Red eye

What is Red Eye?

Red eye is a medical condition induced by digital cameras when taking pictures in low light conditions or in the dark. The flash from the camera illuminates the retina of the eyes of the subject, creating the appearance of “red eye”. Taking a picture in dark or dimly lit surroundings can cause “red eyes” to appear on the photograph or image due to the bright light of the flash bulb reflecting off the eyes of the subject and causing a red reflection.

What Causes Red Eye?

Red eye occurs when a digital camera’s flash is so strong that it naturally reflects off the subject’s retina and appears as a bright red light. The effect is caused by the light from the flash reflecting off the small retinal blood vessels located at the back of the eyeball. The reflection is much stronger in people with lighter colored eyes.

How to Prevent Red Eye

  • Use a diffuser: Use a simple material like a stiff paper, handkerchief, or plastic diffuser over the flash to spread the light in the environment more evenly.
  • Use off-camera flash: Using a separate flash, take the picture away from the camera and thus away from the subject’s line of sight.
  • Decrease distance between subject and flash: Moving the flash away from the lens fixes it from reflecting off the subject’s retinas.
  • Reduce the intensity of the flash: Dim the flash to lessen the reflection.

Red Eye Correction

If you have already taken pictures with red eye, there are several easy ways to edit and reduce the red eye in photographs or images. There are a few software programs that are designed to fix red eye, many of which come included with a digital camera. The most common way to reduce red eye is to use an image editing program to reduce the red color levels in the eye and replace them with the correct color.