Here is a simple app for those who do not have light perception. Recently recommended by Larry Skutchan, a friend of CBT.
Since I don’t have light perception myself, sometimes I have difficulty recognizing the difference between day and night. The DayNight app has become quite useful and I have added it to my toolbox of assistive apps.
From the Developer:
DayNight is designed to help the blind and visually impaired with day and night awareness by scheduling notifications at sunrise and sunset.
Simply navigate through the setup steps so DayNight knows your location and has access to send you notifications. Once complete 1 month of notifications will be scheduled and can be disabled anytime within the app.
DayNight will now use monitor for significant location changes in order to update sunrise and sunset notification schedules.
Requires iOS 10.0 or later. Compatible with iPhone, iPad and iPod touch.