safe to microwave my food in plastic wrap. Is this true or is this an urban myth?
This Internet string was created by an unknown author who got a little carried away about dioxins in the atmosphere. While it is true that the microwaving process releases dioxins, there is only an insignificant amount of these poisons released. Once dioxins enter the body, they are stored in the fatty tissues of the body. Excessive amounts of dioxins can cause problems if you are exposed to them for an extended period of time and in large amounts. Dioxins in plastic wrap are essentially harmless. You can feel confident using any plastic that is marked microwaveable in the microwave. The vast majority of plastics used in food wraps and packaging containers do not contain the chemical constitutes that can form dioxins, which are a family of compounds produced by combustion at temperatures greater than 700 degrees Fahrenheit. And, by the way, if you just so happened to be cooking at that temperature, you wouldn’t be able to eat that crunchy stuff anyway!
Brian Stewart, MD, family practice physician

How Does Chemotherapy Affect Diabetes?
Chemotherapy is a challenging treatment for anyone, but presents some additional specific concerns for people who have diabetes. Some people react to the stress of chemotherapy on the body by developing additional resistance to insulin, so that blood sugar levels increase. This is a temporary effect, but it may cause a diabetic to require additional medication during treatment. Side effects of chemotherapy can include irritation of the digestive tract, including mouth sores, nausea, and diarrhea. If this occurs, you may not eat as well and absorb your nutrients poorly. While nutrition is poor, you may require supplemental nutrition through an intravenous (IV) line. Changes in your total calorie intake will make it necessary for your diabetes treatment to be monitored and adjusted throughout your treatment. It is also common for people who receive intravenous nutrition to receive intravenous insulin out of the same infusion, if the doctor makes this arrangement. Some side effects of chemotherapy are long lasting. One common side effect of certain chemotherapy medicines is nerve damage, called "neuropathy." Because neuropathy is also a common complication of diabetes, these patients may be particularly prone to this problem after chemotherapy.
Henry Goolsby, III, MD, Oncologist with Lake Charles Medical and Surgical Clinic

I have a bump under the skin of my left wrist that comes and goes every few months. Sometimes it is sore and other times I don’t even realize it is there until I accidentally hit it on something. It usually stays for about three or four weeks and then disappears. Should I be concerned?
It sounds like you have a very common ganglion cyst. They are not harmful and can be treated by removal if they severely impact the use of your wrist or hand. Unfortunately, even with surgery, the cysts tend to come back. If the bump becomes too painful, a wrist splint may provide relief. Of course, it’s always best to check with your physician so he or she can look at it and give you more specific instructions.
Marne Devillier, MD, family medicine physician with Maplewood Family Medical Clinic