AMERICAN JOURNAL OF OPHTHALMOLOGY VOLUME 57 APRIL, 1964 NUMBER 4

STEREOSCOPIC FUNDUS PHOTOGRAPHY WITH THE NEW INSTANT POSITIVE PRINT FILMS*

L E E ALLEN Iowa City, Iowa

The value of stereoscopic f undus pictures in diagnosis of ocular lesions and systemic diseases was mentioned in a previous paper, "Ocular fundus photography"1 and demonstrated in a scientific exhibit.2 Their value is now increased in two major re­spects by taking the pictures on the 20 sec. (development) black and white* and the new 50 sec. color* print films.

First, the exposures can be made, the prints (figs. 1 and 2) developed im-

* From the Department of Ophthalmology, College of Medicine, State University of Iowa.

t Polaroid Land, Type 55, P-N film; Polaroid Corporation.

t Polaroid Land, Type 58, color film; Polaroid Corporation.

mediately, trimmed to fit one of the Wheatstone type stereoscopes (fig. 3) and studied during the course of examination of the patient.

Second, the prints can be filed when dry in envelopes attached to the patient's record. Thus, they are again immediately available with the record during sub­sequent examinations—a marked con­trast to the common system of filing of color transparencies as lantern slides in a separate place.

The qualities of the print materials are quite adequate for this purpose. The in­stant black and white prints have been for some time as permanent as those of any other black and white process. The sharp-

Fig. 1 (Allen). First "instant" stereoscopic fundus photograph attempted. Reproduced same size from original print made with type 55 P-N film. X2 accessory lens on camera gives X5 magnification. Illumination intensity setting, IV. Subject: giant drusen bodies on optic disc, Angioid streaks, O.D., in man, aged 22 years. May be viewed with a 25-mm. diameter, plano-convex (convex side toward print) +10D. lens before each eye, at distance of 10 cm. from prints. A trial frame makes a convenient lens holder. The old-fashioned wooden (Keystone "School") stereoscope can be made to work but it gives less magnification.

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ness of detail and the value range in both the original black and white and contact prints are excellent. Representatives of the manufacturer have stated that the dyes in the color prints are as stable as those in any other purely photographic color processes. The sharpness of detail and the value and color contrasts are some­what limited but, together with stereop-sis, these are adequate for identification and differentiation of all but the most subtle features.

A special adapter must be made to fit whatever fundus camera is being used. If others wish, as we do, to record all of the available X5 magnification area of the image, the adapter should be made to fit the 4.0 by 5.0-inch packet (single sheets) film holder. Film costs less in the 3.0 by 4.0-inch film packs, but an adapter for these would require sacrifice of some of the available image.

The adapter shown in Figures 4 and 5 was designed by me for the camera* used in this clinic. Since this model of camera is in rather common use elsewhere, a brief description of the adapter's features and use may be of help to those who would like to do this type of photography. This de­partment will also be willing to furnish a more detailed mechanical drawing upon request. I t is hoped that either the manu­facturer of the film or the camera may choose to produce similar adapters in the future.

To achieve the highest magnification of the image, the adapterais designed to be used only with the X2 accessory magnify­ing lens in place on the camera (this gives X5 magnification on the print). There is a bayonette base on the camera side of the adapter and the 4.0 by 5.0-inch single

Modern Zeiss fundus camera.

Fig. 3 (Allen). Trimmed stereoscopic print in an old stereoscopic viewer* which contains +10D. lenses without need of prism or divider for viewing prints at 100 mm. Similar viewers can be quickly improvised with -HOD. lenses, preferably 25-mm. diameter, plano-convex with the convex side toward the print.

Twenty-five year-old viewer, Keystone View Co., Meadville, Pennsylvania,

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Fig. 4 (Allen). (A) Close-up view of camera side of adapter: (a) bayonette base for support on camera; (b) old Packard type shutter enclosed; (c) micro-switch for relay circuit to flash tube; (d) plunger for opening shutter and tripping microswitch; (e) re­ceptacles for connection of relay circuit cord. (B) Back of adapter: (a) Packard type shutter seen from back; (b) carriage slides; (c) special light baffles; (d) frame divider; (e) film holder retainer strip; (f) film holder retainer clips.

sheet packet film holder locks into the other side.

A sliding carriage is incorporated so that the two pictures of the stereo pairs may be made on the same print, one on each half.

An old Packard type shutter with two-inch aperture is enclosed in the adapter where it is opened by the same lever which normally trips the focal plane shutter of the camera's own film holder.

A built-in microswitch for the relay cir­cuit to the electronic flash tube is syn­chronized with the shutter. A cord connec­tion receptacle for the relay circuit is made from a two way adapter purchased at a camera store.

Most of the parts of the adapter were

milled from aluminum, although brass and bronze were used where strength or spring tension was needed. The device is large and somewhat heavy. Therefore, care must be taken in attaching it to the fundus camera.

Fig. 5 (Allen). (A) Adapter with film holder and film in place on fundus camera with carriage in position for taking left eye view, exposure being made: (a) X2 accessory lens unit between camera and adapter. (B) Device in place on camera, photographer's left hand releasing carriage into left side position for taking right eye view.

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Once it is in place, it is well supported by the steel of the camera's bayonette re­ceptacle.

Before attempting photography with this or any similar device and the instant films, the preceding paper1 should be read. In addition, the following steps should be made:

1. Install the X2 accessory lens on the camera.

2. Turn the focusing eyepiece all the way down against the camera housing, otherwise it is in the way and prevents engagement of the bayonette base.

3. Engage the adapter in the same man­ner as that for the camera's own film holder—using care as already mentioned.

4. Return the focusing eyepiece to the proper, predetermined setting.

5. For stereophotography, slide the carriage to the right for making the pic­ture to be viewed with the left eye. (If un­related pictures are to be taken, the choice of position is naturally of no importance.)

6. Insert the film holder and lock it in place, then insert the 4.0 by 5.0-inch film packet and pull the paper envelope into position for exposure according to the manufacturer's instructions. f 7. Set the aperture and electronic flash intensity for the fundus camera as follows:

FLASH INTENSITY TYPE OF FILM APERTURE SETTING

58; Color 7* III or IV 55; P-N 7* IV

8. Set the focusing light intensity at "2 . "

9. Align and focus the camera and make the exposure according to the system out­lined in the preceding paper.1 Do not hold the shutter open since the focussing light becomes a factor in the exposure with ex­tremely fast films.

10. Slide the carriage of the adapter to the left and take the picture for the right-eye view.

* Aperture must contain the 6.0-mm. central mask detailed in the preceding paper.

11. Develop the film according to the manufacturer's instructions at very high room temperatures for 50 seconds only; then, 60 seconds development makes the color prints too blue for fundus color rendition.

12. Before disengaging the adapter from the camera, be sure again to turn the eye­piece down out of the way.

Instant stereoscopic fundus pictures, especially in color should be of value in other fields of medicine, such as internal medicine and neurology, besides opthal-mology. With the proper equipment in the hands of a capable fundus photographer, they are no harder to make than conven­tional photographs.

ADDENDUM

Since this manuscript was submitted, I have found that the color and value con­trasts in the Type 58 color film can be noticeably increased and, therefore, the recording of subtle features improved by proper control of the film temperature and time in development. A continuous gain is seen as the temperature is lowered toward 60°F. and development time is increased up to a total of two minutes. Our film, film holder and the adapter are now kept in a refrigerator at 60°F. The photographic exposures are made as soon as possible after installing those items on the fundus camera. After the exposures and spreading of the developer, the film is placed back in the refrigerator during the period of de­velopment—except for the few seconds required at the end for handling.

The temperature of the refrigerator is checked with an accurate thermometer. When the temperature is 60°F., and when the photography has required only three or four minutes, the film is allowed to de­velop for about one minute and 55 seconds. For each 1°F. rise of the refrigerator tem­perature, the development time is reduced by five seconds.

The cyan (blue) dye is the last to appear

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in the prints and overdevelopment at any temperature will reduce the richness of the general fundus image by an "overlay" of gray-blue color. This is particularly ob­jectionable in films developed at the higher temperatures. On the other hand, under­developed prints lack definition and color differentiation. In such prints, the unex-posed area around the photographic image is brown instead of the correct jet-black color.

I t is conceivable that cooling of the film and accessories before the photography may create problems of moisture conden­sation on the film in very humid at­mospheres. However, so little air is en­closed in the assembled apparatus that a short delay in pulling the film envelope may be all that will be required to allow

Significant rises in intraocular pressure (Po) and decreases in outflow facility (C) have been noted after the topical adminis­tration of potent glucocorticoids.1-6 The changes were noted in all patients with proved primary open-angle glaucoma, in glaucoma suspects with no other evidence of glaucoma except for positive water pro­vocative tonograms, and in "normal" volunteers. The pressure and facility re-

* From the Department of Ophthalmology and the Oscar Johnson Institute, Washington University School of Medicine. This study was supported in part by a research grant, B-621, from the National Institute of Neurological Diseases and Blindness, National Institutes of Health, Bethesda, Maryland. Presented in part at the Glaucoma Research Con­ference, Hot Springs, Virginia, May 29-June 1, 1963.

what moisture is present to condense on remote metal surfaces of the adapter. If humidity proves to be such a problem, then the exposure can be made on warm film and its development delayed until it has been cooled to the desired tempera­ture. The film and film holder are made to be handled in such a manner according to instructions furnished by the manufac­turer.

Use of the "instant" stereoscopic color prints for aid in diagnosis and visual rec­ords has become part of the routine in this department. The cost of the equipment, as well as the time and materials, is being covered by charges assessed in the same manner as those for laboratory tests.

University Hospitals.

sponses to topical steroids in patients with proved glaucoma and in glaucoma suspects were distributed as single bell-shaped curves. However, the pressure and facility changes induced in volunteers suggested a bimodal distribution or two populations: one which resembled the response to top­ical steroids of glaucomatous patients and glaucoma suspects, and another which was affected to a much lesser degree by the medication. Emphasis was placed on the important clinical implications of this side effect of topical steroids. In addition, the question was raised of the use of topical betamethasone as a diagnostic test for primary open-angle glaucoma. It should be emphasized that Becker and Mills4 and

REFERENCES

1. Allen, L.: Ocular fundus photography. Am. J. Ophth., 57: 13-28 (Jan.) 1964. 2. Biodi, F. C. Braley, A. E., and Allen, L.: Fundus pathology in stereoscopic photography. Scientific

Exhibits, A.M.A. Ann. Meeting, June, 1963.

T O P I C A L C O R T I C O S T E R O I D S A N D H E R E D I T Y I N P R I M A R Y O P E N - A N G L E G L A U C O M A *

B E R N A R D B E C K E R , M . D . , AND K U R T A. H A H N , M . D . Saint Louis, Missouri