Steroids. All steroids can wreck havoc on your body. The most common one for PMR is Prednisone and it's risky. Some people coast through it with barely a problem. I got brittle bones. Three broken ribs on both sides and both of my feet broke. That's was because of falls. The falls were because of rapid and profound weight gain, it put my center of gravity off. I got glaucoma and now have an extra blind spot in my left eye, chronic dry eye, and must have my eye pressures checked 2-4 times a year. To keep my eyes from becoming more damaged, even though I quit the Prednisone back in 2015, I've had 3 laser eye surgeries to reopen the drain in my eyes, so the pressure can naturally reduce. It's nothing to fool around with. I've had surgeries on both feet. One would not heal by itself. Both of them now have metal in them as reinforcement. It's not just the Prednisone for PMR. I also have had steroid injections into various joints. Most of all, into my spine. Sometimes, just so I could walk upright again. All of those steroids pretty much run the same risks. Get your eye pressure checked often and always ask them afterwards what the numbers are. Educate yourself on those numbers. However, there's also something called thick corneas. I have them. So, high numbers need to be evaluated, thicker corneas can withstand a bit higher pressures but it's gotta be determined by an Opthamologist. Good luck.

Cobweb floaters are usually age related. If they are something new for you, I would suggest a comprehensive eye exam.
https://www.mayoclinic.org/diseases-conditions/eye-floaters/symptoms-causes/syc-20372346
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I can't say PMR or prednisone ever caused me to have floaters or blurred vision but uveitis sure did. I think I have seen every type of floater, light flashes and visual disturbance there is . My blurred vision was like a dense fog that would set in so I couldn't see anything. The dense fog was a late stage of uveitis after all the floaters. I had an autoimmune type of uveitis which was treated with high doses of Prednisone.
https://www.mayoclinic.org/diseases-conditions/uveitis/symptoms-causes/syc-20378734
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My main side effect from Prednisone that caused an eye problem was early onset cataracts at the age of 40. I have had the same lens implants for 30 years

Ocular hypertension was a problem but I also have thick corneas so I can relate to what @thenazareneshul writes about. My eye pressures were treated when they would get in the 30's and 40's when I was on higher doses of Prednisone. When I was on lower doses of Prednisone my eye pressures stayed in the 20's and were usually not treated. Now that I'm off Prednisone, my eye pressures are normal so less than 20. I had Prednisone induced glaucoma which is improving.
https://www.aao.org/eyenet/article/management-of-steroid-induced-glaucoma

I can’t prove anything but was diagnosed 5 months ago and been on prednisone for 4 months now, I had a vitreous detachment a week ago. I now have floated in my vision and foggy vision. There’s no doubt in my mind it’s related.