my degree is in optics, and my final year dissertation was on vision and driving, although it was all a long time ago!!
The evidence I'm afraid is mixed! research has been done to see if a prescription specifically for night driving is beneficial or not. Some respondents found it helped, some found it made it worse and some found it made no difference!
basically, if you have to wear glasses, enhance what you have. make sure the lenses are clean and not scratched to improve light transmission and reduce scatter. Have good quality lenses with a good anti reflection coating. Don't use a tint. while a tint reduces glare, it also substantially reduces contrast sensitivity and it is way more detrimental than beneficial. Also get your eyes tested regularly to ensure you give yourself a decent head start by having the correct prescription.We are incredibly fortunate in the UK. Our standards of eyecare and accessibility to it are pretty much unknown anywhere else in the world. In most countries, an optician just tests your vision ( a refraction) to see what spectacles you require. In the UK the eyetest includes a whole range of other tests and examinations to look at the health of the eye, and also the rest of the body as many conditions such as diabetes, high blood pressure, some cancers and many others are first picked up during a routine eye test.
My advice on finding an optician would generally be, avoid the multiples. you might get a good one, but you have no way of knowing. Instead, find a good independant who has been around a few years. there's a reason they are still there! If the test takes 10 minutes, it's not a proper test!! It should take 20-30 minutes depending on your particular needs, age etc.
Clive, with regards to your reading, just old age I'm afraid!! A lens is designed to work at just one focal length. The way the eye gets around that, to allow you to see at different distances is the lens is soft and squidgy. It is suspended on structures rather wonderfully called, the Zonules of Zin. These hold the lens under slight tension. When you go to look close up, these relax their hold on the lens the exactly correct amount, which is rather clever, and the lens slumps down, making it fatter and more curved, therefore stronger (in optical terms) allowing you to read. This is called accommodation. From the age of about 19 the lens starts to harden and become less flexible. This doesn't generally become a problem until you get into your 40s as you start running out of arm length, as you have noticed! This is when those of us that are short sighted get our own back because we can just take our glasses off to read
I sometimes hear people say 'These glasses have made my eyes worse, I used to only need them occasionally, now I need them all the time' or 'these glasses have made my eyes lazy'. All nonsense, I'm afraid it's just the inevitability of age!
with regards to what you are noticing at night time there are a couple of possibilities. One is you are discovering a phenomena they teach soldiers. If you want to look at an object in the dark look slightly to the side of it. this means you are then looking at it with the photoreceptors more sensitive to low light levels, called rods, rather than the cones of your central vision which are less sensitive to low light levels and used principally in the daytime. Incidentally, in low light levels where only the Rods are used of which there is just one type, we see only in black and white. there are 3 different types of cones which are receptive to different wavelengths of light, which is why we see in colour in the daytime.
The other possibility is you have discovered your anatomical blind spot. this is an area of vision that matches up with an area of the retina which has no receptors. This is where all the nerves blood vessels etc exit the eye. You can find your blind spot by closing one eye, then moving a small object until it disappears. This is up and out, in about the 2:00 o'clock position..
The final thing is to get your visual fields checked just to make sure you haven't developed a visual field defect which you are now picking up.
There are some tricks that can help. one is to avoid looking at the headlights of approaching cars, difficult because your eye is naturally drawn to them, but try and look at the nearside kerb a few meters in front of you. Notwithstanding some peoples irritation (and possibly the law!) using front fogs (or driving lamps as mine are called officer!!) helps illuminate the nearside a lot better, especially in the wet. Correctly fitted and adjusted they aren't dazzling to other motorists because they shine down, especially on wet roads they can be very helpful. Similarly, fitting a pair of low powered lights pointing down and used with dipped headlights can massively improve things. these used to be very popular, supplemented by spots on main beam, but seem to have fallen out of favour now. Just don't make them too powerful or you'll dazzle other road users. maybe there is a legal reason you don't see them anymore, dunno!!
Hope that helps!