This is exactly why building this correctly matters. The iPhone 16 Pro has an incredibly powerful A18 Pro chip and a 48MP main sensor. We absolutely should be taking advantage of it.
Here is how we accomplish your two new goals:
### 1. Maxing out the Resolution (4K Support)
By default, web browsers play it safe and request 720p or 1080p to prevent older phones from melting. To get the absolute maximum resolution your iPhone 16 Pro will give Safari, we must use `ideal: 3840, height: 2160` in the constraints. The browser will attempt to hit 4K, and if it cannot, it will gracefully fall back to the highest it supports.
**Critical Math Fix:** If we quadruple the camera resolution, a 25-pixel blur suddenly looks 4 times smaller on the screen! I have updated the GPU shader inside this new code to be **Resolution Independent**. The blur sizes are now calculated as a *percentage of the actual camera feed height*, meaning a 50% severity cataract will look mathematically identical whether the phone is streaming 1080p or 4K.
### 2. Bringing back the Snellen Acuity Scale (20/20)
I have reintegrated the LogMAR math into the UI. Now, when you activate the "Acuity Loss (CSF)" toggle, a new label will dynamically appear next to the severity slider showing the exact Snellen fraction (e.g., `20/20` at 0%, down to `20/399` at 100%).
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### The Upgraded File (v6 - 4K Adaptive + Snellen Math)
Copy this entire block, save it, and push it to your server. When you open it on your iPhone 16 Pro, look at the top left corner—it will display a badge showing the exact maximum resolution Safari granted the camera.
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Live Vision Simulation (4K Adaptive Pipeline)
Live Vision Simulation
Dynamic 4K target with resolution-independent shaders and real-time Snellen scaling.