No abstract

No abstract

AimsThe purpose of this study was to explore the microstructural properties of the major white matter (WM) tracts in constant exotropia (XT) before and after strabismus surgery, and further investigate the association between microstructural alterations and the ocular dominance (OD).MethodsWe collected diffusion tensor imaging data of patients with XT before (n=19) and after (n=15) strabismus surgery and 20 healthy controls and evaluated OD and stereopsis. The probabilistic streamline tractography of the 24 major WM tracts was reconstructed by using the automated fibre quantification package. Fractional anisotropy and mean diffusivity (MD) along each tract were estimated, and their differences between the groups were examined. Furthermore, we evaluated the relationship between OD and the absolute value of altered microstructural parameters.ResultsWhile all postoperative XT patients restored normal stereopsis, most of their OD remained aberrant (9 out of 11). Compared with that of preoperation, the MD of postoperative patients decreased significantly along left anterior thalamic radiation (ATR), left arcuate fasciculus (AF), left corticospinal tract (CST), left cingulum cingulate (CGC) and left inferior fronto-occipital fasciculus. Moreover, OD was negatively correlated with the absolute value of MD changes in left ATR, left AF, left CST and left CGC.ConclusionMicrostructural alterations after surgery in the visuospatial network tracts may contribute to the stereopsis restoration. Additionally, the results of the correlation analysis may signify that the balanced binocular input may be more conducive for the restoration and improvement of binocular visual function, including stereopsis. Thus, restoring normal ocular balance after surgical correction may be necessary to achieve more substantial improvements.

While the aging population is growing, our knowledge regarding age-related deterioration of visual perception remains limited. In the present study, we investigated the effects of aging on orientation and direction sensitivity in a healthy population using a weighted up–down adaptive method to improve the efficiency and reliability of the task. A total of 57 healthy participants aged 22–72 years were included and divided into old and young groups. Raw experimental data were processed using a psychometric method to determine the differences between the two groups. In the orientation task, the threshold of the discrimination angle and bias (i.e., the difference between the perceived midpoint from the logistic function and the reference point) was increased, while the lapsing rate (i.e., 1—the maximum logistic function) did not significantly change in the old group compared with the young group. In the motion direction task, the threshold, bias, and lapsing rate were significantly increased in the old group compared with the young group. These results suggest that the decreased ability of old participants in discrimination of stimulus orientation and motion direction could be related to the impaired function of visual cortex.

Purpose: To determine the possible effects of horizontal rectus surgery on the fundus microvascular network and microcirculation. Methods: A total of 53 eyes from 53 horizontal strabismus who underwent a recession-resection surgery on monocular eye were included. The densities in the capillary plexus of retinal and the area of the foveal avascular zone (FAZ) were imaged and measured by optical coherence tomography angiography (OCT-A) at baseline and 1 day, 2 weeks and 4 weeks after strabismus surgery. Results: The mean whole superficial capillary plexus (SCP) of reoperation and postoperation were 43.02 ± 3.75, 40.17 ± 4.25,42.25 ± 4.51 and 42.87 ± 4.23%, respectively. There was a statistically significant decrease in the measurement of the whole SCP (p < 0.001). The mean whole deep capillary plexus measurements (DCP) of reoperation and postoperation were 48.83 ± 3.33, 49.13 ± 4.13, 49.42 ± 3.90 and 49.66 ± 3.74%, respectively. There was no statistically significant change in the measurement of the whole DCP (p = 0.427). The mean FAZ measurements of reoperation and postoperation were 0.27 ± 0.09, 0.28 ± 0.11, 0.27 ± 0.09 and 0.27 ± 0.10mm2, respectively. There was no statistically significant change in the measurement of FAZ (p = 0.497). Conclusions: Superficial capillary plexus decreased transitorily in short-term follow-up after strabismus surgery. Such changes would not persist over a long period.