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Miguel Garcia Garcia, Arne Ohlendorf, Helmut Wietschorke, Siegfried Wahl; Defocus signal pattern maps for asian myopic subjects.. Invest. Ophthalmol. Vis. Sci. 2018;59(9):2147.
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© ARVO (1962-2015); The Authors (2016-present)
The aim of this study was to quantify the patterns of dioptric defocus maps (DDM) in real life scenarios for myopic subjects with different profiles of peripheral refractive errors (PRX).
To establish the defocus patterns in conjunction with the DDM and the type of peripheral refractive errors, 10 Asian students (mean age=27±3, mean SEQ= -2.98 ± 1.19) were included in the course of the study. Peripheral refraction of the naked eye was measured using a peripheral eccentric photo-refractor, calibrated for Asian subjects. The horizontal peripheral refraction was measured in nine different vertical meridians (each 5°), in order to cover an angle of 40° x 40° of the visual field. Peripheral refractive errors were normalized and categorized into box (n=1), bilinear (n=6) and parabolic (n=3) peripheral refractive profile errors (criterion: RMSE<1, min. avg. residuals). The DDM were obtained for different activities (office work, corridor & living room) for the same visual field. The final defocus patterns were gained by merging the DDM with PRX from the different groups and for analysis, the maps were segmented into 16 regions (Fig 1.I). The defocus pattern distribution (in Diopters) for each region was compared between the PRX and the final maps, using the Kolmogorov Smirnov (KS) and Wilcoxon test.
Significant statistical differences (range ±0.5 Dpt, ρ<0.05) were found almost in all the tested regions, when their distributions were compared using the KS test, but there were also regions without changes (table 1).
The presented defocus patterns include peripheral refractive errors and dioptric defocus maps and allow studying the role of the periphery on the refractive development in more detail. It seems that DDM of the scenes are capable of changing statistically the defocus in the eye, but it remains unclear if these changes are clinically meaningful. In future, the design of different optical approaches that are modifying the defocus signal across the visual field in order to control the progression of myopia can also be incorporated.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
Fig.1 Scheme to illustrate the methodology - I) Region segmentation for the analysis. II a) DDM of a Scene (Desktop), b) Average peripheral refraction profile over the visual field (PRX) and c) Resulting map that incorporates the DDM and the PRX.
Table 1 Regions with no significant changes.
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