After a traumatic half-hour this morning being taught how to put in my trial contact lenses and take them out again, the optician said "I'll just go off for 5 minutes while you try it on your own." Within about 60 seconds I had managed to lose one. Permanently. I wondered if she would think I had lost the lense deliberately, in order to cut short the ordeal. "Don't worry" she said in a resigned voice when she came back, "this happens all the time."