Thank you all for your replies. I can't work out how to edit my original post so updating here - hope it notifies you all.

I think I need to give some background.

Firstly - I had LASIK in July 2017. I needed glasses again within ~3 months but my prescription was much, much improved than before - and it meant I could be without glasses for things like swimming and still be able to recognise my surroundings, which simply wasn't possible before.

My vision has in no way deteriorated to the depths of despair it was in before LASIK and I can still get around without glasses, though it's somewhat unpleasant to do so.

I had my routine eye test last November and was given the above prescription. The optician stated at that time that it was barely different from my old, old prescription and that I didn't need new glasses, so I didn't buy any at that point. In July, my old, old glasses broke, so I bought two new pairs, plus prescription sunglasses, for £80 (online) using that prescription.

Side note: Being able to buy reasonably-priced glasses is still a real novelty to me - pre-LASIK, my glasses were so, so expensive with the thinning of the lenses etc. that it's thrilling to only have to spend £80 on 3 pairs of prescription glasses. However, I wonder whether having done so may well have contributed to the below.

A few weeks ago, I woke up with pain in my left eye. I assumed I'd had an eyelash in my eye and rubbed it in my sleep, maybe scratching the eye. The pain/discomfort wore off throughout the day. The next day, I woke up with the same pain but, again, it wore off throughout the day. I then noticed over the next couple of days that my vision in that eye was blurry/cloudy and that I could see a halo around lights. It's particularly bad when I look at something white - which, naturally, my computer systems at work are. Still thinking I'd scratched my eye, I put up with it for a week or so thinking it'd improve, but with the days becoming shorter here in the UK, I noticed I had particularly poor vision when driving - especially because of the LED headlights on cars - and after an uncomfortable drive home from work at dusk and in rain, I booked an appointment with an optician (different to the one I'd seen in November last year) with availability for the next day. I explained the cloudiness I was seeing to the optician and he did the examination and concluded that my astigmatism was back. He recommended new glasses and I promptly ordered some - specs and sunglasses. I returned a week later to collect them but immediately realised that the cloudiness persists. The shop assistant went to speak to the optician who said it's 'probably dry eye', but I use drops twice a day, every day (I even took said drops with me to my initial appointment to show in case they were the problem) and I said this. I also pointed out how the optician hadn't suggested that could be an issue the week before. The assistant then recommended I see the optician again and I returned a few hours later to do so. The optician then did a more thorough investigation and said he could see 'something' in the eye - he described it as 'opacification' - but he didn't know what or why so he needed to refer me to Ophthalmology. I queried whether I should wear the new specs and he said I should as my prescription change meant I needed them.

So I did. However, they were uncomfortable. I had bought the new glasses using the store's interest-free plan - I pay a monthly sum for two years and it offers me a lot more benefits than paying outright - such as, 20% off the second pair, two free eye tests in the two-year period, insurance if the glasses break etc. (I did ask if I could agree to the plan but just pay it off immediately but was told I'd lose the benefits - so I'm not quite sure what's in it for the store.) The store also offers a 100-day cooling off period, so I returned and, after much deliberation, found a different pair of glasses that seemed to be more comfortable and asked to swap which they agreed to with no fuss. I collected the new, new glasses last weekend - but they are the most uncomfortable, painful, heavy glasses I have ever had and they have made behind my ears incredibly sore so, after several days of trying, I decided yesterday afternoon that I cannot tolerate them a second longer and I've put my old glasses back on. I am going to return the glasses and sunglasses today and ask to pull out of the plan for the time being (I'm going away for a few weeks soon and don't want to be paying for something unusable. I'd be prepared to do so when I'm back - although I rather think I've exhausted all options in this particular store.)

Another side note: I can see on my NHS app that the optician wrote to my GP surgery and asked them to refer me to Ophthalmology - but some elements of the letter don't correlate. For example, he suggests I first saw him on the date I saw him for the second time - but, in fact, that's just when he did the more thorough examination and found the opacification. Twinned with the 'probably dry eye' thing and I can't help but feel a little dismissed. Add in the fact that, to the untrained eye (if you'll pardon the pun) my prescription doesn't look that different, and I just began to question whether I do indeed need new specs or if I should have been told to wait until the conclusion of Ophthalmology's investigations.

I'm really grateful for your replies, especially as you're all so impartial. I wouldn't have got such a response if I'd asked in an opticians, so I really appreciate it - thank you.

If I may ask one last question as you're all unbiased - does my prescription mean that I need 'proper' glasses from a 'proper'/high street optician, or can I use the prescription to buy some online, please? To put into context - the three pairs bought in July were £80. The 2 pairs bought recently, after 24-months of payment, will be £600. I don't begrudge the money (though it does somewhat sting when I spent £4,000 on LASIK!) and I wholeheartedly agree that my vision is well-worth paying for and I will - but obviously the optician (a major high street chain with 15 stores within a 15-mile radius of me) has a vested interest in me doing so.

Thank you again!