Day blindness may causes because of pigmentary chorioretinitis also called as hemeralopia or heliophobia is an insufficient adaptation to bright light inability to see clearly in daylight and is exactly opposite of nyctalopia the word was derived Hemera was the goddess of dat and nyx goddess of night. Causes of day blindness are as follows: Pigmentary chorioretinitis Optic atrophy Iris coloboma Retinal coloboma Unilateral or bilateral post chiasmatic brain injury Share your opinion.