Mallett fixation disparity test - study results

Importance of test instructions

With tests requiring a subjective response it seems possible that the precise instructions given to the patient may influence the result.

The importance of test instructions has received considerable attention in the literature on psychological testing (for example, Harrington, 1975; Nelson et al, 1992; Butcher et al, 2000) and in other clinical tests (such as, Feys et al, 2003).

The type of test instructions has also been shown to influence optometric data (West, 1988; Pola et al, 1992; Stark and Atchison, 1994; Atchison et al, 1997; Stevenson et al, 1997), including fixation disparity variables (Garzia and Nicolson, 1988).