TABLE 1.

Randomized controlled trials demonstrating protection against visual field loss by lowering IOP. Note that AGIS data in support of this effect is derived from post-hoc associative analyses, and CIGTS data demonstrates similarity of medical and surgical IOP-lowering approaches to visual function outcomes.

Study	OHTS	CNTGS	EMGT	AGIS	CIGTS
# patients	1636	230	255	738	607
Randomization	RCT	RCT	RCT	RCT	Longitudinal RCT
Group 1	Topical therapy	Medical or surgical	ALT and betaxolol	ALT–trabeculectomy–trabeculectomy	Filtration surgery
Group 2	Obs	Obs	Obs	trabeculectomy–ALT–trabeculectomy	stepped medication treatment regimen
IOP lowering goal (%)	20%	30%	25%	Three groups: 1. IOP <18 mm Hg 100% 2. <18mmHg 75–100% 3. <18mmHg 50–75% 4. <18 mmHg <50%	3 groups: maximum, mean, standard deviation (SD), range, proportion less than 16, 18, 20, or 22 mmHg
Follow-up	72 months (median)	4,7 years (untreated-treated, respectively)	5 years	6 years	3–9 years
Progression in Group 1	4.4%	12%	45%	Greater worsening of visual field defect score for each of the three elevated IOP groups than for the reference group 1	34.1%
Progression in Group 2	9.5%	35%	62%	The average IOP in group 1 was 12.3 mm Hg over 6 years, and their mean change from baseline in visual field defect score ranged from −0.26 (improvement) at 2 years to +0.46 (worsening) at 4 years	23.1%
Reference	Arch Ophthalmol 120:714–20	Am J Ophthalmol 126:487–97	Ophthalmology 114:1965–72	Am J Ophthalmol 130:429–40	Ophthalmology 118:1766–73

Obs, observation; IOP, intraocular pressure.