DATA COLLECTION

Israel has maintained a nationwide registry of blindness certificates since 1987; the system was computerized in 2012. We conducted a descriptive, retrospective, population-based study and analyzed the data of new certificates of blindness issued in Israel, as well as the causes of blindness by age and sex, from 2009 to 2020. The Service for the Blind, Deaf and Assistive Technology (SfBDAT), under the Ministry of Welfare and Social Affairs (MOWSA), maintains a computerized NRB database. Data were directly retrieved from that database to minimize human errors. The data were then revised by the MOWSA officials responsible for big data mining, to exclude duplications of records and to prevent skewing of data, and to search for possible flaws such as incomplete records. To that end, duplicates of blindness certifications of applicants with a permanent certificate of blindness who reapplied for extended benefits and received them were excluded from the database. Information on the population size of each of the relevant age subgroups during that period was obtained from the database of the Israel Central Bureau of Statistics. The subgroups were as follows: ages 0 to 5, 6 to 18, 19 to 40, 41 to 65, 66 to 80, and 81+ years. The etiologies for blindness available on the application form for blindness certification are listed in Table 1 . All data, comprising demographic information, year of blindness certification, results of visual acuity and visual field testing, and cause of blindness, used to be recorded manually. The information was then extracted, manually collected, and physically stored in the national registry archives. In June 2012, the database became automated. The electronic database included an online application form that included the coded results of the medical examination of the referring ophthalmologist as well as the state-appointed ophthalmologist, and the approval of the administrative committee. This was done to minimize human error in data extraction and analysis and to facilitate quality control and access to the data. This system was upgraded in 2016.

Additional information regarding the certification of blindness is provided in the Appendix (p 2).

RELIABILITY OF DATA

It is reasonable to assume that the vast majority of blind individuals in Israel either have applied for blindness certification or general disability benefits on their own behalf, because of significant economic and emotional benefits provided to blindness certificate holders and their families, ^, or have been advised to apply by an ophthalmologist who determined their eligibility after completing an ophthalmological assessment.

DEFINITION OF BLINDNESS IN ISRAEL

Blindness in Israel corresponds to the World Health Organization (WHO) criteria, and is defined as either a visual acuity at distance for an aged-matched standardized optotype such as LEA numbers or symbols of less than 3/60 in the better-seeing eye, or a visual field with a radius no greater than 10° around central fixation in the better-seeing eye with the best possible optical correction.

OCULAR EXAMINATION

The physical examination included performing dry or cycloplegic refraction adjusted for age: cyclopentolate-phenylephrine 0.2%/0.1% for subjects less than 12 months old, and cyclopentolate 1% twice for subjects at least 1 year old, followed by a standardized best corrected visual acuity assessment. In addition, a slitlamp examination and dilated fundus examination were carried out. Ancillary tests were performed as needed, including automated visual field testing, full field electroretinogram, flash or pattern reversal visual evoked potentials, and, in selected cases, optical coherence tomography (OCT), fluorescein retinal angiography, and other tests as described in previous publications. ^{, ,} In the case of cortical blindness and other neuropathies, brain and orbit computed tomography/magnetic resonance imaging scans were often obtained, followed by a thorough neurological or neuro-ophthalmological assessment.

BLINDNESS CERTIFICATION PROCESS

The Service for the Blind, Deaf and Assistive Technology (SfBDAT) issues a Certificate of Blindness to all individuals who meet the WHO definition of blindness. The certification process is carried out after a referral by a staff ophthalmologist, in a hospital or in the community, who has found the patient to meet the requirements of blind certification. A staff ophthalmologist appointed by the Ministry of Welfare and Social Affairs (MOWSA) carries out an independent ocular examination, and further assessment including additional ancillary testing in light of past medical history, and provides a recommendation as to whether the examinee is eligible for a blindness certificate. ^{, ,}

In the case that the examinee is found not eligible for a blind certificate by the staff ophthalmologist, he/she or a guardian can file an appeal to the SfBDAT and an “appeal committee” will reassess the case, referring to ancillary tests when appropriate, and will make a final decision.

Starting from 2015, blindness certification is considered by MOWSA not only for persons who have applied directly to MOWSA but also to those who have undergone a medical committee commissioned by the National Social Insurance Institute (NII). This was done to cancel the need to apply separately to MOWSA for blindness certification benefits as well as to NII for disability compensation.

ETIOLOGY FOR BLINDNESS

Etiologies were assigned to each eye and were usually concordant. In the minority of cases in which 2 different disease processes were recorded, one for each eye, the main Etiology was assigned to the better-seeing eye.

STATISTICAL ANALYSIS

Data were analyzed using SPSS version 24 (IBM Corp.) and R version 4.0.0 (R Core Team (2020). R: A language and environment for statistical computing, R Foundation for Statistical Computing) was used for the Poisson regression models.

Annual age- and sex-specific rates of all-cause and disease-specific blindness were calculated. Annual age-standardized rates were calculated from the WHO standard world population (2000-2025), using a direct standardization method. χ ² Tests were used to examine sex and age group distributions, as appropriate. Poisson regression models were used to establish time trends of all-cause and disease-specific rates of blindness, according to age and sex. To compute the SE for the rate ratios, we used the delta method. The dependent variable was the annual rate of all-cause or cause-specific blindness, and the independent variables were calendar year, age group, and sex. Interactions between calendar year and sex or age were also examined. A 2-tailed P value of <.05 was considered statistically significant.