Question: Is laser eye surgery safe over the long term? And how well does it fix nearsightedness? I often wonder when I ride the subway and read the ads for all those eye surgeons.
Study: A recent study by a group of Spanish ophthalmologists, writing with Dr. Jorge Alió, looked at long-term outcomes for LASIK, a laser surgery method of eye correction introduced in Europe 18 years ago. The researchers evaluated long-term value and safety for almost 120 patients (196 eyes, in total) with severe myopia—so severe that under today's guidelines they would no longer be eligible for the surgery. The researchers measured how good, stable, and safe the patients' correction of vision was.
Findings: The majority of patients achieved very good correction soon after surgery, though another quarter of them needed a second course of surgery to achieve this level. Over the 10 years that followed, these results slowly regressed a bit for most of the participants, moving the group, on average, from perfect vision to a mild degree of nearsightedness. They ended up on average only about 15 percent as nearsighted as they were before surgery.
Complications: Remarkably, given that safety concerns are the reasons LASIK is no longer used for such severely nearsighted patients, only two eyes of two patients (1 percent) suffered the bad complication called corneal ectasia, in which the cornea loses strength as a result of the procedure and bulges, resulting in poor vision. A few other patients developed other visual problems over time. However, these were related not to the surgery but to the normal aging process, or to problems encountered in the extra-deep eyeballs of badly nearsighted people.
Conclusion: This method, then, seems to have been remarkably successful in improving the eyesight of some very hard-to-treat patients, and with rather less risk than I would have anticipated. This is very good news, indeed, especially since worldwide about 18 million LASIK procedures have been performed since the method was introduced.
Chewing gum and the runs
Problem: Chronic diarrhea without an obvious cause is a difficult condition for physicians to sort out. This distressing symptom, which can result in excessive weight loss, is sometimes caused by allergy; sometimes results from an acquired inability to digest a food ingredient (like milk sugar); and sometimes reflects a bacterial, viral, or parasitic infection. Now medical science has identified yet another cause: chewing gum.
Case study: Juergen Bauditz, writing with four colleagues from the Charité Medical University in Berlin, recently described two patients, a 21-year-old woman and a 46-year-old man, with diarrhea and a lot of weight loss over an eight-month to one-year period. They underwent an intensive but fruitless gastroenterologist's evaluation (don't ask!). And then the puzzled doctors returned to the patients to ask questions. This time, good history-taking identified the real culprit—too much sugarless chewing gum.