Background: Common paediatric perimetry techniques require central fixation and subjective responses, which may be challenging for young or cognitively impaired children. The Saccadic Vector Optokinetic Perimeter (SVOP) was designed to overcome these challenges by using infra-red eye tracking to assess the visual field. This study assessed the clinical feasibility of SVOP in children without visual impairment, comparing it to current paediatric techniques, and in children with visual impairment.
Methods: Participants were recruited into two cohorts: children without visual impairment (visual acuity ≥ 6/7.5) and children with visual impairment (visual acuity ≤ 6/18). Children without visual impairment attempted the Goldmann perimeter, confrontation method, and SVOP. Children with visual impairment attempted SVOP, when clinically indicated, as part of a full ophthalmic assessment. Visual field results and test length were recorded.
Results: Twenty-three children without visual impairment (4-14 years old) attempted all three visual field assessments. Full results were recorded for 91 per cent of children with SVOP, 87 per cent with Goldmann, and 100 per cent with confrontation SVOP was significantly faster than Goldmann (p < 0.001) and confrontation (p = 0.003). Thirty-five children with visual impairment (3-19 years old) with visual acuity ranging from 6/9.5 to worse than 6/360 (mean of 0.8 ± 0.4 logMAR) attempted SVOP, with 26 children able to complete SVOP.
Discussion: This is the largest study to date of the clinical applicability of SVOP in children without visual impairment, as well as assessing the utility of SVOP in children with visual impairment. Further research is needed to assess the accuracy of SVOP in a range of paediatric ocular disorders. SVOP may potentially offer a visual field assessment method for children previously unable to complete current paediatric perimetry techniques.
Keywords: Saccadic Vector Optokinetic Perimeter; paediatric; perimetry; visual field.
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