3)  Check to see that the camera is "on" and that the 35 mm camera back has been selected with the upper/lower switch (24).

4)  Set the eyepiece (8)

	reticule in-focus	reticule out-of-focus

5)  Record patient information on the film. 

This can be accomplished by using the data plate and the data switch (23).  Another common way to record the information on a frame on the film is to take a picture of the information written on a piece of paper (this is called a name tag).  To photograph a name tag:

Set the flash intensity on the lowest setting, set the angle lever (6) to 50 degrees, and set the diopter compensation knob (5) for anterior photography (+ or A).  Hold the name tag a few inches in front of the objective lens (4), frame and focus on the writing, and trigger the flash.

Steps 3, 4, and 5 can be combined into one procedure.  While taking a name tag photo, you are simultaneously testing the system to be sure that everything is operational.  You can adjust the eyepiece while you are holding the name tag paper in place.

1. Set the diopter compensation knob (5) to "normal".  If the patient is aphakic, you may need to use the plus setting.  If the patient is a high myope, you may need to use the minus setting.

2. Set the angle lever (6) to 50 degrees. This is the easiest angle from which to align the eye and to focus on the retina.  If the ophthalmologist has ordered a magnified view, such as a 20 degree view of the optic nerve, switch to the more magnified view after you have initially aligned and focused using the 50 degree setting.

3. Make sure the filter knob (15) is set on the "no filter" setting.

4. Set the illumination diaphragm lever (16) to "N".  This assumes that the patient is sufficiently dilated. Use the "S" setting if the patient does not dilate well (less than 5 mm).

5. Set the upper/lower switch (24) to upper if you are using a digital or a Polaroid system.  Set it to lower if you are using a 35 mm camera back.

6. Set the flash intensity panel (21,22) to a low flash setting depending upon the speed of the film being used (consult the camera instruction manual or test results).

7. Set the "Normal" illumination adjustment (28) to a mid-range position to start with.  This controls the brightness of your viewing light.  For the patient’s comfort, use the lowest setting that allows you to adequately view the retina.

You are now ready to bring your patient into the room and begin the photographic procedure.

7)  Patient instruction 

An informed patient is generally a more cooperative patient.  Explain that a photograph is being taking to document the appearance of the eye for future reference, primarily to be able to detect any changes in the future.  Explain that the flash will be bright and that an after-image, or spot, is normal, and that it will go away in a few minutes.

8) Patient positioning 

This is critical to an efficient (less stressful) photo session.  You must position the patient in such a way that he can comfortably maintain forehead and chin contact with the headrest at all times.

For good photos, the camera-to-retina distance is critical, with little latitude for patient movement.  You will need a patient chair that rolls and has a vertical adjustment.  A chair with a back and arms is preferable to a stool.  Roll the patient close to the camera but leave enough room so that she can lean slightly forward into the headrest.

Positioning is accomplished by manipulating the chinrest adjusting knob (2), the up-down switch on the camera table, and the elevation control on the patient’s chair.  In most situations all three will need to be adjusted.  The last adjustment should be to your stool, so that you can comfortably sight into the eyepiece without straining your back.

9)  Eye alignment

Position the lens barrel (4) in front of the eye to be photographed by grasping the control lever (12) while holding the lever in a straight up position.  Slide the base of the camera so that the lens barrel is directly in front of the eye, about 3 inches away from the cornea.

If the fellow eye has good vision, position the external fixation target (3) directly in front of the fellow eye and instruct the patient to look at it.

Manipulate the control lever (12) so that the "donut" image of the illumination light focuses on the patient’s cornea and projects through the pupil.

At this point you are not looking through the eyepiece (8). You are observing the patient’s eye and the lens barrel from a position off to the side of the camera. This technique is similar to lining up the tonometer head on the patient’s cornea when performing applanation tonometry.

10)  Image alignment

At this point you should be "in the ballpark", meaning you should be able to see an image of the retina when you look through the eyepiece.  If you do not, make sure the camera has been set up properly (step 6) and realign the donut on the cornea.  It is not unusual to totally lose the retinal image when the patient makes gross head movements.

It is generally easier to align and focus the image using the wide angle (50 degrees) setting (6). Once you are aligned and in focus, you can switch to a more magnified view if desired.

When you see an image of the retina, use the following steps to maximize the image quality prior to capturing an image:

• Using the control lever (joystick), make fine adjustments forward and backward to arrive at an image that has deep color saturation and even illumination.  Being too far forward or backward will tend to wash out the image.

• Some cameras use alignment illumination points to aid in alignment.  Position the points equally in the field by lateral adjustment.

 Then move forward or backward to make the points as small as possible.

• Use crescent images (half-moon reflexes created by the illumination light striking the iris) to guide you to good horizontal and vertical alignment.  If you are too far to the left, to the right, up, or down, you may see a crescent image and/or the image will wash out.  If you see a crescent image on the left, it means you need to move slightly to the right until the image disappears and you again have an evenly illuminated retina with good color saturation.

	A crescent reflex to the left of the image tells you that you need to move the joystick to the right to re-align the image.

• Use the focusing knob (9,18) to focus on small blood vessels on the retina.  While focusing, remember that the reticule must be in focus at the same time that the retina is in focus. Otherwise, your captured image will be out of focus.  If the retina looks in focus, but the reticule looks out of focus, then you need to re-adjust your eyepiece (step 4).

	The reticule should be in-focus at the same time that the retina is in-focus.

• Manipulate the external fixation target (3) and the fellow eye so that the area of interest in the eye being photographed comes into view.  Make fine adjustments of the fixation light and the camera angle to "frame" the area of interest (optic nerve, posterior-pole, etc.).

• Recheck the focus and the alignment.

11)  Image capture 

Even small head movements by the patient can throw off your alignment and adversely affect the quality of your photo.  Proper alignment is a continuous process of small adjustments.  If necessary, instruct the patient to maintain contact with the headrest, to stay still, and to keep her eyes wide open.

Press the shutter release button or foot-pedal to capture an image.  If you are using a digital system, you can check the resultant image and make exposure adjustments if necessary.  If the image seems washed out, you will want to decrease the flash intensity (21,22).  If the image is too dark, you will want to increase the flash intensity.

If using an 35 mm camera back, you will want to listen for the sound of the flash going off and the sound of the motor drive winding.  If you are unsure about the proper flash intensity to use, you can bracket your exposures.  This means you would take a frame or two at a particular exposure level, and then take a few more frames at the next higher and/or lower exposure levels.

Handling the difficult patient

The patient who can follow directions the first time, remain perfectly still, and keep his eyes wide open is the exception rather than the rule. The exceptional photographer is the one who knows his camera backwards and forwards and is a good patient coach.

It is never acceptable to verbally belittle or abuse a patient.  Sometime it takes a running commentary of positive statements from the photographer to encourage the patient to hold still in the head rest and to hold her eyes wide open.

Encourage the photophobic patient to keep both eyes open.  Many of them tend to want to close the fellow eye.  If the patient cannot keep the fellow eye open, you can use the internal fixation pointer (17) for fixation instead of the external fixation target (3).  Sometimes a topical anesthetic in both eyes helps the patient keep them open.  Keep the illumination light source (28) as low as possible.

You may need to hold the patient’s eye open with your own fingers or reach behind the patient’s head and gently nudge him toward the forehead rest.  These situations tax your skills (and character) as a photographer, but the patient will be grateful that you accomplished the task in a kind and respectful manner.

Sometimes, no matter what you try, you cannot get the job done by yourself.  Call in an assistant to hold the patient’s head or to help hold the eyelids open (cotton tipped applicators work well for this).

It is sometimes necessary to photograph a lesion, such as a choroidal nevus, that is in the far periphery.  In this situation the internal and external fixation devices may not have enough range to help in aligning the image.

You will need to have the patient look in the direction of the location of the lesion on the retina.  In other words, if the lesion is nasal to the optic nerve in the left eye, then the patient will need to look to his right (your left).  You may find it necessary to give the patient instructions on making small eye movements in one direction or another.  It is sometimes helpful to instruct the patient to look at clock hours.  For instance,  "12 o'clock" means the patient looks straight up.  It may be necessary to swing the camera left or right or tilt it up or down (19) in order to bring the lesion into view.

Since the camera light will be projected through the pupil at an angle, it will take careful alignment and focus in order to optimize the image.  The resultant image may be less than prize winning, but something is better than nothing.  If you encounter difficulty, don’t give up too soon.  If the ophthalmologist can view the lesion with a direct ophthalmoscope, you should be able to get a picture of it.

Top of page        Go to Section 3