When “Free” Treatment Isn’t Accessible: Building AmblyoPunch, a VR Dichoptic Game for Amblyopia
The Canadian generic semaglutide news — a 70 % price drop — is a textbook accessibility win: lower cost → higher adherence → better outcomes. In vision therapy we hit a different wall: experience design. Amblyopia (lazy eye) affects roughly 3 % of the population. The standard prescription is occlusion therapy (patching). The monetary cost is near zero, yet compliance hovers around 50 %. Why? Patching forces hours of monocular blur, offers zero engagement, and provides no feedback loop to keep a patient motivated.
As developers we asked: can we turn the core mechanism of dichoptic training — presenting different images to each eye so the brain must cooperate binocularly — into something that feels like a game? The answer is AmblyoPunch, a standalone Meta Quest experience built by Seven Sportz.
Technical Stack
- Unity 2022 LTS + OpenXR for native Quest standalone deployment.
- Custom shader pipeline that generates Gabor patterns in real time; spatial frequency and orientation are tunable per eye, letting clinicians shape the visual stimulus without leaving the headset.
- Dichoptic rendering via a dual‑camera rig with per‑eye texture control. Each eye receives its own render texture, enabling precise manipulation of contrast, opacity, and disparity.
- Adaptive difficulty engine that drives coin size, spawn speed, spike scale, and stage duration from a rolling performance window, so the challenge evolves with the player.
Dichoptic Pipeline – Step by Step
- Stage 1 – Monocular Advantage: The “lazy‑eye” texture receives high‑contrast targets (coins, spikes); the dominant‑eye texture shows only a neutral background.
- Stage 2 – Binocular Introduction: Both eyes see targets, but the dominant‑eye texture is alpha‑blended to roughly 10‑20 % opacity, forcing the brain to rely on the weaker eye while still receiving binocular cues.
- Stage 3 – Opacity Ramp: Over a series of sub‑steps the dominant‑eye opacity climbs gradually, smoothing the transition to full binocular viewing.
- Stage 4 – Fusion Challenge: Both eyes render at full opacity, yet target positions are offset by a tiny horizontal disparity (measured in arc‑minutes) that sits inside Panum’s fusion area. The player must fuse the images to punch coins or dodge spikes accurately.
Personalization Config
- Lazy‑eye selector (L/R) swaps which render texture receives the “strong” treatment; an incorrect flag would invert the clinical logic.
- Severity tiers (Mild / Moderate / Severe) scale target diameter, spawn rate, movement speed, and stage duration.
- Strabismus type (Esotropia / Exotropia) determines the sign of the Stage 4 horizontal disparity.
- Custom Mode exposes toggles for monocular, binocular, and fusion stages; Automatic Mode chains stages with performance gates, advancing only when the player meets the success threshold.
Progression Logic
A rolling window of the last 10 outcomes (punch = coin hit, dodge = spike avoided) drives advancement.
- Success = coin punched or spike dodged.
- Advance threshold ≥ 70 % (configurable per clinician).
- Demotion if performance falls below 40 %.
- Strabismus profiles require a stricter ≥ 80 % gate before entering Stage 4, protecting against premature fusion demands.
Safety, Positioning & Community
AmblyoPunch is not a medical device and makes no diagnostic or therapeutic claims. It is intended to complement professional vision‑therapy programs, offering an engaging adjunct that can improve adherence. The project is open to feedback from r/VRdev, r/amblyopia, and r/gamedev — what would you add or change?
Try it now: https://www.meta.com/en-gb/experiences/amblyopunch/1239507485902689/
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