Table 6.

Visual Acuity Results in the PTVT Study

	Tube Group	Trabeculectomy Group	P-value
ETDRS VA, mean ± SD
Baseline	73 ± 20	73 ± 20	0.96‡
5 years	69 ± 23	66 ± 27	0.50‡
Change*	−6 ± 17	−11 ± 21	0.13‡
Snellen VA, logMAR mean ± SD
Baseline	0.20 ± 0.42	0.25 ± 0.51	0.42‡
5 years	0.30 ± 0.54	0.42 ± 0.81	0.24‡
Change*	0.16 ± 0.37	0.21 ± 0.52	0.43‡
Loss of ≥ 2 Snellen lines, n (%)†	31 (32)	29 (31)	1.00§
Glaucoma	9	9
Cataract	8	8
Macular disease	5	4
Other	2	5
Unknown	9	3

ETDRS = Early Treatment Diabetic Retinopathy Study; SD = standard deviation; VA = visual acuity

^*Not all patients seen at baseline returned for 5-year visits, so the baseline mean minus the 5-year mean does not equal the change

^†Some patients had more than 1 reason for decreased vision

^‡Student t-test

^§Chi-square test