What you MUST bring on your First Day: 1  Any two of the acceptable forms of identification listed in the Form I-9 list of acceptable documents. 2  A check to verify that information on the direct deposit form is correct. There is no need to void a check.
Manifest refraction - A manifest refraction is the most traditional way of measuring one's refractive error. As mentioned above, it is usually the part where the patient is shown choices and is involved in the process.
Refractive index. The refractive index (or index of refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. For example, typical soda-lime glass has a refractive index of 1.5, which means that in glass, light travels at times the speed of light in a vacuum.