About this project
A free, public tool that generates printable high-contrast visual-stimulation images — correctly sized for the viewer’s visual ability and the distance to the surface they’ll look at — plus an educational blog about how images can support visual development.
The one idea behind it
A high-contrast pattern only “works” when its feature size matches what a particular viewer can resolve at the distance they’re actually looking from. A bullseye that’s perfect at 30 cm on a changing table is an invisible grey blur on a ceiling 2 m away. Off-the-shelf cards are fixed in size, distance assumption, difficulty, and paper format — so they can’t adapt.
This tool reduces every case to just three things —(effective acuity, viewing distance, print medium) — and does the geometry for you. Acuity can come from either path:
- Guided path (default)
- Derive a design acuity from age + prematurity (corrected age). Great for parents of typical or premature babies who just want a good print in a couple of clicks.
- Direct path (advanced)
- Enter a measured acuity (
20/200, logMAR, or cycles-per-degree). Great for low-vision, CVI, clinicians, older children and adults, and experimentation.
That decoupling is the whole trick: the same engine serves a one-month-old and an adult in vision rehabilitation, because both reduce to (acuity, distance, medium). You can read the plain-language version in “The same card won’t work at every distance” and “How big should it be?”.
Who it’s for
It’s built for a wide range of ages and visual needs — not only newborns:
- Parents of typical newborns and infants (monthly progression, close and ceiling prints).
- Parents of premature infants (corrected-age math, conservative sizing, ROP-aware safety notes).
- Caregivers and therapists for CVI / low vision (direct acuity, reduced complexity, preferred-colour, single-target layouts).
- Older children in learning or vision therapy (shapes, labels, richer complexity, colour).
- Adults in vision rehab or sensory contexts (direct acuity, large tiled prints, high contrast, low clutter).
- Hobbyists and educators (full manual control, custom images, variety).
These are design targets to serve, not clinical categories. The tool makes no claim to benefit any condition — it produces correctly-scaled high-contrast prints that you apply at your own discretion and your professionals’ guidance.
What we believe (and how it shows up)
- Defaults first, depth on demand. A tired parent succeeds fast in Basic mode; power users get every parameter in Advanced. “As adjustable as possible” must never become “impossible to use.”
- Match difficulty to ability. Too simple bores; too fine or too busy falls below threshold. We aim for the just-manageable sweet spot — see the Goldilocks principle.
- Exact physical scale is sacred. Cards print clean — the motif and nothing else — and scale is proven once, for your printer, on the check-your-printer page.
- Privacy by default, cheap to host. Everything runs in your browser; uploaded images never leave your device; we collect nothing. See Privacy.
- Safety and professionals win. Secure mounting, safe materials, safe sleep, and clinical guidance override any feature. See the disclaimer.
- The human relationship is the primary stimulus. Prints supplement, never replace face-to-face interaction and professional care.
- Share knowledge responsibly. The blog is evidence-based and cited, and it separates established science from practitioner guidance and our own design opinions. No hype, no fear-based marketing, no overclaiming.
Where it came from
The project started as a personal tool for one premature baby and a specific home — a ceiling above a crib and a changing station a certain distance from a baby’s face. That real case is kept as the reference that keeps the tool grounded, but the tool itself has been generalised into a free, public resource for anyone with a similar need.
How it’s built
It’s a fully client-side, static website: a framework-free sizing/pattern engine runs in a Web Worker in your browser and builds the print-ready PDF on your device. There is no server doing the work — which is what makes it private, cheap to host, and even usable offline once installed. The project is developed in the open, in deliberate phases documented in the repository.
Not a medical device. This is an informed enrichment / accessibility tool built on published research. It does not diagnose, treat, screen, or monitor any condition, and is not a substitute for professional vision or medical care. Please read the full disclaimer.