"Outcome Evaluation of the Visual Preschool Screening in the Province of Trento North East Italy"

Abstract

Introduction: Amblyopia represents the main cause of visual impairment in the developmental age, with a prevalence in preschool children between 1.5 and 4.0%. Preschool visual screening is an evidence-based practice that allows for an early diagnosis of amblyopia and consequently an early treatment that can allow recovery, even total, of visual function. This study reports on the evaluation of the final outcome of visual screening in three consecutive cohorts of children born in the province of Trento and subjected to visual screening at the age of 4, then verifying the quality of vision after 2/3 years. Material and Methods:The subjects identified as amblyopic among children undergoing preschool visual screening at 4 years (second year of kindergarten), in the years 2012-2014, were taken into consideration. These subjects, registered in the screening archive, were followed retrospectively up to three years after the date of the screening to verify, through the Hospital Information System, whether or not they had carried out an eye examination, verifying the acuity vision values achieved for the right eye and the left eye respectively. The data relating to the treatment carried out were also recovered. The difference between the post-treatment and pre-treatment visit acuity values was assessed by the student's T test for the statistical significance of the differences. The assessment of the quality of vision at screening and at the follow-up assessment was also expressed in LOGMar. The significance of the differences between the proportions under comparison (gender, citizenship, residence area) was tested with the chi-squared test or Fisher's exact test, as needed. Proportions are provided by 95% confidence intervals (95% CI).Results: In the years 2012-2014, 13,638 children underwent preschool visual screening, with an average coverage of 96%. Children classified as amblyopic were 208, for an average prevalence of 1.5%. Astigmatism affects 80% of cases. Data on outcome evaluation were recovered at 6/7 years of age in 178 subjects (85.6% of the series). Corrective lenses were prescribed in all 178 cases evaluated. One subject underwent surgical treatment for congenital cataracts. An exclusive occlusive therapy was performed in 171 subjects (96%), in 7 cases the filters were used exclusively, given the impracticability of the occlusive treatment. In a further 9 cases, filters were used after recognition of poor compliance with the occlusive treatment. The average level of visual acuity at the evaluation of 6/7 years passes from 5.3 to 9 tenths for the right eye and from 4.7 to 9 tenths for the left eye. There is a statistically significant increase in the average values of visual acuity and isoacuity. Foreign children reach levels of visual acuity lower than in Italians. There were no differences in outcomes in relation to gender and residence area of the cases. The visual quality achieved is affected by the basic defect present. Discussion: Various aspects, internal and external to the Health Service, do not allow...