I would reccomend finding a mentor in this field. Up until a few weeks ago I was working at the Jewish Guild for the Blind in NYC. You can get on the firstname.lastname@example.org or American Academy of Optometry list-serv. The Jewish Guild, Lighthouse, and AOTA offer distance learning and onsite- continuing ed classes, in addition to a great selection at the national conference.
Another thought is the type of vision therapy you are most interested in. I worked with adults with a variety of visual impairments (Macular Degeneration, Cataracts, Glaucoma, Diabetic Retinopathy, and Retinitis Pigmentosa). Focus was on training with low vision devices, techniques, and ADL's. I found this field to be rewarding because of the quick progess the patients made and the creativity of the treatments.
Neuro-visual rehab is another field focusing on CVA and TBI, using prism glasses and different types of equipment. Rusk and SUNY Optometry specialize in this type of rehab.
Vision therapy with peds is another field. Common conditions are strabismus, visual attention, learning disabilities. Barbara Bassin and Dr Stan Applebaum work together in a pediatric practice in MD.
Hope this helps! If you have any more questions please email Jessirg@aol.com