I have started LR and LM with my daughter when she was 8 months old and only becouse I wasn't sure what it will do to her eyes. But I didn't want to miss the opportunity to teach my daugter all these things. I started making flashcards as well but then it was impossible to keep up with her . I decided to try LR and made sure she sits in the right possition, right lighting.....
I think becouse we watched nothing on tv it wasn't that bad to watch quick short LR presentations. We also did and do eye exercises. If you don't want to let your child watch tv until he is 2 years old I don't think you will harm his eyes. But then again I am not a doctor this is just what was on my mind when I started.
You can also print the flashcards directly from LR but that wasn't and isn't an option in our case. But I know she would loved it even more.
I would love to read what others have to say or whether someone has discussed this with a doctor.