The photo eye of an automatic opening garage door is a safety feature.
Garage door photo eye beam width.
They shoot an invisible beam between them which will sense if something is between them as it breaks the beam.
Lower is easy to stand above with a foot on either side.
Higher than that can miss many low lying objects including pets.
If something breaks the beam while the door is closing the opener motor automatically reverses direction and opens the door.
The second is photoelectric.
Liftmaster 41a5034 replacement safety sensor beam photo eye repair kit 041a5034 5 0 out of 5 stars 2 41a5034 liftmaster sears craftsman sensor cells photo eyes garage door opener.
One unit emits an infrared beam invisible to the naked eye.
If the photo eye senses an obstruction it stops the door from closing and potentially prevents damage or injury to a vehicle.
It consists of two units installed about 4 inches from the floor on each side of the door.
The other unit is a reflector.
If your garage door sensors are outside of this range remove them entirely from the garage door frame and install leveled inside the safe zone.