Investigción originl / Originl reserch Pn Americn Journl of Public Helth Functionl low vision in dults from Ltin Americ: findings from popultion-bsed surveys in 15 countries Hns Limburg, 1 Rosrio Espinoz, 2 Vn C. Lnsingh, 3 nd Jun Crlos Silv 4 Suggested cittion Limburg H, Espinoz R, Lnsingh VC, Silv JC. Functionl low vision in dults from Ltin Americ: findings from popultion-bsed surveys in 15 countries. Rev Pnm Slud Public. 2015;37(6):371 8. bstrct Key words Objective. To review dt on functionl low vision (FLV) (low vision visul cuity (VA) < 6/18 (<20/60) to perception of light (PL+) in the better eye tht is untretble nd uncorrectble) in dults ged 50 yers or older from published popultion-bsed surveys from 15 countries in Ltin Americ nd the Cribben. Methods. Dt from 15 cross-sectionl, popultion-bsed surveys on blindness nd visul impirment (10 ntionl nd five subntionl) covering 55 643 people 50 yers old in 15 countries from 2003 to 2013 were renlyzed to extrct sttistics on FLV. Eleven of the studies used the rpid ssessment of voidble blindness (RAAB) method nd four used the rpid ssessment of ctrct surgicl services (RACSS) method. For the 10 ntionl surveys, gend sex-specific prevlence of FLV ws extrpolted ginst the corresponding popultion to estimte the totl number of people 50 yers old with FLV. Results. Age- nd sex-djusted prevlence of FLV in people 50 yers old rnged from 0.9 (Guteml, Mexico, nd Uruguy) to 2.2 (Brzil nd Cub) nd incresed by ge. The weighted verge prevlence for the 10 ntionl surveys ws 1.6: 1.4 in men nd 1.8 in women. For ll 10 ntionl studies, totl of 509 164 people 50 yers old were estimted to hve FLV. Bsed on the 910 individuls ffected, the min cuses of FLV were ge-relted mculr degenertion (weighted verge prevlence of 26), glucom (23), dibetic retinopthy (19), other posterior segment disese (15), non-trchomtous cornel opcities (7), nd complictions fter ctrct surgery (4). Conclusions. FLV is expected to rise becuse of 1) the exponentil increse of this condition by ge, 2) incresed life expectncy, nd 3) the increse in people 50 yers old. These dt cn be helpful in plnning nd developing low vision services for the region; lrge countries such s Brzil nd Mexico would need more studies. Prevention is mjor strtegy to reduce FLV, s more thn 50 of it is preventble. Eye helth; vision, low; cross-sectionl studies; helth plnning; Argentin; Brzil; Chile; Cub; Dominicn Republic; Ecudor; El Slvdor; Guteml; Hondurs; Mexico; Pnm; Prguy; Peru; Uruguy; Venezuel; Ltin Americ; Cribben Region. 1 Interntionl Centre for Eye Helth, London School of Hygiene & Tropicl Medicine, London, United Kingdom. Send correspondence to: Hns Limburg, hlimburg@quicknet.nl 2 Universidd Perun Cyetno Heredi, Lim, Peru. 3 Instituto Mexicno de Oftlmologí, Querétro, Querétro, Mexico. 4 Pn Americn Helth Orgniztion, Bogotá, Colombi. Despite mjor dvnces in eye cre in recent decdes, n incresing number of people hve functionl low vision (FLV) (low vision visul cuity (VA) < 6/18 (<20/60) to perception of light (PL+) in the better eye tht is untretble nd uncorrectble). There is no medicl or surgicl tretment nd/or refrctive correction tht cn restore their visul cuity to 6/18 or better. Mny of these individuls might benefit from low vision services tht llow people to live more independently (1). Providing these services to people with FLV to improve their vision-relted qulity of life is one of the priorities of VISION 2020, the Rev Pnm Slud Public 37(6), 2015 371
Investigción originl Limburg et l. Functionl low vision in dults from Ltin Americ: results from 15 surveys globl inititive of the World Helth Orgniztion (WHO) nd the Interntionl Agency for the Prevention of Blindness (IAPB) (2). FLV ws first described by WHO in 1993 in Bngkok s follows: A person with low vision is one who hs impirment of visul functioning even fter tretment nd/or stndrd refrctive correction, nd hs visul cuity of less thn [20/60] to light perception, or visul field less thn 10 degrees from the point of fixtion, but who uses, or is potentilly ble to use, vision for the plnning nd/or execution of tsk (3). In 2005, WHO further defined FLV s best-corrected visul cuity (BCVA) of less thn 6/18 (20/60) but with PL+ in the better eye, tht is not due to ny tretble or correctble disese or disorder (4). Consequently, the current WHO Interntionl Sttisticl Clssifiction of Diseses nd Relted Helth Problems, 10th revision (ICD-10) (version 2015) no longer uses the term low vision to describe moderte (ctegory 1) nd severe (ctegory 2) visul impirment (presenting VA (PVA) < 6/18 (20/60) to 3/60 (20/400)) (5). While the epidemiology of tretble nd preventble eye diseses is well documented, epidemiologicl dt on FLV re very scrce. A WHO report on FLV from 1996 estimted tht of the 148 million visully impired ctegory 1 5: best corrected visul cuity (BCVA) < 20/60 but with light perception in the better eye in the world, 35 million (25) were in need of low vision cre (4). The report on globl estimtes for 2010 indictes tht of the estimted 285 million people worldwide with VA < 20/60, 43 hd uncorrected refrctive error (i.e., vision loss correctble with glsses) nd 33 hd ctrct (i.e., vision loss correctble through ctrct surgery) (6). The remining 24 or 68.5 million people 1 of the world s popultion re ssumed to hve irreversible BCVA <20/60 (i.e., FLV). These estimtes suggest tht the number of people with FLV hs doubled since 1996. The shrp increse in FLV might be explined by the incresed life expectncy worldwide nd the incresed risk for chronic eye diseses with irreversible loss of sight t higher ges. The Andhr Prdesh Eye Disese Study (APEDS), popultion-bsed survey in Indi covering 10 293 people of ll ges, nlyzed dt using the WHO definition of FLV. The study reported prevlence of FLV for ll ges of 1.05 (95 confidence intervl (CI): 0.82 1.28), no significnt difference between men (1.06) nd women (1.04), nd n increse in prevlence with decresing socioeconomic sttus from 0.3 (in the very rich) to 1.8 (in the very poor). Prevlence incresed considerbly by ge, from 0.3 (in the 0 15 yer ge group) to 6.2 (in people ged 70 yers nd older) (7). A popultion-bsed study from Pkistn in 2008 reported prevlence of FLV in people ged 30 yers nd older of 1.7 (8). Another study from Nigeri conducted in 2011 reported prevlence of FLV in people ged 40 yers nd older of 3.5 (9). The Pn Americn Helth Orgniztion (PAHO) estimted in 1999 tht 6 million people or 1.2 of the popultion in Ltin Americ nd the Cribben (LAC) hd FLV, defined s BCVA < 6/18 fter tretment nd/or stndrd refrctive correction (10, 11). These estimtes hve been used to ssess the need (nd guide plnning) for low vision services in the region. With dvnces in tretment options, the proportion of people with voidble blindness nd visul impirment is decresing in number of countries (12). At the sme time, both life expectncy nd the number of elderly people is incresing rpidly worldwide, resulting in incresed prevlence of permnent (incurble nd/ or unpreventble) blindness nd visul impirment from cuses such s gerelted mculr degenertion (ARMD), glucom, myopic degenertion, dibetic retinopthy, etc. Given these trends, the number of people with FLV is expected to increse in the coming decdes. This study reviewed dt on FLV in persons 50 yers old from 15 published popultion-bsed surveys from LAC (10 ntionl nd five subntionl). To the best of the uthors knowledge, this is the first popultion-bsed nlysis of country-level dt on the prevlence of FLV in people ged 50 yers in LAC. The results of this nlysis could be used to fcilitte dequte plnning to meet the incresing need for low vision services in the region. MATERIALS AND METHODS Dt from 15 popultion-bsed surveys on blindness nd visul impirment conducted in LAC from 2003 to 2013 (11 using the rpid ssessment of voidble blindness (RAAB) method nd four using the rpid ssessment of ctrct surgicl services (RACSS) method) were nlyzed. Both RAAB nd RACSS use multistge rndom cluster smpling methodology in which, in the first stge, smll popultion units (usully census enumertion res (CEAs)) re selected from smpling frme through systemtic smpling. This ensures rndom selection with probbility proportionl to the size of the popultion unit (13, 14). For the second stge of smpling RACSS ws pplied (until 2005) to select eligible individuls within the CEA through the rndom wlk method, stndrd survey method t the time for ssessing immuniztion coverge. With new insights, from 2005 onwrd, this method ws modified to the compct segment smpling used in the RAAB method (15). Becuse the definition of FLV, dt collection, nd dt nlysis were identicl in both survey methods, the findings of the 15 surveys re fully comprble. The results of ll 15 studies were published in peer-reviewed journls but findings on FLV were not included becuse (until 2013) the coding w s not vilble. For this review, the originl dt from ll 15 surveys were renlyzed nd the relevnt dt extrcted fter consent from the principl investigtors. For the 10 countries where ntionl survey ws crried out, the ge- nd sex-specific prevlence of FLV ws extrpolted ginst the corresponding popultion for the yer of the survey to estimte the totl number of people ged 50 yers with FLV. The popultion dt were obtined t the time of the survey from the ntionl bureu of sttistics of the country where the survey ws conducted nd re prt of the dt files from tht survey. In the surveys reviewed in this study, FLV is defined s BCVA (mesured vi pinhole) < 6/18 t o PL+ in the better eye tht is not due to ctrct, refrctive error, uncorrected phki, or posterior cpsulr opcifiction fter ctrct surgery. In people identified s hving FLV, the min cuses, plus ge- nd sex- specific prevlence, nd VA, were extrcted. Precise ntionl estimtion of low vision cre needs bsed on VA requires dt from ntionl popultion-bsed surveys. Therefore, the studies selected for this review included 10 ntionl, 372 Rev Pnm Slud Public 37(6), 2015
Limburg et l. Functionl low vision in dults from Ltin Americ: results from 15 surveys Investigción originl popultion-bsed surveys. Individul needs for low vision cre re more difficult to ssess becuse they depend on eduction, level of visul disbility, etc. Ethicl pprovl for this study ws provided by the Instituto Mexicn de Oftlmologí (IMO) (Querétro, Mexico). Dt from the originl dtbses were renlyzed nd no ptients were exmined. Ech individul study dhered to the provisions of the Declrtion of Helsinki. RAAB nd RACSS dtbses do not store ny personl dt nd nonymity is preserved. The principl investigtors nd the gencies tht funded ech of the 15 studies grnted the uthors written permission to nlyze their dt for this study. Results A totl of 55 643 persons ged 50 yers were exmined cross the 15 surveys. In 2013, the totl popultion 50 yers nd older for the 15 countries where the surveys were conducted ws 105 million or 86.3 of the 121 million people in tht ge group for the entire LAC region (16). Ten of the surveys covered the entire country while the remining five surveys covered cities or sttes. Tble 1 shows the totl nd sex-specific prevlence of FLV for ech country smple. The smple prevlence vried from 0.9 (in the minly urbn stte of Nuevo Léon in Mexico) to 2.6 (in the urbn popultions of Cmpins (Brzil) nd Hvn (Cub)). Prevlence differed significntly between men nd women. Women were more ffected more thn men in Venezuel (P = 0.023), nd men were more ffected more thn women in Mexico (P = 0.046), Prguy (P = 0.007). Tble 2 shows the sex- nd gespecific prevlence of FLV (by 10-yer ge groups) for ech country smple. As shown in the tble, prevlence incresed with ge. Figure 1 illustrtes the increse with ge s well s the considerble vrition in prevlence cross countries. Bsed on the sex- nd ge-specific smple prevlence for the 10 countries where representtive ntionl surveys were crried out, Tble 3 shows the estimted number of people ged 50 ffected nd the weighted verge prevlence from the 10 countries where representtive ntionl survey ws done. Across the 15 surveys, 910 individuls who were 50 yers old nd hd FLV were identified nd the principl cuses of FLV extrcted. Tble 4 shows the principl cuses of FLV for the 910 individuls expressed s proportions of the totl ffected. ARMD ws the most frequent cuse (with weighted verge prevlence of 26), followed by glucom (23), dibetic retinopthy (19), other posterior segment disese (15), non-trchomtous cornel opcities (7), nd complictions fter ctrct surgery (4). However, there ws considerble vrition cross countries. The bottom hlf of Tble 4 shows the percentge of min cuses of FLV tht re preventble. Of ll cses of FLV in people ged 50 yers cross ll 15 surveys, 37 (in Peru) to 79 (in Prguy) re potentilly preventble (2 10 through primry helth cre (PHC) or primry eye cre (PEC) services nd 46 through improved specilized ophthlmic services for ctrct, glucom, nd dibetic retinopthy). Tble 5 shows the level of VA in the better eye of the 910 individuls 50 yers old identified s hving FLV, expressed s proportion of the totl ffected. The mjority (53.6) hd BCVA < 20/60 20/200, 16.6 hd BCVA < 20/60 20/200, nd 29.7 hd BCVA < 20/400 PL+. The severity of visul impirment my hve implictions for the type of services required (i.e., low vision services vry from opticl to non-opticl services nd rehbilittion nd must be tilored to individul needs). Erlier estimtes of FLV in Ltin Americ ssumed tht the prevlence of FLV ws twice the prevlence of blindness (11). Tble 6 compres the overll (ge- nd sex-djusted) prevlence of ll blindness (PVA < 20/400) nd the overll djusted prevlence of visul impirment (PVA < 20/60) with the overll djusted prevlence of FLV in ech of the 15 surveys. There ws considerble vrition cross countries in the FLV/ blindness rtio (prevlence of FLV divided by prevlence of ll blindness), TABLE 1. Totl nd sex-specific prevlence of FLV in people 50 yers old in 15 studies, by country, Ltin Americ, 2003 2013 Country (city/stte, yer) (reference) Men Women Totl No. () n No. () n No. () n Brzil (Cmpins, 2003) (17) 28 (3.0) 935 29 (2.2) 1 289 57 (2.6) 2 224 Venezuel (ntionl, 2004) (18) 21 (1.4) 1 545 42 (2.4) 1 772 63 (1.9 b ) 3 317 Guteml (four sttes, 2004) (19) 21 (1.2) 1 808 35 (1.2) 2 998 56 (1.2) 4 806 Cub (Hvn, 2005) (20) 22 (2.4) 900 49 (2.7) 1 816 71 (2.6) 2 716 Mexico (Nuevo Léon Stte, 2005) (21) 20 (1.2) 1 624 14 (0.7) 2 140 34 (0.9 b ) 3 764 Chile (Bio Bio Stte, 2006) (22) 24 (2.0) 1 218 34 (2.0) 1 697 58 (2.0) 2 915 Dominicn Republic (ntionl, 2008) (21) 39 (2.1) 1 879 43 (2.2) 1 994 82 (2.1) 3 873 Ecudor (ntionl, 2009) (21) 44 (2.4) 1 840 43 (2.0) 2 172 87 (2.2) 4 012 Prguy (ntionl, 2011) (23) 39 (2.9) 1 343 23 (1.5) 1 519 62 (2.2 b ) 2 862 Uruguy (ntionl, 2011) (24) 16 (1.0) 1 571 20 (0.9) 2 158 36 (1.0) 3 729 Peru (ntionl, 2011) (25) 43 (2.1) 2 015 65 (2.3) 2 837 108 (2.2) 4 852 El Slvdor (ntionl, 2011) (26) 28 (2.0) 1 378 38 (1.9) 2 021 66 (1.9) 3 399 Hondurs (ntionl, 2013) (27) 20 (1.6) 1 219 36 (2.0) 1 780 56 (1.9) 2 999 Pnm (ntionl, 2013) (28) 37 (2.0) 1 875 37 (1.8) 2 250 74 (1.8) 4 125 Argentin (ntionl, 2013) (29) 17 (1.0) 1 691 29 (1.4) 2 079 46 (1.2) 3 770 Totl c 419 22 841 537 30 522 956 55 643 FLV: functionl low vision visul cuity (VA) < 6/18 (<20/60) to perception of light (PL+) in the better eye tht is untretble nd uncorrectble. b Significnt difference in prevlence between men nd women: P < 0.05. c Weight verge percentges could not be clculted becuse five studies were subntionl. Rev Pnm Slud Public 37(6), 2015 373
Investigción originl Limburg et l. Functionl low vision in dults from Ltin Americ: results from 15 surveys Tble 2. Proportion () of people 50 yers old with FLV in 15 studies, by country, sex, nd ge group, Ltin Americ, 2003 2013 Country (city / stte) (reference) 50 59 Men Age group (yers) 60 69 70 79 80 All ( 50) Women Age group (yers) Totl Age group (yers) Brzil (Cmpins) (17) 1.1 1.9 6.0 8.6 2.5 1.0 1.0 3.7 7.1 1.9 1.1 1.4 4.6 7.7 2.2 Venezuel (ntionl) (18) 0.9 0.9 2.4 3.9 0.8 1.3 2.2 3.5 7.9 2.3 1.1 1.6 3.0 6.1 1.6 Guteml (four sttes) (19) 1.0 0.7 0.6 3.9 0.9 0.5 1.2 1.6 3.6 0.9 0.6 1.0 1.2 3.8 0.9 Cub (Hvn) (20) 0.4 0.3 4.5 8.3 1.8 0.8 1.5 2.9 9.3 2.5 0.7 1.1 3.5 9.0 2.2 Mexico (Nuevo Léon Stte) (21) 0.4 1.5 1.9 3.4 1.1 0.4 0.5 0.9 3.4 0.7 0.4 0.9 1.4 3.4 0.9 Chile (Bio Bio Stte) (22) 0.2 2.0 4.5 3.3 1.6 1.4 1.6 2.9 4.0 1.8 0.9 1.8 3.6 3.7 1.8 Dominicn Republic (ntionl) (21) 1.3 1.1 3.0 7.9 1.9 1.1 1.6 2.9 10.0 2.2 1.2 1.3 2.9 9.0 2.1 Ecudor (ntionl) (21) 0.6 3.4 2.3 5.4 1.9 0.7 2.0 3.8 3.6 1.8 0.7 2.7 3.1 4.4 1.8 Prguy (ntionl) (23) 0.9 2.2 5.2 14.0 2.6 0.6 0.7 3.0 7.3 1.4 0.8 1.4 4.1 10.5 2.0 Uruguy (ntionl) (24) 0.2 0.8 1.3 3.2 0.9 0.1 0.5 0.4 4.6 0.9 0.2 0.6 0.8 4.1 0.9 Peru (ntionl) (25) 0.7 2.0 2.1 7.8 1.7 0.3 1.4 4.5 9.3 2.0 0.4 1.7 3.5 8.6 1.8 El Slvdor (ntionl) (26) 0.2 2.0 2.9 5.9 1.7 0.8 1.1 3.1 5.6 1.6 0.6 1.4 3.0 5.7 1.6 Hondurs (ntionl) (27) 0.9 1.1 1.1 6.0 1.3 0.6 1.7 3.9 5.0 1.8 0.7 1.5 2.6 5.5 1.6 Pnm (ntionl) (28) 0.9 1.2 1.8 7.5 1.7 0.8 0.9 0.9 8.8 1.6 0.8 1.0 1.3 8.2 1.7 Argentin (ntionl) (29) 0.6 1.0 1.3 2.9 1.0 1.1 1.2 1.6 3.2 1.5 0.9 1.1 1.5 3.1 1.3 50 59 60 69 70 79 80 All ( 50) FLV: functionl low vision visul cuity (VA) < 6/18 (< 20/60) to perception of light (PL+) in the better eye tht is untretble nd uncorrectble. 50 59 60 69 70 79 80 All ( 50) FIGURE 1. Prevlence of FLV in people 50 yers old in 15 surveys, by country nd ge group, Ltin Americ nd Age-specific the Cribben, prevlence 2003 2013 of Functionl Low Vision in people ged 50+ 11 Brzil (Cmpins) 10 9 8 7 6 Venezuel Guteml (4 Sttes) Cub (Hvn) Mexico (Nuevo Léon) Chile (Bio Bio) Dominicn Republic Ecudor 5 4 3 Peru El Slvdor Uruguy Prguy 2 1 0 Hondurs Argentin Pnm 50 59 60 69 70 79 80 Age group (yers) Prevlence () FLV: functionl low vision visul cuity (VA) < 6/18 (< 20/60) to perception of light (PL+) in the better eye tht is untretble nd uncorrectble. which rnged from 0.2 (in Guteml) to 1.9 (in Argentin). Discussion Bsed on the 10 ntionl surveys, cross ll 10 countries, n estimted 509 000 people ged 50 yers hve FLV. Assuming tht the 10 countries were representtive of the entire LAC region, the djusted nd weighted prevlence of FLV from Tble 3 could be extrpolted to the regionl popultion ged 50 yers in 2013 (16). The estimted number of people ged 50 yers with FLV region-wide would be 1.98 million (812 000 mles nd 1 171 000 femles), considerbly less thn PAHO s 1996 estimte of FLV prevlence (6 million, for ll ge groups). Dt on prevlence of FLV in people less thn 50 yers old re very limited in LAC nd elsewhere in the world. One study from Sntigo, Chile, reports prevlence of 0.21 for FLV in children ged 5 15 yers (22). Dt from Indi, Nigeri, nd Pkistn suggest tht the prevlence of FLV in younger ge groups in those countries is low (9 11) (Figure 2). While there were no comprble dt for LAC for those ge groups, s shown in the figure, weighted ge- nd sex-specific FLV prevlence in people 50 yers old is lower in the region versus those three countries. One importnt finding in this study ws the fct tht 56.7 of ll cses of FLV in people 50+ yers old could hve been 374 Rev Pnm Slud Public 37(6), 2015
Limburg et l. Functionl low vision in dults from Ltin Americ: results from 15 surveys Investigción originl TABLE 3. Estimted totl nd sex-specific prevlence of FLV in people 50 yers old, bsed on ge- nd sex-specific prevlence in 10 ntionl studies, by country, Ltin Americ nd the Cribben, 2003 2013 Country (reference) Men Women Totl No. No. No. Venezuel (18) 30 269 1.3 63 795 2.3 94 064 1.8 Dominicn Republic (21) 17 875 1.9 21 994 2.2 39 869 2.1 Ecudor (21) 28 217 2.1 26 465 1.8 54 682 1.9 Prguy (23) 15 981 2.7 9 866 1.6 25 847 2.2 Uruguy (24) 3 799 0.9 5 371 1.0 9 170 0.9 Peru (25) 45 631 1.7 54 697 1.9 100 328 1.8 El Slvdor (26) 7 640 1.6 9 993 1.7 17 633 1.7 Hondurs (27) 5 808 1.3 9 246 1.7 5 054 1.5 Pnm (28) 5 392 1.6 5 655 1.6 11 047 1.6 Argentin (29) 51 364 1.0 90 107 1.5 141 470 1.3 Totl nd weighted verge 211 974 1.4 297 190 1.8 509 164 1.6 FLV: functionl low vision visul cuity (VA) < 6/18 (<20/60) to perception of light (PL+) in the better eye tht is untretble nd uncorrectble. Tble 4. Min cuses of FLV in people 50 yers old s proportion of totl prevlence (weighted verge) in 15 studies, by country, b Ltin Americ nd the Cribben, 2003 2013 Min cuses of FLV BR VE GT CU 1. Ctrct surgery complictions 5 7 0 1 7 5 3 5 0 3 2 13 4 12 4 2. Non-trchomtous cornel opcity 0 0 0 0 0 0 1 0 0 0 2 3 0 1 0 3. Other cornel opcity 2 11 16 4 4 7 1 4 8 3 8 11 4 7 7 4. Phthisis 0 2 0 0 0 2 0 0 0 0 0 0 0 0 0 5. Onchocercisis 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 6. Glucom 14 40 0 43 25 16 43 23 32 25 24 2 38 24 11 7. Dibetic retinopthy 29 11 0 14 14 30 16 27 39 6 1 16 9 9 33 8. ARMD c 7 20 0 4 0 9 14 33 11 28 55 28 20 14 17 9. Other posterior segment disese 43 9 84 33 46 30 22 10 8 16 7 23 14 27 15 10. All globe/cns d bnormlities 0 0 0 0 4 0 0 0 2 19 1 3 11 5 13 Totl 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 Proportion of min cuses of FLV tht re preventble A. Through PHC/PEC e services (min cuses # 2, 3, 4, 5) 2 13 16 4 4 9 3 4 8 3 10 15 5 8 7 B. Through specilized ophthlmic services (min cuses # 1, 6, 7) 48 58 0 59 46 52 61 54 71 34 27 31 50 46 48 Totl proportion of min cuses tht re preventble (A+B) 50 71 16 63 50 61 64 58 79 38 37 46 55 54 54 FLV: functionl low vision visul cuity (VA) < 6/18 (<20/60) to perception of light (PL+) in the better eye tht is untretble nd uncorrectble. b AR: Argentin; BR: Brzil (Cmpins); CL: Chile (Bio Bio Stte); CU: Cub (Hvn); DO: Dominicn Republic; EC: Ecudor; GT: Guteml (four sttes); HN: Hondurs; MX: Mexico (Nuevo Léon Stte); PA: Pnm; PE: Peru; PY: Prguy; SV: El Slvdor; UY: Uruguy; VE: Venezuel. c ARMD: ge-relted mculr degenertion. d CNS: centrl nervous system. e PHC / PEC: primry helth cre / primry eye cre. MX CL DO EC PY UY PE SV HN PA AR Tble 5. Proportion () of people 50 yers old with FLV in 15 studies, by severity nd by country, b Ltin Americ nd the Cribben, 2003 2013 Severity of FLV BR VE GT CU MX CL < 20/400 PL+ 43 20 29 37 29 29 26 14 19 38 33 33 39 43 15 < 20/200 20/400 20 27 16 13 21 7 17 18 18 13 12 21 14 12 17 < 20/60 20/200 38 53 55 50 50 64 57 67 63 50 55 46 46 45 67 Totl 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 DO FLV: functionl low vision visul cuity (VA) < 6/18 (<20/60) to perception of light (PL+) in the better eye tht is untretble nd uncorrectble. b AR: Argentin; BR: Brzil (Cmpins); CL: Chile (Bio Bio Stte); CU: Cub (Hvn); DO: Dominicn Republic; EC: Ecudor; GT: Guteml (four sttes); HN: Hondurs; MX: Mexico (Nuevo Léon Stte); PA: Pnm; PE: Peru; PY: Prguy; SV: El Slvdor; UY: Uruguy; VE: Venezuel. EC PY UY PE SV HN PA AR Rev Pnm Slud Public 37(6), 2015 375
Investigción originl Limburg et l. Functionl low vision in dults from Ltin Americ: results from 15 surveys Tble 6. Age- nd sex-djusted prevlence of blindness, visul impirment, nd FLV in people 50 yers old in 15 studies, by country, b Ltin Americ nd the Cribben, 2003 2013 Prevlence BR VE GT CU MX CL DO EC PY UY PE SV HN PA AR Blindness (PVA c < 20/400) () 1.6 2.3 3.7 1.9 1.5 1.4 2.2 1.4 1.1 0.9 2.1 2.6 1.9 3.0 0.7 Visul impirment (PVA < 20/60) () 9.4 12.3 18.1 16.2 10.3 10.3 14.3 15.1 13.0 10.2 15.7 19.2 13.0 16.0 12.9 FLV (BCVA d < 20/60 PL+) () 2.2 1.6 0.9 2.2 0.9 1.8 2.1 1.8 2.0 0.9 1.8 1.6 1.6 1.7 1.3 FLV / PVA < 20/400 1.4 0.7 0.2 1.2 0.6 1.3 1.0 1.3 1.8 1.0 0.9 0.6 0.8 0.6 1.9 FLV: functionl low vision visul cuity (VA) < 6/18 (<20/60) to perception of light (PL+) in the better eye tht is untretble nd uncorrectble. b AR: Argentin; BR: Brzil (Cmpins); CL: Chile (Bio Bio Stte); CU: Cub (Hvn); DO: Dominicn Republic; EC: Ecudor; GT: Guteml (four sttes); HN: Hondurs; MX: Mexico (Nuevo Léon Stte); PA: Pnm; PE: Peru; PY: Prguy; SV: El Slvdor; UY: Uruguy; VE: Venezuel. c PVA: presenting visul cuity. d BCVA: best-corrected visul cuity (mesured by pinhole). FIGURE 2. Prevlence of FLV in Indi, Pkistn, nd Nigeri versus weighted vrge for selected countries in Ltin Americ nd the Cribben (LAC), by ge group, 2003 2013 Comprison of ge specific prevlence of FLV in other countries nd LAC 14 12 Prevlence () 10 8 6 4 2 0 0 15 16 29 30 39 40 49 50 59 60 69 70 79 80 Age group (yers) Indi 2002 Pkistn 2008 Nigeri 2011 Weighted verge LAC 2003 13 FLV: functionl low vision visul cuity (VA) < 6/18 (< 20/60) to perception of light (PL+) in the better eye tht is untretble nd uncorrectble. prevented (49.3 though specilized ophthlmic services nd 7.4 through PHC/PEC services). This finding provides strong rgument for blindness prevention s mjor strtegy to reduce FLV. Another interesting finding ws tht prevlence of FLV vried by sex in some countries. For exmple, prevlence ws significntly higher in men versus women in Mexico (P = 0.046) nd Prguy (P = 0.007) nd significntly higher in women versus men in Venezuel (P = 0.023). These differences in prevlence by sex should be investigted further. Strengths nd limittions One strength of this nlysis ws the fct tht ll 15 included studies used the sme survey methodology, protocols, definitions, ge groups, nd methods of dt nlysis. Ten of the studies were ntionl surveys, with smple representtive of the entire country, nd seven of them were conducted in the lst four yers. This study lso hd some limittions. First, in five of the countries, the survey re ws limited to stte, province, district, or city, nd therefore the dt might not be representtive of the entire country. This ws especilly importnt for countries with lrge popultions like Brzil nd Mexico. The uthors hope tht by including these dt, other reserchers my conduct similr surveys in other prts of these countries to get more representtive dt on blindness, visul impirment nd FLV. Second, some of the surveys were conducted bout decde go, so the findings my not be the sme s tody. Becuse both life expectncy nd the proportion/number of people 50 yers old hve incresed considerbly in ll 15 countries studied, nd risk of FLV increses with ge, it is likely tht the dt from the older surveys underrepresent the current sitution. Finlly, this study my hve underestimted the number/percentge of individuls with visul field rdius < 10 degrees round the center of fixtion becuse the RACSS nd RAAB method do not include visul field ssessment (it is too difficult nd time-consuming in field sitution). This could hve ffected the ccurcy of the survey mesurements of FLV from glucom mjor cuse of FLV in LAC s centrl vision remins intct until very lte stge of the disese (wheres bsed on visul field ssessment ptients might hve qulified s hving FLV). Becuse glucom is mjor cuse of FLV in LAC, it is likely tht the dt from the surveys presented here underestimted the prevlence of FLV nd, consequently, the number of people who my benefit from low vision services. Conclusions The uthors hope tht these findings on FLV will be helpful in plnning for 376 Rev Pnm Slud Public 37(6), 2015
Limburg et l. Functionl low vision in dults from Ltin Americ: results from 15 surveys Investigción originl the provision nd development of dequte low vision services t the country level in the LAC region. FLV is expected to rise becuse of the exponentil increse of this condition by ge, incresed life expectncy, nd the increse in the number nd proportion of people 50 yers old. More studies re required for the more highly populted countries such s Brzil nd Mexico, for which only subntionl RAAB/RACSS dt were vilble, to obtin more representtive dt. Finlly, prevention should be mjor strtegy to reduce FLV, s more thn 50 of it is preventble. Acknowledgments. The surveys presented here were conducted with finncil support from VISION 2020 Ltin Americ (Argentin, Hondurs, Pnm, Prguy, Peru, nd Uruguy); PAHO/ WHO (Argentin, Brzil, Chile, Cub, Guteml, Mexico, nd Venezuel); the Christin Blind Mission (Brzil, Chile, Cub, Guteml, Mexico, nd Venezuel); nd UNESCO (El Sl - vdor). Funding. 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Mnuscript received on 24 Februry 2015. Revised version ccepted for publiction on 13 April 2015. Rev Pnm Slud Public 37(6), 2015 377
Investigción originl Limburg et l. Functionl low vision in dults from Ltin Americ: results from 15 surveys resumen Bj visión funcionl en dultos de Améric Ltin: resultdos de ls encuests poblcionles relizds en 15 píses Plbrs clve Objetivo. Anlizr los dtos de ls encuests poblcionles publicds provenientes de 15 píses de Améric Ltin y el Cribe sobre bj visión funcionl (BVF) (bj visión, desde un gudez visul [AV] inferior 6/18 [20/60] hst percepción de luz (PL+), en el mejor ojo, no trtble ni corregible) en dultos de 50 ños de edd o myores. Métodos. Con objeto de extrer informción estdístic en mteri de BVF, se volvieron nlizr los dtos de 15 encuests trnsversles poblcionles sobre ceguer y deficienci visul relizds del 2003 l 2013 (10 escl ncionl y cinco subncionles) que brcron 55 643 persons de 50 ños de edd en 15 píses. Once de los estudios empleron el método de Evlución Rápid de l Ceguer Evitble y cutro utilizron el método de Evlución Rápid de de Ctrt y Servicios Quirúrgicos. Al nlizr ls 10 encuests ncionles, se extrpoló l prevlenci específic por edd y sexo de l BVF frente l poblción correspondiente, con objeto de clculr el número totl de persons de 50 ños de edd con BVF. Resultdos. L prevlenci de l BVF justd por edd y sexo en persons de 50 ños de edd vrió desde 0,9 (en Guteml, México y Uruguy) 2,2 (en Brsil y Cub) y umentó con l edd. L prevlenci promedio ponderd en ls 10 encuests ncionles fue de 1,6: 1,4 en hombres y 1,8 en mujeres. Al considerr los 10 estudios ncionles en su conjunto, se clculron un totl de 509 164 persons de 50 ños de edd con BVF. Con bse en ls 910 persons fectds, ls principles cuss de BVF fueron l degenerción mculr relciond con l edd (prevlenci promedio ponderd de 26), el glucom (23), l retinoptí dibétic (19), otrs enfermeddes del segmento posterior del ojo (15), ls opciddes corneles no trcomtoss (7) y ls complicciones posteriores l cirugí de l ctrt (4). Conclusiones. Se prevé que l BVF umente como consecuenci de 1) el umento exponencil de est fección con l edd, 2) l myor espernz de vid, y 3) el umento de persons de 50 ños de edd. Estos dtos pueden ser útiles pr plnificr y extender los servicios de tención l disminución de l gudez visul en l Región; píses extensos, como Brsil y México, requerirín nuevos estudios. L prevención constituye un estrtegi muy importnte pr reducir l BVF, y que más de 50 de los csos se pueden prevenir. Slud oculr; bj visión; estudios trnsversles; plnificción en slud; Argentin; Brsil; Chile; Cub; Ecudor; El Slvdor; Guteml; Hondurs; México; Pnmá; Prguy; Perú; Repúblic Dominicn; Uruguy; Venezuel; Améric Ltin; Región del Cribe. 378 Rev Pnm Slud Public 37(6), 2015