AIDS Photography Protocol

Fundus Photograph Reading Center

AIDS Photography Protocol

Nine Standard Field Protocol for Fundus Photography

1.0 Introduction

Confirmation of patient eligibility and ocular status require high quality fundus photographs. Color photographs are necessary to describe the pathology present and to confirm that the eye meets the eligibility criteria. Photographs will also be used to determine treatment efficacy. To insure high photographic quality, standard camera equipment, film, film development and photographic technique have been developed and specified. In addition, in order to be certified to take study photographs, the photographer must satisfy the Fundus Photograph Reading Center (FPRC) that he/she understands the photography protocol and can achieve good quality photographs. Specific certification requirements are described in section 1.8 on page 6 of this protocol.

The fundus photographs comprise nine wide-angle views similar to those used in the Study of the Ocular Complications of AIDS and described in the Silicone Study Manual of Operations. Only Field 1-2 is taken as a stereo pair; the remaining eight fields are single photographs. A fundus reflex photograph showing the anterior segment is included to document pupil size and any lens or vitreous opacities that might compromise photo quality.

1.1 Camera Equipment, Film and Processing

Specifications for camera and film are as follows:

Aids patients with CMVR are often quite ill, and sometimes have difficulty cooperating for this extensive photographic procedure. Some patients are able to cooperate better during prolonged sessions if armrests are attached to the camera. A variety of commercial armrests are available. If you need help locating armrests, please call Michael Neider at the Reading Center at (608)263-9858.

1.2 Pupillary Dilation

Because photography includes areas of retina as peripheral as the equator, and because the optical pathway required by the camera itself is relatively large, optimal pupillary dilation is essential for obtaining proper field definition and satisfactory image quality. In some patients with AIDS, compromise of the efferent nerves may make it more difficult to get good dilation. Satisfactory results can usually be obtained by using a double set of drops (e.g., 2.5% Neosynephrine and 1% Mydriacyl), given five minutes apart. Instructing the patient to keep his/her eyes closed for three minutes after the drops are instilled maximizes their effect.

1.3 Photographic Field Definition

The nine standard photographic fields are defined below for both right and left eyes. Stereoscopic photography is required for Field 1-2 only (using the non-simultaneous technique of Allen¹). These fields are illustrated in Figures 1.1 and 1.2.

Field 1-2 (F1-2) - Disc/Macula

Field 8 (F8) - Nasal to Optic Disc

Field 3 (F3) - Temporal to macula

Field 9 (F9) - Superior

Field 6 (F6) - Superior nasal

Field 4 (F4) - Superior temporal

Field 10 (F10) - Inferior

Field 7 (F7) - Inferior nasal

Field 5 (F5) - Inferior temporal

1.4 Obtaining the specified fundus photographs

All of the peripheral fields specified above are obtained through a combination of shifting the camera and directing the gaze of the subject in the appropriate direction. For example, the following sequence of actions works well to locate Field 9 (superior). Starting from Field 1-2 (centered midway between the temporal margin of the disc and the center of the macula), first tilt the back of the camera down to the limit of its travel (this maneuver achieves about half of the vertical elevation required for Field 9). Then move the fixation target up carefully, being sure not to drift nasally or temporally, until the location described in the protocol is reached.

Some of the peripheral field definitions specify offsets of one disc diameter (DD). In most Canon cameras, the cross-hairs in the ocular are spaced 1 DD from the center of the frame, and thus can be used to gauge this offset.

The typical locations of the four ampullae of the vortex veins provide an approximate means for checking the proper placement of some of the peripheral fields. The usual relationship is illustrated in Figure 1.1. Note that at its proper elevation Field 9 (the superior field) tends to be centered between the two superior ampullae, so that they appear at the middle of both horizontal ends of the frame. When the camera is shifted nasally to obtain Field 6, the superonasal ampulla tends to be centered in the middle of the frame. When the camera is shifted temporally, the superotemporal ampulla tends to be centered in the middle of the frame. Similar relationships exist between the inferior photographic fields (Fields 10 and 7) and the inferior ampullae. It is expected that if at all possible photographers will use retinal landmarks rather than the ampullae to determine proper locations of the peripheral fields. However, in a patient with typical placement of the ampullae they can be used as an approximate check on the definition of these fields, particularly when difficulties with patient cooperation interferes with the use of retinal landmarks.

Because of the extent of the periphery photographed, it is not always possible to move the fixation target to the ideal location. It may collide with the nose in some instances, or with the camera lens barrel in others. It may be necessary to instruct the patient to look further to the side than the fixation target for proper alignment of the field. In the case of F4 (superior temporal), the lens barrel may contact the subject's nose, which may restrict the temporal placement of that field.

It will likely be necessary to refocus the camera from field to field, concentrating upon the sharpness of retinal landmarks near the center of each field. Given the curvature of the retina encountered in the peripheral fields, it is not always possible to get all of the retinal features in crisp focus across the entire field. Only if the sole pathology observed in the field is located near the edge should the picture be focused there rather than upon retinal detail near the center.

Since changing the focus has an appreciable effect on the area of retina included in the photographic field (changing the boundary by as much as one disc diameter), it is advisable to focus the camera at least approximately after moving to the desired position of each field and before finalizing its location.

Sometimes it is not possible to obtain even illumination across the entire photographic field, especially in the periphery. This problem is more likely to occur in patients who do not dilate well. If it is not possible to equalize the illumination across the field, it is preferable to restrict the darker area to the more anterior portion of the field.

1.5 Minimum protocol when patients cannot adequately cooperate

Although photographers are strongly encouraged to obtain all of the photographs specified by the protocol at each visit, there may be instances during follow-up in which patients are not able to tolerate the complete procedure. (The full photographic protocol must be carried out at baseline.) In such cases, the following abbreviated procedure (which allows omission of up to four fields if CMV lesions are not present in them) should be substituted:

If the patient is unable to cooperate sufficiently even to carry out the truncated procedure described above, the photographer should make every effort to obtain the stereoscopic photograph of Field 1-2.

1.6 Labeling of photographs and preparation for mailing

The transparencies returned from the processing laboratory are mounted in standard cardboard or plastic 2 X 2 mounts. Each mount is identified on the bottom of the cardboard frame with a label (Figure 1.5a) on which is written or printed the number signifying the clinical center, the patient identification number and initials, the eye (right or left), the field, and the visit code. AVERY laser labels #5267 (1/2" x 1-3/4", 80 labels per sheet/25 sheets per package) fit perfectly on the slide mounts. These labels are produced for each patient visit by the central coordinating center. A convenient format, mirroring the slide mounting diagram, for the label printing for the right and left eyes is shown in Figure 1.6.

The mounted and labeled transparencies are placed in 9 X 11 inch transparent plastic sheets containing 20 pockets per 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. There is less chance of loss when the transparencies are mounted in this manner because they tend to press against each other and thus are held in place. Please do not use frosted plastic pages. Thin archival plastics are discouraged since they collapse on the inclined light tables used for grading. The Reading Center recommends Bardes 20 pocket pages, product number 62022C. They are available through Bardes Products, Inc., 5245 West Clinton Avenue, Milwaukee, WI 53223-9839 (1-800-223-1357).

One plastic sheet should be used for each eye. The transparencies should be mounted so that the pocket openings face to the front, that is, face the person mounting the slides, and the edge with the three holes for a ring binder should be to the left of the mounter. The transparencies should be oriented for viewing in an arrangement approximating the anatomic position (see Figures 1.3 and 1.4).

Each page is labeled with a slide page identification label (Figure 1.5b) approximately 2"x4" (Avery laser label #A5-5163B works well) containing the clinic name, patient identification number and initials, visit code, date of photography and photographer name or certification number.

1.7 Shipment

After photographs are clearly labeled and placed in plastic sheets as described above, they are mailed to the Fundus Photograph Reading Center, Room 450, 610 N. Walnut Street, Madison, Wisconsin 53705. A copy of the second page of the case report form or a shipping manifest accompanies all photographs sent to the Reading Center.

1.8 Photographer Certification

All photographers taking photographs for this study will need to be certified by the FPRC for the nine standard field protocol, before submitting actual patient photographs. Previous certification for the nine standard field protocol by the Reading Center may allow some photographers to be automatically certified for this study. This would be the case when we know the quality of a particular photographer's work because we are already working with the photographer in another study using the same nine standard field protocol.

Each clinical center should provide the Reading Center with a list of photographer names, phone numbers and addresses before the study begins. This can by done via fax: (608)263-0525. Please indicate the name of the trial that you are responding for. If a photographer believes he/she is eligible for automatic certification, a note to that effect should be included and we will confirm the photographer's certification status before study photography is performed.

Photographers not certified, must submit to the Reading Center, photographs of two sample eyes (9 standard fields with field 1-2 in stereo and fundus reflex) from non-study participants to work out any problems prior to the actual start of the study. Pleases send these photographs along with a cover letter requesting certification for to the Fundus Photograph Reading Center, Room 450, 610 N. Walnut Street, Madison, Wisconsin 53705. If you have any questions about the photography protocol, please contact Michael Neider, photographic consultant to the Reading Center at (608) 263-9858.

References

 1. Allen, L: Ocular fundus photography. Am J Ophthalmol 1964; 57:13-28.

Figure 1.6

*Use Avery Laser Labels #5267

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18Dec2000