A US doctor is trying to pioneer a laser treatment that changes patients eye colour. Dr Gregg Homer claims 20 seconds of laser light can remove pigment in brown eyes so they gradually turn blue. He is now seeking up to $750,000 (468,000) of investment to continue clinical trials. However, other eye experts urge caution because destroying eye pigment can cause sight problems if too much light is allowed to enter the pupil. Stroma Medical, the company set up to commercialise the process, estimates it will take at least 18 months to finish the safety tests. The process involves a computerised scanning system that takes a picture of the iris and works out which areas to treat. The laser is then fired, using a proprietary pattern, hitting one spot of the iris at a time. When it has hit every spot it then starts again, repeating the process several times. The laser agitates the pigment on the surface of the iris, Dr Homer - the firms chairman and chief scientific officer - told the BBC. BBC