Three internal images are collected from each eye. This is to create a panoramic view of the retina so the consultant reading the images can view as much of the retina as possible. To achieve the panoramic view, the patient is instructed to look at a series of images. (See picture below.) This directs their optic disc and macula to various positions. I found it helpful to familiarize myself with what patients are seeing from their end of the camera. This makes it easier to tell them in which direction to look if I notice their optic disc is in the wrong position.
We provide a “cheat sheet” that will instruct the photographer which image to direct the patient to look at. The other helpful use of this cheat sheet is that is shows the photographer where the macula and optic nerve should be if the patient is looking in the correct direction. From behind the camera, the photographer can see the placement of the patient’s optic disc very easily. If I notice that the optic disc is not reflecting the placement that the cheat sheet shows, I remind the patient to look at the correct image, and I might have to clarify my instructions. For example, for right field one, the patient should look at the triangle. If I notice the optic disc is in the incorrect position, I will clarify by saying, “Please look at the triangle. You will find the triangle within the large circle in the center, just to the side of the bars in the center.”
If a patient is blind in one eye or is having a hard time focusing on the images, the external fixation light can guide their gaze to the correct position. The eyes work in tandem so, if a patient cannot see out of one eye, you can direct their working eye to look in the correct direction and the non working eye will follow. It is important to get retinal images of both eyes, even if the patient is already blind in one of them.
If you have any questions or would like us to resend you a cheat sheet of the images guide, please contact us at firstname.lastname@example.org.