Why does Andrea bocelli keep his eyes closed?

Andrea Bocelli was born with glaucoma. at the age of 12 during a soccer game he hit his head. a few days later in the hospital he had bleeding on the brain. he has been totally blind ever since.. one of the reasons hekeepshis eyesclosedmay be due tothefact that some blind peoplehave a sensitivity to light. the big stage lights may hurt his eyes