Table 4.

PVR rate according to three groups of centers.

Centers (N)	Patients per center	PVR rate				P value
		S1		S2
		2004-2005		2006–2008
		N (%)	95% CI	N (%)	95% CI
G1 (8)	60 ± 31	10 (4.9%)	1.9%–7.9%	17 (6.1%)	3.3%–8.9%	0.956
G2 (3)	67.33 ± 33	13 (15.9%)	7.9%–23.8%	7 (5.8%)	1.6%–10%	0.043
G3 (6)	60.5 ± 58	45 (23%)	17.1%–28.8%	22 (13.2%)	8%–18.3%	0.041

PVR: proliferative vitreo-retinopathy; N (%): number and percent of PVR cases; CI: confidence interval; G1: <9% final PVR rate; G2: 9–13% final PVR rate; G3: ≥13 % final PVR rate.