The clip the kept my eye open was very painful...it felt like scooping my eyeball out which was very unusual according to all the painless reports on the web. However, it's worthwhile as I obtained better than 20/20 vision and had no infections so far, the waiting time was 2 hours in Shaftesbury Ave branch which may be a longer wait than any other branch in UK. They also told me after treatment that I was not supposed to take a tube home because of the dust but that was too late.