For an infrared sauna type use, I made my own 4 bulb Rubylux infrared sauna but opted after a year to go with a Relax Sauna. With my homemade sauna I had a hard time getting the temps up without a burning smell of material or burning sensation on my skin. I don’t have these issues with the Relax Sauna - it produces a reliable high heat sauna experience and my head is outside the sauna which I wanted.
For non sauna applications, using red/near infrared light, I like these https://www.amazon.com/ABI-Light-Therapy-850nm-Infrared/dp/B07SH39YT4
I also use a 660/830nm red light panel for near whole body (one side) use.
Regarding improving vision, check this out:
I started this on our 13 year old dog and his vision definitely has improved and he is much more active now! I had seen Dr. Hamblin’s papers on using red light therapy / photobiomodulation for eye conditions, but I hadn’t see until that article that it should be done in the morning. Per my other post, 660/830-850nm light stopped a floater I had as a kid when my eye was scratched by a thrown acorn.