Eye tests..?

Question

What part (s) of an eye test decides whether or not you need glasses??

Answer 1

Mostly the refractive part of the exam-(Eye Charts) which means if you didnt need glasses, you would end up with no Rx in the machine (Phoropter)- However there are several tests the Doctor will do to determine exactly what you need.

Answer 2

Essentially, the discussion with the examiner at the end!

By that stage they should be able to show you how much better (sharper, or more comfortable) your vision could be with a correction.

Apart from with young children, where there are development issues, and the question of legal limits, especially for driving, whether the improvement is worth having is down to you, not some arbitrary limit, a number obtained from a chart or instrument.

"need" is almost always the wrong word.
The question is rather whether they'd be sufficiently "useful".

I had one person who wore his glasses half-a-dozen times a year. But, competing in the world model power boat championships, on a few occasions that tiny Rx was of critical benefit. Just that fraction of extra performance that competition is often about.

Acuity, refraction and binocular stability are all useful pointers, in an eye test. But the decision is almost totally yours...
Provided you're not driving, there no rule that says walking around half-blind is wrong. And some people hate glasses sufficently that that's what they'd rather do. Good for them: it's their call.

Answer 3

All parts of an eye test help in determining if you need glasses.