Optometry ref.data means reference data.
ref.data is a contraction of reference data, meaning reference data. (The reference data given by a computerized optometrist).
Interpreting optometry:
ref.data-Reference data
VD-Vision Distance: the distance from the back vertex of the spectacle lens to the front of the eye.
R-Right eye: black bolded data is the average of three optometry sessions.
L-Left eye: black bolded data is the average of three optometry sessions.
S-Sphere: "-" for myopia, "+" for hyperopia.
Photometry:
Photometry is the examination of the gathering of light rays after they are incident on the eye, which measures the degree of difference in gathering and dispersion between the examined eye and the orthopic eye, using the state of the orthopic eye as a standard. Since many people will almost always be associated with eyeglasses in their lifetime, optometry is one of the most basic, common but important tasks for optometrists, so as far as the term optometry is concerned, it is very familiar to both ophthalmologists and the general public in social life.
The optometry is mainly to check the deformation of the eye, generally use two methods, one is to use the instrument to check, you can initially measure the deformation of the eye, one is to use the lens to try to replace, with a pair of glasses with interchangeable lenses, to determine the number of glasses need to wear, so as to be able to match a pair of suitable glasses. Large optical stores use the above two methods of optometry.
The above content reference? Baidu Encyclopedia - Optometry