Abstract
Purpose:
Comprehensive pediatric vision screening requires objective, non-cycloplegic, and binocular assessments of no less than a refraction, an ocular alignment, and a pupil tests. This pilot study tested the feasibility of integrating these 3 functions into one versatile device, the Dynamic Ocular Evaluation System (DOES) [U.S. patent #7,427,135 & 7,878,652]. The specific objectives were to (1) test feasibility of using 3D images to relax accommodation in the refraction test, (2) determine eye alignment precision that is required for strabismus assessment, and (3) test feasibility of a dynamic pupillogram.
Methods:
DOES functions as a versatile near-infrared (NIR) video retinoscope. Subject: 71 patients of ages 4 to 81 years were recruited in Walmart vision center in Tullahoma, TN. DOES testing: (1) Accommodation test: In 2 room-lighting conditions, 8 measurements were acquired as the patient viewed a cartoon figure projected by a 3D screen at 4 distances (0.75, 1.5, 2.7, and >6 m); a 6 cm IPD was assumed. (2) DOES used dynamic Hirschberg analysis to track the eye gaze. Calibration was performed with 5 fixation-points on screen. (3) Binocular pupil video was recorded during 3D visible stimulation from the 3D screen at 75-cm distance. All patients received standard clinical refraction eye examinations, ocular alignment assessment, and pupil assessment.
Results:
(1) Without cycloplegic eye drops, young hyperopic patients showed significant variation in the measurement results due to active accommodation. The tested eyes relaxed as the stimuli distance was increased from 75 cm. Although not perfectly, the measured refractions approached the targeted clinical gold standard values at far stimulus distances. (2) Tracking capability of sub-prism spatial gaze/strabismus- angle resolution at 20-50 Hz was achieved. Fixation discrepancy was identified for various fixation target designs and analyzed for 3 age groups. No significant age-dependence was found. (3) Pupillograms were achieved with 20Hz speed and 0.1mm pupil resolution. Pupil sizes were recorded while the 2 eyes were stimulated independently.
Conclusions:
This study demonstrated the feasibility of a low-cost and multi-functional device for pediatric vision screening. A 3D display may be utilized to connect multiple tests into one objective vision screening test.
Keywords: 417 amblyopia •
723 strabismus: diagnosis and detection •
434 binocular vision/stereopsis