Complex sentence: Pollock was born to Barbara and Johnny in Holywood, County Down.When Mark was five, he lost the sight of his right eye and was forced during the remainder of his childhood to avoid contact team sports to preserve the vision in his left eye.
Split into simpler sentences: Pollock was born to Barbara and Johnny in Holywood, County Down. When he was five, he lost all sight with his right eye during the remainder of his childhood, he avoided the rough team sports, to preserve the vision in his left eye.