Table 2.

Mean $\pm$ standard deviation (range) of the rate of improvement (days)

Operation	Groups
	Umbilical cord serum ( n = 40)	Placebo ( n = 40)	Total	Diff (95% CI)	P -value (Between)
Vitrectomy	2.4 $\pm$ 0.7 (2 to 5)	3.8 $\pm$ 2.1 (2 to 12)	–1.3 (–2.1 to –0.6)	$<$ 0.001 $†$
$†$ Based on t-test