Unfortunately, it does seem something of a postcode lottery.
About 2-3 years ago (certainly prepandemic) my optician told me I had the start of cataracts, but not to worry, it would be 10 years before they became a problem. I took his advice not to worry, in fact I completely forgot about it!
Just over a year ago, my eyesight started deteriorating rapidly. As I'd forgotten this diagnosis, I went back to the optician expecting just to have my prescription changed. They examined me and said the cataracts were worsening quicker than normal, and I needed a opthalmology appointment as soon as. My GP made the referral, but in the meantime my eyesight deteriorated to the point I had to go off work sick. I couldn't see the computer properly and was making mistakes left, right and centre and was getting pain in my neck, shoulders and back from trying to view the computer properly. I'm mid 50s and it's not unheard of to get cataracts at my age, but obviously it's more common in older people.
I'm not sure if going off sick made my GP put pressure on the hospital to see me quicker (I'm an NHS nurse myself) but I got my first eye done within about 3 months of the GP making the referral. While my sight wasn't perfect after, it had improved enough to get back to work.
Unfortunately I then had a number of delays in getting my 2nd eye done. Last summer I had to postpone it because I was having gallbladder surgery, then a month after that I fell off my bike and badly broke my shoulder needing further surgery.
Fortunately I have now had the 2nd done I had the appointment in Feb and the surgery in March. So both eyes done within a year of referral, and all that with the shadow of covid, and my own health issues.
I do appear to have been lucky, but am eternally grateful to the NHS. The cataract surgery was definitely one of those 'life changing but not life saving ' treatments and I'm delighted with the results.