Before anyone can understand any functional visual improvements that may occur from my recent participation in a stem cell clinical trial, an explanation of my disease and its progression over the years is in order. Without that, it may be tough to explain what I may or may not notice in functional visual improvement moving forward. In a normal eye, a high concentration of healthy cone photoreceptor cells are centrally located in the macula, providing superior visual acuity, resolution and color definition when you look directly at an object. In simple terms, these cone cells act like the auto-focus of a camera. Just like the camera, your eye starts its auto-focus function when you look directly at the subject. With Stargardt Disease, instead of providing photoreceptor protection, unhealthy cells in the RPE layer are causing degeneration of those amazing cone cells. Therefore, their ability to focus with any reasonable resolution while looking directly at something is reduced dramatically depending on the exact stage of degeneration.
I’ve lived with Stargardt Disease for a very long time, moving from perfect vision to very poor central vision over a period of 30-40 years. But it can be tough to mark specific points on a degenerative continuum; it’s more like a grayscale with an infinite number of points of interest. It complicates it further since so many of those markers are functionally insignificant; when you can’t recognize someone’s face, it doesn’t really matter if it’s because you can’t see enough detail or if you do not see any features at all. For me personally, when I use both of my less than perfect eyes, I can see facial features at close range but they lack fine detail; I may not be able to distinguish this face from three other similar faces that I know.
And since I don’t typically walk around with one eye closed, it is not often that I pay attention to the visual ability of one eye alone. However, when I learned that I was going to participate in this trial and get my functionally worse (left) eye treated, I began paying closer attention to exactly what I could see just using that eye. While in Minneapolis at the Visions 2012 conference, I remember sitting under a shady tree on the steamy streets while doing a little people watching covering my best (right) eye. Depending on the distance away from me, I observed walkers completely disappear as they passed through the void of my central vision. It’s like they were actually swallowed up by their surrounding scenery. It’s not a black spot or white spot – it’s just that it looks like you’re seeing right through them, their edges indistinct, perhaps like a Monet painting without the luxury of subtle color differentiation. At a closer distance, it’s kind of fun when you can just see their head and their walking legs and feet clearly but their body is simply missing as they pass right by.
More scientifically, the eye chart at four meters does not exist for my left eye’s central vision. I might as well be staring at a blank wall. When I look in the center of a big lighted ETDRS visual acuity chart and it’s slowly pulled towards me to one meter away, I can see that there are letters on the top line, down the right hand side, and toward the bottom; all of this sight lies on the outskirts of the big circle of central vision blankness, where there is not even a hint of any text. But normal peripheral vision has a visual acuity no better than 20/200 so it’s odd to try to distinguish letters without looking straight at them. These letters are still hard or impossible to read depending on their size and location.
And I stepped up my observation of the Ansler grid before surgery as well. With my left eye, not only is the middle dot invisible, but an entire circle of grid lines are missing. While looking straight into the middle, I can see grid lines at the four corners of the square with my peripheral vision. But those grid lines are narrow and too light, leaving me wanting more information. With my trusty thick black Sharpie, which I always keep close at hand, I drew a heavy black circle around that little black dot in the center, forming a circle two inches in diameter. Again with the grid about 12 inches from my nose, that bold circle I’ve drawn is wiped off the face of the earth. You might say that my central vision loss in this eye is at the “end stage”; there are no good spots.
On the other hand, when I look straight on at the middle black dot on this Ansler grid with my “better” right eye, only the bottom half of that thick circle I’ve drawn is missing. This “sweet spot” in the top half of my central vision functionally serves me very well. Though to a retina specialist, my retinal photographs appear to be equally worse in both eyes, the usefulness of my right eye is drastically different. This is somewhat apparent in the visual field tests I’ve taken but I don’t think one could argue against the fact that it is the combination of test results and personal observation that gives the complete picture as to my actual functioning vision. But more tests will be coming in the future, giving the doctors solid points of comparison before and after surgery.
There was just one more thing on my list before getting my eye injected with good RPE cells that could potentially change things forever. I remember even at 18 having trouble with those color vision tests required to get a driver’s license. This would have been the 1976-1978 time-frame. Remember those numbers buried in different colored dots? Evidently I passed enough to get a license but it was always a struggle for me. So the day before surgery, I went online and found such a color vision test. I failed miserably with my left eye – 0 percent. I also took a color vision test at Mass Eye and Ear around 1995. There were about 10 circular wooden chips with varying degrees of two opposing colors. I was supposed to put them in order of intensity from one color to the other. I was only able to identify the two endpoints, the two solid colors; all the various shades of color looked identical to me I imagine it will be a while before I’ll even attempt a color test again since my injected RPE cells would have to make up for 15-30 years of degeneration.
But post- surgery, you can bet that I have repeated some of these little unscientific tests over and over again. My daughter says “stop doing that!” when I stare at her face with my good eye closed. Like that grayscale, it’s really hard to pinpoint a difference between gray and gray, so I’ve added a new test: while lying in bed, looking up at the white ceiling, I move my hand across my face at arm’s length. Because of the white ceiling, it appears that my hand disappears behind a very thick cloud. I can’t tell that my fingers are wiggling or even that it is a hand. I am realistic – there’s a lot of fog for those new RPE cells to munch up.
I spent my first ten years at Ai Squared working in a technical support position, helping people use ZoomText. It was common for me to talk with 20 to 30 low vision ZoomText users per day. We often would compare notes on our eye conditions and what visual activities we had trouble with. As far as the retinal degenerative diseases go, there were a lot of similarities like bright light sensitivity, a need for contrast, and an inability to perform functions that required detail (reading text or doing any crafts or handyman work). But the degeneration is a continuum and though two people may test with the same visual acuity, actual functioning sight depends on many factors: the location, size, and degree of the visual atrophy as well as one’s ability to adapt.
And no two eyes are alike even in the same person. For example, when I hold my hand at arm’s length and move it across my “blind” spot using just my left eye, it completely disappears into the background for a span of about three hand widths both horizontally and vertically. But in my “better” untreated eye, this blind spot is only about two hand widths, leaving some remaining functional vision that I rely on heavily.
While walking around a familiar city, I’m lucky enough to be able to walk as fast and as confidently as anybody. Knowing where the curbs are likely to be helps me see them. Just don’t ask me to find a particular store or read the street signs. I also can thoroughly enjoy a scenic landscape. Just don’t ask me to look at a particular tree or animal – that’s the job for the central vision.
There has been a lot of talk about what the timeline and degree of improvement were for the first two patients in this trial. I ask you to refer back to the original Lancet report for that plus take a second look at the trial’s outcome measures, which don’t include visual improvement. No two people are alike so I suspect that timelines and actual functional improvement will vary. Will those missing letters on the eye chart start appearing in gray? Or will a visual “sweet spot” grow in my central vision and if so, at what point does that become large enough to be functionally useful? There are no guarantees and only time will tell. In the meantime, I will look over my doctor’s shoulder with eagerness as he intently observes my retinal photographs and test results. All I feel comfortable saying at this point is that there is definitely no bad news. September and October are the milestones I’ll be looking for. And with good advice from my sister, I’m going to relax a bit and stop driving my daughter crazy being a one-eyed pirate and just hope those new RPE cells are extremely ambitious workers.
Disclosure: Maurie Hill is a patient in this Stargardt clinical trial and is also an Advanced Cell Technology (ACT) stockholder. ACT is the trial’s sponsor.