Most people I have spoken to have NOT been required to have an eyesight test as a part of there medical.
should one be carried out, this is the guidance from DVLA on the eyesight requirement for driving:
If you think there may be a problem with your eyesight, You would be best to do what is said at the end - see your optician and..... Show him this requirement, because it means nothing to me, except for the first bit about reading a number plate!
Standards of vision for driving
You must be able to read (with glasses or contact lenses, if necessary) a car number plate made after 1 September 2001 from 20 metres.
You must also meet the minimum eyesight standard for driving by having a visual acuity of at least decimal 0.5 (6/12) measured on the Snellen scale(with glasses or contact lenses, if necessary) using both eyes together or, if you have sight in one eye only, in that eye.
You must also have an adequate field of vision - your optician can tell you about this and do a test.