Online optical stores give us a new channel of buying cheap yet high quality eyeglasses. As it is impossible for you to have your eye examined in “virtual” online stores, therefore you need to visit your local brand vision optometrist’s office first to have vision testing and then obtain your vision prescription. All the online store websites will prompt a window for you to fill in your vision prescription to finish ordering process. In order for you to fill in the vision prescription properly to avoid any mistakes, you’d better understand the meaning of vision prescription.
Though different brand vision testing companies have their own forms, basically every vision prescription has three numbers. The first number represents the strength of your farsightedness or nearsightedness, which is a unit of measurement with the name of “diopter”. The bigger the number is, the stronger your vision prescription is. The + sign means hyperopia and the – sign means myopia. The second number is the amount of your astigmatism. Astigmatism also have (+) sign and (-) sign. The third number is the axis, meaning where the astigmatism is located. 90 means the astigmatism is positioned in the vertical axis, and 180 means the positioning is in a horizontal direction.
You are entitled to ask for a copy vision prescription from your local brand vision operator. This is your personal property based on US laws.
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