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Lei Shi, Ying-Ling Chen, James Lewis, Ming Wang; Clinical testing of a new objective binocular refraction device. Invest. Ophthalmol. Vis. Sci. 2013;54(15):5673.
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Objective, non-cycloplegic, and binocular refraction measurements are the most important part of pediatric vision screening. Accuracies of current methods are strongly compromised by variations of pupil size, and intraocular scattering. This study evaluates a new device, the Dynamic Ocular Evaluation System (DOES) [US patents: 7,427,135 7,878,652] and the dependence of its accuracy on pupil size and age.
The DOES optical design uses infrared video photorefraction (PR) with multi-eccentricities and meridians. Subj: 71 patients of age 4 to 81 years were recruited. Hyperopic or mild myopic (SE>-1) subjects younger than 50 years old were excluded for possible error due to accommodation. DOES testing: 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. All patients received standard clinical refraction examinations. Accuracy evaluation: After eliminating images with technical faults (eye lids and saturation), 69 eyes of 35 patients of ages 8- 81 yielded 453 refraction data (n=453) for analysis. We used the Bland-Altman statistical method to evaluate agreement between DOES and the clinical gold standard measurements. The standard errors (σ) of the spherical equivalent (SE) and crossed cylinders (J0 and J45) were obtained. To examine the influence of intraocular scattering, σ were compared in three age groups; kids (8-13yrs, 18 eyes, SE=0.9±2.7D, n=142), adults (17-38yrs, 13 eyes, SE=1.5±3D, n=93), and older adults (41-81yrs, 38 eyes, SE=2.2±0.2D, n= 218). Pupil size influence was examined in 2 groups with pupil=6.37±0.83mm (age=17-22, n=49) and pupil=3.73±0.51mm (22-38yrs, n=44).
The standard errors for DOES refraction measurements of SE, J0, and J45 are 0.47, 0.3 and 0.17 D, respectively. σ_SE in the 3 age groups are 0.49, 0.44, and 0.47 D. In the 2 pupil groups σ_SE =0.55 and 0.28D.
Between -3 and +2D, the region of concern for referrals, the device shows outstanding binocular refractive error performance with σ_SE =0.42D (n=297), while across the full-range of age 8-81 and pupil of 2.5-8.3mm, σ_SE =0.47D (n=453). Large pupils appear to correlate with larger error. No discrimination among age groups was found, which indicates the effectiveness of DOES in calibrating individual intraocular scattering.
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