iPhone 6s/6s Plus features a flashlight function for the front camera. This comes to help when taking a selfie in the low light condition. The biggest problem for taking a selfie in low light is that the flash leaves its reflection on the eyes and the image shows your eyeballs as red.
This is called a red eye image. People try taking a selfie in different angels with different pose, just to avoid this red eye effect. Many users also have different apps installed on their iPhone or iPad to edit this effect. To your surprise, there's a feature in Photos app in iOS 9 to completely remove this red eye effect from any image. Just check the tutorial below for complete details.
How to Remove Red Eye from Photos on iPhone or iPad
Step #1. Open the Photos app from the home screen.
Step #2. Now open the image you wish to edit that has a red eye.
Step #3. Tap on the “Edit” located at the top-right side of the screen.
Step #4. Zoom the image a little to get a proper view of red eye.
Step #5. After you are comfortable with zoom, tap on the “Eye” icon located at the top-left side of the screen.
Step #6. Now tap on the red eye of the image and let iOS do its job.
Step #7. It's time for the other eye to edit. Tap on the second red eye and wait till the iOS removes the red eye effect.
Step #8. After you are done with it, tap on “Done” located at the bottom-right side of the screen.
Voila! Your image is free from red eye. You won't need to capture many different images just to avoid red eye effect in low-light conditions.