Elevated Plasma Endothelin-1 Levels in Normal Tension Glaucoma and Primary Open-Angle Glaucoma: A Meta-Analysis

Table 1

Characteristics of the included studies.

First author	Year	Country	Case			Control
				Age (years)	ET-1 (pg/mL)		Age (years)	ET-1 (pg/mL)
NTG studies
Henry	2006	England	8			8
Lee	2012	Korea	45			35
Sugiyama	1995	Japan	52			10
Chen	2013	China	18			37
Kunimatsu	2006	Japan	30			19
Galassi	2011	Italy	44			40
Cellini	1997	Italy	15	64.7		15	65.8
POAG studies
Sugiyama	1995	Japan	10			10
Chen	2013	China	31			37
Nicolela	2003	Canada	41			24
Cellini	2012	Italy	40			40
Kunimatsu	2006	Japan	18			19
Holló	1998	Hungary	20			44

: number; data are expressed as mean ± standard deviation (SD).