Effect of refractive correction on ocular optical quality measurement using double-pass system.
BACKGROUND
Optical Quality Analysis System II (OQAS, Visiometrics, Terrassa, Spain) that uses double-pass (DP) technique is the only commercially available device that allows objective measurement of ocular retinal image quality. This study aimed to evaluate the impact of spectacle lenses on the ocular optical quality parameters and the validity of the optometer within OQAS.


METHODS
Seventy eyes of healthy volunteers were enrolled. Optical quality measurements were performed using OQAS with an artificial pupil diameter of 4.0 mm. Three consecutive measurements were obtained from spectacle correction corresponding to subjective refraction and from the OQAS built-in optometer separately. The modulation transfer function cutoff frequency, the Strehl ratio, the width of the point spread function (PSF) at 10% of its maximal height (PSF10), and the width of the PSF at 50% of its maximal height (PSF50) were analyzed.


RESULTS
There was no significant difference in any of the parameters between the spectacle correction and the optometer correction (all P > 0.05, paired t-test). A good agreement was found between both the methods and a good intraobserver repeatability in both the correction methods. Difference in best focus between two methods was the only parameter associated significantly with optical quality parameter differences. Best focus difference, built-in optometer correction with or without external cylindrical lens, and age were associated significantly with PSF10 difference. No linear correlation between refractive status and optical quality measurement difference was observed. A hyperopic bias (best focus difference of (0.50 ± 0.44) D) and a relatively better optical quality using spectacle correction in high myopia group were found.


CONCLUSIONS
OQAS based on DP system is a clinically reliable instrument. In patients with high myopia, measurements using built-in optometer correction should be considered and interpreted with caution.
Beijing Institute of Ophthalmology, Beijing 100730, China; Beijing Tongren Eye Center, Beijing 100730, China; Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Science Key Laboratory, Beijing 100730, China.
Xiu-Hua
XH
Wan
Xiao-Gu
XG
Cai
Li-Ya
LY
Qiao
Ye
Y
Zhang
Jia-Xuan
JX
Tan
Jhanji
J
Vishal
Ning-Li
NL
Wang
D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012029:Refraction, Ocular; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult