we stay in a cold place where temperatures is aroud 10_12 degrees through the day and 4_5 degrees at night. off latey child is blinking his eyea way too much. when i ask his why he says that his eyes are very mildly aching. what could be the issue that he blinks so much. i tried to make him read numbers from a distance and he reads fine. could his eyes be dry. why is he blinking so much?