I have used S..... S for years, have worn varifocals for over 20 years and never had any problems however could never get a 2nd free pair (always had to pay extra) because of my prescription. Earlier this year I was desperate for new glasses but decided to go to Asda, so pleased that I did, 2 pairs slimline varifocals, 1 pair as sunglasses. Eye test was excellent and optician told me I have macular degeneration, explained about it etc and told me it will be monitored at each test. Merseybelle2 if you can't read, at normal reading distance with your new glasses you definitely need to go back with them. As far as the computer is concerned you will need a different strength at this is an 'intermediate' distance.