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"PERFECT FLUORESCEIN ANGIOGRAPHY"

by Scott "Genghis" Wong

Photo by Genghis

CHICAGO'S STATE STREET:
This street sits near the Chicago Hilton.

Perfection in any photographic discipline is long sought after, yet rarely achieved. It is in the field of fluorescein angiography of the ocular fundus however, that I have developed techniques that will produce perfect imaging results, on a replicable basis. These techniques that I describe in an annual lecture that I present for the Joint Commsion on Allied Health Personnel in Ophthalmology (JCAHPO), revolve around what I recognize to be the primary technical goal in the performance of fluorescein angiographic studies, which is to make sure that every single exposure made during fluorescein angiography, is as perfect as possible as a repeatable technique. Techniques taught by other teachers to this end are general, and not specific enough compared to the techniques I will out line later in this article. I've just given my annual lecture here in Chicago, and here are some thoughts about the techniques I described in my talk, and the state of the teaching or retinal photography in general.

For the non-ophthalmological reader and general photographer, let's first define what fluorescein angiography is. Fluorescein angiography is a revolutionary diagnostic test, that transfomed retinal photography from a novel curiosity before 1961, into an indispensable powerhouse tool in ophthalmology. Before fluorescein angiography came along, fundus or retinal photography, was not considered important, having been disdained merely as a novel way of documenting the appearance of diseases of the back of the eye. On an significance scale, it might not have even rivaled the level of a blood pressure measurement for clinical importance. A visual acuity measurement might've been deemed more valuable. Neither was photography of the retina done as routinely, but performed just occasionally by disparate types of personnel in clinics and offices. These disparate types, who were not tethered by specialty or professional direction, were medical photographers, nurses, and medical assistants. Many of these personnel did not even work in ophthalmology. Retinal photography was thought of as a vestigal digit, superfluous and an afterthought to the main events. In short, photography of the retina was perceived as an academic toy, instead of as a bona fide diagnostic tool.

In 1961, a seismic event took place in ophthalmology. It was then that two American medical students named Harold Novotny and David Alvis successfully performed fluorescein aniography of the human fundus. Many attempts by other investigators for years prior to 1961 to perform retinal angiography on humans utilizing other dyes besides sodium fluorescein, yielded less than satisfactory results. Novotny and Alvis enjoyed stunning success, and in 1961 they introduced fluorescein angiography to the world. Interestingly, their paper was turned down by the major ophthalmology papers of the day. As far as these hallowed journals were concerned, any test involving retinal photography, was too insignificant for their rarefied tastes.

Novotny and Alvis eventually had their paper published in an obscure general medical journal called "Circulation." Once that publication took place, the world of ophthalmology noticed, and retinal photography---and the personnel performing it---began to be seen in an enitrely new and positive light. The disparate professionals doing retinal photography, the medical photographers, nurses and physicians' assistants who previously had no connection to one another, were suddenly given cohesion and a common mission---to provide important diagnostic answers heretofore unavaliable. Fluorescein angiography's ascendancy as a breakthrough diagnostic weapon, drew many of these people into the ophthalmology specialty. Finally, an ancillary ophthalmic workforce was growing in droves, attracted and nurtured by the brave new world of fluorescein studies. Fluorescein angiography was a breakthrough of the highest order in medicine. It also inalterably changed the career trajectory of people who now performed this transformative test.

This led to the creation of organizations that revolved around the fluorescein angiography revolution, which the Ophthalmic Photographers' Society (OPS) totally was, and the Joint Commission on Allied Health Personnel in Ophthalmology (JCAHPO) partially was. The OPS would not have existed, if it was not for fluorescein angiography. Slit-lamp photography and external photography of the eye, could not support a subspecialized group of eye photographers like the OPS. These photographic techniques were too insignificant compared to fluorescein angiography, to have provided a platform for that.

Likewise, visual fields and ultrasound of the eye, could not as diagnostic modalities, support the creation and growth of a certifying body like JCAHPO. I truly believe that fluorescein angiography gave JCAHPO the impetus it needed, to have gained the stature that it has enjoyed. Suddenly, all these disparate personnel became a cohesive and influential segment of the ophthalmology team, held together by the glue of the diagnostic power of fluorescein angiography. This gave them status as a subspecialialty group that they hadn't enjoyed before.

Today, the important role of ancillary personnel in ophthalmology, is taken for granted. Not many of today's certified ancillary professionals give much thought to the role that fluorescein angiography played, that shaped their professions, or the elevated status that ophthalmic photographers and technicians enjoy today, thanks to the influence that fluorescein angiography held in the world of ophthalmology. Today's photogaphers and techs are accustomed to the routine hands-on workshops and lectures that teach them how to perform retinal photography and fluorescein angiography, but it was not always so before 1981. Before 1981, the training in workshops of the dynamic process of fluorescein angiography had not yet been standardized. The standard formula prior to 1981, was to have students view model eyes through retinal cameras. Occasionally, volunteers were dilated and photographed on Polaroid prints. To the extent that these workshops were standardized, they still lacked a method for practicing fluorescein angiography on a dilated volunteer. In 1961, I conceived of the teaching technique that has since been universally adopted: The "simulated angiogram." The simulated, or mock angiogram, is now a default element of retinal photography workshops.

I conceived of the simulated angiogram, and introduced the concept as a teaching device in my JCAHPO hands-on workshops in the early 1980s. The simulation of fluorescein angiography, is just what it sounds like: A performance of an angiogram done with a motorized retinal camera, but without the dye injection. Before mock angiography became the accepted standard method of teaching the practice of fluorescein angiography using motorized serial photography, the teaching of retinal photography centered around the taking of single-frame photographs with Polaroid pictures. This was a static exercise that had little to do with the dynamic process of the fluorescein angiogram. Simulated angiography allowed the student to fully participate in the angiographic environment, training to meet the challenges of a fast-moving process.

Along with simulated angiography in my workshops of the 1980s, I presented lectures regarding the specific techniques that would provide perfect imaging in angiography. These specific techniques are a process that are separate from the practical application of simulating the angiographic procedure. It is a process that focuses in on how one's retinal camera should relate to the anatomy of the eye, in space. If the simulated angiogram is a wide overview of the angiographic environment, then these techniques that will result in perfect images within the angiographic environment, are a microscopic examination of how to maximize the quality of each and every frame in fluorescein studies. It is macro versus micro, but the micro guarantees a superior macro. What I formulated in the early 1970s in my technique, became the basis for this technique for creating perfect images in angiography.

A fluorescein agiogram consists initially, of a series of images taken of the retina for the first minute following the dye injection. This is followed 10 minutes later, by a set of exposures made, for comparison's sake. On the logical face of it, the angiographer's biggest challenge is to make sure that every one of those images in the study are as perfect as possible. I've found that most ophthalmic photographers approach this in a haphazard way. The technique I developed, methodically maintains the ideal positioning of the retinal camera in space, in relationship to the anatomical peculiarities of the eye, as a constant. Chance misalignments are eliminated as a problem, and the perfect positioning of the camera in relation to the eye is replicable, as a constant. This constant maintenance of perfect camera positioning, is the key feature that provides perfect imaging in angiography.

Getting to the crux of it, the achievement of perfect imaging in angiography means maximizing the quality of illumination from the retinal camera, that strikes the ocular fundus (retina). The quality of illumination, differs from "focus" in retinal photography. To achieve optimal "focus" in retinal photography is to make sure that the details of the retina are as sharp as possible. This is dependent on the initial establishment of the correct camera-to-eye distance. Keep in mind that once that correct camera-to-eye distance is established, that it is no longer relevant to image quality. This is a difficult concept for many to grasp, let alone accept. It is counterintuitive for a photographer to believe that focus does not degrade if the camera's distance from the subject changes. It is however, true in fundus photography. In fundus photography, the photographer must forget about focus after achieving it, and concentrate on what's important: From here on in, it is the quality of ullumination that must be managed.

What I call the "quality of illumination" in retinal photography, is an entirely different entity than "focus." Focus in retinal photography is managed differently than in general photography. The focus in general photography is dictated by a given distance between the camera and subject, as is the focus in retinal photography---but with one big difference. If that distance is changed in general photography, then the original focus attained is corrupted, invalidated. As an example, if you attain correct focus of a subject three feet away in gneral photography, and you move the camera an additional four feet away from the subject, then the original focus will no longer be valid. That is because the objective lens in general photography, is the lens of the camera. Maintaining correct focus on a subject in general photography is entirely dependant on keeping the correct distance between the film plane or digital sensor from the subject. The validity of that focus is subject to corruption if that distance varies.

This however, is not true in retinal photography. In retinal photography, once correct focus is established, focus will remain valid even if the distance between camera and eye varies. Let's try to understand this. In retinal photography, the objective lens of the system is the patient's lens which resides inside the eye, and other focusing structures at the front of the eye. That is why when after achieving perfect focus of a retina with the focusing knob of the camera, focus does not change, no matter how far the camera is moved in relation to the eye after that. After attaining perfect focus with the focusing knob, the key concern should be to find and maintain perfect quality of illumination, for that eye. This is done with two controls called the joy stick and vertical control. "Focusing" is overrated in fundus photography. My advice is to acquire focus quickly, and trust your first focus acquisition. Do not rack the focusing knob back and forth in an effort to "improve" focus--your first acquisition, will always be the best. Then, forget about the focusing control and move on to the important techniques.

The joy stick is the control that allows movement of the camera from side to side and back and forward. The vertical control is a round wheel that moves the camera up or down. These are used to position the camera in the two critical alignments, that determine the "quality of illuimination." To know how to achieve these "critical alignments," one must understand the anatomical hindrances that must be navigated, for the camera's light to navigate cleanly to the retina, so that a clean image returns to the film plane or digital sensor. An anatomical hindrance is any physical structure that intercepts and blocks the camera's light as the light makes its way to the retina at the back of the eye.

In order to perform effective retinal photography, the eye's pupil must be dilated with eyedrops. The pupil is the space opened in the center of the eye's iris (the colored part of the eye) during dilation. The larger the opening of the iris, the larger the opening that the camera's light has, to pass through on its way to the retina. Ideally, a pupil should be 7 mm or larger. One must attempt to pass the camera's flash through the pupil by manipulating camera positioning, avoiding any interference from the iris. It is obvious that the cleanest path, with the least physical blocking of the light by the iris, would be through the center of the pupil. Any part of the iris that blocks the camera's light due to misalignment of the camera, is one of the anatomical hindranaces I mentioned. You can appreciate the hard task of shooting through an opening of only 7 millimeters, without the light striking any of the iris as it passes through. This is the first of the two crtitical alignments that we have to be cognizant of, and this is to pass through the center of the pupil, without any light encroaching on the iris. Any stray light caused by misaligning the camera that strikes the iris, will cause misalignment anomalies.

It is not only keeping the camera's flash centered through the pupil we have to be concerned about. We must also maintain the ideal camera-to-eye distance, in order to maintain optimal color saturation and detail visualization. This the second critical distance, which is the distance along the optical axis. I define the optical axis for teaching purposes, as the distance between the photographer's eye and the patient's eye. This eye to eye reference is easily relatable for working retinal photographers.

The technique I developed in the 1970s to maintain these two critical alignments, allows the practiced angiographer to obtain perfect imaging on every frame in angiograms. This is because the technique is repeatable between each frame of an angiogram. I call this the Side-To-Side, Up-And-Down, Backward-And-Forward Technique. The time lapse between the image frames of an angiogram, can be used to guarantee absolutely correct alignments, using this technique. When one becomes adept at this technique, it can be accomplished in less than one second, allowing it to be performed between each and frame of a fluorescein angiogram, ensuring perfect fluorescein angiography where every individual image is optimized.

Speed and fluidity with this side-to-side, up-and-down, backward-and-forward technique, provides the angiographer confidence that the ultimate control over the fluorescein angiographic process, lies in the photographer's hands. When I conceived of , and implemented this technique into my angiographic workflow in the 1970s, it only took me a few months to master the bilateral movements of both camera controls, to the speed I've had with the technique since. For angiographers who adopt this side-to-side, up-and-down, backward-and-forward technique, the muscle memory behind the movements will become the basis for their perfect imaging in fluorescein studies. An experienced practitioner of this technique, will be able to secure perfect individual images during angiography. The adoption of this technqiue, has as much to do with personal confidence as technical efficacy. The confidence this technique imparts to the angiographer cannot be overvalued. Here's how it's done:

First, we must ascertain the first critical alignment that will guarantee correct camera positioning---that of staying centered through the pupil. This is all observed through the eyepiece of the camera. To keep the camera flash constantly through the center of the pupil without interference from the iris. one moves the joy stick from side to side, noting where the light strikes the iris on either side. One simultaneously moves the camera up and down with the vertical control, to note where the light strikes the iris on the top and the bottom With both movements, the side to side and up and down maneuvers, the limits as defined by iris interference are easily identified when light hits the iris. The borders will light up as bright crescents. It is easy to gauge where the center of the pupil is, using these bright crescents as landmarks. That takes care of securing the first critical alignment that ensures proper camera-to-eye positioning--staying through the center of the pupil.

Now we must find the second critical alignment, which is along the optical axis. This is that imaginary line drawn between the photographer's eye and the patient's eye. This is the eye to eye idea I use with students. To maintain the correct distance along the optical axis, one engages in a constant and gentle backward and forward movement with the joy stick, looking for and staying with the deepest color saturation of the retina. Remember, this back and forth movement need only be very small, as the ideal position is small, being comprised of a zone only a few millimeters long. The misalignment areas outside of this zone become perfectly obvious, once we leave this ideal zone, making corrections back to the zone ten millimeters or less. Retinal colors vary from pale orange to brown depending on pigmentation. Straying from that ideal distance from the eye will cause a loss of color, and the introduction of a haze. Staying in that centralized ideal position while gently moving back and forth with the joy stick, will ensure that the deepest color of the fundus is maintained, which means that misalignment anomalies will be eliminated. The prescence of the most profound retinal color guarantees that haze and loss of resolution, will not happen. The ability to establish both critical alignments, does guarantee perfect imaging in fluorescein angiography.

The Side-To-Side, Up-And-Down, Backward-And Forward Technique, is the key to obtaining perfect imaging in fluorescein angiography. I haven't seen from other lecturers, any approaches to camera control as specific or systematic as my Side-To-Side, Up-and-Down, Backward-And-Forward Technique. Others I believe, offer a genral exhortation to students to "avoid artifacts." This approach is not proactive enough. It is like a read-and react defense in football, as opposed to an attacking defense that dictates what the opposing offense will do, and the game goes. The angiographer should always dictate how angiograms go, not circumstance, My very specific systematic approach goes beyond generality, offering a proactive technique in detail. This is the technique I've been teaching since 1981. My latest lecture on this technique took place in Chicago, as I mentioned.

I vividly recall the first time I unveiled this technqiue. It was at the 1981 annual meeting, during the first of my JCAHPO hands-on workshops on retinal photography and fluorescein angiography. This took place at the Hyatt Regency in San Francisco. This was an exciting time to be doing angiographic workshops, as there was so much new ground to cover in terms of innovation in teaching techniques. As a prelude to the workshops, I gave a short twenty minute lecture, describing the Side-To-Side, Up-And-Down, Backward-And Forward Technique. My brother Don Wong was there and he commented after seeing this technique described for the first time, "Why didn't I think of that?"

Don's remark was very telling to me. This revealed to me that many experienced angiographers of many years' experience, who were clearly proficient, instinctively employed at least parts of Side-To-Side, Up-And-Down, Backward-And-Forward Technique in their workflow, without arranging it systematically in their minds, and without articulating it as a systematic approach when teaching fundus photography. My approach to this has been as a system that can be practiced and implemented, to ensure perfect angiographic imaging.

This year was weird for my wife and I, because for the week previous to our depatrure for Chicago, we had no electricity, running water or heat due to Hurricane Sandy's devastation. We live in lower Manhattan, where power was lost for a week. The 14 foot storm surge from Sandy overran the East River's and Hudson River's storm surge walls, and flooded a Con Edison substation that controlled all of lower Manhattan, all the way from 40th Street on down to the tip of Manhattan. The subway tunnels underneath the East River, where trains run to Queens and Brooklyn, as well the Midtown Tunnel to Queens and the Holland Tunnel to New Jersey, were entirely filled with water. It was a trying time, but we have to count our blessings.

The inconvenience we experienced for a week, is nothing compared to the thousands in the New York, New Jersey and Connecticut area who lost everything. Many are homeless as I write this. I would like to wish these people the best of luck for a speedy recovery to normal life. I truly believe from the lingering aftermath of misery on the east coast, that the decimation from Sandy is worse than what Hurricane Katrina left behind. Just as we got ready to leave New York City, our power, heat and hot water returned, just in time for our trip to LaGuardia Airport. LaGuardia Airport iself, was closed for the week because it became a part of Flushing Bay, as the bay's waters rose far above the airport's ground by a couple of feet.

I always enjoy giving my course on achieving perfect fluoresecin angiography, and my lecture this past monday at the Chicago Hilton was no exception. It has become particularly enjoyable since I switched to PowerPoint (from this very laptop, on which your humble reporter writes) from slide lectures. My slide lectures entailed dual projection requiring seven slide trays. Now, the same material is condensed into the hard drive of my laptop, which makes traveling much easier. Digital lecturing is a joy. I could bring my lecture on a CD and leave my laptop home, and use the meeting's laptop, but I just feel more comfortable with my own laptop. I do travel with two CDs of my PowerPoint lecture though, just to be on the safe side. This year was Chicago, next year will in New Orleans, a city used to dealing with its own natural disasters. I get the feeling that the effects of Sandy will prove to be worse than those from Katrina. Later.