|
KMID : 1159320210230030295
|
|
Korean Journal of Vision Science
2021 Volume.23 No. 3 p.295 ~ p.306
|
|
|
Optical Quality of Ready-Made Reading Spectacles and Symmetry during Manufacturing Process are Good Enough?
|
|
Park Hyung-Min
Jung Yee-Rin
Chu Byoung-Sun
|
|
|
Abstract
|
|
|
Purpose : This study aimed to assess whether the ready-made reading spectacles (RMS) in Korea comply with the required optical standard. In addition, symmetricity of RMS was also investigated.
Methods : A total of 100 of RMS of power +1.00, +2.00, +3.00, and +4.00 D currently available in optical practice were collected. Optical quality of the RMS including refractive power, optical center distance (OCD) between right lens (RL) and left lens (LL), optical centre height (Oh) were measured. Optical quality tolerances was compared with the ISO standard (ISO 8980-1 and ISO 16034:2002) and the RAL-RG-915. Induced horizontal and vertical prism were calculated from discrepancy between OCD and average pupillary distance (PD) of male and female using the prentice rule. In addition, asymmetric RMS due to manufacturing error was measured by difference of monocular OCD and Oh.
Results : Twenty-three percent of the 100 RMS did not meet the ISO 8980-1 in spectacle power. Average OCD of the RMS was 62.06±1.41 mm and induced horizontal prism due to discrepancy between OCD and PD were 0.53±0.54 △ BI (range of 0.18~1.06 △) for male and 0.98±0.68 △ BI (range of 0.37~1.78 △) for female. For monocular OCD from the centre of frame, 85% of RMS had more than 1 mm monocular OCD difference between RL and LL. Optical centre height difference between RL and LL was 1.26±0.83 mm and the range of induced vertical prism was 0.12~0.45 △.
Conclusion : Large amount of RMS in the study did not meet the optical quality. As RMS cannot consider the wearer’s facial shape, there was a mismatch of OCD and PD which induced significant amount of horizontal prism. Therefore, wearing RMS with improper optical quality may not provide comfort vision rather than causing additional visual burden and intervention from professional to confirm the quality of RMS is strongly recommend.
|
|
|
KEYWORD
|
|
|
Induced prism, Optical standard, Presbyopia, Pupillary distance, Ready-made reading spectacles
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
|
|