ABSTRACT
BACKGROUND@#In recent years, visual quality has been extensively investigated in various conditions. In this community-based population study, we analyzed the effects of aging, refraction, and Lens Opacification Classification System III (LOCSIII) score on retinal imaging quality in healthy Chinese adults.@*METHODS@#This cross-sectional study was conducted on sub-group subjects from The Handan Eye Study between October 2012 and January 2013. Healthy subjects over 30-years-old with logarithm of the minimal angle of resolution (logMAR) best-corrected visual acuity (BCVA) less than 0 were included. Retinal image quality was measured by optical quality analysis system (OQAS) and recorded as modulation transfer function cutoff frequency (MTFcutoff), OQAS value (OV) 100%, OV20%, OV9%, Strehl ratio (SR), and objective scatter index (OSI). The correlation between age, spherical equivalent refraction (SE), LOCSIII score, and optical quality parameters were investigated by multivariate analysis.@*RESULTS@#Among 1108 verified subjects, 690 subjects (1380 eyes) met the inclusion criteria. Their age ranged from 30 to 76 years, SE ranged from -4.75 to 2.75 D. They were divided into five age groups (30-39, 40-49, 50-59, 60-69, and ≥70 years) for further analysis. After multivariate analysis by mixed-effect linear model, SR (t = -3.03, P = 0.002), OV20% (t = -2.39, P = 0.017), and OV9% (t = -3.16, P = 0.001) significantly decreased with the increasing age, whereas logMAR BCVA (t = 4.42, P < 0.001) and OSI (t = 4.46, P < 0.001) significantly increased with age. As SE increased, SR (t = 2.74, P = 0.01), OV20% (t = 2.31, P = 0.02), and OV9% (t = 2.79, P = 0.005) significantly elevated, and OSI (t = -3.38, P < 0.001) significantly decreased. With the increase in cortical opacity score, all optical quality parameters except for SR significantly decreased, including MTFcutoff (t = -2.78, P = 0.01), OV100% (t = -2.78, P = 0.005), OV20% (t = -2.60, P = 0.009), and OV9% (t = -2.05, P = 0.040). As posterior sub capsular opacity score increased, MTFcutoff (t = -2.40, P = 0.02) and OV100% (t = -2.40, P = 0.01) significantly decreased, while OSI (t = 7.56, P < 0.001) significantly increased.@*CONCLUSIONS@#In healthy Chinese adult population, optical quality-related parameters significantly decrease with the increasing age, and OSI significantly increases with age. In normal BCVA subjects, optical quality is significantly impacted by cortical and posterior sub capsular opacity rather than by nuclear opacity.
ABSTRACT
<p><b>BACKGROUND</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>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.</p>
Subject(s)
Adolescent , Adult , Aged , Female , Humans , Male , Middle Aged , Young Adult , Refraction, Ocular , Visual Acuity , PhysiologyABSTRACT
<p><b>OBJECTIVE</b>To evaluate the technique of C1-C2 transarticular screw fixation for atlantoaxial instability or dislocation.</p><p><b>METHODS</b>Among 14 patients with atlantoaxial instability, 10 were male and 4 patients were female, with an average age of 38.6 years ranging from 17 to 62 years. All patients were treated by internal fixation with transarticular screws.</p><p><b>RESULTS</b>There were 28 screws applied in 14 patients. All patients were followed up. The average follow-up period was 16 months (range, 9 to 35 months). The postoperative JOA score was ranging from 13.8 to 15.8 with the average score of (14.50 +/- 0.66) and the improved rate of (76.12 +/- 4.94)%. No spinal injury and vertical artery injury was found and osseous fusion was completed in all patients.</p><p><b>CONCLUSION</b>The technique of C1-C2 transarticular screw fixation is one of the best treatments for atlantoaxial instability. Without the help of structural bone graft and aided internal fixation, morselized cancellous bone graft can acquire effective osseous fusion.</p>