Ask the person you are taking the photo of to look straight into the lens of your camera.
Ask them to open their eyes very wide so that you can see the entire iris. Take your time to get the right distance from the person for best clarity of your photo.
Adjust head to be able to see the whole iris. Tap the screen where the eyeball is to pinpoint the focus of the camera in the area of their eye, and ask the person to keep their eye open really big when you take the shot.
Take multiple photos, some with flash and some without and use the best one. Make sure you have the entire iris in the photo. Make sure you have at least one good photo of the iris of each eye.
Repeat this same process for photos of the sclera (the whites of the eyes). Have the person look all the way to the left. Make sure it is straight left, not left and up or left and down. Make sure you can see as much of the whites of the eyes as possible by having them open their eyes big.
Again, take multiple photos at different distances and some with and without flash so that you can find what gives you the best clarity.
Repeat this process by having them look directly to the right.
Continue by having them pull down their eyelid with their index finger and look straight up. Again, make sure it is directly up and not up to the right or up to the left. Take multiple photos of the whites of the eyes and use the clearest ones.
Repeat this exact process on the opposite eye. Sometimes you may require a little bit more lighting and the use of a flash from the side can be appropriate. It will depend on the room setup, the light, the persons eyes and requires a little trial and error to get it right. If you use the flash, try and make sure you don’t wash out the area with too much light.
If your photos come out blurry just re-take them and make sure you get the distance and the focus right.
Make sure you get 4 photos of each eye. 1 photo of the iris, 1 photo of the sclera looking to the left, 1 photo of the sclera looking to the right and 1 photo of the sclera looking up.
Use the front facing camera of your phone and make sure you have a good light source and then follow the instructions as above.
Make sure you capture 4 photos of each eye.
Alternatively you can make a video looking straight at the camera, then looking left, looking right and then pulling your eye lid down and looking up and move the camera in and out a little bit. The video needs to be clear so that you can identify your eyes and the markings inside your eyes clearly.
Then watch your video and if you have captured some areas that are really clear you can make a photo / screenshot of that.