What is BVD on my Eye Sight Test?

Question

Hello,

This is my prescription:

Right eye has:

Sph -4.00

No Cyl or Axis

Left eye has:

Sph -3.50

Cyl -0.25

Axis 50.0

Which eye is the worse? By how much? What is Cyl and Axis, and why is that only affecting my Left Eye?

Also it says BVD = 12mm R+L

What does this mean?

Thanks =)

Answer 1

Bilateral Vertex Distance (?).  Judging by the 12mm reading,  I'm assuming that's what it means.  Generally, the average pair of glasses sits 12mm from the corneal surface.  Sometimes we will note the distance at which our instrument measured your vision so that if you get a pair of glasses that sits closer or farther from your eye than our instrument, the focal length can be adjusted to allow for the difference.

Answer 2

Your right eye is worse. Your right eye has a spherical RX. Your left eye is almost as bad, but has a cylinder Correction for astigmatism. Your BVD is the didstance for right and left (R+L) that the refraction was done at away form your eye. this just tells the person fitting your glasses that if your new glasses sit further or closer the Rx might have to be adjusted a bit. The further a lense sits from your eye, the chances of the Rx being idfferent increases, but I have never really done this until someone reaches about a -8.00 or so and most glasses do not sit that much different on most people. But it is just a little bit of info that they put on there. So, what is affecting your left eye only? I am not sure what you are asking here. Have a happy day!

Answer 3

Your right eye is worse but not by much, only by -0.25. Cyl and Axis basically mean that you have an astigmatism of -0.25 at 50 in that eye. Basically the angle of which the light enters your eye is altered by the shape of your eye. So your right eye is shaped like a football while your left is like a rugby ball. So the light will have to be adjusted by 50 when entering your eye, so the lens on your prescription should alter this at 90+50=140. (Not to be all technical on you)lol. Remember all they are ever doing in optics is playing with light via lenses to make the image fall on the retina. But its absolutely normal. Some people have astigmatisms some dont and some, like you, only in one eye. I do in both eyes. Im sorry im not sure what BVD stands for though! I THINK it may have something to do with prisms in your eye. Sorry i couldnt help with that one.