Poor vision is certainly a contributing factor to reading difficulties. A child who only sees words on a page as fuzzy blobs, or worse still overlapping fuzzy blobs is never going to understand how reading can be enjoyed. Even a child with reasonably clear vision will still struggle to read fluently if their eyes have to strain to keep letters clear, focused and single. Often glasses and/or simple eye exercises maybe all that is needed to make reading easier.
The first step to helping your child to read has to be a Sight Test.This is free to you (the NHS pays optometrists from your taxes), and children get a voucher which effectively means that you should not need to pay for a basic pair of children's glasses (today's specs are so much nicer than the old NHS 524 frame with glass lenses).
If you want a spare pair of glasses, a stronger frame, a designer name, or protective lenses (to protect from UV, reflections, scratches or just more physical protection), then your DO can quote you a reasonable charge for these options. However it is important to remember that children's eyes change faster than adults, so their lenses may need upgrading every 6 months – about as often as they need new shoes.
If exercises are suggested they need to be done regularly, every day. Not all Community Optometrist offer this additional service, though most should be able to suggest simple eye exercises or recommend a colleague who specialises in orthoptics. The NHS does not fund community optometrists to provide this service so unfortunately we need to charge you for our time and any additional equipment needed.
Simple traditional paper based activities can help children acquire basic skills which will help their reading skills. Commercial puzzle books or try http://www.allkidsnetwork.com/activities for some downloadable dot-to-dot, mazes and colouring by number puzzles. These are fun activities which will help tracking and hand-eye-brain coordination.