Prevalence and risk factors for refractive errors in the South Indian adult population: The Andhra Pradesh Eye disease study

Figures & data

Table 1 Crude and adjusted prevalence estimates of refractive errors in an adult population of Southern India (n = 3642)

	Prevalence etimates (%)
	Crude	Adjusted*(95% CI)
Myopia	36.5	34.6 (33.1–36.1)
High mopia	4.8	4.5 (3.8–5.2)
Hyperopia	18.1	18.4 (17.1–19.7)
Astigmatism	38.2	37.6 (36–39.2)
Anisometropia	13.6	13.0 (11.9–14.1)

Note: *Age, gender and area adjusted according to the 2000 Indian population.

Abbreviation: CI, confidence interval.

Table 2 Prevalence estimates of myopia, high myopia, and hyperopia by potential risk factors in the study population (n = 3642)

		Myopia (SE < −0.5 D)		High myopia (SE < −5.0 D)		Hyperopia (SE > +0.5 D)
	Total population	n	% (95% CI)	n	% (95% CI)	n	% (95% CI)
Age (y)
40–49	1416	272	19.2 (17.2–21.3)	31	2.2 (1.4–2.9)	251	17.7 (15.7–19.7)
50–59	1035	396	38.3 (35.3–41.2)	50	4.8 (3.5–6.1)	226	21.8 (19.3–24.4)
60–69	858	480	56 (52.7–59.3)	71	8.3 (6.4–10.1)	126	14.7 (12.3–17.1)
70+	333	180	54.1 (48.7–59.4)	23	6.9 (4.2–9.6)	58	17.4 (13.3–21.5)
			P < 0.0001		P < 0.0001		P = 0.001
Gender
Male	1711	648	37.9 (35.6–40.2)	89	5.2 (4.1–6.1)	228	13.3 (11.7–14.9)
Female	1931	680	35.2 (33.1–37.4)	86	4.5 (3.5–5.4)	433	22.4 (20.6–24.3)
			P = 0.105		P = 0.313		P < 0.0001
Socioeconomic status†
≤200	408	173	42.4 (37.6–47.2)	27	6.6 (4.2–9.0)	58	14.2 (10.8–17.6)
201–500	1756	686	39.1 (36.8–41.4)	101	5.8 (4.7–6.8)	264	15.0 (13.4–16.7)
501–2000	1283	403	31.4 (28.9–33.9)	42	3.3 (2.3–4.2)	284	22.1 (19.9–24.4)
>2000	143	38	26.6 (19.3–33.8)	2	1.4 (0.0–3.3)	49	34.3 (26.5–42.0)
			P < 0.0001		P = 0.001		P < 0.0001
Educational level‡
Illiterate	2156	916	42.5 (40.4–44.6)	126	5.8 (4.9–6.8)	291	13.5 (12.1–14.9)
Class 1–5	752	234	31.1 (27.8–34.4)	26	3.5 (2.2–4.8)	189	25.1 (22.0–28.2)
Class 6–10	469	107	22.8 (19.0–26.6)	14	3.0 (1.4–4.5)	110	23.5 (19.6–27.3)
Class 11–12	111	36	32.4 (23.7–41.1)	5	4.5 (1.0–8.4)	26	23.4 (15.5–31.3)
Higher than class 12	148	32	21.6 (14.9–28.3)	4	2.7 (0.1–5.3)	44	29.7 (22.4–37.1)
			P < 0.0001		P = 0.012		P < 0.0001
Area
Urban	899	287	31.9 (28.9–34.9)	34	3.8 (2.5–5.0)	224	24.9 (22.1–27.7)
Rural	2743	1041	38.0 (36.1–39.8)	141	5.1 (4.2–5.9)	437	15.9 (14.6–17.3)
			P = 0.001		P = 0.109		P < 0.0001
Hypertension
No	1881	682	36.3 (34.1–38.4)	92	4.9 (3.9–5.9)	287	15.3 (13.6–16.9)
Yes	1761	646	36.7 (34.5–38.9)	83	4.7 (3.7–5.7)	374	21.2 (19.3–23.1)
			P = 0.783		P = 0.817		P < 0.0001
Diabetes
No	3456	1266	36.7 (35.1–38.3)	168	4.9 (4.1–5.6)	616	17.8 (16.5–19.1)
Yes	185	60	32.4 (25.7–39.2)	7	3.8 (1.0–6.5)	45	24.3 (18.1–30.5)
			P = 0.272		P = 0.601		P = 0.031
Smoking
Never a smoker	2293	767	33.5 (31.5–35.4)	90	3.9 (3.1–4.7)	508	22.2 (20.5–23.9)
Current smoker	1057	454	43.0 (40.0–45.9)	65	6.1 (4.7–7.6)	102	9.6 (7.9–11.4)
Ex-smoker	291	107	36.8 (31.2–42.3)	20	6.9 (4.0–9.8)	51	17.5 (13.2–21.9)
			P < 0.0001		P = 0.005		P < 0.0001
AMD§
No	3577	1297	36.3 (34.7–37.8)	169	4.7 (4.0–5.3)	646	18.1 (16.8–19.3)
Yes	64	31	48.4 (36.2–60.7)	6	9.4 (2.2–16.5)	15	23.4 (13.1–33.8)
			P = 0.050		P = 0.126		P = 0.255
ARM
No	3315	1170	35.3 (33.7–36.9)	154	4.6 (3.9–5.3)	602	18.2 (16.8–19.5)
Yes	326	158	48.5 (43.0–53.9)	21	6.4 (3.8–9.1)	59	18.1 (13.9–22.3)
			P < 0.0001		P = 0.173		P = 1.000
Nuclear cataract (LOCS III grade)
Grade < 2	1700	229	13.5 (11.9–15.1)	16	1.0 (0.5–1.4)	354	20.8 (18.9–22.8)
Grade 2 to 3.5	1717	998	58.1 (55.8–60.4)	133	7.7 (6.5–9.0)	271	15.8 (14.1–17.5)
Grade > 3.5	158	94	59.5 (51.8–67.1)	26	16.5 (10.7–22.2)	13	8.2 (3.9–12.5)
			P < 0.0001		P < 0.0001		P < 0.0001

Notes: ^†Socioeconomic status defined according to monthly per capita income in rupees: extreme lower ≤200 (US$5.10), lower 201–500, middle 501–2000, and upper >2000. Data on socioeconomic status not available for 52 subjects;

^‡ Data on educational level not available for six subjects;

^§ AMD, age-related macular degeneration (includes both dry and wet forms).

Table 3 Prevalence estimates of astigmatism and anisometropia by potential risk factors in the study population (n = 3642)

		Astigmatism (Cylinder <− 0.5 D)		Anisometropia (SE Difference > 0.5 D)
	Total population	N	% (95% CI)	N	% (95% CI)
Age (y)
40–49	1416	424	29.9 (27.6–32.3)	99	7.0 (5.7–8.3)
50–59	1035	468	45.2 (42.2–48.2)	156	15.1 (12.9–17.3)
60–69	858	364	42.5 (39.2–45.8)	166	19.3 (16.7–21.9)
70+	333	137	41.1 (35.9–46.4)	75	22.5 (18.0–27.0)
			P < 0.0001		P < 0.0001
Gender
Male	1711	667	39.0 (36.7–41.3)	222	13.0 (11.4–14.6)
Female	1931	726	37.6 (35.5–39.8)	274	14.2 (12.6–15.7)
			P = 0.412		P = 0.288
Socioeconomic status†
≤200	408	160	39.2 (34.5–44.0)	55	13.5 (10.2–16.8)
201–500	1756	660	37.6 (35.3–39.9)	249	14.2 (12.5–15.8)
501–2000	1283	508	39.6 (36.9–42.3)	172	13.4 (11.5–15.3)
>2000	143	49	34.3 (26.5–42.0)	11	7.7 (3.3–12.1)
			P = 0.480		P = 0.187
Educational level‡
Illiterate	2156	837	38.8 (36.8–40.9)	331	15.4 (13.8–16.9)
Class 1–5	752	289	38.4 (35.0–41.9)	107	14.2 (11.7–16.7)
Class 6–10	469	167	35.6 (31.3–39.9)	37	7.9 (5.4–10.3)
Class 11–12	111	43	38.7 (29.7–47.8)	10	9.0 (3.7–14.3)
Higher than class 12	148	55	37.2 (29.4–44.9)	10	6.8 (2.7–10.8)
			P = 0.773		P < 0.0001
Area
Urban	899	309	34.4 (31.3–37.5)	85	9.5 (7.5–11.4)
Rural	2743	1084	39.5 (37.7–41.4)	411	15.0 (13.6–16.3)
			P = 0.006		P < 0.0001
Hypertension
No	1881	686	36.5 (34.3–38.6)	247	13.1 (11.6–14.7)
Yes	1761	707	40.2 (37.9–42.5)	249	14.1 (12.5–15.8)
			P = 0.122		P = 0.384
Diabetes
No	3456	1314	38.0 (36.4–39.6)	473	13.7 (12.5–14.8)
Yes	185	79	42.7 (35.6–49.8)	23	12.4 (7.7–17.2)
			P = 0.214		P = 0.741
Smoking
Never a smoker	2293	846	36.9 (34.9–38.9)	302	13.2 (11.8–14.6)
Current smoker	1057	417	39.5 (36.5–42.4)	146	13.8 (11.7–15.9)
Ex-smoker	291	130	44.7 (39.0–50.4)	48	16.5 (12.2–20.8)
			P = 0.024		P = 0.291
AMD§
No	3577	1355	37.9 (36.3–39.5)	479	13.4 (12.3–14.5)
Yes	64	38	59.4 (47.3–71.4)	17	26.6 (15.7–37.4)
			P = 0.001		P = 0.005
ARM
No	3315	1257	37.9 (36.3–39.6)	436	13.2 (12.0–14.3)
Yes	326	136	41.7 (36.4–47.1)	60	18.4 (14.2–22.6)
			P = 0.189		P = 0.011
Nuclear cataract (LOCS III grade)
Grade < 2	1700	559	32.9 (30.7–35.1)	–	–
Grade 2 to 3.5	1717	767	44.7 (42.3–46.9)	–	–
Grade > 3.5	158	34	21.5 (15.1–27.9)	–	–
			P < 0.0001

Notes: ^†Socioeconomic status defined according to monthly per capita income in rupees: extreme lower ≤200 (US$5.10), lower 201–500, middle 501–2000, and upper >2000. Data on socioeconomic status not available for 53 subjects;

^‡ Data on educational level not available for six subjects;

^§ AMD, age-related macular degeneration (includes both dry and wet forms).

Table 4 Multivariable logistic regression models assessing the adjusted odds ratio (95% CI) of refractive errors

	Myopia (SE < −0.5 D)	PARη	Hyperopia (SE > +0.5 D)	PARη
Age (y)
40–49	1.00		1.00
50–59	1.22 (0.98–1.52)	–	1.72 (1.37–2.16)	–
60–69	1.62 (1.28–2.06)	–	1.24 (1.00–1.66)	–
≥70	1.45 (1.05–1.98)	–	1.68 (1.13–2.51)	–
Sex
Male	1.00		1.00
Female	0.81 (0.65–1.02)	–	2.2 (1.69–2.85)	–
Socioeconomic status
Extreme lower + lower	1.23 (1.03–1.46)	–	0.8 (0.66–0.96)	–
Middle + upper	1.00		1.00
Educational level
Illiterate	1.00		1.00
Class 1–5	0.60 (0.48–0.74)	–	2.47 (1.96–3.11)	–
Class 6–10	0.62 (0.46–0.82)	–	2.06 (1.54–2.77)	–
Class 11–12	0.98 (0.59–1.59)	–	2.02 (1.21–3.39)	–
Higher than class 12	0.72 (0.44–1.19)	–	2.49 (1.51–3.95)	–
Area
Urban	1.00		1.00
Rural	1.44 (1.16–1.78)	–	0.71 (0.57–0.89)	–
Hypertension
No	1.00		1.00
Yes	1.00 (0.81–1.12)	0.0 (0.0–0.06)	1.24 (1.03–1.49)	0.08 (0.01–0.19)
Diabetes
No	1.00		1.00
Yes	1.00 (0.62–1.31)	0.0 (0.0–0.02)	1.00 (0.65–1.4)	0.0 (0.0–0.02)
Smoking
Never a smoker	1.00		1.00
Current smoker	1.08 (0.80–1.45)	0.02 (0.0–0.12)	0.65 (0.49–1.00)	0.0 (0.0–0.0)
Ex-smoker	1.46 (1.10–1.94)	0.04 (0.01–0.07)	1.07 (0.44–1.56)	0.01 (0.0–0.04)
AMD§
No	1.00		1.00
Yes	0.96 (0.58–1.60)	–	1.71 (1.01–3.21)	–
ARM§
No	1.00		1.00
Yes	1.33 (1.04–1.70)	–	1.00 (0.72–1.36)	–
Nuclear cataract (LOCS III grade)
Grade < 2	1.00		1.00
Grade 2 to 3.5	7.61 (6.02–9.32)	0.76 (0.70–0.80)	0.63 (0.50–0.78)	–
Grade > 3.5	7.95 (5.37–11.76)	0.23 (0.16–0.32)	0.26 (0.14–0.49)	–

Notes: ^ηPAR estimates were derived from multivariable logistic regression model and therefore are not additive. The parentheses contain 95% CI’s;

^§ AMD and ARM variables were replaced in the multivariable logistic regression model.

Table 5 Multivariable logistic regression models assessing the adjusted odds ratio (95% CI) of refractive errors

	Astigmatism (Cylinder < −0.5 D)	PARη	Anisometropia (SE difference > 0.5 D)	PARη
Age (y)
40–49	1.00		1.00
50–59	1.68 (1.40–2.02)	–	1.37 (1.02–1.84)	–
60–69	1.41 (1.13–1.75)	–	1.26 (1.00–1.74)	–
≥70	1.37 (1.02–1.85)	–	1.52 (1.02–2.25)	–
Sex
Male	1.00		1.00
Female	1.03 (0.84–1.26)	–	1.06 (0.79–1.42)	–
Socioeconomic status
Extreme lower + lower	0.94 (0.81–1.10)	–	–
Middle + upper	1.00		–
Educational level
Illiterate	1.00		–
Class 1–5	1.01 (0.84–1.21)	–	–
Class 6–10	1.01 (0.79–1.28)	–	–
Class 11–12	1.12 (0.73–1.72)	–	–
Higher than class 12	1.22 (0.81–1.82)	–	–
Area
Urban	1.00		–
Rural	1.38 (1.14–1.67)	–	–
Hypertension
No	1.00		–
Yes	1.19 (1.03–1.38)	0.08 (0.01–0.16)	–
Diabetes
No	1.00		–
Yes	1.22 (0.88–1.68)	0.01 (0.0–0.03)	–
Smoking
Never a smoker	1.00		–
Current smoker	1.09 (0.88–1.34)	0.03 (0.0–0.09)	–
Ex-smoker	1.29 (0.97–1.72)	0.02 (0.0–0.06)	–
AMD§
No	1.00		–
Yes	2.54 (1.54–4.21)	–	–
ARM§
No	1.00		–
Yes	1.08 (0.85–1.37)	–	–	–
Nuclear cataract (LOCS III grade)
Grade < 2	–	–	–
Grade 2 to 3.5	–	–	–
Grade > 3.5	–	–	–

Notes: ^ηPAR estimates were derived from multivariable logistic regression model and therefore are not additive. The parentheses contain 95% CIs;

^§ AMD and ARM variables were replaced in the multivariable logistic regression model.