Eyecare practitioners have been able to capture widefield retinal images using standard imaging techniques with fundus cameras since the 1970s -- albeit with some limitations.
For example, our view with a fundus camera was limited to between 30° and 60° of the retina. To view the periphery, we had to ask our patients to move their eyes into the direction of the fundus area in question. Tilting the camera along the horizontal plane could increase the peripheral field of view in the 3 o'clock and 9 o'clock positions. And some fundus cameras could be tilted along the vertical plane to capture the 12 o'clock to 6 o'clock positions.
Even with these tilting techniques, however, our imaging capabilities were limited because of the camera's optics and some patients' inability to sustain far gaze long enough for us to obtain a good view.
What's more, when the eye is in a far gaze position, the entrance pupil changes from round to oval, which decreases its effective pupillary diameter, making it more difficult to obtain a good image. Obviously, it took a concerted effort to obtain more peripheral images.
William L. Jones, OD
Company: Optometric Management
CE Credits: 1
CE Format: Online text/photos
COPE ID: 11534-GO