What is my prescription in 20/20 terms? Idk if I’m wording that right but my prescription is +3 -5 in both eyes and I always wonder what the numbers would be in the other form.
This is a very common question eye doctors are asked. The number ratio
"20/20 or 20/40 etc." is a measurement of visual acuity. If
your visual acuity is not 20/20, it can be from pathology (like cataract) or it
can be from what we call "refractive error" e.g. nearsightedness,
astigmatism, farsightedness -which are not at all the same thing.
Refractive errors are measured in units called diopters, such as the +3
or -5 D. you mention. You just don't know at that point in an eye exam
what the refractive error is or how much there is. While generally speaking,
the severity of the refractive error follows the degree of blurred vision, it
is not at all a direct correlation like +1.50 =20/25 and +2.00 = 20/30. So
while "refractive error" and "visual acuity" are both about
vision, they are quite different things that do not parallel one another
closely.
_Written by J. Trevor Woodhams, M.D. - Chief
of Surgery, Woodhams Eye Clinic