While most patients try to give the best answers to the question, “Which is better, one or two?” there are still a few who will skew their answers to try to make their vision seem better (to obtain a driver’s license, for example), or worse, in an effort to qualify for low vision benefits. To catch these “cheaters,” a team of researchers from Amsterdam found a pattern: patients who purposely misrepresented their answers on vision tests had significantly more variable responses.

Researchers tested the visual acuity of 13 participants with simulated vision impairment using the Berkeley Rudimentary Vision Test. Participants were tested in an honest condition when providing their best effort and in a cheating condition when attempting to make their visual acuity appear to be markedly worse. The investigators also tested visual acuity of 17 participants with a wide range of vision impairments.

Participants were successfully able to “cheat” on the tests; however, their responses were significantly more variable when cheating. Although the variability in visual acuity was larger in individuals with actual vision impairment compared with those providing honest answers with simulated impairment, their responses remained significantly less variable than those individuals who were cheating.

“The variability in the estimations of vision provides a promising novel means of detecting the intentional underrepresentation of vision and could help to minimize the chance of successfully cheating on tests of vision,” researchers said.