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David Anderson, Deepta Abhay Ghate, Sachin Kedar, Matthew Rizzo; Piloting A New Method For Estimating Effects Of Visual Field Loss In A Panoramic Naturalistic Environment. Invest. Ophthalmol. Vis. Sci. 2017;58(8):2847. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Visual field (VF) defects negatively affect driving performance in glaucoma patients. Driving Simulator VF (DSVF) was designed in a high-fidelity driving simulation system with 290° panoramic environment to explore the external validity of clinic Humphrey VF (HVF) in naturalistic driving settings.
Subjects were experienced field takers. DSVF tested 40 grid locations spanning 60° horizontal and 20° vertical visual angle at 2.5 m. Red supra-threshold stimuli (0.5° visual angle, 6° between loci straddling the vertical and horizontal meridian similar to HVF 30-2 strategy with stimulus III) on gray background were presented randomly with each location tested 4 times. Test duration was 4 minutes. Subjects maintained central fixation and responded after each stimulus detection. Response rates (0-4) and cortical magnification weights were used to calculate a global VF index (DS-VFI) and mean response scores (MRS). Monocular and binocular DSVFs were performed twice in randomized order.
3 glaucoma suspects (HVF-VFI range 99-100%) and 2 glaucoma subjects (HVF-VFI range 43-100%) underwent DSVF. Glaucoma suspect DS-VFI was 93.5±3.6% (mean ±SD) for binocular fields, 87.7±1.4% left eye (OS), and 85.5±3.6% right eye(OD); (Figure 1 and 2)1. DSVF were reproducible. Absolute VFI difference between each of 2 trials per tested field was 2 ±2% (glaucoma suspects) and 4±3% (glaucoma patients).2. DVSF and HVF grayscales were similar. Blind spot mapped correctly (15° location) in 18/20 monocular fields in all patients. Glaucoma-specific scotoma mapped correctly binocular (Patient A) and OS (Patient B) VF defects.3. A-pillar scotoma: In all 30 trials, decrease in DS-VFI compared to HVF-VFI occurred in the same left hemifield location (21-27°), corresponding to the vehicle’s A-pillar.
DSVF is a novel platform to estimate reliable and reproducible VFs in a naturalistic setting. We also identified a new artificial scotoma in the DSVF attributable to in-cab geometry. Future studies will use the DSVF to evaluate the impact of pathologic and artificial scotomas on driving performance.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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