Characteristics of macular microvasculature before and after idiopathic macular hole surgery

INTRODUCTION

An idiopathic macular hole (MH), caused by tangential traction, can be successfully closed by pars plana vitrectomy with gas-fluid exchange. The anatomic and functional outcomes were further improved by the advent of peeling of the internal limiting membrane (ILM). However,the postoperative visual acuity (VA) is sometimes poor despite successful anatomic closure. Long-term restoration of the microstructure and function of the fovea has been evaluated following surgery for idiopathic MH. Previous studies in eyes with MH have focused mainly on disruption of the outer retina, including the external limiting membrane (ELM), the ellipsoid zone (EZ), and the photoreceptors with respect to the visual prognosis.

Recently, researchers demonstrated an association of disorganization of the retinal inner layers (DRIL) with VA in various retinal diseases. The presence of vitreous cortex,proliferative glial tissue, and retinal hydration has been suggested as factors in the formation of macular holes in histologic studiesand possibly contribute to DRIL. DRIL indicates specific anatomic damage to the structures in the retinal layers that transmit visual data and also a poor inner retinal circulation.

對于公路工程施工所使用的機械設備，應該確保機械設備不是老舊設備，若經常出現故障將直接影響施工進度，應該在項目資金可支配的情況下，優先考慮購買或者租賃技術先進的機械設備，確保項目的施工效果和施工進度能夠滿足預期的要求。

With the development of imaging technology, optical coherence tomography angiography (OCTA) provides highresolution, depth-resolved images for evaluation of the retinal capillary plexuses in eyes with MH in a noninvasive and dye-free manner. In our previous work, we used a commercially available OCTA device with custom-built imaging software and concluded that disorders in the inner retinal vessels corresponded to disruption of the outer retinal layers and VA in the setting of dysfunctional vasculature.The recovery of the retinal microvasculature in patients with a surgically closed MH remains to be elucidated. Meanwhile,limited information is available regarding quantitative evaluation of the preoperative status of the retinal microvasculature in eyes with MH. Accurate OCTA measurements should correct for ocular magnification and require information on axial length.Until now, no study has accurately quantified the changes that occur in the vasculature of the macula in eyes with MH after surgical treatment or the relationship between preoperative vascular parameters and the postoperative VA.The aims of this retrospective study were to characterize macular microvasculature in the superficial and deep retinal layers following surgery in patients with idiopathic MH using OCTA and to investigate the association of preoperative microvascular parameters in the inner retina with postoperative best-corrected visual acuity (BCVA) and healing.

SUBJECTS AND METHODS

This study was approved by the Ethics Committee at Wenzhou Medical University and complied with the tenets of the Declaration of Helsinki. Informed consent was obtained from all patients.

Independent-test and Mann-Whitneytest were used to compare continuous variables between the groups. Repeated-measures analysis of variance was used to evaluate differences in the chronologic data. Post multiple comparisons were evaluated using the Bonferroni test. The Pearson correlation test was used to determine the associations between preoperative vascular parameters and postoperative BCVA. The associations between preoperative vascular parameters and postoperative healing stage were evaluated using the Spearman correlation test. All data are expressed as the means±standard deviations and analyzed with SPSS version 22.0 software (IBM Corp., Armonk, NY, USA).logMAR values of 2.0 and 3.0 were assigned for counting fingers and hand motion vision, respectively.<0.05 indicated statistical significance.

The AngioVue version 2017.1.0.155 software was used. The macular region was imaged using a central 3×3 mmarea. Low-quality OCTA images with a scan quality <5/10, severe artifacts attributable to poor fixation, or failure of automatic layer segmentation were excluded. The area and perimeter of the foveal avascular zone (FAZ) were determined by the software embedded in the instrument. The vessel density (VD) was calculated as the percentage of pixels with a flow signal greater than the threshold value and automatically measured using custom-built imaging software implemented in MATLAB (Mathworks,Natick, MA, USA). The mean brightness of the FAZ was taken as the threshold for the retinal vessels. Parafoveal and perifoveal VDs were calculated in the regions of the radius between 0.5 and 0.875 mm and between 0.875 and 1.25 mm,respectively, from the foveal center (Figure 1A, 1B). To reduce the effects of decentration of the FAZ and the artifacts at the edge of the scan, a circular area with a diameter of 2.5 mm was used instead of the entire 3×3-mmarea.

這樣支撐背后的壓力和心酸，我也有過切身體會。他坦言，也有撐不住的時候。2014到2015年間，因為太過忙碌，他一度感覺到崩潰。“有段時間我喝什么酒都沒味道，喝什么酒都不開心，再好的酒也覺得提不起來興奮點，身邊的人能明顯感受到。那段時間該做的工作還是在做，該進行的課也還在講。很多東西比較得心應手了，不會做得太差，但當時狀態是不好的。明顯感覺到自己學習狀態不夠好，精神不夠集中，喝酒也有點食肉不知其味那種感覺。”幸好，他都撐過來了。不對！可以說，你發現所有厲害的牛人，在贏得掌聲之后，永遠都還覺得自己不夠努力。他們把這歸結為不夠上進，其實是謙遜使然。

layer, and outer plexiform layer could not be identified. Two independent observers interpreted the OCTA and OCT images.The observers reached a consensus in all cases.To eliminate the effect of magnification, the images obtained by OCTA and OCT were corrected by Bennett’s formula using the axial length. The relationship between the OCT image measurements and the actual scan diameter was expressed by the formula t=p×q×s, where t is the actual axial length, p is the magnification factor determined by the camera of the OCT imaging system, q is the magnification factor in relation to the eye, and s is the original measurement obtained from the OCT image. The correction factor q was determined using q=0.01306×(AL–1.82).

Preoperative minimum diameter of the MH was measured in the OCT images. The postoperative healing stage,,restoration of the photoreceptor layer, was graded from 1 to 3. Grade 1 was assigned when the EZ and ELM were disrupted, grade 2 when the EZ was disrupted but the ELM was restored, and grade 3 when both the ELM and EZ were restored. DRIL was defined as the horizontal extent within the central 2000 μm for which any boundaries between the ganglion cell-inner plexiform layer complex, inner nuclear

英國人洛克曾說過“在缺乏教養的人身上，勇敢就會成為粗暴，學識就會成為迂腐，機制就會成為逗趣，質樸就會成為粗魯，溫厚就會成為諂媚。”若這種現象發生在承載著實現中華民族偉大復興夢希望的大學生身上，恐怕是所有人都不想看到的。而事實卻是部分大學生責任感與使命感缺乏、浮躁與迷惘俱在、審美價值觀扭曲，這是不容否認的現象。因此，面對當前的大學生審美價值觀現狀，作為審美教育的影視藝術教育理應成為改變這一現狀的中堅力量，積極引導大學生樹立正確的審美價值觀。……