09-07-2020, 06:19 AM
The best practice when focusing the lens is to view the size of the corneal reflection in the camera image. When the lens is properly focused on the surface of the eye, the corneal reflection will appear small and crisp; as the lens moves out of focus, the corneal reflection will begin to blur and appear larger. So when changing the focus of the lens its best to watch for when the corneal reflection is as small as possible, and that is the proper point of focus. Think of it like using a magnifying glass to focus the suns rays - you want the spot to be as small and as bright as possible. Please note that a focused corneal reflection may result in a slight blurring of the actual pupil of the eye.
