TY - JOUR
T1 - Downward deviation of progressive addition lenses in a myopia control trial
AU - Hasebe, Satoshi
AU - Nakatsuka, Chiaki
AU - Hamasaki, Ichiro
AU - Ohtsuki, Hiroshi
PY - 2005/7/1
Y1 - 2005/7/1
N2 - Purpose: To clarify how the downward deviation of progressive addition lenses (PALs) reduces their near-addition effect in schoolchildren participating in a myopia control trial. Methods: Among 95 schoolchildren wearing PALs for 6 months (age range: 6-12 years; refractive error range: -6.00 to -1.25 D), facial images were captured with a digital still camera placed 60 cm in front of the eyes while he or she was looking ahead with natural head posture. The vertical deviations of PALs from their ideal position (mm) were evaluated by analysing these images. Results: The mean (±SD) downward deviations of PALs for the right and left eyes were 3.7 ± 2.3 and 3.7 ± 2.0 mm, respectively, and the largest downward deviation was 10.2 mm. For simulations using the average downward deviation, the near-addition effect of PALs was reduced to 30 and 63% of the expected value at the 10° and 20° downward eye positions, respectively. Conclusions: The downward deviation of PALs is a significant factor in reducing their therapeutic effect for near-addition. To ensure the proper alignment of PALs in children, the conventional spectacle-frame-fitting procedure is not sufficient, and repeated confirmation using a testing method similar to that used in this study is required.
AB - Purpose: To clarify how the downward deviation of progressive addition lenses (PALs) reduces their near-addition effect in schoolchildren participating in a myopia control trial. Methods: Among 95 schoolchildren wearing PALs for 6 months (age range: 6-12 years; refractive error range: -6.00 to -1.25 D), facial images were captured with a digital still camera placed 60 cm in front of the eyes while he or she was looking ahead with natural head posture. The vertical deviations of PALs from their ideal position (mm) were evaluated by analysing these images. Results: The mean (±SD) downward deviations of PALs for the right and left eyes were 3.7 ± 2.3 and 3.7 ± 2.0 mm, respectively, and the largest downward deviation was 10.2 mm. For simulations using the average downward deviation, the near-addition effect of PALs was reduced to 30 and 63% of the expected value at the 10° and 20° downward eye positions, respectively. Conclusions: The downward deviation of PALs is a significant factor in reducing their therapeutic effect for near-addition. To ensure the proper alignment of PALs in children, the conventional spectacle-frame-fitting procedure is not sufficient, and repeated confirmation using a testing method similar to that used in this study is required.
KW - Lag of accommodation
KW - Myopia control
KW - Pediatric dispensing
KW - Progressive addition lens
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U2 - 10.1111/j.1475-1313.2005.00301.x
DO - 10.1111/j.1475-1313.2005.00301.x
M3 - Article
C2 - 15953115
AN - SCOPUS:24944484309
VL - 25
SP - 310
EP - 314
JO - Ophthalmic and Physiological Optics
JF - Ophthalmic and Physiological Optics
SN - 0275-5408
IS - 4
ER -