The fogging test đ 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 (youâre checking if they can see better than claimed).
- If they suddenly read smaller lines, theyâre likely malingering (using the âbadâ eye all along).
Sneaky part
- They think the âgoodâ eye is being tested (because itâs fogged).
- If they see better with the âbadâ eye, it proves vision is actually better than claimed.
Tips
- Donât tip them off â act like youâre testing the âgoodâ eye.
- Quick switch lenses if needed to confirm findings.
- Combine with other tests (e.g., stereoacuity) for stronger evidence.
Example
- âTestâ right eye (fogged with +5 D). Patient reads 20/20 with left eye â suggests left eye is actually seeing fine (malingering?).
Limitations
- Not foolproof â some patients catch on.
- Cooperation needed â wonât work if they refuse to read.

