Table 1.
Summary of studies results
| 1st author | Country (city) | Gender percentage male | Age mean, range | SS | UCVA % (95% CI) |
|---|---|---|---|---|---|
| Abu-Shagra et al., 199142 | Saudi Arabia | 100 | 10.9 (6-19) | 1188 | - |
| Adhikari et al., 201443 | Nepal | 47.3 | 5.7±3.1 (0-10) | 10,950 | - |
| Ajaiyeoba et al., 200744 | Nigeria | 44.1 | 11.8±3.8 (4-18) | 1144 | - |
| Akogun 199245 | Nigeria | 54.5 | 9-19 | 1600 | - |
| A1 Faran et al., 199346 | Saudi Arabia | 49.0 | 0-19 | 1909 | - |
| Alrasheed et al., 201647 | Sudan | - | 6-15 | 1678 | 6.40 (4.90-7.90) |
| Beiram 197148 | Sudan | - | 0-19 | 127,426 | - |
| Bucher and Ijsselmuiden, 198849 | South Africa | 40.5 | 0-19 | 44,977 | - |
| Casson et al., 201250 | Asia | 49.9 | 6-11 | 2899 | - |
| Congdon et al., 200827 | China | 50.2 | 14.7±0.8 (11.4-17.1) | 1892 | 41.17 (38.94-43.42) |
| Dandona et al., 199940 | India | - | 0-15 | 663 | - |
| Dandona et al., 200151 | India | - | 0-15 | 2859 | - |
| Darge et al., 201752 | Ethiopia | 50.8 | 11.05±2.5 (5-16) | 378 | - |
| Demissie and Solomon, 201153 | Ethiopia | - | 0-15 | 58,480 | - |
| Dorairaj et al., 200854 | India | - | 3-15 | 13,241 | - |
| Drews et al., 199255 | Atlanta | - | 10 | 89,534 | - |
| Farber 200356 | Israel | 48.6 | 0-18 | 1161 | - |
| Feghhi et al., 200957 | Iran | 40.5 | 5-19 | 2492 | - |
| Flanagan et al., 200358 | Ireland | - | 10.5±4.8 (1-18) | 47,110 | - |
| Fotouhi et al., 200729 | Iran | 52.1 | 7-15 | 5544 | - |
| Ghosh et al., 201259 | India | 45.8 | 6-14 | 2570 | 4.24 (3.41-5.10) |
| Gilbert et al., 200826 | Six countries | 51.7 | 5-15 | 40,779 | - |
| Goh et al., 200532 | Malaysia | 50.8 | 7-15 | 4634 | 17.07 (15.99-18.18) |
| Hashemi et al., 201811 | Iran | - | 1-15 | 766 | - |
| He et al., 201417 | China | 57.9 | 7-12 | 9512 | 13.33 (12.65-14.03) |
| He et al., 200728 | China | 52.5 | 13-17 | 2454 | 27.04 (25.27-28.86) |
| He et al., 200433 | China | 51.9 | 5-15 | 4364 | 22.27 (21.04-23.54) |
| Heijthuijsen et al., 201360 | Suriname | - | 8-16 | 4643 | - |
| Jamali et al., 200961 | Iran | - | 6 | 902 | 3.55 (2.39-5.07) |
| Johnson and Minassian, 198962 | Africa | - | 0-6 | 5436 | - |
| Kaphle et al., 201663 | Malawi | 54.8 | 0-15 | 635 | - |
| Kedir and Girma, 201464 | Ethiopia | 54.1 | 7-15 | 592 | - |
| Kemmanu et al., 201665 | India | - | ≤15 | 23,087 | - |
| Khandekar et al., 200266 | Oman | 52.1 | 0-15 | 6208 | - |
| Kingo and Ndawi, 200967 | Tanzania | - | 6-17 | 400 | - |
| Kumah et al., 201319 | Ghana | 46.6 | 12-15 | 2453 | 3.65 (2.94-4.47) |
| Li et al., 201568 | China | 51.5 | 0-19 | 22,148 | - |
| Limburg et al., 201220 | Vietnam | 52.2 | 0-15 | 28,800 | - |
| Lu et al., 200924 | Beijing | 52.2 | 4.41±1.09 (0-6) | 17,699 | - |
| Ma et al., 201613 | China | 54.0 | 3-10 | 8267 | 19.79 (18.93-20.66) |
| Maul et al., 200039 | Chile | 50.7 | 5-15 | 5303 | 15.72 (14.75-16.73) |
| Moraes Ibrahim et al., 201318 | Brazil | 51.0 | 12.4±1.6 (10-15) | 1590 | 5.72 (4.63-6.98) |
| Moser et al., 200269 | Equatorial Guinea | 47.9 | 0-19 | 812 | - |
| Murthy et al., 200236 | India | 51.9 | 7-15 | 6447 | 6.40 (5.79-7.05) |
| Naidoo et al., 200335 | South Africa | 49.3 | 5-15 | 4679 | 1.34 (1.03-1.71) |
| Newland et al., 199270 | Vanuatu | - | 6-19 | 483 | - |
| O’Donoghue et al., 201071 | Northern Ireland | 50.5 | 13.1±0.38 (12-13) | 661 | 12.85 (10.40-15.65) |
| Pai et al., 201121 | Sydney | 51.3 | 2-4 | 475 | - |
| Pan et al., 201612 | China | 53.3 | 4-6 | 713 | - |
| Park et al., 201416 | South Korea | 52.6 | 5-19 | 4394 | - |
| Paudel et al., 201415 | Vietnam | 46.1 | 12-15 | 2238 | 19.39 (17.77-21.09) |
| Pi et al., 201272 | Western China | 52.4 | 6-15 | 3079 | - |
| Pokharel et al., 200038 | Nepal | 51.7 | 5-15 | 4803 | 2.87 (2.41-3.38) |
| Premsenthil et al., 201373 | Malaysia | 49.0 | 4-6 | 400 | - |
| Raihan et al., 200574 | Bangladesh | 50.2 | 5-15 | 28,835 | - |
| Razavi et al., 201075 | Iran | - | 6-13 | 123 | - |
| Rezvan et al., 201276 | Iran | 41.5 | 11.2±2.4 (6-17) | 1547 | 2.20 (1.41-2.90) |
| Robaei et al., 200531 | Sydney | 50.6 | 6.7 (5-9) | 1738 | 1.32 (0.84-1.97) |
| Rustagi et al., 201277 | Delhi | 46.8 | 14.25 (11-18) | 1075 | 2.88 (1.96-4.06) |
| Salomão et al., 200978 | Brazil | 48.2 | 11-14 | 2440 | 4.83 (4.01-5.76) |
| Sapkota et al., 200825 | Kathmandu | 53.5 | 10-15 | 4282 | 18.63 (17.47-19.83) |
| Sewunet et al., 201479 | Ethiopia | 43.1 | 7-15 | 420 | 11.66 (8.75-15.12) |
| Shahriari et al., 200780 | Iran | 46.2 | 10-19 | 2307 | - |
| Sharma et al., 201781 | Haryana | 40.3 | 6-15 | 1265 | 2.68 (1.86-3.73) |
| Srivastava and Verma, 197882 | India | 54.4 | 0-14 | 7822 | - |
| Tabbara and Ross-Degnan, 198683 | Saudi Arabia | 50.4 | 0-19 | 4467 | - |
| Tananuvat et al., 200484 | Chiang Mai | - | 6-7 | 3467 | - |
| Taylor et al., 201085 | Australia | - | 5-15 | 1694 | - |
| Thulasiraj et al., 200334 | India | - | 6-19 | 5342 | - |
| Unsal et al., 200986 | Turkey | 53.7 | 10.52±2.2 (6-17) | 1606 | - |
| Varma et al., 201787 | United States | - | 3-5 | - | - |
| Vitale et al., 200630 | United States | 43.8 | 12-19 | 4564 | - |
| Wu et al., 201388 | China | 52.9 | 9.7±3.3 (4-18) | 6026 | 27.09 (25.97-28.24) |
| Xiao et al., 201189 | China | - | <16 | 23,675 | - |
| Yamamah et al., 201514 | Egypt | 50.6 | 10.7±3.1 (5-17) | 2070 | 29.42 (27.46-31.43) |
| Yekta et al., 201022 | Iran | 53.5 | 10.9±2.2 (7-15) | 1872 | 6.46 (4.96-7.96) |
| Zainal et al., 200290 | Malaysia | 47.0 | 0-9 | 4690 | - |
| Zerihun and Mabey, 199791 | Ethiopia | 50.5 | 0-19 | 4084 | - |
| Zhao et al., 200037 | China | 48.8 | 5-15 | 5884 | 12.81 (11.97-13.69) |
| MEPEDS Group 200923 | African-American Hispanic |
- | 2-6 | 1592 165 |
- |
| Abu-Shagra et al., 199142 | 11.86 (10.08-13.84) | - | ≤6/12 in the better eye | Medium risk | |
| Adhikari et al., 201443 | 0.1 (0.04-0.15) | - | 0.07 (0.02-0.12) | VI: <6/18 in the better eye BL: PVA <6/60 |
Low risk |
| Ajaiyeoba et al., 200744 | 1.32 (0.74-2.18) | 0.17 (0.02-0.63) | VI: <6/18 either in one or both eyes BL: VA <3/60 |
Low risk | |
| Akogun 199245 | 8.12 (6.83-9.57) | - | 3.81 (2.92-4.87) | VI: <6/18 in the better eye BL: VA <6/60 in the better eye |
High risk |
| A1 Faran et al., 199346 | - | 1.67 (1.14-2.35) | - | <6/18 in the better eye | Medium risk |
| Alrasheed et al., 201647 | 4.40 (2.90-5.90) | 1.20 (0.30-2.70) | - | ≤6/12 in the better eye | Low risk |
| Beiram 197148 | - | - | 0.071 (0.057-0.087) | VA ≤3/60 in the better eye | High risk |
| Bucher and Ijsselmuiden, 198849 | - | - | 0.006 (0.001-0.019) | PVA <3/60 in the better eye | High risk |
| Casson et al., 201250 | 1.90 (1.43-2.46) | - | - | <20/32 in the better eye | Low risk |
| Congdon et al., 200827 | 19.29 (17.53-21.14) | 0.47 (0.21-0.90) | - | ≤6/12 in the better eye | Low risk |
| Dandona et al., 199940 | 2.86 (1.73-4.43) | - | - | <20/40 in the better eye | Medium risk |
| Dandona et al., 200151 | - | - | 0.17 (0.05-0.40) | PVA <6/60 in the better eye | Medium risk |
| Darge et al., 201752 | 5.82 (3.68-8.67) | - | - | ≤6/12 in the either eye | Low risk |
| Demissie and Solomon, 201153 | - | - | 0.05 (0.03-0.07) | PVA <6/60 in the better eye | Low risk |
| Dorairaj et al., 200854 | - | - | 0.11 (0.06-0.17) | BCVA <3/60 in the better eye | Low risk |
| Drews et al., 199255 | - | - | 0.068 (0.05-0.08) | BCVA <20/200 in the better eye | High risk |
| Farber 200356 | - | - | 14.41 (12.41-16.60) | VA ≤20/400 in the better eye | High risk |
| Feghhi et al., 200957 | - | 5.09 (4.26-6.03) | - | <20/60 in the better eye | Medium risk |
| Flanagan et al., 200358 | - | 0.057 (0.03-0.08) | - | ≤6/18 in the better eye | High risk |
| Fotouhi et al., 200729 | 1.73 (1.40-2.11) | 0.25 (0.13-0.42) | - | ≤20/40 in the better eye | Low risk |
| Ghosh et al., 201259 | - | 0.19 (0.06-0.45) | - | <6/12 in the better eye | Medium risk |
| Gilbert et al., 200826 | - | 0.14 (0.11-0.18) | - | <6/18 in the better eye | Low risk |
| Goh et al., 200432 | 10.08 (9.22-10.98) | 1.42 (1.10-1.81) | 2.033 (1.64-2.48) | VI: ≤20/40 in the better eye BL: ≤20/200 in the better eye |
Low risk |
| Hashemi et al., 201711 | 1.30 (0.63-2.38) | 0.52 (0.14-1.33) | 0.78 (0.28-1.69) | VI: ≤20/60 in the better eye BL: VA <20/400 in the better eye |
Low risk |
| He et al., 201417 | 11.25 (10.63-11.91) | 0.63 (0.48-0.81) | - | ≤20/40 in the better eye | Low risk |
| He et al., 200728 | 16.58 (15.11-18.13) | 0.45 (0.22-0.81) | - | ≤20/40 in the better eye | Low risk |
| He et al., 200433 | 10.25 (9.36-11.19) | 0.61 (0.41-0.89) | - | ≤20/40 in the better eye | Low risk |
| Heijthuijsen et al., 201360 | 2.30 (1.89-2.77) | - | 0.81 (0.57-1.12) | VI: <6/18 in the better eye BL: PVA <3/60 in the better eye |
Medium risk |
| Jamali et al., 200961 | - | - | - | <6/12 in either eye | Medium risk |
| Johnson and Minassian, 198962 | - | - | 0.11 (0.04-0.24) | VA<3/60 in the better eye | Medium risk |
| Kaphle et al., 201663 | 3.60 (0.43-12.31) | - | 1.78 (0.04-9.55) | VI: VA <6/18 in the better eye BL: PVA <3/60 in the better eye |
Medium risk |
| Kedir and Girma, 201064 | 1.75 (0.84- 3.20) | 1.40 (0.61-2.74) | - | <6/18 in the better eye | Low risk |
| Kemmanu et al., 201565 | - | - | 0.077 (0.046-0.12) | BCVA <3/60 in the better eye | Low risk |
| Khandekar et al., 200266 | - | - | 0.08 (0.02-0.18) | PVA<3/60 in the better eye | Low risk |
| Kingo and Ndawi, 200967 | 9.50 (6.81-12.80) | - | - | VI: VA<6/18 in the better eye | Medium risk |
| Kumah et al., 201319 | 3.53 (2.83-4.34) | 0.41 (0.19-0.75) | - | ≤20/40 in the better eye | Low risk |
| Li et al., 201568 | - | 0.07 (0.04-0.11) | 0.02 (0.007-0.05) | VI: <6/18 in the better eye BL: BCVA <3/60 in the better eye |
Low risk |
| Limburg et al., 201220 | - | - | 0.07 (0.05-0.11) | PVA <3/60 in the better eye | Medium risk |
| Lu et al., 200924 | 0.42 (0.33-0.53) | - | - | <6/18 in the better eye | Medium risk |
| Ma et al., 201613 | 15.53 (14.75-16.33) | 1.69 (1.42-1.99) | - | ≤20/40 in the better eye | Low risk |
| Maul et al., 199939 | 14.57 (13.63-15.55) | 7.29 (6.61-8.03) | - | <20/40 in at least one eye | Low risk |
| Moraes Ibrahim et al., 201318 | 2.83 (2.07-3.76) | 0.81 (0.43-1.39) | - | ≤20/40 in the better eye | Medium risk |
| Moser et al., 200269 | - | - | 0.61 (0.20-1.43) | VA <3/60 in the better eye | Medium risk |
| Murthy et al., 200136 | 4.85 (4.32-5.43) | 0.81 (0.59-1.06) | - | <20/40 in the better eye | Low risk |
| Naidoo et al., 200335 | 1.17 (0.88-1.52) | 0.32 (0.17-0.52) | - | VA ≤20/40 in the better eye | Low risk |
| Newland et al., 199270 | - | - | 0.21 (0.005-1.14) | VA <6/18 in the better eye | High risk |
| O’Donoghue et al., 201071 | 3.17 (1.97-4.81) | - | - | <6/12 in the better eye | Low risk |
| Pai et al., 201121 | 6.10 (4.12-8.65) | - | - | <20/50 in the better eye | Low risk |
| Pan et al., 201612 | 6.59 (4.88-8.66) | - | - | <20/40 in the better eye | Low risk |
| Park et al., 201416 | 6.12 (5.43-6.87) | - | 0.25 (0.12-0.44) | VI: <20/60 in the better eye BL: VA <20/400 in the better eye |
Low risk |
| Paudel et al., 201415 | 12.19 (10.87-13.62) | - | 0.26 (0.09-0.58) | VI: VA ≤6/12 in the better eye BL: PVA ≤6/120 in the better eye |
Low risk |
| Pi et al., 201272 | 7.69 (6.78-8.69) | - | - | ≤20/40 in the better eye | Low risk |
| Pokharel et al., 200038 | 2.83 (2.38-3.34) | 1.35 (1.04-1.72) | - | ≤20/40 in the better eye | Medium risk |
| Premsenthil et al., 201373 | 5.0 (3.08-7.61) | - | - | ≤6/12 in the better eye | Low risk |
| Raihan et al., 200574 | - | - | 0.06 (0.04-0.11) | PVA <3/60 in the better eye | High risk |
| Razavi et al., 201075 | - | - | 17.88 (11.56-25.81) | VA <3/60 in the better eye | Low risk |
| Rezvan et al., 201276 | 1.0 (0.59-1.67) | 0.25 (0.07-0.66) | - | ≤6/12 in the better eye | Low risk |
| Robaei et al., 200531 | 0.86 (0.48-1.41) | - | - | ≤20/40 in the better eye | Low risk |
| Rustagi et al., 201277 | - | - | 0.93 (0.44-1.70) | VI: <20/60 in the better eye BL: VA <20/200 in the better eye |
Medium risk |
| Salomão et al., 200978 | 2.70 (2.09-3.42) | 0.40 (0.19-0.75) | - | ≤20/40 in the better eye | Low risk |
| Sapkota et al., 200825 | 9.08 (8.24-9.98) | 0.86 (0.60- 1.18) | - | ≤20/40 in the better eye | Medium risk |
| Sewunet et al., 201479 | - | 6.42 (4.27-9.21) | - | <20/40 in the better eye | Medium risk |
| Shahriari et al., 200780 | - | 1.51 (0.98-2.04) | <20/60 using a pinhole | Low risk | |
| Sharma et al., 201781 | - | - | - | ≤6/18 in the better eye | High risk |
| Srivastava and Verma, 197882 | - | - | 0.14 (0.07-0.25) | PVA <3/60 in the better eye | High risk |
| Tabbara and Ross-Degnan, 198683 | 11.59 (10.67-12.57) | - | 2.39 (1.96-2.88) | VI: <6/18 in the better eye BL: PVA <3/60 in the better eye |
Low risk |
| Tananuvat et al., 200484 | 8.68 (7.76- 9.66) | - | - | ≤20/40 at least one eye | Medium risk |
| Taylor et al., 201085 | 1.68 (1.12-2.43) | - | 0.18 (0.03-0.52) | VI: <6/12 in the better eye BL: PVA<6/60 in the better eye |
Low risk |
| Thulasiraj et al., 200334 | 0.73 (0.52-0.99) | 0.48 (0.32-0.72) | 0.07 (0.02-0.19) | VI: <6/18 in the better eye BL: PVA<3/60 in the better eye |
Low risk |
| Unsal et al., 200986 | 1.68 (1.11-2.43) | - | - | <20/40 in the better eye | High risk |
| Varma et al., 201787 | 1.50 (1.20-1.80) | - | - | <20/50 or 20/40 in the better eye | Low risk |
| Vitale et al., 200630 | 9.70 (8.86-10.60) | - | - | ≤20/50 in the better eye | Low risk |
| Wu et al., 201388 | - | 0.31 (0.19-0.49) | - | ≤20/40 in the better eye | Low risk |
| Xiao et al., 201189 | - | - | 0.02 (0.006-0.049) | PVA <3/60 in the better eye | Medium risk |
| Yamamah et al., 201514 | - | - | - | ≤6/9 in the better eye | Medium risk |
| Yekta et al., 201022 | 1.49 (0.82-2.15) | 0.90 (0.30-2.74) | - | ≤6/12 in the better eye | Low risk |
| Zainal et al., 200290 | 0.44 (0.27-0.68) | - | 0.04 (0.005-0.15) | VI: <6/18 in the better eye BL: PVA <3/60 in the better eye |
Low risk |
| Zerihun and Mabey, 199791 | 0.18 (0.04-0.53) | - | 0.07 (0.01-0.21) | VI: <6/18 in the better eye BL: PVA <3/60 in the better eye |
High risk |
| Zhao et al., 200037 | 10.92 (10.14-11.75) | 1.75 (1.43-2.11) | - | ≤20/40 in the better eye | Low risk |
| MEPEDS Group 200923 | 2.76 (2.01-3.69) | 0.78 (0.41-1.33) | - | <20/50 or 20/40 in the better eye | Low risk |
| 2.47 (1.77-3.35) | 0.71 (0.36-1.22) |
SS: Sample size, UCVA: Uncorrected visual acuity, PVA: Presenting visual acuity, BCVA: Best corrected visual acuity, CI: Confidence interval, VI: Visual impairment, BL: Blindness, VA: Visual acuity