Notes
Notes.
Plain-English science on contrast sensitivity, vision, and the screening tool we built.
- May 21, 202615 min readcalibrationmethodologytrust
Why your screen settings matter: calibration in remote vision testing
Why a remote contrast sensitivity test has to calibrate to your screen — and what each calibration step is actually preventing.
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- May 21, 202610 min readprivacydesign-philosophydata
Why we don't store your test results (and why some products do)
Most online tests silently keep your results on a server. We don't — and we want to be explicit about what that means, the trade-offs, and what would change.
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- May 21, 20269 min readmetaorigin
Why we built a free, open contrast sensitivity test
There is a real visual measurement most eye exams skip, the popular online version of it is broken, and the fix turned out not to be hard. So we wrote one.
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- May 21, 202612 min read20/20snellenmeasurement
Why visual acuity (20/20) is a misleading single number
20/20 is a real measurement of one specific thing. It is also a single point on a multidimensional function — and most of what vision does happens elsewhere.
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- May 21, 202610 min readlongitudinaltrackingstatistics
Why one test isn't enough: tracking contrast sensitivity over months
How to read your own contrast-sensitivity record across months — variance sources, pattern types, regression to the mean, and when a trend is worth acting on.
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- May 21, 202614 min readprimercsfvisual-acuity
What contrast sensitivity actually measures (and why visual acuity isn't enough)
Visual acuity samples one point on a curve. Contrast sensitivity measures the whole curve — the difference between passing an eye chart and seeing well.
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- May 21, 202613 min readvisual-snowvssneurosciencerare-conditions
Visual snow syndrome: when 'static' is constant, and what it means for contrast
Visual snow syndrome is real, continuous, and underrecognized. What the literature says, what's mapped, and where contrast sensitivity fits in honestly.
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- May 21, 202612 min readbrain-fogchronic-illnesslong-covidvision
Vision and brain fog: when 'feeling foggy' has an eye component
Brain fog often has a quiet visual component. Here's how contrast sensitivity can surface a vision layer you might not have noticed — and what to do with it.
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- May 21, 202611 min readpediatricsamblyopiadevelopment
Contrast sensitivity in children: what we know
Children's contrast sensitivity matures over years. Here is what the research shows, where amblyopia fits, and why our test is built for adolescents and adults.
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- May 21, 202611 min readtick-bornebabesiabartonellarocky-mountainco-infections
Tick-borne co-infections and vision: what the literature shows
Bartonella, Babesia, Anaplasma, Ehrlichia, and Rocky Mountain spotted fever can affect the eye. Here is what the peer-reviewed literature actually documents.
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- May 21, 202611 min readtask-lightinghome-setuppractical
Task lighting for contrast: practical setup for reading, working, and aging eyes
A practical guide to lighting your home for contrast — lux, color temperature, CRI, flicker, lamp placement. What to buy, what to skip, and why it matters.
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- May 21, 202613 min readprimerspatial-frequencycsf
Spatial frequency in plain English (and why 3 cpd matters)
Cycles per degree, in three panels. What spatial frequency really means, why human vision peaks around 3 cpd, and where the cliffs at each end come from.
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- May 21, 202612 min readself-trackingchronic-illnesscommunity
Self-tracking vision: a beginner's guide for chronic-illness patients
A practical, sourced guide for chronic-illness patients on tracking your vision over time — what to measure, how often, how to bring the trend to a clinician.
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- May 21, 202611 min readscreensdark-modecircadian
Why screens at night feel different (and what your eye is doing)
Same screen at midnight feels brighter, harsher, harder to read than at 3 p.m. What your visual system is doing — and what evidence supports for dark mode.
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- May 21, 202612 min readcalibrationdisplay-techexplainer
The science of grayscale: how monitors lie about contrast
Why #808080 is not 50% gray, how sRGB and gamma curves quietly bend reality, and why OLED, LCD, and HDR each lie about contrast in a different accent.
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- May 21, 202619 min readcampbell-robsoncsfexplainerdiy
Reading the Campbell-Robson chart: how to see your own contrast sensitivity function
An interactive eye exam you can do with one image. The Campbell-Robson chart makes your contrast sensitivity function visible — here is how to read it.
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- May 21, 202612 min readpresbyopiacontrastdiagnostics
Reading glasses won't fix this: distinguishing focus problems from contrast loss
Your new readers make the page sharper but reading still feels harder than it should. Here's how to tell focus problems from contrast loss — and what to ask.
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- May 21, 202612 min readprogressive-lensesmultifocaltrade-offs
Progressive lenses and contrast: the trade-offs nobody mentioned
Your progressives sharpened reading but something else feels off — depth, peripheral motion, dim-light contrast. Here's the lens-design trade-off behind it.
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- May 21, 202612 min readconcussiontbineuro-optometry
Vision changes after a concussion: when contrast sensitivity tells you something
After a concussion the eye chart often looks fine while the world feels different. Contrast sensitivity is the measurement that can register what acuity doesn't.
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- May 21, 202613 min readcataract-surgeryiolexpectations
Cataract surgery IOL choices: what to expect for contrast
Monofocal, multifocal, EDOF, toric, light-adjustable: a patient-respectful tour of how each cataract-surgery IOL changes the contrast you will see for life.
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- May 21, 202613 min readphotophobialight-sensitivityneuroscience
Photophobia: why light hurts, and what it has to do with contrast
Light shouldn't hurt — but for migraine, post-concussion, and dry-eye patients it often does. The neuroscience, the conditions, and where contrast fits in.
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- May 21, 202615 min readmethodologypelli-robsonfactqcsf
Pelli-Robson vs FACT vs qCSF: a tour of the major contrast sensitivity tests
Three families of contrast sensitivity test dominate clinical and research use. They measure different things, with different precision, and the numbers do not interchange.
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- May 21, 202611 min readclinician-handoffpatient-guideself-advocacy
A patient's guide to bringing your CSF result to your eye doctor
You took the test and you have a number. Here is a practical guide to bringing it to your next eye-care appointment so the conversation that follows is better.
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- May 21, 202611 min readneuro-optometryvision-rehabpatient-guide
What a neuro-optometric rehab appointment actually looks like
Someone told you to see a neuro-optometrist. Here is what the appointment involves, what therapy looks like, what it costs, and what the evidence says.
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- May 21, 202614 min readcirsmoldcontroversyscreening
Mold, CIRS, and the Shoemaker contrast pattern: what is and isn't established
A careful, sourced look at the contrast sensitivity claim in CIRS — what the framework proposes, what the literature supports, and what is still contested.
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- May 21, 202612 min readmigraineauraneuroscience
Migraine aura and contrast sensitivity
Between attacks, many people with migraine show subtle contrast-sensitivity differences. A careful tour of what the interictal literature does and doesn't show.
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- May 21, 202615 min readlymeneuro-borreliosiscontested
Lyme disease and vision changes: what the literature shows
Acute Lyme has documented ocular findings. Post-treatment Lyme is contested terrain. Here is what the peer-reviewed literature actually says about vision.
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- May 21, 202613 min readlightingmesopic-visionscreening
Low light, low contrast: why poor lighting hits some eyes harder
Dim rooms, twilight, parking garages. The same eye performs differently as light drops — and the gap between people widens. Here is the physiology behind it.
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- May 21, 202613 min readlong-covidneuroinflammationemerging
Long COVID and contrast sensitivity: early reports and open questions
Emerging Long COVID research has begun looking at contrast sensitivity. The literature is small and early. Here is what is reported and what remains open.
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- May 21, 202616 min readhow-tocalibrationscreening
How to take a contrast sensitivity test online (and what the result means)
A step-by-step guide to taking a contrast sensitivity test in your browser — what good calibration feels like, and how to read your CSF curve once it's drawn.
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- May 21, 20262 min readprimercsf
Hello — what this blog is for
A short note on what this blog covers — contrast sensitivity in plain English, what the science says, and what it doesn't.
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- May 21, 202612 min readglaucomaearly-detectionscreening
Glaucoma and contrast sensitivity: an underused early signal
Glaucoma can quietly damage the optic nerve before the standard tests register it. Contrast sensitivity sometimes picks up the early signal — but it's not a substitute for an ophthalmologist.
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- May 21, 202612 min readglarevision-qualitycataractnight-driving
Glare disability: when bright light is the visual problem, not the solution
Bright light is supposed to help you see. For some eyes it does the opposite. Here is the physics of glare disability, and the testing the eye chart skips.
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- May 21, 20269 min readlisticleshareableoverview
Five conditions that quietly affect contrast sensitivity
Five common conditions quietly degrade contrast sensitivity — sometimes years before the eye chart notices. What to watch for, and what the science says.
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- May 21, 202612 min readdrivingmesopic-visionsafety
Driving at dusk: contrast sensitivity changes nobody warned you about
The 30-minute window after sunset is when crash risk climbs sharply. Here is what is happening to your eyes in that window — and what to do about it.
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- May 21, 202612 min readdiabetic-retinopathydiabetesearly-detection
Diabetic retinopathy and contrast: what early signs look like
Contrast sensitivity can drop before diabetic retinopathy is visible on a dilated exam. Useful as a self-tracking signal — not a replacement for the exam.
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- May 21, 202612 min readdark-adaptationrods-and-conesamdneuroscience
Dark adaptation: the 20-minute curve nobody talks about (and what slows it down)
Walk from sun into a dim hallway and for half a minute you're blind. Twenty minutes later you can see stars. The curve between those two points is gorgeous.
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- May 21, 202611 min readamblyopiapediatricscritical-periodsvision-development
Critical periods in amblyopia: what 'treatment windows' actually mean
The old framing said amblyopia must be treated before age 7. Modern evidence shows a gradient, not a cliff — and meaningful reason for hope past that window.
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- May 21, 202614 min readmultiple-sclerosisneuro-ophthalmologytracking
Contrast sensitivity in MS: what the research says
Contrast sensitivity is a sensitive probe of optic-pathway involvement in MS — often abnormal when acuity is 20/20. A careful tour of the literature.
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- May 21, 202613 min readconcussiontbirecoveryself-tracking
Concussion recovery: what to expect week by week for vision
A rough week-by-week roadmap of post-concussion vision changes — what tends to be normal early on, when to be patient, and when to escalate to a specialist.
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- May 21, 202613 min readcataractnight-drivingscreening
Cataract and contrast: why your eye exam might say 20/20 while you struggle to drive at night
Night driving is harder, but your eye doctor said 20/20. Here's the part of vision the chart doesn't measure — and what to ask at your next appointment.
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- May 21, 202612 min readlifestyleself-trackingvariance
Caffeine, alcohol, sleep: short-term effects on contrast vision
Three everyday inputs — caffeine, alcohol, and sleep — can nudge your contrast sensitivity reading between sessions. Here's what the science actually shows.
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- May 21, 202613 min readblue-lightfiltersevidence-based
Blue-light filters and contrast sensitivity: what the data actually says
What the 2023 Cochrane review and the contrast-sensitivity RCTs actually show about blue-light glasses for eye strain, sleep, and CSF — and where FL-41 fits.
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- May 21, 202614 min readamdmacular-degenerationearly-detection
Age-related macular degeneration: contrast as an early signal
AMD is the leading cause of central vision loss in adults over 50. Contrast sensitivity often slips before acuity does — here's how to use that signal.
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- May 21, 202614 min readmethodologypsychophysicsstaircase
Adaptive staircase methods: why one number isn't enough
Why a single fixed contrast level cannot measure threshold, how the 2-down-1-up transformed staircase converges to 70.7% correct, and what we actually run.
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- May 21, 202613 min readadaptdxdark-adaptationamdpatient-guide
AdaptDx in the chair: what a dark-adaptation test actually feels like
Your ophthalmologist mentioned a dark-adaptation test. Here is what AdaptDx measures, what the appointment feels like, what it costs, and what it cannot tell you.
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