Table 3. Z-scores for the individual driving performance parameters employed to calculate the ODPS.

	Control	Cataract
Z score (SDLP)	0.46 ± 0.61	-0.42 ± 1.19
Z score (total distance travelled outside the lane)	0.56 ± 0.39	-0.62 ± 1.12
Z score (total time)	0.47 ± 0.65	-0.65 ± 0.99
ODPS (Mean z-score)*	0.50 ± 0.42	-0.56 ± 0.79

Notes: Z-scores were converted so that positives values represented a better performance than the mean; ODPS, overall driving performance score.

* p = 0.004 (independent t-test)