Binocular inhibition of visual performance in patients with cataract. The influence of test reliability

Patients with cataract may show binocular inhibition: their sight improves on closing the eye in which vision is poorer. Of 36 patients questioned, one-third reported this to be the case. To quantify this phenomenon, all patients undertook a battery of tests of spatial visual performance and, in an attempt to define the reliability of their scores, were tested on two separate occasions. Patients generally performed inconsistently: at best, of 8 patients who demonstrated inhibition on a single test, only 5 did so again when re-tested after a short interval. In general, the magnitude of inhibition was less than that which could be reliably detected using the test battery. In addition, self-reported inhibition was not predictive of inhibition measured psychophysically. It is concluded that clinical tests of form vision lack either the necessary reliability or sensitivity to identify patients with cataract who report inhibition of binocular visual function.