I – along with most Israelis – went to see the 3-D movie Avatar in the cinema. Wearing the special glasses, I started to feel nauseous and was uncomfortable through most of the long film. Why did watching the movie through these glasses cause such a reaction? Are they safe? Do they mean I have a vision problem? I read that movie producers are increasingly going to make films in 3-D, so I don’t know how I will be able to watch them. – S.Y., HerzliyaGene Stollman, a semi-retired veteran Jerusalem optometrist, replies:Indeed, a recent article in The New York Times described forthcoming new technologies in 3-D films to improve their popularity and noted that the general demand for 3-D theaters is increasing. Those of us with good binocular vision – that is good working sight with or without glasses from both eyes – will enjoy the excitement of having objects and scenes rushing or floating out toward us in our seats.Stereopsis is the the visual perception of depth or the ability to see three-dimensionally. To enjoy 3-D effects, both eyes must work together. But there are 2 percent or 3% of the general population whose eyes do not work together due to amblyopia (“lazy eye”), an injury or some ocular pathology. Children with strabismus (cross-eye, in which one eye does not coordinate its viewing with the other), people who have undergone eye surgery, those who do eye exercises, eyeglass wearers or a combination of these may have difficulty “appreciating” the 3-D effects.Adults, young or old, with medical eye problems such as monocular (in one eye) cataract or macular degeneration will also not feel the near-and-far visual effects. You must have a proper eye examination to determine not only maximum correctable vision in each eye, but how well the two eyes work together. My daughter started menstruating at the age of 12. She was regular having a period every month for three years. Last September, when she was 15, she left home to attend a live-away high school. She continued to have her period for three months, and then it stopped. She has not had a menstrual cycle now for five months. She claims she is eating well, though she is thin. She has not lost weight, but she is very careful what she eats. I am not sure if the problem is emotionally related or connected to her diet or to hormones. What should we do? – M.G. Ra’ananaProf. Amnon Brzezinski, veteran gynecologist at the Hadassah University Medical Center in Jerusalem’s Ein Kerem and director of its Women’s Health Center, comments: Irregular and missing menstrual periods in teenagers are common and don’t necessarily point to any problem or disease. At a young age, the female reproductive system is very sensitive to behavioral changes such as different eating habits or mood changes. Despite this, it is worth taking your daughter to a gynecologist, who is likely to send her for a blood test for a hormone profile that will be able to point to the reason for the halt in her periods.I am a 30-year-old man, a bit overweight but still healthy. Two weeks ago I suddenly suffered weakness of the muscles on the left side of my face. I went to my doctor immediately, and he diagnosed something called Bell’s palsy. He said it would go away without treatment. He did not give many details or say how long it would take. Unfortunately, I haven’t seen much improvement since then. – N.S., ArielJudy Siegel-Itzkovich comments: The Mayo Clinic Health Letter recently published an article on Bell’s palsy. The publication described it as an abrupt weakness or limpness on one side of the face and noted that most Bell’s palsy patients don’t experience total paralysis. Other symptoms include a dry, irritated eye with tears dripping from the corner; pain around the ear or jaw; ringing in the ears and/or sensitivity to noise; headache; and a loss of taste or a decrease in saliva production. According to the Mayo Clinic, Bell’s palsy can affect anyone at any age. The risk rises until about age 40 and then begins to decrease. The condition is most likely to occur in people who have certain viral infections, such as cold sores or upper respiratory infections, or diabetes.It explained that the condition is not associated with stroke, and most people recover completely. It often results from a viral infection of the nerve that controls facial muscles and passes through a narrow corridor of bone on its way to the face. If that nerve is inflamed or swollen, it can become compressed, irritated and injured in this narrow pathway. Although Bell’s palsy is usually self-limiting (passing on its own, without treatment), victims should still seek emergency care to confirm a diagnosis, which is what you did. One can just wait, but treatment with a course of oral corticosteroids to help reduce inflammation around the facial nerve is often given to increase the likelihood of full recovery and shorten recovery time. Researchers have studied antiviral drugs as a way to speedrecovery, but there’s some controversy on their effectiveness. Mayodoctors believe there may be some benefit if the drugs are given withinthree days of symptom onset. For most people, symptoms begin to improvewithin a few weeks. Complete recovery may take three to six months oreven longer in severe cases. About 85 percent of those with Bell’spalsy recover completely.Rx for Readers welcomesqueries from readers about medical problems. Experts will answer thosewe find most interesting. Write Rx for Readers, The JerusalemPost, POB 81, Jerusalem 91000, fax your question to JudySiegel-Itzkovich at (02) 538-9527, or e-mail it to email@example.com,giving your initials, age and residence.