Table 4.

Principal causes and prevalence of presenting blindness (<20/200)

	Unilaterally blind persons		Bilaterally blind persons
Principal cause	Persons No. (%)	Prevalence (%)	Persons* No. (%)	Prevalence* (%)
Retinal disorders	80 (33.9)	2.20	26 (47.3)	0.71
Diabetic retinopathy	12(5.1)	0.33	9 (16.4)	0.25
Macular degeneration	5(2.1)	0.14	9 (16.4)	0.25
Other retinal disorders	58 (24.6)	1.59	7(12.7)	0.19
Retinal detachment	5(2.1)	0.14	1 (1.8)	0.03
Cataract	63 (26.7)	1.73	22 (40.0)	0.60
Glaucoma	11 (4.7)	0.30	11 (20.0)	0.30
Absent/disorganized globe	12(5.1)	0.33	5(9.1)	0.14
Refractive error†	8 (3.4)	0.22	3 (5.5)	0.08
Other optic atrophy	10 (4.2)	0.27	1 (1.8)	0.03
Amblyopia	26 (11.0)	0.71	0 (0.0)	0.00
Corneal opacity/scar	20 (8.5)	0.55	0 (0.0)	0.00
Other causes	3(1.3)	0.08	1 (1.8)	0.03
Undetermined	3(1.3)	0.08	3 (5.5)	0.08
All (any cause)	236 (100.0)	6.48	55 (100.0)	1.51

^*The totals for the cause specific prevalence exceed the “ALL (any cause)” prevalence because a person can represent two different causes of blindness.

^†Includes only cases improving to >20/32 with subjective refraction.