Hole Repair Research Articles

Direct Macular Hole Manipulation Results in High Success Rate in Secondary Macular Hole Repair.

To investigate closure rates and functional outcomes of surgery for refractory and recurrent macular holes (MH) in a real-world setting. Retrospective review of secondary MH surgeries. A total of 72 eyes from 72 patients were included. Eyes had a mean of 1.51 surgeries before inclusion into the study with a mean MH size of 762 µm and a mean baseline logMAR BCVA of 1.11(∼20/260 Snellen). Closure rates were 89.3 % for tissue transplantation, 77.3 % for ILM flaps, 92.9 % for MH manipulation, and 12.5 % for repeat ILM peeling (p<0.05). BCVA changes in logMAR from baseline to postoperative month 6 were +0.29 for ILM peeling alone (15 ETDRS letters worse), -0.39 for macular hole manipulation (20 ETDRS letters improved), -0.23 for tissue transplantation (13 ETDRS letters improved), and -0.2 for ILM flaps (10 ETDRS letters improved; p<0.05). Secondary MH closure is possible using various surgical techniques with acceptable anatomical closure rates. Repeat ILM peeling is associated with the lowest closure rates and poorest functional results. To distinguish between techniques would require a large sample size of about 750 eyes.

Особенности хирургического лечения макулярного отверстия с атипичной эпиретинальной тканью: серия клинических случаев

Purpose. To present the surgical features of successful repair of macular hole with atypical epiretinal proliferation. Material and methods. A retrospective analysis of the treatment of 4 patients with macular hole-associated epiretinal proliferation. All patients underwent a preoperative examination – a standard ophthalmological examination, optical coherence tomography of the macular area with hole diameter measurement, confirmation of the presence of epiretinal tissue. Surgery consisted of the stages: vitrectomy, staining of the epiretinal tissue, its careful exfoliation with end-griping forceps, cutting off the floating part by a vitrector using «shaving» mode and preserving the remnants of the tissue around the edges of the hole, finishing with air tamponade. During the postoperative period the patient followed the «face down» position continuously for 3 hours. Results. In all cases the best corrected visual acuity (BCVA) increased and closure of the macular hole was achieved. Conclusions. 1. Surgical treatment of a macular hole with atypical epiretinal tissue has specific features that are not characteristic of the traditional treatment of an idiopathic macular hole. 2. The presence of a fixed perifoveal border of epiretinal tissue is an intraoperative feature. 3. Preservation of the perifoveolar border of epiretinal proliferation contributes to the closure of the macular hole without any additional mechanical manipulations or the use of biological adjuvants. 4. For a better understanding of the regenerative properties of epiretinal proliferation, it is necessary to increase the study sample, as well as to conduct histological studies of this tissue. Keywords: macular hole, epiretinal proliferation, atypical tissue, yellow tissue, perifovea corona phenomenon

Long-term effects of combined brilliant blue G and xenon light induced retinal toxicity following macular hole repair surgery

BackgroundThe purpose of this study was to look at the long-term effects of retinal phototoxicity after macular hole repair surgery using xenon endolight illumination and Brilliant blue G (BBG) dye.Case presentationAn elderly man in his late seventies underwent para plana vitrectomy with BBG dye to repair an idiopathic full-thickness macular hole (MH) in his right eye. Prior to macular hole surgery, his visual acuity in the right eye was 6/60, N24 at the time of presentation. The MH closed with type 1 closure immediately after surgery, but there was extensive damage to the outer retinal layers and retinal pigment epithelium (RPE) at the macula, resulting in a reduction in visual acuity to 2/60. We presumed that the combination of BBG and xenon light, is the probable reason of retinotoxicity in the current patient. There was a progressive increase in the area of retinal and RPE layer damage and choroidal thinning over a 4-year period.ConclusionDue to combined BBG-induced dye and endoilluminator toxicity, a rare case of continuously progressing RPE layer damage with choroidal thinning over a long follow-up interval was described. Such long-term effects of BBG and endolight induced retinotoxicity have not been reported in the literature, to the best of our knowledge.

Additional value-added conditional moving least squares method for point cloud hole repair

Additional value-added conditional moving least squares method for point cloud hole repair

Feature Analysis of Scanning Point Cloud of Structure and Research on Hole Repair Technology Considering Space-Ground Multi-Source 3D Data Acquisition.

As one of the best means of obtaining the geometry information of special shaped structures, point cloud data acquisition can be achieved by laser scanning or photogrammetry. However, there are some differences in the quantity, quality, and information type of point clouds obtained by different methods when collecting point clouds of the same structure, due to differences in sensor mechanisms and collection paths. Thus, this study aimed to combine the complementary advantages of multi-source point cloud data and provide the high-quality basic data required for structure measurement and modeling. Specifically, low-altitude photogrammetry technologies such as hand-held laser scanners (HLS), terrestrial laser scanners (TLS), and unmanned aerial systems (UAS) were adopted to collect point cloud data of the same special-shaped structure in different paths. The advantages and disadvantages of different point cloud acquisition methods of special-shaped structures were analyzed from the perspective of the point cloud acquisition mechanism of different sensors, point cloud data integrity, and single-point geometric characteristics of the point cloud. Additionally, a point cloud void repair technology based on the TLS point cloud was proposed according to the analysis results. Under the premise of unifying the spatial position relationship of the three point clouds, the M3C2 distance algorithm was performed to extract the point clouds with significant spatial position differences in the same area of the structure from the three point clouds. Meanwhile, the single-point geometric feature differences of the multi-source point cloud in the area with the same neighborhood radius was calculated. With the kernel density distribution of the feature difference, the feature points filtered from the HLS point cloud and the TLS point cloud were fused to enrich the number of feature points in the TLS point cloud. In addition, the TLS point cloud voids were located by raster projection, and the point clouds within the void range were extracted, or the closest points were retrieved from the other two heterologous point clouds, to repair the top surface and façade voids of the TLS point cloud. Finally, high-quality basic point cloud data of the special-shaped structure were generated.

Commentary: Indistinct retinal outer layers in the walls of idiopathic full thickness macular hole - A potential predictive biomarker for surgical outcomes.

Commentary: Indistinct retinal outer layers in the walls of idiopathic full thickness macular hole - A potential predictive biomarker for surgical outcomes.

Cave feature extraction and classification from rockery point clouds acquired with handheld laser scanners

Rockeries are unique elements of Chinese classical gardens with historical, cultural, artistic, and scientific value. One of the essential characteristics of garden rockery is the cave features since cave morphological features determine the degree of “Tou” (riddled through) and “Lou” (hollowed out well) features as the defined by rockery appreciation theory, which is important for rockery heritage conservation, assessment, and management. However, in heritage studies, accurately identifying and evaluating rockery caves is a difficult task because of a cave's irregular shape. This paper proposes a methodology to extract and classify cave features by point clouds obtained from data using a handheld laser scanner with a camera. Without completing surface reconstruction, the rockery point cloud is first sliced into chips, then cave chips were extracted from these approximately two-dimensional chips and next merged to obtain three-dimensional cave point clouds. Finally, the cave boundary points are extracted from the cave and fitted by an ellipse for classification. To extract and classify cave features, a methodology to improve rockery digitalization quality is also proposed. The raw point cloud data were preprocessed by pose adjustment, noise removal, and hole repair. The experimental results for the two rockeries in Tongji University and Qiuxiapu Garden indicate that the improved digitization scheme generates complete and closed rockery point clouds, all types of caves were effectively extracted and classified by our proposed method. Additionally, the extracted caves are still represented by point clouds, which suggest the possibility for other research in the future.

Experimental study of scour characteristics and scour hole dimensions in consolidated silt sediment under a current

Field observations show that silt is not always loose and that silt consolidation is common. In the study reported here, the characteristics of pile scour in consolidated silt (CS) under clear-water conditions were investigated and compared with those in loose silt. Experiments were performed to study the dimensions of equilibrium scour holes in CS, and the results show that the scour depth and radius in CS are smaller than those in loose silt, but the slope angle in CS is larger and the scour depth is inversely proportional to the dry density. It is found that the scour characteristics in CS differ from those in commonly used fine sand and silt, and most of the existing scour equations cannot predict the scour depth in CS. A mathematical relationship between the scour hole dimensions and the maximum scour depth applicable to CS is established, and a new equation is proposed for computing the maximum scour depth in CS with an error of less than 25%. The present work offers theoretical guidance for the design of scour prevention of piles and scour hole repair in CS.

RGB-D Camera for 3D Laser Point Cloud Hole Repair in Mine Access Shaft Roadway

With the rapid development of the geographic information service industry, point cloud data are widely used in various fields, such as architecture, planning, cultural relics protection, mining engineering, etc. Despite that there are many approaches to collecting point clouds, we are facing the problem of point cloud holes caused by the inability of a 3D laser scanner to collect data completely in the narrow space of the mine access shaft. Thus, this paper uses RGB-D cameras to collect data and reconstruct the hole in the point cloud. We used a 3D laser scanner and RGB-D depth camera to collect the 3D point cloud data of the access shaft roadway. The maximum error was 2.617 cm and the minimum error was 0.031 cm by measuring the distance between the feature points, which satisfied the visualization repair of the missing parts of the 3D laser scanner data collection. We used the FPTH + ICP algorithm, ISS + ICP algorithm, SVD + ICP algorithm, and 3D-NDT algorithm to perform registration and fusion of the processed 3D point cloud and the original point cloud and finally repaired the hole. The study results show that the ISS + ICP registration algorithm had the most matching points and the lowest RMSE value of 13.8524 mm. In addition, in the closed and narrow roadway, the RGB-D camera was light and easy to operate and the point data acquired by it had relatively high precision. The three-dimensional point cloud of the repaired access shaft roadway has a good fit and can meet the repair requirements.

Intraretinal human amniotic membrane after macular hole repair.

to describe a unique complication of macular hole repair surgery using a subretinal human amniotic membrane (hAM) plug. retrospective, interventional case report. A 71-year-old man presented with a chronic full thickness macular hole in his left eye. We performed conventional 23-Gauge pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling and implantation of a subretinal hAM plug. In the postoperative period, centripetal growth of external retinal layers was observed under the plug. 6 months after surgery, the hAM plug was full integrated into the retina. this is the first reported case of intraretinal integration of a hAM plug following macular hole repair surgery.

Commentary: To evaluate the functional and anatomical outcomes for autologous retinal autograft with Finesse™ Flex Loop for failed macular holes.

Commentary: To evaluate the functional and anatomical outcomes for autologous retinal autograft with Finesse™ Flex Loop for failed macular holes.

Варианты репаративного ответа при закрытии макулярного разрыва различными способами

Baсkground. Recently, additional microtraumatization of neuroretinal tissue has been proven during removal of the internal limiting membrane (ILM) due to its close connection with the inner layers of the retina and with Muller cells. These factors may influence functional results after surgery for closure of macular hole. Purpose. To propose a new technique of surgery for macular hole, which is based on the preservation of ILM and to assess the dynamics of the functional parameters of the retina. Methods. The results of OCT of 60 patients (60 eyes) with the diagnosis of macular hole were analyzed. Group 1 (30 eyes) – patients who underwent surgical treatment with inverted flap. Group 2 (30 eyes) – patients who were operated using the original method with preservation of ILM in the central zone. All patients underwent standard ophthalmological examination before and after surgery, including visometry, biomicroscopy, ophthalmoscopy, and OCT. Results. Preoperative functional parameters of the retina were comparable in both groups of patients. The study identified 3 types of macular hole closure. When studying morphological changes in macular hole repair by the “pseudocyst” type in patients of both groups, it showed a more pronounced resistance of neuroretinal tissue in patients of group 1. In the 2nd group, more pronounced dynamics of reducing the morphological parameters of the hyporeflective defect was revealed throughout the entire observation period. When the macular hole is completely closed, there is a higher rate of regression of neuroepithelial tissue edema in group 2 patients. Non-closure of the macular hole was observed only in group 1 patients, and in this type of repair, there was a deterioration in morphological parameters. Conclusion. Based on this study, we can conclude that using this technique the ILM is preserved, which reduces the risk of intraoperative damage to the retinal layers. Key words: macular hole; peeling; microperimetry.

Research on an Intelligent Identification and Classification Method of Complex Holes in Triangle Meshes for 3D Printing.

In triangular mesh models, the repair of complex hole poses a difficult problem, which always causes serious repair defects. Therefore, it is needed to develop an intelligent identification and classification method of complex holes to reduce repair difficulties. First, the topological structure of the complex hole is studied and all the holes are divided into single holes and continuous holes depending on whether there are intersection points. Second, to tackle the nesting and connecting of complex continuous holes, a decomposition method of multiply connected domains based on intersection points is proposed to partition or reconstruct complex continuous holes into single holes. Based on the different geometric structures, single holes are classified into five common hole types and a corresponding identification method of single holes is presented. Finally, an experiment is carried out to verify the repair quality and efficiency of the proposed method. Compared with Geomagic software, the proposed method can automatically identify and partition complex holes with fewer defects and similar efficiency. It can reduce the difficulties of repairing complex holes and enable the repair of complex holes based on existing methods. It is shown that the method can be applied to complex hole repair of 3D printing models without the participation of technicians.

Point Cloud Data Hole Repair Aggregation Algorithm Based on Optimized Neural Network

In order to solve the problem of cost cloud data and hole repair efficiency and accuracy, this article offers a study of integrated cloud network hole algorithm research based on optimal neural network. This paper first introduces a common point cloud hole-filling algorithm, provides a neural network-based point cloud blank filling algorithm, and introduces hotspot problems in a given algorithm, combined with the technology related to high-performance computing, the parallel optimization technology based on OpenMP and CUDA is adopted to accelerate the algorithm accordingly. Experiments have shown that the accuracy of pre- and postoptimization of CUDA-based algorithms varies. As the model and input point cloud data increase, the accuracy of the algorithm decreases slightly. However, when the data increases to 104 orders of magnitude, the rate of accuracy decline meets an inflection point and finally stabilizes to about 96.8% in the environment of 132457 data of monk model. The point cloud hole-filling algorithm based on the optimal neural network given in this article is highly predictable, can well repair incomplete point cloud holes, has good repair effect on point cloud holes, and can obtain high acceleration ratio, which can provide reference for practical engineering application.

An Intelligent Identification and Repair Method for Annular Holes in 3D Printing.

With the popularization of 3D printing in the consumer goods field, there is a specific type of hole named annular hole in the narrow features, surface bumps, or folded parts of products. The traditional triangular mesh repair method is not effective for such holes. The structural characteristics of the annular hole are analyzed in this research, and the definition and identification method for annular holes is presented through the shape and position relationship of two closed hole lines. To improve the repair efficiency and the applicability of the algorithm, the traditional hole repair method and process are ameliorated. A repair strategy of hole boundary stitching and filling, triangulation optimization, implicit surface construction based on Radial Basis Function, and surface integral deformation is adopted to achieve a smooth joint of the repaired hole surface with the original triangular mesh surface. The method can ensure surface smoothness and accuracy. Finally, two experiments are carried out to verify the repair quality and efficiency of our method. Compared with Geomagic software, the proposed method can automatically identify and repair annular holes with fewer defects and similar efficiency. Compared with a traditional hole repair method, the evaluation results demonstrate that the proposed method is much faster, and the repair quality is higher without the influences of human operations. It is shown that our method can be applied to annular hole repair of 3D printing models without the participation of technicians.

3D Face Geometry Optimization Using Artificial Intelligence and Computer Graphics

Human face plays an indispensable role in emotional expression and information exchange, which attracts large number of researchers to study face recognition. Nowadays, with the rapid development of computer graphics, artificial intelligence, and other technologies, the ability of the human vision system to recognize facial expressions and facial organs is enhanced. More and more experts think about how to make the computer vision system have this capability. By combining artificial intelligence and computer graphics, this paper studies how to optimize the 3D face network model and extract geometric features for 3D face recognition. We propose a 3D face network model based on Poisson equation to realize face hole recognition and boundary preprocessing. Besides, we also establish the 3D face surface equation and equal face value extraction and enhance the face feature based on facial semantic information. We study the hole repair of 3D face model based on Poisson equation integrating semantic information and achieve the purpose of optimizing the 3D face model. After the optimization, the method is compared with mesh repair and Poisson repair, which demonstrates that our Poisson-based 3D face hole repairing model obtains the best results among compared methods.

Insertion of large diameter through-thickness metallic pins in composites

Existing Through-Thickness Reinforcement (TTR) methods for laminated composites using semi or fully rigid reinforcing elements, like tufting, stitching, and z-pinning, present limitations on reinforcing element geometry, strength, and stiffness. Where these application envelopes are exceeded, TTR element insertion results in unacceptable levels of damage to both the composite and/or TTR elements. Here, we demonstrate that low-speed insertion of rigid reinforcements into heated prepreg preforms is a feasible and robust reinforcement process capable of providing accurate TTR element placement with minimal tow disturbance compared with existing methods for similar pin sizes. The insertion process is characterised with respect to insertion forces, and mesoscale laminate deformation/damage for carbon-benzoxazine prepreg preforms. The research investigates the influence of pin leading edge on insertion for a range of pin diameters (1.2, 1.5, and 2.0 mm) and preform consolidation states, describing low insertion forces and good quality laminate preforms. Insertion forces increase with pin diameter, typically resulting from increased pin-tow contact area and friction. Large diameter sizes and low insertion forces expand the range and forms of materials that can be inserted compared to existing TTR methods and show that this method can potentially be transferred to benefit work on composite hole creation, joining, and repair.

ILM peeling with ILM flap transposition vs. classic ILM peeling for small and medium macula holes-aprospective randomized trial.

BackgroundThe aim of the present study was to compare macular hole closure rates of patients with small and medium-sized macular holes who underwent vitrectomy with internal limiting membrane (ILM) peeling combined with ILM flap transposition over the macular hole, compared with classic ILM peeling.MethodsThis prospective randomized trial was designed as a pilot study with two groups: ILM peeling with ILM flap transposition over the macular hole vs. classic ILM peeling.ResultsAmong 20 patients recruited, complete analysis could be performed for 16 patients. The macular hole closure rates were 100% in both groups, without significant differences with respect to postsurgical subfoveal hyporeflective zones (p = 1.0, Fisher’s exact test), postsurgical visual acuity (p = 0.7, t-test), and postsurgical irregularities of the ellipsoid zone (p = 1.0, Fisher’s exact test).ConclusionVitrectomy with ILM peeling combined with ILM flap transposition over the macular hole and classic ILM peeling are both successful methods for the repair of macular holes of small and medium size and are associated with comparable outcomes.

Three-Dimensional Reconstruction of Rolling Contact Fatigue Characteristics

Focusing on the 3D topographic characteristics of rolling contact fatigue, a reconstruction method of the fatigue surface of roller based on point cloud data was proposed in this research. A 3D laser scanner was used to capture the data of point cloud on the surface of the fatigue roller. The gradient segmentation method was used to achieve segmentation of the fatigue contact surface, and the Kd-Tree algorithm in Statistical Outlier Removal filter was adopted to remove different types of noise. The greedy triangulation and hole repair and reconstruction of the curled point cloud were conducted. The experimental results showed that the segmentation accuracy of the fatigue contact surface was above 97.7%, the curling error rate of point cloud was 0.09%, and the maximum deviation of the reconstructed fatigue roller surface was 0.0199 mm. These methods can be applied to analyze the working conditions of roller specimen and contact fatigue.

A Review of Surgical Techniques for the Treatment of Large Idiopathic Macular Holes

This meta-analysis reviews available surgical techniques for the repair of macular holes (MHs) >650 μm. PubMed search criteria were used to identify 17 studies outlining surgical techniques for the repair of MHs >650 μm. Thirteen of the studies identified individual cases and were further analyzed based on MH classification. Success was defined as functional improvement and anatomic closure of the hole. Two hundred and six MHs were included in this study. There were clinically significant differences between the repair of primary and refractory MHs. Autologous retinal transplant resulted in a visual acuity improvement of -0.48 ± 0.36 log-MAR, whereas an inverted internal limiting membrane (ILM) flap and pedicle ILM flap resulted in visual acuity improvements of -0.15 ± 0.17 and -0.14 ± 0.91 logMAR, respectively. An inverted or pedicle ILM flap appears more effective for primary MHs, whereas refractory MHs benefit from a free flap. [Ophthalmic Surg Lasers Imaging Retina. 2022;53:52-61.].