Fundus Photography

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- Medical questions directed to the physician; speak in a calm/reassuring tone as the voice of competence inspires confidence

- What the patient needs to know: 1) You are not being x-rayed; 2) Your pictures are being taken with ordinary color (or B&W) film; 3) The flash is bright, but lasts only a fraction of a second; 4) Please follow the fixation light (or stick) with your eyes only; 5) Keep your head in the face rest so that you stay in the camera’s focus range; 6) You may blink unless told so

- Wash hands in front of patient after explaining the instructions

- The order in which the eyes are imaged matters little in fundus photography

- For most table-mounted fundus cameras, camera-to-patient distance will be around 45 mm

- When the patient’s eye is opened, it is confirmed that you are at the correct working distance by looking into the eyepiece

- When in proper range, the retina will be evenly illuminated

- If too far from or too close to the eye, unwanted light reflections will appear in the picture

- If off-centered, a crescent-shaped light reflection is seen; to get rid of this, move the camera’s joystick in the direction opposite the unwanted reflection.

- It may be impossible to eliminate this artifact completely if the patient is not completely dilated

- Make sure the retina is sharp and in focus. If the grid (cross hairs, reticule, reticle) is blurry, an out-of-focus photograph will result

- Focusing the grid compensates for refractive error

Stereoscopic Fundus Photography

- 1850s: stereo photography was introduced in the U.S. (after great success in Europe)

- Ubiquitous fly test- evaluates a patient’s stereoscopic depth perception

- Those with stereoscopic vision perceive depth because our brains are capable of combining the two slightly different views provided by each eye into one picture

- During stereo fundus photography, we use a single fundus camera to take two pictures of the same object, also from a slightly different position, mimicking the view seen with each eye

- Most stereo photographs are taken in sequence using an ordinary fundus camera, and the resultant slides are viewed with magnification from a pair of plus lenses with illumination from a light box

- Patients will small pupils and moving eyes will make stereo fundus photography more difficult

- A good 3-D representation of the subject will result if the eye remains stationary

Problems and Solutions

- First step in obtaining pictures of the inner eye: establishing appropriate working distance and aligning fundus camera

- Standard lens used if patient is emmetropic or has a small refractive error

- Patients with refractive errors greater than the range covered by the camera’s standard lens need to be optically corrected in order to get sharp fundus photographs

- If patient wears contact lenses, necessary correction is made by photographing the eye with the contact in place using standard camera lens.

- Spectacles are not to be worn during fundus photography since there will be unwanted reflections by the glasses

- Patient’s optical correction provided by fundus camera

- Prior to patient removing his/her glasses, decide whether the lenses have plus or minus power

- Plus lenses: magnifies the wearer’s eyes

- Minus lenses makes the eyes look smaller

- Dialing in the plus lens on the diopter compensation device enables to take external eye photographs with fundus camera; provides satisfactory results when used on the convex surface of the outer eye

- Droopy eyelid needs to be lifted or the retina won’t be evenly illuminated. It will be seen in the bottom of the photograph rather than on top. This is because the lid is outside the working distance of the fundus camera

- Media opacity (e.g. cataract) will make it difficult to get a good luck at the ocular fundus

- Careful manipulation of the joystick is the easiest way to dodge such media opacities while searching for a better view