Visual Communications: The Eye as a Window

This piece is intended as a handout to biology and photography students, high school seniors and beginning undergrads especially, who are trying to decide on a career path. It is one of many to choose from, but it is important for seniors to be exposed to every possibility. It includes not only a career description of ophthalmic photography, but also some intriguing facts about the eye, and the practice in general, to spur interest and exploration. Even if not a single student who reads it chooses this rout, I will consider it a success should they at least become curious about the field and want to learn more. As a high school student I know I would love to have been exposed to this sooner. For this reason, I seek to reach out to students like myself.

Communications is a field that is often overlooked, but is a fundamental part of every single workplace. Communications professionals are everywhere, be it visually based or language based. Behind every scientist and doctor there’s a technician; behind every journalist there’s a photographer; behind every celebrity there’s a PR specialist. As communicators, it is our job to not just bridge the gap between audiences, but do so in a way that upholds integrity and understanding.

Ophthalmic photography is a particularly interesting and useful skill set. It falls under the category of visual communication. There are many subcategories of this, but among the most important is diagnostic communication—and that’s where we come in. The doctor performs the diagnosis, and prescribes the treatment—but under the radar, we provide the necessary information for him or her to make a sound decision.

It is important to preface the discussion with a look at what’s called descriptive interpretation. This is a fundamental principle that ophthalmic photographers live by. The doctor may be administering the diagnosis, but it’s our job to provide initial observations and interpretation. It is important to view every retinal photograph as a scientist observes an experiment. Do not draw conclusions right away; take time to make important observations about what may (or may not!) be important for the diagnosis, as compared to what’s considered normal. What color is the retina? How dark or light is it? Do you notice any artifacts? Is there anything unusual about the image? As a communicator, supplying only the image is doing half the job—we must make these key observations. Some of them may even lead to more photographs—images that explore in greater detail what we suspect to be important indicators within the retina.

In this way, the eye can act as a window into the human body—both figuratively and literally. Many people don’t realize, but when you look into someone’s eyes, you’re literally looking into them! The pupil is a hole, around which the iris contracts or relaxes to allow in more or less light, much like the aperture of a camera. If you were to shine a light into the pupil as you peer in, you would see the back of their eyeball—the retina. This is exactly what ophthalmic photography does. Using a special light that shines directly through the lens of a camera system and into the pupil, we get a glimpse of what’s inside the human eye. The image of the retina is reflected back through the lens and onto a film plane or sensor, and thus, a fundus (retinal) photograph is born (right). It’s important to note just what makes the retina so incredible and useful: it is literally the only way to observe blood vessels and nerves without surgery. Not only that, but no incisions whatsoever, no x-rays, no ultrasound, no CAT scans; just a light and a camera. This makes the retina an invaluable diagnostic tool.

Observations of someone’s retina can tell a lot about an individual. Did you know that you could tell someone’s ethnicity by the pigmentation of his or her retina? African-Americans and Asians both tend to have darker retinas, as they have a greater amount of pigment. Europeans, especially blond-haired, have very little pigment and so the retina will be very light.

But more importantly, the retina can be used to identify potential diseases. Take glaucoma, for example. It’s the second most common cause of blindness in the Unites States. The front of the eye is filled with a clear fluid called the aqueous humor; glaucoma occurs when something slows or blocks the flow of this liquid out of the eye, causing an increase in pressure. Excessive eye pressure can eventually cause damage to the optic nerve, which transmits signals from the eye to the brain for sight. Eyesight loss is irreversible, unfortunately; the goal of every ophthalmologist is to slow or stop the loss in its tracks, as that is currently the most anyone can do. There is no cure for glaucoma, but catching it early enough and administering medication can slow the loss of vision enough for someone to live the rest of their life without ever going completely blind.

Eye diseases aren’t the only types that can be diagnosed this way, though; since the retina provides a sampling of blood vessels, observing their behavior can indicate other diseases. Diabetes is a disease in which there are excess levels of glucose in the blood, and it affects 8.3 percent of the United States. 80 percent of patients who have diabetes for ten years or more experience retinopothy—or damage to the retina. It is common for some to see signs of this even earlier, and it often occurs with little or no warning signs. The patient may not be able to tell light from dark in one or both eyes.

Some common observations to search for as indicators of diabetes in the retina include leaking and hemorrhaging blood vessels; they will appear as black splotches on the fundus. Some retinal swelling is also common, and occasionally white, fatty deposits will be observed. Due to the sub-par blood flow, nerve tissue may be damaged, and over a period of time changes to the blood vessels can be observed, often including disappearance and re-growth as the body attempts to deliver oxygen to dying areas of the retina.

In order to aid in the diagnosis, a method called OCT (Optical Coherence Tomography) is often used, which takes traditional retinal photography a level further. This method uses interference technology, analogous to ultrasound, to produce a cross-section of the retina (above). This enables the doctor to observe its thickness, as well as any swelling or leaking beneath the visible surface.

The perfect view of blood vessels can aid in the indication of other health problems as well, such as high blood pressure. When it affects the retina, it’s called “hypertensive retinopothy,” and has similar observations to diabetes. Damaged or leaking blood vessels are common, as well as bubbling of veins and arteries due to the increase in pressure. Additionally, due to poor blood flow, damage to nerves is common. Occasionally swelling may also occur, particularly to the optic nerve and the macula (the center of vision).

When you hear someone say, “The eye is a window,” it’s not just a metaphor; it’s a true, literal fact. This window provides a useful tool for doctors, and it’s the job of communicators like us to utilize this tool and gather the necessary visual information. Ophthalmic photography is a realm of endlessly intriguing discoveries, and is a fairly young field of study—there’s yet more to discover, if only you take the time to look!

Sources:

Face-to-Face Interview. Sisson, Christye. Ophthalmic Photography professor.

http://www.ncbi.nlm.nih.gov/

Ophthalmic Photography: Retinal Photography, Angiography, and Electronic

Imaging. Second edition. Saine, Patrick. Tyler, Marshall. 2002.