entoptic phenomena: Events taking place totally within the eye
The way my patients squint and squirm in the chair, you’d think I was coming at them with a dentist’s drill. Or worse yet, a serpentine colonoscope, which, aside from a sword, is perhaps the coldest and most impersonal use of steel man has ever devised.
But I’m not that kind of doctor. I’m an optometrist, and the only instruments of torture I’m wielding—at the moment, anyway—are a large, table-mounted flashlight which, when turned all the way to “11,” rivals the glory of the sun, and a tiny, hand-held Coke-bottle thick magnifying glass, the kind you used to fry ants when you were a kid.
I place the lens a scant few millimeters in front of my patient’s eye and then grab the joystick, slowly moving my light source to bring the image into focus. It approaches, like the headlight of a train in a dark tunnel. That’s the moment when the FAQS of an eye exam usually start.
He is leaning over the edge of the exam chair, his chin resting in a hard, off-white, concave plastic cup and his forehead against a more flexible strip that resembles the headband that Olivia Newton-John wore when she was getting “Physical” back in 1981. That people willingly place themselves in a device that looks like a trap from Saw IV never ceases to amaze me. He is in there but good, and there is little vertical leeway for the sort of locomotion necessary for intelligible speech. The sound of his voice is muffled and distorted slightly, but not as badly as it might be at the dentist’s office after a shot of novocaine—more 60 Minutes “whistle-blower” than Charlie Brown teacher voice.
“Damn doc, that light is like looking into the sun! Can this make me go blind?”
The image is bobbing up and down now in synch with his jaw, and I hold the lens with the tips of my fingers, adjusting it with subtle micro-motions in an attempt to corral the stray, Mars-red orb of light back within the boundary of my scope and into sharper focus. I resist the urge to tell him to shut up. This is the South, and I don’t want to appear rude to him—bless his heart.
Try to keep your teeth together as I look into the back of your eye, okay? Yes, I know we tell you not to look into the sun, and look at us now. Such rank hypocrisy! But no, you would never sit still long enough for that to happen. Besides I try my best not to blind my patients and always let off the gas at the faintest whiff of charbroiled cornea.
“Well, do I have a brain, doc?” he asks, chuckling and thinking himself quite clever.
He’s actually cleverer than he thinks since the retina, the diaphanous, film-like tissue that lines the back of the eye, is part of the brain. It is a jumping-on point, an outlying suburban platform serving a long, twisting train that winds its way through busy intersections of white and gray matter, crackling with the electricity of life, and terminates some distance away in the occipital lobe, a mysterious Grand Central Station where particles of disparate photons are fused into three-dimensional perceptions, some of them burned into the brain like inky tattoos.
Oh yes, I say, you most certainly have a brain. Technically, anyway. I’ll be sure to tell your wife.
He smiles, which causes the image to shift again. I make the necessary adjustments and continue.
Occasionally, he will get more philosophical than funny and ask if I can see his soul. The dark, round window through which I peer is alleged to reveal its core, but all I see is living tissue and corpuscles shuffling along like harried commuters in branching tubes, hurrying off to deliver their life-giving load. This leads me to believe that flesh and spirit cannot be so easily cleaved–sorry, Plato.
“I bet you see some Cadillacs back there, don’cha?”
It’s an old joke, but I still have to be careful, since some patients believe that “Cadillacs” really are “cataracts” and not just a play on words. This reminds me of a missed opportunity, that what I should have done at the outset of my career was to keep a journal and compile all the funny mispronunciations and misperceptions, perhaps publishing them in a book entitled, Patients Say the Blindest Things.
No, I don’t see any “Cadillacs.” Not even a Toyota. And there’s no guacamole, I mean glaucoma, either.
Obviously, I can dish it out as well as I can take it.
He is silent for awhile, allowing me to finish the exam with relatively few tremors. As I move the scanning beam across the back of his eye, a quirk of brain physiology affords him a fleeting flash of my view. This startles him, and he leans back into his chair, his face the chalky, pallid white of someone who has possibly seen a ghost.
“What was that? Was that the back of my eye? I wish that I could see what you’re seeing. Is there any way I can?”
Yes, I say, let me show you.
I have him lean back into the headrest for stability and close his eyes. I take a thin, curved reed of a flashlight and touch his lids on the outside corner, at the angle where the upper and lower meet, and begin to gently massage. The combination of internal illumination and mechanical touch stimulates the retinal cells to generate phosphenes, sparks of light which form a negative afterimage of the blood vessels which course throughout his retina and divide like the branches of a tall, primeval tree.
It is a pattern that is often repeated in nature, from the veins on a leaf to the bifurcating, tumbling tributaries of a mighty river. It marks each of us for life, as unique as a fingerprint. The entoptic phenomenon enables him to gain my perspective, to see through my eyes. Sometimes he sits in silent wonder, and at others he whistles softly or merely says, “Ah, now I see.”
It would be awkward to keep this up for too long, but I continue long enough for him to get the gist. For a few seconds, at least, as the swirl of my busy office and the turmoil of these days spin like a counterclockwise cyclone around us, the two of us sit together in the eye of the storm, bobbing gently along calm, smooth waters, hopeful that a mere glimpse into such penetrating mysteries will be food enough to sustain us for the long haul ahead.
Every word of this post turned my stomach. You have the gift of descriptive writing. Good work!
Mike the Eyeguy
I was aiming for awe more than nausea, but I’ll take what I can get!
I’m sorry. It’s just that going to the eye doctor horrifies me. When I was little, my cousin had a rather traumatic ophthalmic injury and I haven’t been the same since watching it happen.
Mike the Eyeguy
Oh, no need for apologies. I sometimes take it for granted that eyes are “safe” to talk about. But I can see how you might think otherwise.
I love this. We need more science in our theology/philosophy of life! And next time I get my eyes checked I’m totally gonna ask if my doc can do this…
Mike the Eyeguy
Thanks very much for your kind comment.
Although a regular penlight is a little big, you still might be able to see the entoptic phenomena at home with one of those. But be careful–I’d hate to heard that you got a corneal abrasion trying! 🙂
Mike the Eyeguy
By the way, the entoptic phenomenon of the retinal blood vessels is called the Purkinje tree, first described by–who else?–Bohemian physiologist Jan Evangelista Purkinje in 1823.
Our professions have something in common … people who tell the same, tired, centuries old jokes thinking we are hearing them for the first time. I keep a 2-million candle light spot light in the mortuary van (night time pickups … finding house numbers, also keeps vampires at bay). If I hold that against the side of my head and rub my eye the right way, will I get that entoptic phenomena?
Mike the Eyeguy
2-million candles? Seriously? Wow. I’m feeling a little lumen-envy over here.
I think that anybody who stares into that one might experience their last phenomena.
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