Samantha Watkins, Stuti Misra, Charles McGhee,Shuan Dai
The Saccadic Vector Optokinetic Perimeter(SVOP) utilises eye-tracking to allow accurateperimetry results without a subjective response. Stand-ard visual field machines are unsuitable for many chil-dren due to restricted head posture and prolongedtesting time. This study aims to determine the clinicalapplicability of SVOP for children with visual impairment.
Visual field tests were conducted for 30 con-secutive cases at the Blind Low Vision EducationNetwork of New Zealand (BLENNZ) Clinic, Auckland,using the SVOP (i2eye Diagnostics). Visual acuity wasmeasured on a back-lit Snellen chart. Children were40–50 cm from the SVOP LCD screen, with testing duration and visual field results automatically rec-orded by SVOP software. Other variables includingbinocular vs monocular fields, Goldmann size ofstimulus and number of points tested were determinedby clinical requirements, with 14-point binocular asthe standard option. Test stimuli had a duration of200 ms and luminance of 14dB.
Thirty children with a range of diagnosesattempted SVOP, 22 (14.33 ± 4.89 years) were success-ful and 8 (7.96 ± 5.07 years) were unable to completedue to count fingers or worse visual acuity, or othercognitive delays. The first field measurement of eachchild was analysed. The testing duration of those whosuccessfully completed was 102.07 ± 92.95 seconds.Visual acuity of the children able to perform the testranged from 6/6 to <6/120 with a median acuity of<6/38. Conclusion: SVOP can be successfully utilised in chil-dren with visual impairment and provide valuableclinical visual field information that cannot beachieved with other standard methods.