According to the editor of the study, its results are of the utmost importance, as Israel currently has an advanced system of genetic testing and genetic counseling to detect eye diseases from childhood. The system helps families find the cause of a family member's eye disease and then helps families process the information, and subsequently prevent the disease from recurring in the family
A study led by Dr. Claudia Yahlom, a pediatric ophthalmologist and director of the Michaelson Institute for Vision Rehabilitation at the Hadassah Medical Center and the Hebrew University, which was recently published in the journal eye on behalf of nature, showed that the main cause of poor vision and blindness in children in developed countries is acquired eye diseases. The researchers collected data over five years in which visually impaired patients continuously visited the Michaelson Institute. The clinic treats children from all over the country with visual impairment due to various reasons and a variety of eye diseases and sometimes systemic diseases. The large amount of data was collected from the institute from the beginning of 2015 to the end of 2019.
Patients were defined as having "poor vision" when the visual acuity was 6/18 to 6/60, and were defined as having "blindness" when the visual acuity was less than 6/60 or a reduced visual field of less than 20 degrees (the World Health Organization defines blindness as vision lower than 3/60, with the Israeli definition of blindness being less rigid). 1,393 patients were included in the study, with the average age being 8 years, with an age range of six months to 18 years. The "poor vision" group included 73.6% of the patients and the "blindness" group included 26.4% of the patients. 11% of the patients had systemic involvement (whole body) such as cerebral palsy or a syndrome involving hearing impairment with visual impairment.
A breakdown by ethnicity showed that most of the patients were Jews (67.8%), followed by Arab Muslims (26.9%) and others, mainly Druze Arabs and Christians (5.2%). Also, a statistically significant correlation was found between the most common eye diseases and ethnicity. Among the Jews, albinism was the most common disease affecting vision (48.4%) and among Arab Muslims genetic diseases of the retina were the most common (50.6%).
It was also found that hereditary eye diseases were the cause of poor vision in 77.4% of the patients. The hereditary eye diseases were albinism, retinal diseases (such as RP (retinitis pigmentosa, achromatopsia, BEST disease, STARGARDT disease, and cone rod dystrophy), aniridia, hereditary optic atrophy, hereditary cataract, and retinoblastoma. Non-hereditary eye diseases found in the patients included Retinopathy of prematurity, cerebrovascular injury (CVI), glaucoma and cataract without genetic proof, and optic nerve degeneration on other grounds such as hydrocephalus and lack of oxygen around birth.
In recent years, articles have been published showing that a brain injury called CVI is the main cause of blindness in developed countries such as England. Also in the current study, CVI was the cause of 22% of the cases of blindness. "But when you look at all the influencing factors, you can see that the hereditary diseases as a single group are actually the main cause of poor eyesight and blindness in children in Israel, also in other developed countries," explains Dr. Yahlom this week following the research findings.
Accordingly, in the scientific article several studies were presented in which the link between poor vision and blindness in advanced European countries was shown to heredity. In 2004, a study found that the main cause of visual impairment in 53% of children born in Finland is "genetic eye diseases", and emphasized the lack of treatment for these genetic eye disorders during the two decades in which the study was conducted. In another study, carried out in 2012, it was claimed that hereditary eye diseases accounted for 44% of childhood blindness in Europe based on a literature review carried out. In another study in the same year, it was found that in the first decade of the 21st century in the Netherlands, genetic eye diseases and CVI became the main causes of childhood blindness after the improvement of the possibilities for diagnosing eye diseases in the country.
According to the editor of the study, its results are of the utmost importance, as Israel currently has an advanced system of genetic testing and genetic counseling to detect eye diseases from childhood. The system helps families find the cause of a family member's eye disease and then helps families process the information, and subsequently prevent the disease from recurring in the family. By making the population and attending physicians aware of the results of the study, and patients being referred for genetic counseling, it will be possible to reduce these diseases and consequently reduce the visual impairment in Israel. "Despite great progress in understanding IED (inherited eye diseases), treatment options remain limited. Improved methods for identifying mutations, along with genetic counseling, genetic testing and prenatal genetic diagnosis, provide a possible approach to preventing the recurrence of these diseases in the same family," the article explains.
The research was carried out in partnership with Dr. Karen Handler, pediatric ophthalmologist and low vision specialist at the Hadassah Medical Center. The collection and analysis of the data and the writing of the article were helped and advised by Mr. Ron Brown (medical student), Dr. Rani Patel, an ophthalmologist, Dr. Anat Blumenfeld, director of the eye-genetic laboratory at Hadassah, Ibrahim Saada, an optometrist, Ms. Michal Makarov, a genetic counselor at the Michaelson Institute and the genetic clinic of Hadassah, and Dr. Karen Handler is a pediatric ophthalmologist and a specialist in low vision.
