Trends in the incidence and causes of severe visual impairment and blindness in children from Israel Eedy Mezer, MD,a,b Angela Chetrit, MHA,c Ofra Kalter-Leibovici, MD,c,d Michael Kinori, MD,d,e Itay Ben-Zion, MD,d,e and Tamara Wygnanski-Jaffe, MDd,e PURPOSE
To describe trends in the incidence and causes of legal childhood blindness in Israel, one of the few countries worldwide that maintain a national registry of the blind.
METHODS
We performed a historical cohort study of annual reports of the National Registry of the Blind (NRB) between 1999 and 2013. All data regarding demographic information, year of registration and cause of blindness of children 0-18 years of age registered for blind certification were obtained from the annual reports of the NRB. Causes of legal blindness analyzed were optic atrophy, retinitis pigmentosa, retinopathy of prematurity (ROP), albinism, other retinal disorders, cataract, and glaucoma. The main outcome measure was the incidence of new cases of certified legal blindness.
RESULTS
The incidence of newly registered legally blind children in Israel almost halved from 7.7 per 100,000 in 1999 to 3.1 per 100,000 in 2013. The decline was mainly attributable to a decreased incidence of blindness resulting from retinitis pigmentosa and ROP. The incidence of registered cases due to cerebral visual impairment increased.
CONCLUSIONS
During the past decade the incidence of severe childhood visual impairment and blindness declined in Israel. A continuous decline in consanguineous marriages among the Jewish and Arab populations in Israel may have contributed to the decrease in the rate of vision loss due to retinitis pigmentosa in children. ( J AAPOS 2015;19:260-265)
I
n 2010 the World Health Organization (WHO) estimated that 19 million children under the age of 15 worldwide were visually impaired. Of these, 7 million cases were visually impaired due to causes other than uncorrected refractive errors. A total of 1.4 million children were irreversibly blind.1 Although the worldwide incidence rate of childhood blindness declined by 10% between 1999 and 2010, the rate increased in India and in Sub-Saharan Africa.2 Childhood blindness accounts for 3.6% of total blindness worldwide.3 The estimated global prevalence of childhood blindness is 80/100,000.4 The effect of blindness on neurobehavioral development is of major concern, and the psychological and financial impact on the families, institutional support systems, and health care providers cannot be overrated. Israel, Finland, and the United Kingdom are the only 3 countries that maintains a nationwide blindness registry.5-11
Author affiliations: aDepartment of Ophthalmology, Rambam Health Care Campus, Haifa, Israel; bRuth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, Haifa, Israel; cUnit of Cardiovascular Epidemiology, Gertner Institute for Epidemiology & Health Policy Research, Tel Hashomer, Israel; dSackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; eThe Goldschleger Eye Institute, Sheba Medical Center, Tel Hashomer, Israel Submitted December 27, 2014. Revision accepted April 4, 2015. Correspondence: Dr Eedy Mezer, MD, PO Box 9907, Haifa 3109901, Israel (email: [email protected]). Copyright Ó 2015 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 http://dx.doi.org/10.1016/j.jaapos.2015.04.002
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Data derived from national registries are preferable to data from fragmented, local resources or incomplete statewide surveys for analysis of time trends. National registry data may be less prone to selection bias, providing that reporting is compulsory and complete. It provides information that enables understanding health care processes and supports health policy decision making. This study aimed to describe the incidence and causes of legal childhood blindness in Israel from 1999 to 2013.
Materials and Methods The study and data collection conformed to all local laws and adhered to the principles of the Declaration of Helsinki. This study included children 0-18 years of age who were found to be eligible according to the definition of legal blindness in Israel, after being registered and completing the process of blindness certification provided by the Ministry of Welfare and Social Services. Manual registry of blindness certificates was carried out from 1990; a computerized national registry was established later and contains data from 1999 onward. We conducted a historical cohort study and analyzed the incidence of legal blindness certificates issued between 1999 and 2013. Records on the cause of blindness were available from 2003 onward and are outlined in Table 1. In 2009 cortical visual impairment (CVI) was added to the list of causes of blindness. CVI was usually diagnosed by an ophthalmologist as bilaterally diminished visual acuity caused by damage shown on MRI to the occipital lobes or to the visual pathways; prior to 2009 it was coded by default as bilateral optic
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Volume 19 Number 3 / June 2015 Table 1. Causes of visual impairment listed in the certification of blindness application form Parts of the eye Eyeball
Uveal tract Cornea and sclera Glaucoma Cataract
Retina and vitreous
Optic nerve and pathways
Medical diagnosis Phthisis Anophthalmos Microphthalmos Albinism Nystagmus Amblyopia Uveitis Central opacity Keratoconus Primary Congenital Secondary Senile Congenital Complicated Operated Retinopathy of prematurity Retinitis pigmentosa Retinal detachment Myopic maculopathy Diabetic maculopathy and retinopathy Age-related macular degeneration Vitreous hemorrhage Central venous or arterial occlusion Optic atrophy Other neuropathy CVI
atrophy. The diagnosis of CVI was supported by an appropriate medical history. Routine screening eye examinations, consisting of noncycloplegic manual retinoscopy and detection of strabismus and other external eye anomalies, are performed between the age of 1.5 and 3 years at the Ministry of Health Mother and Child Clinics by a medical team consisting of an ophthalmologist or a trained optometrist or a certified orthoptist. Visual acuity testing is carried out adjusted to the age and cognitive abilities of the child. In addition, some health maintenance organizations (HMOs) in Israel provide routine vision screening examinations performed by a community general ophthalmologist or pediatric ophthalmologist between the ages of 1.5 and 3 years. Furthermore, every child in Israel undergoes an additional mandatory visual acuity test before entering elementary school at the age of 6 years. Children with abnormal visual acuity, retinoscopy, ocular alignment or red reflex test are referred for further evaluation by a pediatric ophthalmologist either in the community or in one of the country’s 25 public hospitals. In Israel legal blindness is defined by either best-corrected visual acuity of less than 3/60 in the better-seeing eye or a central visual field of less than 20 in the better-seeing eye. The process of certification of blindness is initiated when children are referred for evaluation after failed visual acuity screening test or because they are afflicted with a medical condition that causes severe visual impairment. Therefore, there is no uniform age at which children were registered and included in the registry. Complete eye examination includes age-appropriate best-corrected visual acuity assessment, a thorough ophthalmologic examination, and visual
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field testing where applicable (the latter is obtained usually in children .8 years of age). In preverbal or mentally challenged children, nonverbal techniques, such as matching displayed symbols or Teller acuity cards, are used. Specific data is lacking, because the examination methods are not included in the application form. One disorder is coded as the main cause for visual impairment for the better-seeing eye in the standardized application form for blind certification. Other causes for visual impairment in each eye are also coded but not as the main cause. If the patient is considered eligible by the referring ophthalmologist, the certification request is forwarded to a senior ophthalmology consultant appointed by the National Service for the Blind within the Israeli Ministry of Welfare and Social Services. The diagnosis used for analysis is the opinion of the senior ophthalmology consultant appointed by the National Service for the Blind. In the uncommon event of discrepancies between the diagnosis of the referring ophthalmologist and the consultant appointed by the National Service for the Blind, the opinion of the appointed ophthalmologist is used, sometimes after additional ancillary testing to further verify the extent and nature of the visual impairment. If the diagnosis is confirmed by the consultant, a recommendation is issued. The ophthalmologist records on the application form the results of the visual acuity and visual field assessments for each eye. In addition, the major and minor causes for visual impairment out of 31 possible diagnoses are recorded. The result of the visual acuity testing is classified into the following categories: light perception, perception of hand movement, best-corrected visual acuity of 1/60 or worse; best-corrected visual acuity of less of 3/60 or worse; or best-corrected visual acuity better than 3/60. Visual field data is classified into one of the following categories: \10 from point of fixation in each quadrant; .10 but \20 ; or $20 . A regional committee provides the final approval of the blindness certificate. Demographic data, year of registration, and cause of blindness is routinely collected by the national registry and published in an annual report. We assume that almost every blind child in Israel is registered, because the access to ophthalmologic healthcare services is free of charge and widely available; furthermore, the incentives for voluntary registration are high. Medical benefits include rehabilitation services for the child and his or her family, discounts on low-vision aid products, and discounts on other health care services. Financial benefits include discounts on kindergarten and school payments, discounts on municipal taxes, free public transportation, tax benefits, and a monthly allowance. Schooling benefits are also provided in the form of a part-time personal assistant at school. Temporary blind certification usually for 2 years is granted in cases were visual acuity may improve following medical or surgical treatment or in babies too young to be tested but presenting with a medical condition thought to make the patient eligible for blind certification (ie, Leber’s congenital amaurosis). Information on the size of the population (age #18 years) during the study period was obtained from the database of the Israel Central Bureau of Statistics. Annual rates of all-cause, sex-specific, and disease-specific legal blindness were calculated. Poisson regression models were used to assess time-trends of all-cause, sex and disease-specific rates of blindness.
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Table 2. Population size (children #18 years of age); number and crude rates (95% CI) of new certificates of blindnessa issued between 1999 and 2013
Year
Population (in millions)
Number of new certificates of blindness
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
2.19 2.23 2.28 2.31 2.34 2.38 2.42 2.46 2.50 2.54 2.67 2.75 2.81 2.67 2.72
168 172 153 153 109 134 152 108 133 119 111 104 121 110 83
Rate per 100,000
95% CI
7.67 7.68 6.71 6.61 4.64 5.62 6.28 4.39 5.31 4.67 4.15 3.77 4.30 4.12 3.05
6.51-8.83 6.54-8.83 5.64-7.77 5.56-7.65 3.77-5.51 4.67-6.57 5.28-7.27 3.56-5.22 4.41-6.22 3.83-5.51 3.37-4.92 3.05-4.49 3.53-5.06 3.35-4.89 2.40-3.71
a
In Israel, legal blindness is defined by either best-corrected visual acuity of less than 0.05 in the better seeing eye or a central visual field of less than 20 in the better-seeing eye.
Results Between 1999 and 2013 the incidence of newly registered blindness in children declined by 60%, from 7.67/ 100,000 in 1999 to 3.05/100,000 in 2013. The average annual decline was 5.6% (95% CI, 4.5%-6.6%; P \ 0.001). See Table 2 and Figure 1. The average annual decline was greater in females (6.6%; 95% CI, 5.0%-8.3%; P \ 0.001) than in males (4.8%; 95% CI, 3.5%-6.2%; P \ 0.001). Optic atrophy and retinitis pigmentosa (RP) were the leading causes of childhood blindness in Israel (Table 3). There was a statistically significant decline in the annual incidence of optic atrophy, RP, retinopathy of prematurity (ROP), and albinism during this period (Table 4). The average annual declines of new cases of childhood blindness due to optic atrophy was 8.1% (95% CI, 3.8%-12.4%; P 5 0.002); to RP, 7.1% (95% CI, 3.0%-11.2%; P 5 0.008); to ROP, 14.9% (95% CI, 6.8%-22.9%; P 5 0.003); and to albinism, 7.6% (95% CI, 0.9%-14.3%; P 5 0.03). The rates of blindness due to retinal vitreous disorders, congenital glaucoma, and congenital cataract did not significantly change during this time period. There was also a modest decline in blindness due to other causes grouped together (eg, nystagmus, amblyopia, central opacity, myopic maculopathy); the mean annual change was 3.4% (95% CI, 6.1 to 0.6). However, due to the small number of cases in each specific diagnosis, it was not possible to further investigate each underlying cause. In 2011 there was an increase in newly certified cases of childhood blindness due to the addition of CVI added in 2009. This increased the incidence of new cases per year from 3 during 2009-2010, to 14 in 2011, 8 in 2012, and 6
FIG 1. Incidence of newly registered childhood blindness in Israel between 1999 and 2013.
in 2013. Before 2011, most CVI cases may have been combined with optic atrophy cases. If these 2 groups are combined the annual change in the rate of newly certified blindness cases due to both was 4.0%, which is borderline statistically significant (95% CI, 8.02 to 0.01%; P 5 0.05).
Discussion Childhood blindness has major socioeconomic, educational, and psychological consequences.12 Most studies addressing the rates of childhood blindness rely on partial data from clinics or schools for the blind (see Appendix for references). The present study, based on 15 years of data from a national registry, found a significant decline in the annual rate of childhood blindness in Israel over time. This decline is attributable mainly to a decrease in the number of blindness due to optic atrophy, RP, ROP, and albinism. Our findings differ from a recent British study, which demonstrated an increase in the rate of childhood blindness in the last 3 decades.9 The authors explained this trend by increased awareness and a higher prevalence of low birth weight and preterm deliveries, underlying CVI, and improved survival of children with multiple disabilities. Although CVI appears to be among the most prevalent etiologies, if not the most common cause of childhood blindness in developed countries,13-18 it was not listed as an official cause of blindness in Israel until 2009. We suspect that community ophthalmologists documented this cause of blindness as optic atrophy, causing an artificially high incidence of optic atrophy as an etiology for childhood blindness in the years preceding 2009. Indeed, when new cases of CVI were combined with optic atrophy, the decline in the incidence of certified blindness classified as optic atrophy was of borderline statistical significance. This assumption is further supported by the finding that optic atrophy is diagnosed in 30% to 40% of children with CVI.15,19 The increase
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Table 3. The distribution of new certificates of blindness N (%) issued to children in Israel between 2003 and 2013 by specific causesa Year
Total
OA
RP
ROP
Albinism
Other retinal disorders
Cataract
Glaucoma
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
109 134 152 108 133 119 111 104 121 110 83
25 (23) 26(19) 30 (20) 13 (12) 18 (14) 21 (18) 17 (15) 22 (21) 15 (12) 17 (16) 11 (13)
17 (16) 30 (22) 30 (20) 27 (25) 22 (17) 20 (17) 18 (16) 18 (17) 20 (17) 20 (18) 11 (13)
8 (7) 8 (6) 10 (7) 7 (6) 11 (8) 7 (6) 3 (3) 3 (3) 4 (3) 2 (2) 3 (4)
7 (6) 9 (7) 10 (7) 15 (14) 11 (8) 4 (3) 3 (3) 8 (8) 10 (8) 7 (6) 3 (4)
9 (8) 9 (7) 12 (8) 10 (9) 11 (8) 18 (15) 16 (14) 15 (14) 15 (12) 13 (12) 9 (11)
4 (4) 5 (4) 3 (2) 7 (6) 8 (6) 2 (2) 6 (5) 6 (6) 7 (6) 3 (3) 1 (1)
1 (1) 5 (4) 2 (1) 4 (4) 5 (4) 6 (5) 4 (4) 6 (6) 4 (3) 4 (4) 3 (4)
OA, optic atrophy; RP, retinitis pigmentosa; ROP, retinopathy of prematurity. a Records of the cause of blindness were available only from 2003 onwards. The main cause for visual impairment for the better seeing eye was coded.
in the number of children with certified blindness due to CVI between 2009 and 2013 may be attributed to increasing awareness of CVI as a cause of blindness20-22 rather than a true increase in its incidence. Nevertheless, a true increase in the incidence of CVI in Israel cannot be ruled out and could be associated with better survival rates and comprehensive postnatal care of extremely low birth weight and preterm infants, which are risk factors for CVI.10,23 We observed a statistically significant decrease in the rate of childhood blindness in Israel especially in RP, albinism, and ROP. Consanguineous marriages continue to be prevalent in the Middle East and in the Israeli Arab minority in particular, raising the frequency of autosomal recessive diseases, including RP24-29 and albinism.30,31 The prevalence of consanguineous marriages in Israeli Jews declined from 9.7% in 195632 to 2.3% in 1991.25 A significant decrease was also evident in the Israeli Arab population, from 52.9% between 1961 and 1970 to 32.8% in 1991 and 199827,33 as well as 35.8% before 2000 to 24% among those married in 2005-2009.34 Therefore, we believe that the decline in the rates of new childhood blindness due to RP and albinism may be attributed to the decrease in consanguinity rates during the study period26,27 some of which may be due to better access to and availability of genetic counseling.35,36 Infant mortality in Israel over the last decades has markedly declined.37 Improvement in postnatal growth in very low birth weight preterm infants in Israel may play a role in decreasing mortality and morbidity including ROP.38,39 Severe postnatal growth failure decreased from 11.7% in 1995-2000 to 7.2% in 2001-2005 and 5.2% in 20062010. A study of 317 very low birth weight preterm babies revealed that low weight gain by 6 weeks of life was an important and independent risk factor for severe ROP.40 Thus the decline in new cases of blind certification due to ROP might have been secondary to the improved growth in very low birth weight infants. In addition, ROP management with diode laser and antivascular endothelial growth factor agents, may contribute
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to the decrease in blindness due to ROP; this decrease is in accordance with reports in the developed world and may reflect improvement in screening and treating protocols.41-45 This study has several limitations. Although based on a national registry data, a selection bias due to an underreporting of the blind children is possible due to the fact that registration is not legally required in Israel. Additionally, children who suffer from multiple congenital anomalies may fail to register. However, the substantial medical, financial, and social benefits may decrease the likelihood for a selection bias and encourage parents and legal custodians to apply for blind certification. It is not possible to determine the capture rate of blind children in the registry. Blind children can also apply for benefits from the National Insurance Institute of Israel. The capture rate of blind children in the registry could have potentially shed light on the portion of blind children who applied for registration of the total number of these children. However, there is currently no database that accumulates information that can be utilized to that end. A national registry contains a set of parameters that are routinely acquired. This might prevent subgroup analysis and adjustment for confounders that are not part of the reported parameters in the registry. When the patient suffers from multiple conditions, only one is reported as the major cause of blindness, although multiple causes may play a role. Furthermore, reporting patterns can change due for example to coding a secondary cause of visual impairment as the main cause. Misclassification of specific etiologies of blindness can occur when the diagnosis cannot be coded according to the preset criteria used in the registry, for example, cone-rod dystrophy, which is not by definition RP. Finally, we mentioned possible public heath trends that might account for the decrease in blindness due to RP and ROP that was observed. This data was not studied in the children with blind certification and therefore remains a conjecture.
7.7 to 11.1% 0.73
The authors thank Dr Ilana Gleitman, Director of the Service for the Blind, the Israeli Ministry of Welfare and Social Services for providing access to national registry data and Mrs. Myrna Perlmutter for her English language editing services.
13.3 to 4.0% 0.29 CI, confidence interval; OA, optic atrophy; ROP, retinopathy of prematurity; RP, retinitis pigmentosa. a Records of the cause of blindness were available only from 2003 onward.
4.1 to 6.5% 0.66 14.3 to 0.9% 0.03 11.2 to 3.0% 0.008 12.4 to 3.8% 0.002
22.9 to 6.8% 0.003
Glaucoma Cataract
0.17 (0.003 to 0.34) 0.21 (0.03 to 0.39) 0.12 ( 0.02 to 0.26) 0.28 (0.07 to 0.50) 0.12 (0.10 to 0.54) 0.08 ( 0.03 to 0.19) 0.22 (0.04 to 0.39) 0.22 (0.04 to 0.39) 0.25 (0.06 to 0.43) 0.11 ( 0.01 to 0.24) 0.04 ( 0.04 to 0.11) 4.7% 0.38 (0.13 to 0.63) 0.38 (0.13 to 0.62) 0.49 (0.22 to 0.78) 0.41 (0.15 to 0.66) 0.44 (0.18 to 0.70) 0.71 (0.38 to 1.03) 0.60 (0.30 to 0.89) 0.54 (0.27 to 0.82) 0.53 (0.26 to 0.80) 0.49 (0.22 to 0.75) 0.33 (0.11 to 0.55) 11.2%
Other retinal disorders Albinism
0.30 (0.08 to 0.52) 0.38 (0.13 to 0.62) 0.41 (0.16 to 0.67) 0.61 (0.30 to 0.92) 0.44 (0.18 to 0.70) 0.16 (0.003 to 0.31) 0.11 ( 0.01 to 0.24) 0.29 (0.09 to 0.49) 0.36 (0.14 to 0.58) 0.26 (0.07 to 0.46) 0.11 ( 0.01 to 0.24) 7.6% 0.72 (0.38 to 1.07) 1.25 (0.81 to 1.71) 1.24 (0.80 to 1.68) 1.10 (0.68 to 1.51) 0.88 (0.51 to 1.25) 0.79 (0.44 to 1.13) 0.67 (0.36 to 0.98) 0.65 (0.35 to 0.95) 0.71 (0.40 to 1.02) 0.75 (0.42 to 1.08) 0.40 (0.17 to 0.64) 7.1%
OA
1.06 (0.65 to 1.48) 1.09 (0.67 to 1.51) 1.24 (0.80 to 1.68) 0.53 (0.24 to 0.82) 0.72 (0.39 to 1.05) 0.82 (0.47 to 1.18) 0.63 (0.33 to 0.94) 0.80 (0.46 to 1.13) 0.53 (0.26 to 0.80) 0.64 (0.33 to 0.94) 0.40 (0.17 to 0.64) 8.1%
RP
Acknowledgments
References
Year
ROP
Volume 19 Number 3 / June 2015
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 Mean annual change 95% CI P value
Table 4. Incidence rates (95% CI) per 100,000 and mean annual change of certified childhood blindness in Israel between 2003 and 2013 to by specific causesa
0.04 ( 0.04 to 0.13) 0.21 (0.03 to 0.39) 0.08 ( 0.03 to 0.20) 0.16 (0.003 to 0.32) 0.20 (0.02 to 0.37) 0.23 (0.05 to 0.42) 0.15 (0.003 to 0.30) 0.22 (0.04 to 0.39) 0.14 (0.003 to 0.28) 0.15 (0.003 to 0.30) 0.11 ( 0.01 to 0.24) 11.7%
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0.34 (0.10 to 0.58) 0.34 (0.10 to 0.57) 0.41 (0.16 to 0.67) 0.28 (0.07 to 0.48) 0.44 (0.18 to 0.70) 0.27 (0.07 to 0.48) 0.11 ( 0.01 to 0.24) 0.11 ( 0.01 to 0.23) 0.14 (0.003 to 0.28) 0.07 ( 0.03 to 0.18) 0.11 ( 0.01 to 0.24) 14.9%
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35. Carmi R. Genetic counselling to a traditional society. Lancet 1991; 337:306. 36. Shiloh S, Reznik H, Bat-Miriam-Katznelson M, Goldman B. Premarital genetic counselling to consanguineous couples: attitudes, beliefs and decisions among counselled, noncounselled and unrelated couples in Israel. Soc Sci Med 1995;41:1301-10. 37. Amitai Y, Haklai Z, Tarabeia J, et al. Infant mortality in Israel during 1950-2000: rates, causes, demographic characteristics and trends. Paediatr Perinat Epidemiol 2005;19:145-51. 38. Grisaru-Granovsky S, Reichman B, Lerner-Geva L, et al. Mortality and morbidity in preterm small-for-gestational-age infants: a population-based study. Am J Obstet Gynecol 2012;206:150.e151-7. 39. Ofek Shlomai N, Reichman B, Lerner-Geva L, Boyko V, Bar-Oz B. Population-based study shows improved postnatal growth in preterm very low birth weight infants between 1995 and 2010. Acta Paediatr 2014;103:498-503. 40. Fortes Filho JB, Bonomo PP, Maia M, Procianoy RS. Weight gain measured at 6 weeks after birth as a predictor for severe retinopathy of prematurity: study with 317 very low birth weight preterm babies. Graefes Arch Clin Exp Ophthalmol 2009;247:831-6. 41. Wu WC, Kuo HK, Yeh PT, Yang CM, Lai CC, Chen SN. An updated study of the use of bevacizumab in the treatment of patients with prethreshold retinopathy of prematurity in taiwan. Am J Ophthalmol 2013;155:150-58.e151. 42. Salvin JH, Lehman SS, Jin J, Hendricks DH. Update on retinopathy of prematurity: treatment options and outcomes. Curr Opin Ophthalmol 2010;21:329-34. 43. Mintz-Hittner HA, Kennedy KA, Chuang AZ. Efficacy of intravitreal bevacizumab for stage 31 retinopathy of prematurity. N Engl J Med 2011;364:603-15. 44. Good WV, Hardy RJ, Dobson V, et al., Early Treatment for Retinopathy of Prematurity Cooperative Group. Final visual acuity results in the early treatment for retinopathy of prematurity study. Arch Ophthalmol 2010;128:663-71. 45. Early Treatment For Retinopathy Of Prematurity Cooperative Group. Revised indications for the treatment of retinopathy of prematurity: results of the early treatment for retinopathy of prematurity randomized trial. Arch Ophthalmol 2003;121:1684-94.
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Appendix. Additional references relying on partial data of childhood blindness 1. Kerby CE. Causes and prevention of blindness in children of school age. Sight Sav Rev 1952;22:22-31. 2. Hilgartner HL Jr. Texas State School for the Blind: causes of blindness in children. Tex Med 1967;63:38-9. 3. Mets MB. Childhood blindness and visual loss: an assessment at two institutions including a “new” cause. Trans Am Ophthalmol Soc 1999;97:653-96. 4. Blohme J, Tornqvist K. Visual impairment in Swedish children. III. Diagnoses. Acta Ophthalmol Scand 1997;75:681-7. 5. Blohme J, Tornqvist K. Visual impairment in Swedish children. II. Etiological factors. Acta Ophthalmol Scand 1997;75:199-205. 6. Blohme J, Tornqvist K. Visual impairment in Swedish children. I. Register and prevalence data. Acta Ophthalmol Scand 1997;75:194-8. 7. Alagaratnam J, Sharma TK, Lim CS, Fleck BW. A survey of visual impairment in children attending the Royal Blind School, Edinburgh using the WHO childhood visual impairment database. Eye (Lond) 2002;16:557-61. 8. Goggin M, O’Keefe M. Childhood blindness in the Republic of Ireland: a national survey. Br J Ophthalmol 1991;75:425-9. 9. Rohrschneider K, Mackensen I. Causes of blindness in students at the school for blind children in Ilvesheim. Changes between 1885 and 2008 [in German]. Ophthalmologe 2013;110:331-8. 10. Gilbert C, Foster A. Causes of blindness in children attending four schools for the blind in Thailand and the Philippines: a comparison between urban and rural blind school populations. Int Ophthalmol1993;17:229–234. 11. Hornby SJ, Xiao Y, Gilbert CE, et al. Causes of childhood blindness in the People’s Republic of China: results from 1131 blind school students in 18 provinces. Br J Ophthalmol 1999;83:929-32.
Volume 19 Number 3 / June 2015 12. Rahi JS, Sripathi S, Gilbert CE, Foster A. Childhood blindness in India: causes in 1318 blind school students in nine states. Eye (Lond) 1995;9(Pt 5):545-50. 13. Waddell KM. Childhood blindness and low vision in Uganda. Eye (Lond) 1998;12(Pt 2):184-92. 14. Chirambo MC, Benezra D. Causes of blindness among students in blind school institutions in a developing country. Br J Ophthalmol 1976;60:665-8. 15. Olurin O. Etiology of blindness in Nigerian children. Am J Ophthalmol 1970;70:533-40. 16. Akinsola FB, Ajaiyeoba AI. Causes of low vision and blindness in children in a blind school in Lagos, Nigeria. West Afr J Med 2002;21: 63-5. 17. Ajaiyeoba AI, Isawumi MA, Adeoye AO, Oluleye TS. Prevalence and causes of blindness and visual impairment among school children in south-western Nigeria. Int Ophthalmol 2005;26:121-5. 18. Gilbert CE, Canovas R, Hagan M, Rao S, Foster A. Causes of childhood blindness: results from west Africa, south India and Chile. Eye (Lond) 1993;7(Pt 1):184-8. 19. Merin S, Lapithis AG, Horovitz D, Michaelson IC. Childhood blindness in Cyprus. Am J Ophthalmol 1972;74:538-42. 20. Baghdassarian SA, Tabbara KF. Childhood blindness in Lebanon. Am J Ophthalmol 1975;79:827-30. 21. Kotb AA, Hammouda EF, Tabbara KF. Childhood blindness at a school for the blind in Riyadh, Saudi Arabia. Ophthalmic Epidemiol 2006;13:1-5. 22. Tabbara KF, Badr IA. Changing pattern of childhood blindness in Saudi Arabia. Br J Ophthalmol 1985;69:312-15. 23. Tabbara KF, El-Sheikh HF, Shawaf SS. Pattern of childhood blindness at a referral center in Saudi Arabia. Ann Saudi Med 2005;25: 18-21.
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To describe trends in the incidence and causes of legal childhood blindness in Israel, one of the few countries worldwide that maintain a national registry of the blind.
METHODS
We performed a historical cohort study of annual reports of the National Registry of the Blind (NRB) between 1999 and 2013. All data regarding demographic information, year of registration and cause of blindness of children 0-18 years of age registered for blind certification were obtained from the annual reports of the NRB. Causes of legal blindness analyzed were optic atrophy, retinitis pigmentosa, retinopathy of prematurity (ROP), albinism, other retinal disorders, cataract, and glaucoma. The main outcome measure was the incidence of new cases of certified legal blindness.
RESULTS
The incidence of newly registered legally blind children in Israel almost halved from 7.7 per 100,000 in 1999 to 3.1 per 100,000 in 2013. The decline was mainly attributable to a decreased incidence of blindness resulting from retinitis pigmentosa and ROP. The incidence of registered cases due to cerebral visual impairment increased.
CONCLUSIONS
During the past decade the incidence of severe childhood visual impairment and blindness declined in Israel. A continuous decline in consanguineous marriages among the Jewish and Arab populations in Israel may have contributed to the decrease in the rate of vision loss due to retinitis pigmentosa in children. ( J AAPOS 2015;19:260-265)
I
n 2010 the World Health Organization (WHO) estimated that 19 million children under the age of 15 worldwide were visually impaired. Of these, 7 million cases were visually impaired due to causes other than uncorrected refractive errors. A total of 1.4 million children were irreversibly blind.1 Although the worldwide incidence rate of childhood blindness declined by 10% between 1999 and 2010, the rate increased in India and in Sub-Saharan Africa.2 Childhood blindness accounts for 3.6% of total blindness worldwide.3 The estimated global prevalence of childhood blindness is 80/100,000.4 The effect of blindness on neurobehavioral development is of major concern, and the psychological and financial impact on the families, institutional support systems, and health care providers cannot be overrated. Israel, Finland, and the United Kingdom are the only 3 countries that maintains a nationwide blindness registry.5-11
Author affiliations: aDepartment of Ophthalmology, Rambam Health Care Campus, Haifa, Israel; bRuth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, Haifa, Israel; cUnit of Cardiovascular Epidemiology, Gertner Institute for Epidemiology & Health Policy Research, Tel Hashomer, Israel; dSackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; eThe Goldschleger Eye Institute, Sheba Medical Center, Tel Hashomer, Israel Submitted December 27, 2014. Revision accepted April 4, 2015. Correspondence: Dr Eedy Mezer, MD, PO Box 9907, Haifa 3109901, Israel (email: [email protected]). Copyright Ó 2015 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 http://dx.doi.org/10.1016/j.jaapos.2015.04.002
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Data derived from national registries are preferable to data from fragmented, local resources or incomplete statewide surveys for analysis of time trends. National registry data may be less prone to selection bias, providing that reporting is compulsory and complete. It provides information that enables understanding health care processes and supports health policy decision making. This study aimed to describe the incidence and causes of legal childhood blindness in Israel from 1999 to 2013.
Materials and Methods The study and data collection conformed to all local laws and adhered to the principles of the Declaration of Helsinki. This study included children 0-18 years of age who were found to be eligible according to the definition of legal blindness in Israel, after being registered and completing the process of blindness certification provided by the Ministry of Welfare and Social Services. Manual registry of blindness certificates was carried out from 1990; a computerized national registry was established later and contains data from 1999 onward. We conducted a historical cohort study and analyzed the incidence of legal blindness certificates issued between 1999 and 2013. Records on the cause of blindness were available from 2003 onward and are outlined in Table 1. In 2009 cortical visual impairment (CVI) was added to the list of causes of blindness. CVI was usually diagnosed by an ophthalmologist as bilaterally diminished visual acuity caused by damage shown on MRI to the occipital lobes or to the visual pathways; prior to 2009 it was coded by default as bilateral optic
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Volume 19 Number 3 / June 2015 Table 1. Causes of visual impairment listed in the certification of blindness application form Parts of the eye Eyeball
Uveal tract Cornea and sclera Glaucoma Cataract
Retina and vitreous
Optic nerve and pathways
Medical diagnosis Phthisis Anophthalmos Microphthalmos Albinism Nystagmus Amblyopia Uveitis Central opacity Keratoconus Primary Congenital Secondary Senile Congenital Complicated Operated Retinopathy of prematurity Retinitis pigmentosa Retinal detachment Myopic maculopathy Diabetic maculopathy and retinopathy Age-related macular degeneration Vitreous hemorrhage Central venous or arterial occlusion Optic atrophy Other neuropathy CVI
atrophy. The diagnosis of CVI was supported by an appropriate medical history. Routine screening eye examinations, consisting of noncycloplegic manual retinoscopy and detection of strabismus and other external eye anomalies, are performed between the age of 1.5 and 3 years at the Ministry of Health Mother and Child Clinics by a medical team consisting of an ophthalmologist or a trained optometrist or a certified orthoptist. Visual acuity testing is carried out adjusted to the age and cognitive abilities of the child. In addition, some health maintenance organizations (HMOs) in Israel provide routine vision screening examinations performed by a community general ophthalmologist or pediatric ophthalmologist between the ages of 1.5 and 3 years. Furthermore, every child in Israel undergoes an additional mandatory visual acuity test before entering elementary school at the age of 6 years. Children with abnormal visual acuity, retinoscopy, ocular alignment or red reflex test are referred for further evaluation by a pediatric ophthalmologist either in the community or in one of the country’s 25 public hospitals. In Israel legal blindness is defined by either best-corrected visual acuity of less than 3/60 in the better-seeing eye or a central visual field of less than 20 in the better-seeing eye. The process of certification of blindness is initiated when children are referred for evaluation after failed visual acuity screening test or because they are afflicted with a medical condition that causes severe visual impairment. Therefore, there is no uniform age at which children were registered and included in the registry. Complete eye examination includes age-appropriate best-corrected visual acuity assessment, a thorough ophthalmologic examination, and visual
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field testing where applicable (the latter is obtained usually in children .8 years of age). In preverbal or mentally challenged children, nonverbal techniques, such as matching displayed symbols or Teller acuity cards, are used. Specific data is lacking, because the examination methods are not included in the application form. One disorder is coded as the main cause for visual impairment for the better-seeing eye in the standardized application form for blind certification. Other causes for visual impairment in each eye are also coded but not as the main cause. If the patient is considered eligible by the referring ophthalmologist, the certification request is forwarded to a senior ophthalmology consultant appointed by the National Service for the Blind within the Israeli Ministry of Welfare and Social Services. The diagnosis used for analysis is the opinion of the senior ophthalmology consultant appointed by the National Service for the Blind. In the uncommon event of discrepancies between the diagnosis of the referring ophthalmologist and the consultant appointed by the National Service for the Blind, the opinion of the appointed ophthalmologist is used, sometimes after additional ancillary testing to further verify the extent and nature of the visual impairment. If the diagnosis is confirmed by the consultant, a recommendation is issued. The ophthalmologist records on the application form the results of the visual acuity and visual field assessments for each eye. In addition, the major and minor causes for visual impairment out of 31 possible diagnoses are recorded. The result of the visual acuity testing is classified into the following categories: light perception, perception of hand movement, best-corrected visual acuity of 1/60 or worse; best-corrected visual acuity of less of 3/60 or worse; or best-corrected visual acuity better than 3/60. Visual field data is classified into one of the following categories: \10 from point of fixation in each quadrant; .10 but \20 ; or $20 . A regional committee provides the final approval of the blindness certificate. Demographic data, year of registration, and cause of blindness is routinely collected by the national registry and published in an annual report. We assume that almost every blind child in Israel is registered, because the access to ophthalmologic healthcare services is free of charge and widely available; furthermore, the incentives for voluntary registration are high. Medical benefits include rehabilitation services for the child and his or her family, discounts on low-vision aid products, and discounts on other health care services. Financial benefits include discounts on kindergarten and school payments, discounts on municipal taxes, free public transportation, tax benefits, and a monthly allowance. Schooling benefits are also provided in the form of a part-time personal assistant at school. Temporary blind certification usually for 2 years is granted in cases were visual acuity may improve following medical or surgical treatment or in babies too young to be tested but presenting with a medical condition thought to make the patient eligible for blind certification (ie, Leber’s congenital amaurosis). Information on the size of the population (age #18 years) during the study period was obtained from the database of the Israel Central Bureau of Statistics. Annual rates of all-cause, sex-specific, and disease-specific legal blindness were calculated. Poisson regression models were used to assess time-trends of all-cause, sex and disease-specific rates of blindness.
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Table 2. Population size (children #18 years of age); number and crude rates (95% CI) of new certificates of blindnessa issued between 1999 and 2013
Year
Population (in millions)
Number of new certificates of blindness
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
2.19 2.23 2.28 2.31 2.34 2.38 2.42 2.46 2.50 2.54 2.67 2.75 2.81 2.67 2.72
168 172 153 153 109 134 152 108 133 119 111 104 121 110 83
Rate per 100,000
95% CI
7.67 7.68 6.71 6.61 4.64 5.62 6.28 4.39 5.31 4.67 4.15 3.77 4.30 4.12 3.05
6.51-8.83 6.54-8.83 5.64-7.77 5.56-7.65 3.77-5.51 4.67-6.57 5.28-7.27 3.56-5.22 4.41-6.22 3.83-5.51 3.37-4.92 3.05-4.49 3.53-5.06 3.35-4.89 2.40-3.71
a
In Israel, legal blindness is defined by either best-corrected visual acuity of less than 0.05 in the better seeing eye or a central visual field of less than 20 in the better-seeing eye.
Results Between 1999 and 2013 the incidence of newly registered blindness in children declined by 60%, from 7.67/ 100,000 in 1999 to 3.05/100,000 in 2013. The average annual decline was 5.6% (95% CI, 4.5%-6.6%; P \ 0.001). See Table 2 and Figure 1. The average annual decline was greater in females (6.6%; 95% CI, 5.0%-8.3%; P \ 0.001) than in males (4.8%; 95% CI, 3.5%-6.2%; P \ 0.001). Optic atrophy and retinitis pigmentosa (RP) were the leading causes of childhood blindness in Israel (Table 3). There was a statistically significant decline in the annual incidence of optic atrophy, RP, retinopathy of prematurity (ROP), and albinism during this period (Table 4). The average annual declines of new cases of childhood blindness due to optic atrophy was 8.1% (95% CI, 3.8%-12.4%; P 5 0.002); to RP, 7.1% (95% CI, 3.0%-11.2%; P 5 0.008); to ROP, 14.9% (95% CI, 6.8%-22.9%; P 5 0.003); and to albinism, 7.6% (95% CI, 0.9%-14.3%; P 5 0.03). The rates of blindness due to retinal vitreous disorders, congenital glaucoma, and congenital cataract did not significantly change during this time period. There was also a modest decline in blindness due to other causes grouped together (eg, nystagmus, amblyopia, central opacity, myopic maculopathy); the mean annual change was 3.4% (95% CI, 6.1 to 0.6). However, due to the small number of cases in each specific diagnosis, it was not possible to further investigate each underlying cause. In 2011 there was an increase in newly certified cases of childhood blindness due to the addition of CVI added in 2009. This increased the incidence of new cases per year from 3 during 2009-2010, to 14 in 2011, 8 in 2012, and 6
FIG 1. Incidence of newly registered childhood blindness in Israel between 1999 and 2013.
in 2013. Before 2011, most CVI cases may have been combined with optic atrophy cases. If these 2 groups are combined the annual change in the rate of newly certified blindness cases due to both was 4.0%, which is borderline statistically significant (95% CI, 8.02 to 0.01%; P 5 0.05).
Discussion Childhood blindness has major socioeconomic, educational, and psychological consequences.12 Most studies addressing the rates of childhood blindness rely on partial data from clinics or schools for the blind (see Appendix for references). The present study, based on 15 years of data from a national registry, found a significant decline in the annual rate of childhood blindness in Israel over time. This decline is attributable mainly to a decrease in the number of blindness due to optic atrophy, RP, ROP, and albinism. Our findings differ from a recent British study, which demonstrated an increase in the rate of childhood blindness in the last 3 decades.9 The authors explained this trend by increased awareness and a higher prevalence of low birth weight and preterm deliveries, underlying CVI, and improved survival of children with multiple disabilities. Although CVI appears to be among the most prevalent etiologies, if not the most common cause of childhood blindness in developed countries,13-18 it was not listed as an official cause of blindness in Israel until 2009. We suspect that community ophthalmologists documented this cause of blindness as optic atrophy, causing an artificially high incidence of optic atrophy as an etiology for childhood blindness in the years preceding 2009. Indeed, when new cases of CVI were combined with optic atrophy, the decline in the incidence of certified blindness classified as optic atrophy was of borderline statistical significance. This assumption is further supported by the finding that optic atrophy is diagnosed in 30% to 40% of children with CVI.15,19 The increase
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Table 3. The distribution of new certificates of blindness N (%) issued to children in Israel between 2003 and 2013 by specific causesa Year
Total
OA
RP
ROP
Albinism
Other retinal disorders
Cataract
Glaucoma
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
109 134 152 108 133 119 111 104 121 110 83
25 (23) 26(19) 30 (20) 13 (12) 18 (14) 21 (18) 17 (15) 22 (21) 15 (12) 17 (16) 11 (13)
17 (16) 30 (22) 30 (20) 27 (25) 22 (17) 20 (17) 18 (16) 18 (17) 20 (17) 20 (18) 11 (13)
8 (7) 8 (6) 10 (7) 7 (6) 11 (8) 7 (6) 3 (3) 3 (3) 4 (3) 2 (2) 3 (4)
7 (6) 9 (7) 10 (7) 15 (14) 11 (8) 4 (3) 3 (3) 8 (8) 10 (8) 7 (6) 3 (4)
9 (8) 9 (7) 12 (8) 10 (9) 11 (8) 18 (15) 16 (14) 15 (14) 15 (12) 13 (12) 9 (11)
4 (4) 5 (4) 3 (2) 7 (6) 8 (6) 2 (2) 6 (5) 6 (6) 7 (6) 3 (3) 1 (1)
1 (1) 5 (4) 2 (1) 4 (4) 5 (4) 6 (5) 4 (4) 6 (6) 4 (3) 4 (4) 3 (4)
OA, optic atrophy; RP, retinitis pigmentosa; ROP, retinopathy of prematurity. a Records of the cause of blindness were available only from 2003 onwards. The main cause for visual impairment for the better seeing eye was coded.
in the number of children with certified blindness due to CVI between 2009 and 2013 may be attributed to increasing awareness of CVI as a cause of blindness20-22 rather than a true increase in its incidence. Nevertheless, a true increase in the incidence of CVI in Israel cannot be ruled out and could be associated with better survival rates and comprehensive postnatal care of extremely low birth weight and preterm infants, which are risk factors for CVI.10,23 We observed a statistically significant decrease in the rate of childhood blindness in Israel especially in RP, albinism, and ROP. Consanguineous marriages continue to be prevalent in the Middle East and in the Israeli Arab minority in particular, raising the frequency of autosomal recessive diseases, including RP24-29 and albinism.30,31 The prevalence of consanguineous marriages in Israeli Jews declined from 9.7% in 195632 to 2.3% in 1991.25 A significant decrease was also evident in the Israeli Arab population, from 52.9% between 1961 and 1970 to 32.8% in 1991 and 199827,33 as well as 35.8% before 2000 to 24% among those married in 2005-2009.34 Therefore, we believe that the decline in the rates of new childhood blindness due to RP and albinism may be attributed to the decrease in consanguinity rates during the study period26,27 some of which may be due to better access to and availability of genetic counseling.35,36 Infant mortality in Israel over the last decades has markedly declined.37 Improvement in postnatal growth in very low birth weight preterm infants in Israel may play a role in decreasing mortality and morbidity including ROP.38,39 Severe postnatal growth failure decreased from 11.7% in 1995-2000 to 7.2% in 2001-2005 and 5.2% in 20062010. A study of 317 very low birth weight preterm babies revealed that low weight gain by 6 weeks of life was an important and independent risk factor for severe ROP.40 Thus the decline in new cases of blind certification due to ROP might have been secondary to the improved growth in very low birth weight infants. In addition, ROP management with diode laser and antivascular endothelial growth factor agents, may contribute
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to the decrease in blindness due to ROP; this decrease is in accordance with reports in the developed world and may reflect improvement in screening and treating protocols.41-45 This study has several limitations. Although based on a national registry data, a selection bias due to an underreporting of the blind children is possible due to the fact that registration is not legally required in Israel. Additionally, children who suffer from multiple congenital anomalies may fail to register. However, the substantial medical, financial, and social benefits may decrease the likelihood for a selection bias and encourage parents and legal custodians to apply for blind certification. It is not possible to determine the capture rate of blind children in the registry. Blind children can also apply for benefits from the National Insurance Institute of Israel. The capture rate of blind children in the registry could have potentially shed light on the portion of blind children who applied for registration of the total number of these children. However, there is currently no database that accumulates information that can be utilized to that end. A national registry contains a set of parameters that are routinely acquired. This might prevent subgroup analysis and adjustment for confounders that are not part of the reported parameters in the registry. When the patient suffers from multiple conditions, only one is reported as the major cause of blindness, although multiple causes may play a role. Furthermore, reporting patterns can change due for example to coding a secondary cause of visual impairment as the main cause. Misclassification of specific etiologies of blindness can occur when the diagnosis cannot be coded according to the preset criteria used in the registry, for example, cone-rod dystrophy, which is not by definition RP. Finally, we mentioned possible public heath trends that might account for the decrease in blindness due to RP and ROP that was observed. This data was not studied in the children with blind certification and therefore remains a conjecture.
7.7 to 11.1% 0.73
The authors thank Dr Ilana Gleitman, Director of the Service for the Blind, the Israeli Ministry of Welfare and Social Services for providing access to national registry data and Mrs. Myrna Perlmutter for her English language editing services.
13.3 to 4.0% 0.29 CI, confidence interval; OA, optic atrophy; ROP, retinopathy of prematurity; RP, retinitis pigmentosa. a Records of the cause of blindness were available only from 2003 onward.
4.1 to 6.5% 0.66 14.3 to 0.9% 0.03 11.2 to 3.0% 0.008 12.4 to 3.8% 0.002
22.9 to 6.8% 0.003
Glaucoma Cataract
0.17 (0.003 to 0.34) 0.21 (0.03 to 0.39) 0.12 ( 0.02 to 0.26) 0.28 (0.07 to 0.50) 0.12 (0.10 to 0.54) 0.08 ( 0.03 to 0.19) 0.22 (0.04 to 0.39) 0.22 (0.04 to 0.39) 0.25 (0.06 to 0.43) 0.11 ( 0.01 to 0.24) 0.04 ( 0.04 to 0.11) 4.7% 0.38 (0.13 to 0.63) 0.38 (0.13 to 0.62) 0.49 (0.22 to 0.78) 0.41 (0.15 to 0.66) 0.44 (0.18 to 0.70) 0.71 (0.38 to 1.03) 0.60 (0.30 to 0.89) 0.54 (0.27 to 0.82) 0.53 (0.26 to 0.80) 0.49 (0.22 to 0.75) 0.33 (0.11 to 0.55) 11.2%
Other retinal disorders Albinism
0.30 (0.08 to 0.52) 0.38 (0.13 to 0.62) 0.41 (0.16 to 0.67) 0.61 (0.30 to 0.92) 0.44 (0.18 to 0.70) 0.16 (0.003 to 0.31) 0.11 ( 0.01 to 0.24) 0.29 (0.09 to 0.49) 0.36 (0.14 to 0.58) 0.26 (0.07 to 0.46) 0.11 ( 0.01 to 0.24) 7.6% 0.72 (0.38 to 1.07) 1.25 (0.81 to 1.71) 1.24 (0.80 to 1.68) 1.10 (0.68 to 1.51) 0.88 (0.51 to 1.25) 0.79 (0.44 to 1.13) 0.67 (0.36 to 0.98) 0.65 (0.35 to 0.95) 0.71 (0.40 to 1.02) 0.75 (0.42 to 1.08) 0.40 (0.17 to 0.64) 7.1%
OA
1.06 (0.65 to 1.48) 1.09 (0.67 to 1.51) 1.24 (0.80 to 1.68) 0.53 (0.24 to 0.82) 0.72 (0.39 to 1.05) 0.82 (0.47 to 1.18) 0.63 (0.33 to 0.94) 0.80 (0.46 to 1.13) 0.53 (0.26 to 0.80) 0.64 (0.33 to 0.94) 0.40 (0.17 to 0.64) 8.1%
RP
Acknowledgments
References
Year
ROP
Volume 19 Number 3 / June 2015
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 Mean annual change 95% CI P value
Table 4. Incidence rates (95% CI) per 100,000 and mean annual change of certified childhood blindness in Israel between 2003 and 2013 to by specific causesa
0.04 ( 0.04 to 0.13) 0.21 (0.03 to 0.39) 0.08 ( 0.03 to 0.20) 0.16 (0.003 to 0.32) 0.20 (0.02 to 0.37) 0.23 (0.05 to 0.42) 0.15 (0.003 to 0.30) 0.22 (0.04 to 0.39) 0.14 (0.003 to 0.28) 0.15 (0.003 to 0.30) 0.11 ( 0.01 to 0.24) 11.7%
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0.34 (0.10 to 0.58) 0.34 (0.10 to 0.57) 0.41 (0.16 to 0.67) 0.28 (0.07 to 0.48) 0.44 (0.18 to 0.70) 0.27 (0.07 to 0.48) 0.11 ( 0.01 to 0.24) 0.11 ( 0.01 to 0.23) 0.14 (0.003 to 0.28) 0.07 ( 0.03 to 0.18) 0.11 ( 0.01 to 0.24) 14.9%
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