I am a university student who takes a lot of exams at the end of each semester. I was wondering if there was a recommended diet that can improve my test performance. I also suffer from dry, tired eyes, while studying for weeks, and would like to know how to avoid the condition.I.N., Jerusalem Clinicial dietitian Ruti Abiri comments: During testing periods, many students give low priority to their health, and studying pushes all other issues aside. They often stay awake late at night and eat junk food while studying. As a result, they suffer from an unbalanced diet, constant stress and don’t get exercise for weeks at a time. Success in studies requires good health, energy and the ability to concentrate, thus nutrition is very important.Do not skip breakfast before a test: Breakfast is the meal that actually breaks the night’s fast. During this time, the body’s sugar and energy levels drop; a healthful, nutritious breakfast restores the body’s energy, which is needed by the body and brain to promote memory and concentration. If you come to a test without eating nutritious food, your energy stores will empty out and impair your physical and cognitive functioning.Pre-test breakfasts should be comprised of all the food groups, relatively quick to eat, not be too heavy (as it will make you sleepy) and be tasty. Examples are whole-grain cereal and milk without added sugar; yogurt with granola or cereal; eggs, whole wheat bread with tuna or white or yellow cheese, avocado, tehina or hummus or other vegetables.In long days of studying, avoid empty-calorie snacks. Prepare food in advance for the whole day that can be eaten cold or warmed up. A nutritious sandwich on whole-wheat bread can also be a satisfying, healthful and balanced meal that contains a combination of carbohydrates and proteins, and also provides essential vitamins and minerals.Be sure to drink enough water throughout the day, as it improves cognitive performance, reduces fatigue and contributes to better performance. Even mild dehydration can damage short-term memory and cause symptoms of fatigue and headaches, which in turn impair concentration and thinking. Always have a bottle of water next to you, and drink not only when you are thirsty.Do not use coffee to keep you awake when you get tired. Caffeine is a stimulant for staying awake, but it does not improve the ability to concentrate. Caffeine increases the secretion of adrenalin in the blood and actually damages the ability to think and to concentrate. So instead of a cup of coffee while studying, do three minutes of stimulating physical activity, including stretching.Prof. Or Kaiserman, head of the cornea and dry-eye clinic at Barzilai Medical Center in Ashkelon, adds: Unlike in the past, today’s students spend many hours learning and studying for tests using laptop computers rather than with notebooks and pens. This is not very good for the eyes, as it can lead to chronic fatigue; dry, itchy and burning eyes; and blurred vision. It has been dubbed “computer vision syndrome” (CVS).Millions of people around the world suffer from this modern phenomenon, which is one of the main reasons for all referrals to ophthalmologists.Dry eyes affect quality of life and vision. A person with dry eyes feels tired, and even during the day, feels the need to close his eyes. It also affects professionals who work all day in front of computer screens.In addition, air-conditioned classrooms that are heated or cooled reduce humidity, thus contributing to the evaporation of the layer of tears that protects our eyes and preserves their moisture. Recent studies show that about 70% of workers with screens – stationary computers, laptops, tablets, TV screens, smartphones and more suffer from dry eyes.Medically, the dryer the eye, the higher the salt concentration in tears, resulting in toxicity and damage to the cells coating the surface of the eye. This can lead to a chronic inflammatory response in the eye. Damage can be caused to the eyelid glands that secrete the tear components due to the continuous irritation and damage the surface of the eye.It’s important to rest your eyes and look at a distance a few minutes every hour. You can also apply over-the-counter drops to lubricate the eyes.I was wondering how meaningful the “Sell By…” dates on frozen food are. I have frozen fish in the freezer with a sell-by notice of until October 2017. It is sell by, but not “consume by.” After that date, does the food become toxic in some minor or major way or are the frozen food companies adhering to some arbitrary law?P.C., Binyamina Eli Gordon, director of the Health Ministry’s National Food Service, answers: The manufacturer’s instructions should be considered subject to validity and a final date for use as a guiding rule, including the consumption of frozen food. In other words, the ministry recommends that no expired product be used or consumed in any way.Rx for Readers welcomes queries from readers about medical problems. Experts will answer those we find most interesting. Write Rx for Readers, The Jerusalem Post, POB 81, Jerusalem 9100002, fax your question to Judy Siegel-Itzkovich at (02) 538-9527, or email it to jsiegel@ jpost.com, giving your initials, age and place of residence.