20/140?  You might be ok, but what about the person
you run over?

-Quick

If your vision is correctable to 20/40, then you're OK.

<http://www.dmv.ca.gov/dl/dl_info.htm#VISION>

** **

Vision exam requirement

A 20/40 visual acuity with or without glasses is the
department's vision guideline. Customers applying for
a Class A, B, or commercial C license must see 20/40
with both eyes and each eye individually. The departmental
authority for administering the vision exam is
12804.9 (a) (1) (E) of the California Vehicle Code.

Visual acuity measurements are obtained for both eyes
together and for each eye separately while both eyes
remain open, as in normal driving. There are two methods
of testing, a Snellen chart or Optec 1000 Vision Tester.

The Snellen chart contains five lines of letters and
measures the portion of an applicant's general seeing
ability, known as visual acuity or keenness of vision.
The Optec 1000 Vision Tester obtains a more precise
vision score by providing a test situation, which is
equivalent to placing the applicant at one end of a
room 26 feet long to read a test target at the opposite
end of the room.

Applicants who do not pass either exams may, depending
on the circumstances, be referred to a vision specialist.
The vision specialist may prescribe eye glasses or a
stronger prescription for the current eye glasses worn.

Arnold says:

"You need good vision to drive safely."

Also, to obtain a driver's license you:

"Pass an eye exam.  Any person with a best corrected vision of 20/200 or
worse in the better eye cannot be issued a driver license..."

It's very complicated, and changes every week (not really, it just seems
that way).

You have to prove that you can see well enough to drive.  This is a
multi-step process.  If you pass the initial vision screening, then you
are done.  If not, there's the visit to the eye doctor, who has to sign
a DMV form saying that you can see well enough to drive, and then
there's the driving test, where you actually prove that you can drive.

My wife and I have both been through this.

Your minimum driving vision for CA is 20/40 in one eye with your best
corrected vision (i.e. glasses, contacts).  Also, you may have 20/20 but if
your vidsual field is less than 20 degrees (tunnel vision as in from glaucoma)
, that eye is considered leaglly blind.

You can go to DMV's website and pull up the vision form that your eye doctor
needs to fill out.  Generally, they will accept his vision findings, but I
have heard that in certain instances, when there is a change like this, they
may want you to take a road test to see how well handle a car with impairment.

Dr. Tom