1 Visual acuity (sharpness) tests help your doctor find out if you have a problem that affects how well you can see. 2  They measure the eye's ability to see details at near and far distances. 3  The tests usually involve reading letters or looking at symbols of different sizes on an eye chart.
Amount of calcium. Elemental calcium is key because it's the actual amount of calcium in the supplement. It's what your body absorbs for bone growth and other health benefits. The Supplement Facts label on calcium supplements is helpful in determining how much calcium is in one serving.
How to Best Absorb Magnesium Supplements. Magnesium is needed for hundreds of your body's basic functions, including regulating your heart and blood pressure and helping to metabolize sugar and fats. It also helps your nervous system and combats such problems as insomnia and anxiety.