I've read that blurry vision is linked to migraines, headaches, and other neurological symptoms so check for underlying conditions.

Improving your vision will help your brain, not overstimulate it.

I know you've read about nutrition, but I'll mention this book anyway:
Stop Vision Loss Now! Large Print Edition: Prevent and Heal Cataracts, Glaucoma, Macular Degeneration, and Other Common Eye Disorders
There's more to it than just coconut oil. He says a very Low carb diet that is high in fat will give the brain the conditions it needs to heal and improve eyesight.