Member Question: Prism, Optics, and Middle-Age

This series of comments and questions came in and I felt it was worth sharing as many people will relate to at least part of the discussion.
“Hello. I am an OT. I recently completed the Functional Rehabilitation Specialist Certification Course through PESI. It was over 37 hours of material and fascinating! I am still trying to wrap my head around all of the information. “
– This is great. The first of my courses are in depth, and foundational. What comes next is a lot closer to clinical practice. Watch for the new courses. Also, we’re doing a live cast even June 11, 2024 at 6PM Central. Here’s the link if you care to ask questions/join in:
“ I was interested in ordering a pair of prism glassess from Bernell. Either you or Robert suggested that 7 diopters should be enough. I have found them on the Bernell website but they require a choice between FLAT prisms or Corrected Curve. I would be ordering them primarily right now for myself to explore but then to use eventually with my clientele (I am a school based OT but looking to start treating privately very soon). Can you recommend one or the other?”
– By prism glasses, I will assume you mean goggles, where you can rotate the bases of the prisms to make ‘yoked’ pairs for intermittent / periodic and brief use. I would never have you or anyone wear prism indiscriminately. Re: Flat vs Corrected, better optics on corrected but whether this matters is up for discussion and is context sensitive. For your purposes, to play/investigate, go w/flat as they’re likely to be cheaper. Best advise re: powers is to have a range in 4 diopter increments, so 4, 8, 12, 16. If you want to try one, 6  or 8 is fine, the higher numbers giving you the greatest effect.
“Also, I am highly motivated to improve my own eyesight before reverting to the use of bifocals. I realize that this is a flexibility issue in my lens (and not a refractive error). I recently requested a copy of my refractive slip from my eye doctor so I could try to analyze it (following your class). As I already know, my left eye is very near-sighted, with a significant astigmatism (values -5.50 and -1.75 and 145). When I need to see up close (without my glasses on, I just close that eye). But even with glasses on, I am struggling but very much denying/delaying bifocals. I am wondering if there are specific exercises for the astigmatism. Would either accommodation exercises or convergence exercises help at all? I think if my left eye was stronger, I could delay the use of bifocals. I am 46… age is not on my side. Or is the aged lens issue going to overpower any sort of remedial exercises I attempt at this point? Thank you for any clarification.”
– I’m going to’ big brother’ you on this. There is NO reason to avoid proper accommodation for a physical disability. YOU KNOW THIS. Now, stop making excuses. Your eyes will continue to change in time, ‘worsen’ in the sense that we all lose accommodative range, so we lose the ability to pull focus to near targets. Astigmatism will shift on its own as your natural lenses mature, change – sometimes this means more astigmatism, sometimes less in time. No exercises will help. I just now had a similar case (I’ll assume both of your eyes are similar in refractive state) – nearsighted, mid-late 40’s, loads of near work/computer time. VERY resistant to multifocals, worn contacts all her life. You can use bifocals, but these are extremely limited given only two focal points to work with: near/far. You need a good progressive lens; nay, you need two sets: One for when you’re on your bum, working with your hands/computers, using more your mind (i.e. central vision); one for when you’re on your feet and are primarily interested in peripheral vision at distance (obstacle avoidance, seeking behaviour). Near progressives are ‘all purpose’ but mostly for distance; computer or ‘near’ progressives give you a greater clarity, bigger field for up close. As I’m writing to you (nearing my 57th birthday), I am wearing my near progressive – it’s my clinical lens, you’d love one of these. When I leave, I’ll switch this out for my general, or distance bias progressive, more suited to driving/hiking.
– I’ll add one more observation – You close one eye to see up close. This generally points to diplopia (double vision) and/or blur. It would seem to me that your eyes have very different refractive states; this condition is called ‘anisometropia’ and can and does lead to eye strain and blur. Contact lenses can help to reduce the strain of anisometropia, but in my experience they’re not great for extended desktop computer work. Eisekonic lenses are available through – Shaw provides lens designs specifically to account for anisometropia.
Don’t fight it, adapt. Find someone who offers options on lenses (i.e. Lenscrafters typically only has one ‘near’ progressive option, Costco likewise; most private providers will have more options. I am now wearing what Hoya calls their ‘Zoom’ lens, and I’ll replace it with my distance-bias progressive for driving.) As I’m fond of saying, ‘If you were my sister/brother, I’d get you a pair for your birthday.’
Hope that helps.

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