Gameplayer has gone hands-on with Sight Training (known as Flash Focus in the USA. They have detailed their experience in this article.
"Self-improvement is all the rage on the DS. Like Dr. Kawashima's Brain Training before it, Sight Training promises to deliver the player a genuine physical improvement just by spending a few minutes a day performing simple puzzle tasks. The difference is that instead of increasing blood-flow to your frontal lobes, the idea is to refine your control over your eye movements."