Table 5. Principal Causes of Low Vision and Blindness in Persons with Presenting and Best-Corrected Visual Impairment.

Causes	Based on PVA						Causes	Based on BCVA
	Visual							Visual
	Low Vision#		Blindness*		Impairment‡			Low Vision#		Blindness*		Impairment‡
	(n = 287)		(n = 64)		(n = 351)			(n = 145)		(n = 46)		(n = 191)
	No.	%	No.	%	No	%		No.	%	No.	%	No.	%
Cataract	180	62.7	44	68.8	224	63.8	Cataract	97	66.9	34	73.9	131	68.6
Refractive error	34	11.8	0	0.0	34	9.7	AMD	16	11.0	1	2.2	17	8.9
AMD	19	6.6	3	4.7	22	6.3	Myopic maculopathy	11	7.6	3	6.5	14	7.3
Myopic maculopathy	13	4.5	6	9.4	19	5.4	Corneal opacity	4	2.8	2	4.3	6	3.1
Glaucoma	6	2.1	4	6.3	10	2.8	Glaucoma	1	0.7	4	8.7	5	2.6
Pterygium	8	2.8	0	0.0	8	2.3	Pterygium	4	2.8	0	0.0	4	2.1
Corneal opacity	3	1.0	3	4.7	6	1.7	Vascular retinopathy	1	0.7	1	2.2	2	1.0
Vascular retinopathy	4	1.4	1	1.6	5	1.4	Others	11	7.6	1	2.2	12	6.3
Others	20	7.0	3	4.7	23	6.6

Abbreviation: PVA, presenting visual acuity; BCVA, best-corrected visual acuity; AMD, age-related macular degeneration.

^*Defined as visual acuity <20/400.

^#Defined as visual acuity <20/63 and ≥20/400.

^‡Blindness plus low vision, defined as visual acuity <20/63.