Prevalence and causes of blindness, visual impairment, and cataract surgery in Timor-Leste

Figures & data

Table 1 Comparison on sample vs census population data

Age group, years	Sample, %	Census, %
50–59	49.2	51.7
60–69	35.7	31.9
70–79	10.5	13.7
80–99	4.5	2.7
All	100.0	100.0

Table 2 Description of enrolled and examined participants

Study participants	Enrolled	Examined	Not available/refused	Response rate, %
Males	1,629	1,577	52	96.8
Females	1,721	1,676	45	97.4
All	3,350	3,253	97	97.1

Table 3 Age- and gender-adjusted prevalence of blindness and visual impairment

VA category	Males		Females		All
	%	95% CI	%	95% CI	%	95% CI
Blindness-VA <3/60 in the better eye with available correction (presenting VA)
All bilateral cases	2.4	1.1–3.6	3.1	2.0–4.3	2.8	1.8–3.8
All eyes	4.7	3.4–6.0	4.5	3.4–5.7	4.6	3.6–5.7
VA <6/60 in the better eye with available correction (PVA)
All bilateral cases	4	2.5–5.4	4.9	3.4–6.5	4.5	3.2–5.7
All eyes	6.8	5.3–8.3	6.7	5.2–8.3	6.8	5.5–8.1
VA <6/60 in the better eye with available correction (PVA)
All bilateral cases	12	9.5–14.4	13.1	10.7–15.4	12.5	10.5–14.6
All eyes	15.9	13.5–18.3	16.3	13.9–18.8	16.1	14.1–18.1

Abbreviations: VA, visual acuity; PVA, presenting visual acuity.

Table 4 Age-specific prevalence of blindness (%): PVA <3/60 according to gender

Age group, years	Males %, n, (total examined)	Females %, n, (total examined)	All %, n, (total examined)
50–59 years	0, 0, (789)	0.5, 4, (812)	0.2, 4, (1,601)
60–69 years	2.2, 12, (550)	2.6, 16, (611)	2.4, 28, (1,161)
70–79 years	10, 17, (170)	8.1, 14, (173)	9.0, 31, (343)
80+ years	16.2, 11, (68)	28.8, 23, (80)	23.0, 34, (148)
Total	2.5, 40, (1,577)	3.4, 57, (1,676)	3.0, 97, (3,253)

Abbreviations: n, number examined; PVA, presenting visual acuity.

Table 5 Causes of blindness

Causes of blindness	Males		Females		All
	n	Male, %	n	Female, %	n	All, %
Principal causes of blindness in people: PVA <3/60 in better eye
Cataract	28	70.0	49	86.0	77	79.4
Non-trachomatous corneal opacity	2	5.0	0	0.0	2	2.1
Phthisis	0	0.0	2	3.5	2	2.1
Glaucoma	4	10.0	1	1.8	5	5.2
Posterior segment disease	5	12.5	1	1.8	6	6.2
Globe/CNS	1	2.5	4	7.0	5	5.2
Total	40	100	57	100	97	100

Abbreviations: CNS, central nervous system; n, number; PVA, presenting visual acuity.

Table 6 Causes of severe visual impairment

Causes	Males		Females		All
	n	%	n	%	n	%
Principal causes of severe visual impairment in people:: PVA <6/60–3/60
Refractive error	1	3.7	0	0.0	1	1.8
Cataract	25	92.6	29	100.0	54	96.4
Non-trachomatous corneal opacity	1	3.7	0	0.0	1	1.8
Total	27	100.0	29	100.0	56	100.0
Principal causes of moderate visual impairment in people: PVA <6/18–6/60
Refractive error	53	40.5	33	24.3	86	32.2
Cataract	73	55.7	99	72.8	172	64.4
Cataract surgical complications	3	2.3	1	0.7	4	1.5
Trachomatous corneal opacity	0	0.0	1	0.7	1	0.4
Non-trachomatous corneal opacity	0	0.0	1	0.7	1	0.4
Glaucoma	1	0.8	0	0.0	1	0.4
Other posterior segment disease	0	0.0	1	0.7	1	0.4
All other globe/CNS abnormalities	1	0.8	0	0.0	1	0.4
Total	131	100.0	136	100.0	267	100.0

Abbreviations: CNS, central nervous system; PVA, presenting visual acuity.

Table 7 Age- and gender-adjusted cataract surgical coverage (%)

Visual acuity	Males	Females	OR, 95% CI, and P-value, compared with males	All
Cataract surgical coverage in eyes (percentage)
<3/60	52.6	30.4	OR 0.4 (95% CI 0.2–0.6, P<0.01)	41.5
<6/60	40.3	22.0	OR 0.4 (95% CI 0.2–0.8, P<0.01)	30.9
<6/18	23.5	11.3	OR 0.4 (95% CI 0.2–0.9, P=0.02)	16.8
Cataract surgical coverage in people (percentage)
<3/60	65.8	31.3	OR 0.2 (95% CI 0.1–0.4, P<0.01)	48.6
<6/60	51.4	26.4	OR 0.3 (95% CI 0.2–0.6, P<0.01)	38.1
<6/18	31.0	15.5	OR 0.4 (95% CI 0.2–0.8, P=0.01)	22.4

Table 8 Visual outcome among the cataract-operated eyes

	Non-IOL		IOL		All
	Eyes	%	Eyes	%	Eyes	%
Outcome PVA
Good outcome	2	66.7	83	61.9	85	62.1
Borderline	0	0.0	31	23.1	31	22.6
Poor	1	33.3	20	14.9	21	15.3
Total	3	100	134	100	137	100
Outcome BCVA
Good outcome	2	66.7	101	75.4	103	75.2
Borderline	0	0.0	16	11.9	16	11.7
Poor	1	33.3	17	12.7	18	13.1
Total	3	100	134	100	137	100

Note: WHO defines the visual outcome of cataract surgery as good for vision >6/18, borderline for vision <6/18–6/60, and poor for vision <6/60.

Abbreviations: BCVA, best-corrected visual acuity; IOL, intraocular lens; PVA, presenting visual acuity; WHO, World Health Organization.

Table 9 Visual outcome in operated eyes by years after surgery

Visual outcome	<3 years		4–6 years		>7 years
	Eyes	%	Eyes	%	Eyes	%
Good outcome	49	57.0	15	62.5	21	77.8
Borderline	22	25.6	4	16.7	5	18.5
Poor	15	17.4	5	20.8	1	3.7
Total	86	100	24	100	27	100

Table 10 Postoperative presenting visual acuity and causes of borderline and poor outcome after cataract surgery

Visual outcome	Ocular comorbidity		Surgical complication		Refractive error		Long-term complication		Total
	Eyes	%	Eyes	%	Eyes	%	Eyes	%	Eyes	%
Borderline outcome	2	6.50	3	9.70	14	45.20	12	38.70	31	100.0
Poor outcome	2	9.50	7	33.30	1	4.80	11	52.40	21	100.0
Total	4	2.90	10	7.30	15	10.90	23	16.80	52	37.9

Table 11 Barriers to cataract surgery (bilateral BCVA <6/60 due to cataract)

Barriers	Males		Females		All
	n	%	n	%	n	%
Need not felt	7	15.2	16	21.3	23	19
Fear	5	10.9	3	4.0	8	6.6
Cost	0	0.0	0	0.0	0	0.0
Treatment differed by provider	2	4.3	0	0.0	2	1.7
Unaware that treatment is possible	1	2.2	2	2.7	3	2.5
Cannot access treatment	19	41.3	36	48	55	45.5
No one to accompany	12	26.1	18	24	30	24.8
All	46	100	75	100	121	100

Abbreviation: BCVA, best-corrected visual acuity.