The primary issues will be a sight test, colourblindness test and hearing test. The hearing test usually involves a soundproof booth and a range of varying beeps in one ear at a time through headphones. Eyesight will likely be letters on a board, and colourblindness tends to use the Ishihara test (Google it if unsure what that is!), although I believe other methods are available.
They’ll test your blood pressure, dip for diabetes and drugs, and that’ll probably be about it. I don’t know what the blood pressure limits are, but if there’s an issue they’ll likely discuss how best to go forwards - blood pressure can be managed accordingly, so it isn’t necessarily an instant ‘fail’!