The fogging test đź‘€ is a clever way to uncover malingering (faking vision loss in one eye).
How it works
- Patient wears trial frame with +5.00 D lens over the “good” eye (blurs vision).
- Read the chart with “bad” eye (you’re checking if they can see better than claimed).
- If they suddenly read smaller lines, they’re likely malingering (using the “bad” eye all along).
Sneaky part
- They think the “good” eye is being tested (because it’s fogged).
- If they see better with the “bad” eye, it proves vision is actually better than claimed.
Tips
- Don’t tip them off → act like you’re testing the “good” eye.
- Quick switch lenses if needed to confirm findings.
- Combine with other tests (e.g., stereoacuity) for stronger evidence.
Example
- “Test” right eye (fogged with +5 D). Patient reads 20/20 with left eye → suggests left eye is actually seeing fine (malingering?).
Limitations
- Not foolproof → some patients catch on.
- Cooperation needed → won’t work if they refuse to read.