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Modified 7-Standard Field Color Fundus Photography Procedure

• Certification 
• Camera & Film 
• Good Image Quality
• Modified 7 Standard Fields
• Transmission, Retakes and Evaluation
• References 

Attachment A: Pointers on Photographic Technique

6.0 Modified 7-standard Fields and Fundus Reflex Photographs [Figure 1]

The modified 7-standard fields for color photography specified by this procedure differs from the ETDRS 7-standard field protocol in the position of two fields: Field 1M and Field 3M are both modified to include the center of the macula, in Field 1M near the edge of the field and in Field 3M midway between the edge and center of the field.

Figure 1

The following descriptions of the standard fields assume that there are two cross hairs in the camera ocular, one vertical and the other horizontal intersecting in the center of the ocular.

Field 1M - Disc (example Left Eye   Right Eye): Center the temporal edge of the optic disc at the intersection of the cross hairs in the ocular.

Field 2 - Macula (example Left Eye   Right Eye): Center the macula near the intersection of the cross hairs in the ocular. To keep the central gray artifact created by some cameras from obscuring the center of the macula, the intersection of the cross hairs should be placed about 1/8 - 1/4 DD above the center of the macula. A suitable position can often be obtained by rotating the camera temporally from the Field 1M position, without vertical adjustment.

Field 3M - Temporal to Macula (example Left Eye   Right Eye): Position the intersection of the cross hairs in the ocular 1.0-1.5DD temporal to the center of the macula. If Field 2 was centered above the center of the macula, as suggested above, Field 3M may be centered 1.0-1.5 DD temporal to Field 2, a position easily achieved by rotating the camera without making any vertical adjustment or movement of the fixation device.

Field 4 - Superior Temporal (example Left Eye   Right Eye): The lower edge of the field is tangent to a horizontal line passing through the upper edge of the optic disc and the nasal edge of the field is tangent to a vertical line passing through the center of the disc.

It is convenient to take Field 6 immediately after Field 4 by rotating the camera nasally.

Field 6 - Superior Nasal (example Left Eye   Right Eye): The lower edge of the field is tangent to a horizontal line passing through the upper edge of optic disc and the temporal edge of the field is tangent to a vertical line passing through the center of the disc. 

Field 5 - Inferior Temporal (example Left Eye   Right Eye): The upper edge of the field is tangent to a horizontal line passing through the lower edge of the optic disc and the nasal edge of the field is tangent to a vertical line passing through the center of the disc. 

Field 7 - Inferior Nasal (example Left Eye   Right Eye): The upper edge of the field is tangent to a horizontal line passing through the lower edge of the optic disc and the temporal edge of the field is tangent to a vertical line passing through the center of the disc. 

Field 8 - An optional field outside the modified 7-standard fields should be taken to document new vessels and/or pre-retinal or vitreous hemorrhage when these features are not well documented in the standard fields. The label should reflect the area photographed.

If two or more photographs outside the modified 7-standard fields are needed to document new vessels, they should be labeled "Field 8a," "Field 8b," and so on sequentially. If one or more Field 8's are taken at screening, their location should be noted and these fields should be taken at each follow-up visit.

At all visits, a stereoscopic fundus reflex photograph should be taken to document media opacities. The photographer is asked to use his/her discretion to achieve a limbal diameter of approximately 13mm on the finished slide. The best stereo effect is obtained by moving the camera laterally about 3mm between exposures. The lateral shift can be obtained by moving the joystick, sliding the camera, or using the Allen stereo separator. A fixation target should be positioned to direct the subject's gaze in the primary (straight ahead) position, so that the optic nerve does not appear directly behind the lens.

7.0 Mounting and Labeling Photographs [Figure 2]

The transparencies returned from the processing lab are mounted in standard 2X2 inch mounts. The mounted transparencies are labeled with individual labels (see Attachment B (Study Specific)). 

Photographs of each eye should be mounted in an individual plastic sheet.+ The plastic sheets should be constructed so that the pockets open at the side rather than at the top; that is, the open side of the left pocket should face the open side of the right pocket. A sheet identification label is completed and attached to the front of each plastic sheet (see Attachment B (Study Specific)).

Figure 2

Photographs submitted in frosted plastic pages or thin "archival" plastics may be returned to the site for remounting.

It is suggested, but not required, that duplicates of the photographs be retained at the clinical center for patient management.

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