Material data sheets provide an amazing amount of information at a glance but as with all types of engineering knowledge it takes background knowledge on what the numbers mean to interpret that data and a good engineer to evaluate the properties and choose the right material for a design.
How to read eyeglasses spec sheet.
They are latin abbreviations.
Using material data sheets for your design.
How to read eyeglasses prescriptions when you look at a standard prescription the first word you ll see is distance this term refers to what power of lens you will need to see distant objects clearly.
Most prescriptions will include at least two rows of numbers one labelled o d.
So the prescription for reading glasses for the right eye would be 0 25 0 50 x 180.
In the example above it is 2 00 1 75 0 25.
The type of rx glasses may be noted on a prescription such as dv distance vision nearsightedness and nv near vision reading.
Some prescriptions may use r e.
Find the first 2 digit number to read your eye size.
For multi focal glasses as well as reading and computer glasses your rx will include an add or nv value.
Your prescription may be written out on a blank rx pad instead of a pre made rx pad for eyeglasses only.
However you have to do a little algebra to figure the total power needed for single vision reading glasses.
For the left eye the calculation is 1 75 1 00 2 75 d s.
Your ophthalmologist or optometrist determines this power by trying different lenses while you read an eye chart in the exam.
Occasionally you may see a prescription with a line labeled o u or oculus uterque for both eyes.
This number always has a sign.
This number measures the width of 1 lens spanning the distance at its widest point.
A number over 5 is generally considered to be on the stronger side.
The higher the number on your prescription the stronger your prescription is.
A number with a minus symbol before it means you are nearsighted and a number with a plus symbol or no symbol means you are farsighted.
They are abbreviations for oculus dexter and oculus sinister which are latin terms for right eye and left eye your eyeglass prescription also may have a column labeled ou.
When you look at your prescription for eyeglasses you will see numbers listed under the headings of os and od.
Os oculus sinister means the left eye and od oculus.
Your eyes size is the only measurement that falls between 40 to 60 millimetres 1 6 to 2 4 in so you can use this range to ensure that you re reading the correct number.
J nv near vision your prescription is for reading only k pd pupillary distance the measurement in millimeters mm between both pupils l 75 0 75 m 125 1 25.