Mark G. Hubers – Just an Engineer with USH
Revision A – February 2026
I read 20/25 on an eye chart. Near-perfect acuity. But I see one to two words at a time through about 10 degrees of vision – down from a full wide-open view, and still shrinking. The eye chart says I’m fine. I can barely see the wall it’s hanging on.
And that 20/25 isn’t even what it looks like. My left eye is the sharper one. My right eye is closer to 20/40 – the cornea is too distorted to do better. Doctors call it a “lazy eye” but it’s not lazy. It’s damaged. When I use both eyes together, my brain combines two imperfect inputs and somehow produces something better than either one alone. Engineers call it sensor fusion. And honestly, it doesn’t even make sense to me. In my world – software, systems, engineering – you need at least three sources to get a better answer. Two disagree, the third breaks the tie. But my brain takes two broken signals with no tiebreaker and builds something sharper than either one. I do this for a living and I still can’t tell you how that works. Sorry – got off track. Back to plain English. 20/25 isn’t a measurement of what my eyes see. It’s a measurement of what my brain builds out of two broken signals. The system writes down one number and calls it my vision.
I know what you’re thinking. He’s got 20/25. He’s not blind. Keep reading.
That’s what retinitis pigmentosa does. It takes the periphery first and usually leaves the center for last. Other conditions can blur even that – in my case, keratoconus warps the cornea – but the center is typically the last thing to go. And it’s the first thing they test. And the entire medical system is built around that one number.
The Wrong Test
Here’s how a standard eye exam works. You sit in a chair, look at a chart on the wall, and read the smallest line you can see. The doctor writes down a number – 20/20, 20/25, 20/40 – and that number follows you everywhere. Insurance forms. Disability applications. Workplace accommodations. Driver’s license renewals. Prescription updates. That number IS your vision, as far as the system is concerned.
The problem is that number measures one thing: how sharp your center is. It says nothing about how much you can actually see.
Think of it this way. Imagine looking through a paper towel roll. The image at the end is perfectly clear. You could read a book through it. But you can’t see the room. You can’t see someone standing next to you. You can’t see the car coming from the left. The picture is clear enough to read. The window is almost gone.
Want to try it? Grab a toilet paper roll and hold it up to one eye. Close the other. Look across the room – about ten feet. That’s roughly 20 degrees of visual field, right at the legal blindness line. Now try a paper towel roll. That’s roughly 10 degrees – closer to what I have on a typical day.
It’s not a perfect simulation. What you see through the tube changes depending on how far away you’re looking – up close you see just a few inches, across the room you see a couple feet. My actual vision is more complicated than any tube can show: it shifts with lighting, fatigue, time of day, and my brain fills in gaps the tube can’t. But it gets the basic idea across. Walk around your house with that paper towel roll for five minutes. You’ll understand more about RP than most eye doctors explain in an hour.
That’s 20/25 with 10 degrees of field. Near-perfect acuity, legally blind. Both true at the same time. And nobody built a system that handles both being true at the same time.
There IS a test that measures what I actually lost. It’s called a visual field test (Goldmann or Humphrey). You look into a dome and click a button when you see a light flash on the sides. It maps how much peripheral vision you have left. That’s the test that matters for RP. That’s the one that shows I’m legally blind. It’s still not the whole picture – but at least it’s measuring what I’ve lost.
But it’s not the one they check first. It’s not the one on the forms. It’s not the one insurance or the system cares about. And in my experience, the equipment is often old, miscalibrated, and wrong. I’m an engineer. I can hear when a machine isn’t working right. I told them – more than once – “you know this thing isn’t working right.” They ran the test anyway. And the results said I was OK.
I wasn’t OK.
One Year for a Piece of Paper
It took me over a year to get my doctor’s technician to fill out a legal blindness form. Over a year. In a retina specialist’s office. A place that exists specifically for people like me.
She knew what 20/200 means – that’s the only definition of blindness she’d ever heard. Night blindness, field loss, none of that was on her radar. But the legal definition has two paths: either your best corrected acuity is 20/200 or worse, OR your visual field is 20 degrees or less. I qualify on the field side. My field is well under 20 degrees. I’ve been legally blind for years.
But the technician saw 20/25 on my chart and couldn’t process it. How can someone who reads 20/25 be legally blind? She didn’t know the field criteria existed. And this was in a retina specialist’s office. Not a general practice. Not a walk-in clinic. A retina specialist.
I had to go back. Multiple visits. Each time explaining the same thing. Each time being told they’d “look into it.” Each time leaving without the form. Finally, I was in the office and forced them to talk to the doctor about it while I was sitting right there. He told her – yes, the field qualifies. Fill out the form. It took him thirty seconds to confirm what I’d been saying for a year.
One year. For a piece of paper that acknowledges what I live every day.
You Can’t Even Get Your Own Numbers
Here’s something that shouldn’t surprise me but still does. I don’t know my exact per-eye acuity. Not because I haven’t been tested – because they don’t tell me. They don’t put it on the papers I take home. They don’t include it in the visit summary. They write it in my chart, behind a system I can barely access, and move on.
I know my left eye is sharper. I know my right is closer to 20/40. I know both together test somewhere around 20/25 – but honestly, I’m not even sure of that. Is that for distance? For close up? Nobody wrote it down clearly enough for me to tell you. I’m writing an essay about a number I can’t even verify. Let that sink in. Sounds great – except that 20/25 comes with flashing lights across my vision, fogging that rolls in and out, glare that washes out everything, and a center that falls apart the moment the lights go down. But hey – 20/25. You’re not blind.
I had to piece that together myself from fragments of conversations and half-remembered readouts. My genetic test report? I have every letter of it – because I requested it myself. My audiogram? I have the graph – because I took a picture of the screen before they closed it. My acuity numbers by eye? I have to ask. And every time I do, I get the same look – a pause, a glance at the screen, “hmm, let me see what we have in the chart.” Like nobody’s ever asked before. Like my own numbers are a surprise request. Meanwhile, that same data – my data – gets stripped of my name and sold to the highest bidder. They can profit from it. I can’t even get a clean copy.
The system collects data about me all day long. It measures my eyes, maps my field, scans my retina, tests my pressure. It builds a detailed picture of my vision. And then it puts that picture in a folder I can’t see and hands me a checkout sheet that says “follow up in 6 months.”
I’m an engineer. I make decisions based on data. You’d think the medical system would want its patients to have their own data. You’d be wrong.
The Forms Don’t Have a Box
Here’s why this matters beyond one frustrated patient.
Every medical form, every insurance screen, every disability checklist starts with acuity. “What is your best corrected visual acuity?” You write 20/25. The system sees that and thinks: this person can see. Check. Move on.
There’s no box for “can read the chart but can’t see the room.”
There’s no box for “legally blind by visual field with near-perfect central acuity.”
There’s no follow-up question: “What is your visual field?” On most forms, it doesn’t exist. The entire intake system is designed around a single number that measures the one thing we still have.
Insurance denials. Accommodation requests. Disability applications. Parking placards. Tax documentation. All of them start with acuity. All of them see 20/25 and stop reading.
What 10 Degrees Actually Looks Like
People hear “legally blind” and they picture darkness. That’s not what this is.
I can read a text message. I can see your face – if it’s directly in front of me and I’m close enough. I can read a menu. In most cases of RP, the center still works – it’s the last part the disease touches. Mine is decent, though other problems like keratoconus blur it more than RP alone would.
But here’s what 10 degrees means in objects you already know. Hold a post-it note at arm’s length. That’s roughly the center – the part I can actually read and make sense of. Around it, the view starts to fade – and in that fading zone, my brain is still trying to do what it used to do with full vision: catch motion, recognize shapes, build a picture of the room. But the light-sensing cells (photoreceptors) thin out the further you get from center – more and more dead as you reach the edge of my 10 degrees – so the brain is running on less signal, more guesses, and memory. I can see about six inches across, but I can only read or make out detail in the inner three. Everything outside that is gone. Not dark. Gone. A credit card barely fits in the center. A smartphone? I have to scan it top to bottom. A full page? Forget it – I’m reading it one post-it-sized piece at a time.
Now step back. At conversation distance – about five feet – 10 degrees gives me a face. That’s it. Your face. Not your hands. Not what you’re holding. Not the person standing next to you. Just a face, floating in nothing. At ten feet across a room? Head and shoulders. At twenty feet in a parking lot? Waist to head – if I’m looking right at you. Wave at me from across the room and I will never see it.
And here’s something people don’t expect. Sometimes I step BACK from something to see it better. Sighted people lean in. I back up. At two feet, 10 degrees gives me a post-it note. At four feet, it gives me a dinner plate. I doubled what I can see by stepping away. Then once I spot what I need, I step back in to read the detail. Every moment is a zoom decision – see more, or see sharper. You can’t have both at the same time. Sighted people never think about this because they get both for free. I had both once too.
Drop something on a dark floor and the math gets worse. A dime is less than an inch wide. My window at arm’s length is about three inches. That’s not a glance – that’s a search operation. Grid by grid. Square by square. Five minutes to find what a sighted person spots in a second.
Everything outside that post-it note is gone. And the medical system says 20/25.
The Tax Break That Costs More Than It Saves
Once I finally got that legal blindness form, I learned something. The tax deduction for legal blindness is roughly the same as a dental write-off. Barely noticeable on a return.
But the doctor visits required to maintain that documentation? Thousands of dollars a year. I wait two to three hours per visit. I pay out of pocket for most of it. My insurance covers almost nothing for retina specialists. And I have to go back regularly to keep the paperwork current.
You pay more to prove you’re blind than the system gives you back for being blind. That’s the math. Nobody talks about it because nobody with 20/25 is supposed to be in this conversation.
The Broken Equipment
I mentioned the visual field test – the one that maps peripheral vision. It should be the gold standard for RP patients. But in my experience, the machines are often the oldest equipment in the office.
I sat in that dome multiple times over the years. I could hear the mechanisms moving. And as an engineer who’s spent a career listening to machines, I knew something was off. The light would stutter. The positioning would skip. I’d tell them – this isn’t working right. They’d run it anyway.
And even when the machine works, the test itself is flawed. They flash a bright, wide light at your peripheral vision and ask “do you see it?” Yeah, I see it. It’s a bright light in a dark dome. But that’s not how real life works. In real life, things at the edge of your vision are dim, small, and moving. A person walking up beside you. A car pulling out from the left. A step below your line of sight. The test uses a stimulus so strong that you can catch it early in the disease even as your real-world peripheral vision is already failing. The test says you’re fine. You’re not fine – the test just isn’t asking the right question.
The test would come back and say I was fine. I wasn’t fine. But the printout said so, and the printout is what goes in the chart.
When I finally got to a doctor with modern equipment, the results matched what I’d been living for years. Not fine. Not even close. The difference wasn’t my eyes – it was the machine. And nobody listened when I told them.
That’s the other part of this. The test that actually matters for us is the one that gets the oldest equipment, the least attention, and the most skepticism when a patient says it isn’t working.
The Workplace Version
At work, I’m productive. I’m a principal-level cloud architect. My boss is the best I’ve ever had – she’s never seen this get in the way of my work. If anything, she counts on me more because of what I bring, and she’s never once made me feel like I need to be helped. She fights for me and she knows what I can do. If she ever reads this, I need her to know that. But one good boss doesn’t fix a broken system.
I need a monitor that’s bright enough and sharp enough for my eyes to work – that costs four or five times what the standard budget allows. I didn’t tell HR for years. Last year I finally let them know – not even asking for help, just disclosing it. Nothing came back. No follow-up. No “what do you need?” Just silence. I need help with lighting. With screen contrast. With knowing when someone walks into my workspace. With not falling down stairs I can’t see. And hearing aids? Not covered. The two things I need most to do my job – see the screen and hear the meeting – I pay for myself.
And here’s the part nobody says out loud. I have to be careful how hard I push. Because if the system actually saw me – really saw what I need – I’d be expensive. And the question every disabled worker carries in the back of their mind is: who wants to hire someone who’s deaf and going blind? You fight to be recognized. But you’re afraid of what happens when you are.
But the form says 20/25. And 20/25 means “fine.”
They’re Not Measuring My Eyes
Here’s what I keep coming back to. That 20/25 isn’t a measurement of my eyes. It’s a measurement of my brain and whatever hardware is strapped to my face – glasses, contacts, specialty lenses – all stacked together.
And the system always uses the best number it can find – both eyes together, best correction applied. They don’t track what each eye sees on its own or what happens without the lenses. Real numbers cost time and money. So they write down the best one and move on.
If you’re a doctor reading this, I know that might sting at first. Sit with it for a second. Am I wrong?
My brain takes two imperfect, distorted signals – one from a cornea that’s coned out of shape, one that’s slightly better – and fuses them in real time into something sharper than either one alone. It does this automatically. I don’t feel it. I don’t think about it. It just happens. Every second of every day, my brain is running a compensation algorithm that no doctor measures and no form captures.
And it goes further than that. My brain is also filling in the gaps around that 10-degree center. In familiar places, it uses memory to build a model of the room so I feel like I see more than I do. It’s predicting where objects are. It’s guessing what’s in my peripheral based on what was there last time I looked. It’s working overtime to make my world feel complete – and it mostly succeeds, until it doesn’t. Until I walk into something. Until I miss someone waving. Until I trip on a step I didn’t see.
And here’s the thing – writing this essay is what made me see it. My brain started reverse-engineering itself, and somewhere between the post-it note and the paper towel roll, I realized I was writing my second research hypothesis about how RP vision actually works. These brain cells – the ones I hope don’t die like my photoreceptors – apparently have opinions.
All of that processing costs energy. By mid-afternoon I’m drained – not from what I did, but from what my brain did FOR me without asking. The system doesn’t measure that. There’s no test for “how hard is your brain working to keep you functional.” There’s no billing code for cognitive compensation. There’s just 20/25 on the chart and a technician who thinks I’m fine.
The Label Problem
I have a learning disability too. Not the kind where you can’t learn – the kind where you can’t get what you’ve learned out onto paper. My brain processes fast. My logic scores test in the top percentile. But written output? That’s where it breaks.
It’s the same pattern. “Learning disability” measures the output and calls the whole person disabled. “Legally blind with 20/25” measures the center and calls the whole person sighted. And “lazy eye” – the label they gave my right eye – means “we don’t know why it’s weaker.” Three labels that describe a symptom and pretend it’s an explanation.
Both vision and learning – the system looks at one number, draws a conclusion about the entire person, and files them away. Both miss the actual problem. And both force us to spend years explaining what the number doesn’t capture.
I’m not getting dumber – my desk is shrinking. Same brain, less room to work with. The acuity chart doesn’t measure the size of my desk. It measures the sharpness of my pencil. And the pencil is fine. The desk is almost gone.
What Should Change
This isn’t complicated. Four things would fix most of it.
Put visual field on the intake form. Right next to acuity. Two numbers instead of one. “Best corrected acuity: . Visual field (degrees): .” That’s it. One extra line. Every RP patient, every glaucoma patient, every stroke patient with visual field loss would benefit. The data already exists in the chart – it just doesn’t make it onto the forms that matter.
Train the front office. The technician who didn’t know what 20/200 means works in a retina specialist’s office. If the front-line staff in a retinal practice don’t understand field-based blindness, what chance does a patient have at a general practice? A ten-minute training session would fix this. Nobody’s done it.
Track the real numbers. Not just the best corrected, both-eyes-together result. Track each eye on its own. Track uncorrected vision. Track the visual field. Track the scans. Give patients their own data – clearly, every visit, without having to ask. The full picture costs a few extra minutes. Not having it costs us years of fighting a system that only sees one number.
Stop using acuity as a gate. Insurance forms, disability applications, accommodation requests – stop making acuity the first and only filter. If someone qualifies as legally blind by visual field, the system should recognize that without requiring us to fight for it for a year.
The eye chart is a useful test. It measures what it measures. But it was never designed to capture what RP takes from us. Using it as the only measure of vision is like judging how well you can hear by testing only one ear. In a quiet room. With no background noise. And then telling you you’re fine.
The eye chart measures the one thing we still have and misses everything we’ve lost. That’s not a medical problem. That’s a design problem. And I’m an engineer. I notice design problems.