Comparison 1. Preoperative testing versus selective or no preoperative testing.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Total medical adverse events	3		Odds Ratio (M‐H, Fixed, 95% CI)	Subtotals only
1.1 Overall medical adverse events	3	21531	Odds Ratio (M‐H, Fixed, 95% CI)	1.00 [0.86, 1.16]
1.2 Intraoperative medical adverse events	3	21531	Odds Ratio (M‐H, Fixed, 95% CI)	1.02 [0.85, 1.22]
1.3 Postoperative medical adverse events	2	20526	Odds Ratio (M‐H, Fixed, 95% CI)	0.96 [0.74, 1.24]
2 Total hospitalizations	1		Odds Ratio (M‐H, Fixed, 95% CI)	Totals not selected
2.1 Overall hospitalizations	1		Odds Ratio (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]
2.2 Intraoperative hospitalizations	1		Odds Ratio (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]
2.3 Postoperative hospitalizations	1		Odds Ratio (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]
3 Total deaths	2	20526	Odds Ratio (M‐H, Fixed, 95% CI)	0.50 [0.05, 5.52]
4 Total ocular adverse events	2		Odds Ratio (M‐H, Fixed, 95% CI)	Subtotals only
4.1 Intraoperative ocular adverse events	2	2281	Odds Ratio (M‐H, Fixed, 95% CI)	0.99 [0.71, 1.38]
4.2 Postoperative ocular adverse events	2	2281	Odds Ratio (M‐H, Fixed, 95% CI)	1.11 [0.74, 1.67]
5 Cancellation of cataract surgery	2	20582	Odds Ratio (M‐H, Fixed, 95% CI)	0.97 [0.78, 1.21]