Vision Therapy is controversial, but my take on it is that the controversy arrises from situations where some optometrists sell it as a cure-all for everything under the sun from dyslexia to adhd etc. - which it really isn't. It is, however, incredibly amazing and successful when it's done under the guidance of a qualified and responsible Developmental Optometrist for specific types of diagnoses. I've seen it work amazingly well for one of my children, so I have personal experience both with seeing it succeed and with being exposed to the two flip sides of the controversy surrounding it.
My first thought for you, LAF, is - have you had any kind of professional suggest to you that a D.O. eval might be worth looking into? If not, what are you specifically seeing in your child's academics or other functioning that would make you suspect there is either an issue or suspect a vision issue specifically?
In my dd's case, we had lots of signs of a vision issue but didn't recognize them until she was in 2nd grade and came home telling us she couldn't read what the teacher wrote on the board. We took her for an exam with our regular eye dr and she didn't find any issues - instead she found 20/20 eyesight - so we then assumed nothing was an issue with dd's eyes… and later that year landed in a neuropsych eval when school became insanely difficult for dd. The neuropsych recommended a D.O. eval based on dd's testing results and her observations of dd while testing. I was sooooo so danged skeptical - but I also had an acquaintance who's slightly older dd had been through vision therapy with the same dr we were referred to, so I asked her opinion and found out that her dd went from a struggling reader to loving reading within just a few months of focused therapy and daily exercises. That *still* wasn't enough to convince me to give it a try, so I went back to our regular eye dr to ask her if it was hocus-pocus or worth pursuing, and she told us that YES, it really was worth pursuing, if it was an issue related to muscle weakness in the eye. She also told us that nothing she did as a regular part of her eye exams would pick up an issue with muscle weakness, tracking, or anything related to the eyes working *together* - her exams were all about eyesight acuity in each individual eye. So, we went for the eval and found out (I saw this with my own eyes at the eval) that my dd had severe double vision (among other issues). Never in a million years would I have guessed my dd had double vision, but when we asked her, she said "Well yeah,I always see two of everything. I thought you knew!". Anyway, I'm rambling. DD went through over a year of vision therapy, and it worked. The first three months, in particular, were simply amazing - like our friends' dd, she went from a struggling reader to a girl who loves loves LOVES to read and is always walking around hiding her face behind a book

I realize "anecdotes" don't count for much, but fwiw, I also ran into an adult acquaintance when dd was in VT who told me she, too, had been in VT for awhile because when she hit that 40-something age point where she her eyes started bugging her and she thought she needed reading glasses, her *regular* eye dr did some type of screen and found the issue wasn't her eyesight, it was convergence/tracking issues related to muscles weakening. She too had very successful results with VT.
And - again, anecdotal, but fwiw - it's been several years now since my dd was diagnosed and treated. We still see the same "regular" eye dr - and that eye dr now includes screening in her regular exams for things like double vision and tracking, and regularly refers patients to our local DO when there is a concern from the screening.
So maybe it's anecdotal, but yes, I've seen it be very successful for a child with a legitimate *need* and diagnosis, and I also feel like I've had very reliable referrals for it from a neuropsych and a "regular" eye dr.
Also anecdotal, but I have an acquaintance who's dd had VT that was paid for as part of her IEP services through the local school district. That in and of itself must say *something* about the credibility of it - it's danged tough to get *anything* in the way of services here

Best wishes,
polarbear