Circular Networks from Distorted Metrics

Trees have long been used as a graphical representation of species relationships. However complex evolutionary events, such as genetic reassortments or hybrid speciations which occur commonly in viruses, bacteria and plants, do not fit into this elementary framework. Alternatively, various network representations have been developed. Circular networks are a natural generalization of leaf-labeled trees interpreted as split systems, that is, collections of bipartitions over leaf labels corresponding to current species. Although such networks do not explicitly model specific evolutionary events of interest, their straightforward visualization and fast reconstruction have made them a popular exploratory tool to detect network-like evolution in genetic datasets. Standard reconstruction methods for circular networks, such as Neighbor-Net, rely on an associated metric on the species set. Such a metric is first estimated from DNA sequences, which leads to a key difficulty: distantly related sequences produce statistically unreliable estimates. This is problematic for Neighbor-Net as it is based on the popular tree reconstruction method Neighbor-Joining, whose sensitivity to distance estimation errors is well established theoretically. In the tree case, more robust reconstruction methods have been developed using the notion of a distorted metric, which captures the dependence of the error in the distance through a radius of accuracy. Here we design the first circular network reconstruction method based on distorted metrics. Our method is computationally efficient. Moreover, the analysis of its radius of accuracy highlights the important role played by the maximum incompatibility, a measure of the extent to which the network differs from a tree.Comment: Submitte

The staining pattern of brilliant blue G during macular hole surgery: a clinicopathologic study

Purpose.: To describe the intraoperative staining pattern of the internal limiting membrane (ILM)-specific dye Brilliant Blue G (BBG) in a cohort of patients with idiopathic macular holes; to analyze the associations of the staining pattern with pre- and postoperative variables and to correlate the staining pattern with transmission electron microscopy (TEM) of the excised ILM. Methods.: Fifty-five consecutive patients were studied. The staining pattern was divided into three subtypes based on the intraoperative appearance. The presence of a narrow rim of nonstaining around the macular hole (MH) edge was noted and measured. In the final 21 patients, the excised ILM was examined with TEM. Results.: The pattern of staining observed was categorized as uniform in 33 patients (60%), patchy nonstaining in 17 (31%), and no visible staining in 5 (9%). The staining pattern correlated with the MH stage. In the patients with uniform or patchy staining, a nonstaining rim was observed in 26 (52%) of the 50. The presence of a rim was associated with a greater hole diameter and lower postoperative visual acuity. The stain pattern correlated significantly with the amount of cellular tissue on the vitreous side of the ILM on TEM, with a greater proportion of multicellular layer membranes and new collagen in the incomplete staining groups. Conclusions.: A variety of nonstaining patterns around macular holes can be observed using BBG, and these patterns correlate to the amount of cellular tissue on the vitreous side of the ILM seen histologically. These patterns could be used to guide the ILM peeling requirement or extent in future studies

Comparison of the use of internal limiting membrane flaps versus conventional ILM peeling on post-operative anatomical and visual outcomes in large macular holes

\ua9 The Author(s) 2024. Background: Idiopathic full-thickness macular hole (iFTMH) closure rates following conventional vitrectomy, gas tamponade and internal limiting membrane (ILM) peeling decrease when the minimum linear diameter (MLD) ≥ 500 microns. ILM flap creation has been proposed to improve closure in larger holes. This study evaluated the anatomical and functional impact of ILM flap introduction to routine practice in iFTMH ≥500 microns. Methods: Retrospective, interventional analysis of prospectively collected data of 191 eyes from consecutive surgeries for primary iFTMH ≥500 microns performed by two surgeons between June 2018 and June 2022, during which both surgeons replaced ILM peeling with ILM flap creation. Post-operative best-corrected visual acuity (BCVA) and anatomical closure were compared between Group 1 (ILM peel) and Group 2 (ILM flap) in an intention-to-treat analysis. Results: Rates of iFTMH closure were greater in the ILM flap group (77/80; 96.3%) than the ILM peel group (94/110; 85.5%) (OR = 4.37, 95% CI = 1.23–15.55, p = 0.023). A non-significant increase in post-operative BCVA improvement was observed in the ILM flap group (p = 0.084). There was no statistically significant difference in final BCVA (p = 0.83). Multivariate logistic regression found only MLD (OR = 0.993, 95% CI = 0.989–0.997, p = 0.001) and ILM flap group (OR = 5.795, 95% CI = 1.313–25.570, p = 0.020) predicted primary closure. Conclusion: ILM flap creation improves closure rates in larger holes and should be considered routinely in iFTMH ≥500 microns. Whether ILM flaps affect post-operative visual function remains uncertain

A minimum specification dataset for liquid ocular endotamponades: recommendations by a European expert panel

\ua9 2023, The Author(s). Purpose: To propose a minimum specification dataset to characterize liquid ocular endotamponades (OEs), namely silicone oil (SO), heavy SO (HSO), perfluorodecalin (PFD), and perfluoro-octane (PFO), in terms of physicochemical properties, purity and available evidence of safety, in line with ISO16672:2020. Methods: An evidence-based consensus using the expert panel technique was conducted. Two facilitators led a committee of 11 European experts. Facilitators prepared a dataset for each compound including the list of specifications relevant for the safety, identified by the group members on the basis of expertise and a comprehensive literature review. Each item was ranked by each member using a 9-point scale from 1 “absolutely to not include” to 9 “absolutely to include” in two rounds followed by discussion. Only items reaching consensus (score ≥ 7 from ≥ 75% of members) were included in the final datasets. Results: For all OEs, consensus was reached to include manufacturer, density, refractive index, chemical composition, dynamic viscosity, interfacial and surface tension, endotoxins, in vitro cytotoxicity assessment, and any evidence from ex vivo and/or in vivo tests for safety assessment. Additional specifications were added for SO (molecular weight distribution, content of oligosiloxanes with MW ≤ 1000 g/mol, spectral transmittance) and PFD/PFO (% of pure PFD/PFO in the final product, vapor pressure, chemical analyses performed for safety assessment). Conclusion: The proposed evidence-based minimum specification datasets for SO, HSO, PFD, and PFO have the potential to provide surgeons and health service purchasers with an easily available overview of the most relevant information for the safety assessment of OEs. [Figure not available: see fulltext.

Surgical interventions for degenerative lamellar macular holes

Objectives This is a protocol for a Cochrane Review (intervention). The objectives are as follows: To assess the effect of surgical interventions on postoperative visual and anatomical outcomes in people with a confirmed degenerative lamellar macular hole

Three-dimensional retinal displacement before and after macular pucker surgery

\ua9 by Ophthalmic Communications Society, Inc. Purpose:To measure the coronal and sagittal retinal displacement before and after surgery for epiretinal membranes in InfraRed horizontal foveal sections and optical coherence tomography scans and describe displacement tridimensionality, vision loss, and metamorphopsia.Methods:Retrospective series with greater than 6-month average follow-up before and after surgery. The record included best-corrected visual acuity, optical coherence tomography, M-charts, and InfraRed retinography. Overall, pre- and postoperative coronal and sagittal retinal displacement across the entire field, concentric circles at 0.5-, 1.5-, and 4.5-mm radii, and the central horizontal and vertical meridian were calculated as the optical flow of consecutive images.Results:This study comprised 10 patients (4 men, 6 women), with 22.7 \ub1 25.2 months follow-up before surgery and 16.2 \ub1 7.3 months after. Best-corrected visual acuity reduced before surgery (0.15 \ub1 0.67 logarithm of minimum angle of resolution to 0.38 \ub1 0.85 logarithm of minimum angle of resolution; P < 0.05) and increased afterward (0.086 \ub1 0.61 logarithm of minimum angle of resolution; P = 0.003). Preoperative coronal displacement was 30.1 \ub1 29.1 \ub5m versus 67.0 \ub1 23.4 \ub5m after (P = 0.002). Sagittal retinal displacement was 140.9 \ub1 84.6 \ub5m before surgery, 339.7 \ub1 172.5 \ub5m after (P = 0.017), and 357.6 \ub1 320.8 \ub5m across the entire follow-up. Preoperative best-corrected visual acuity decreases correlated with the foveal coronal displacement. Vertical metamorphopsia correlated with the average coronal displacement within a 4.5-mm radius. Pre- and postoperative sagittal displacement correlated with horizontal metamorphopsia (P = 0.006 and P = 0.026). Postoperative sagittal displacement correlated with postoperative best-corrected visual acuity (P = 0.026) and foveal thickness (P = 0.009).Conclusion:This study confirms that postoperative displacement is greater than preoperative and that sagittal displacement is greater than coronal and correlates with best-corrected visual acuity and metamorphopsia changes

Twenty-seven-gauge vitrectomy: a consecutive, single-centre case series with exclusive use over a 4-year period

\ua9 2023, The Author(s).Background: To assess the safety and effectiveness of the exclusive use of 27-gauge instruments for all vitreoretinal diseases requiring vitrectomy. Methods: In this retrospective study, 1020 consecutive surgeries were performed on 958 eyes of 848 patients using 27-gauge instruments from March 2017 to June 2021. Patients with a minimum follow-up of 3 months were included. Surgical case-mix, best-corrected visual acuity (BCVA), intraocular pressure (IOP), intra- and post-operative complications, and surgery times were recorded. Results: The study patients were followed up for averagely 11 months. Of the 1020 vitrectomies, 958 were primary procedures. Of the 148 retinal detachment (RD) cases, 138 (93%) required a single vitrectomy. Primary macular hole closure was achieved in 143 of 145 (99%) cases. The average surgical times were 55 and 38 min for RD surgeries and for all other indications, respectively. BCVA improved significantly at the final visit (20/49) compared with the pre-operative visit (20/78) (p < 0.01). IOP was similar at the pre-operative (14.8mmHg) and final (14.3mmHg) visits. Complications recorded include transient hypotony in 39 eyes, iatrogenic retinal breaks in 2 eyes, and a vitreous bleed in 1 other eye. Conclusion: This study revealed that 27-gauge vitrectomy instruments can be used for a wide range of indications, with exclusive use in certain settings. The outcomes were similar to other gauges, including for rhegmatogenous retinal detachment, with minimal complications

Wound Healing in a Porcine Model of Retinal Holes

Purpose: To investigate retinal wound healing, we created a new porcine model of retinal hole and identified the cells involved in hole closure. Methods: Sixteen landrace pigs underwent vitrectomy, and a subretinal bleb was created before cutting a retinal hole using a 23G vitrector. No tamponade was used. Before surgery and one, two, and four weeks after surgery, the eyes were examined by optical coherence tomography and color fundus photos. At the end of follow-up, the eyes were enucleated for histology. Tissue sections of 5 \ub5m were prepared for hematoxylin-eosin staining and immunohistochemical analysis with antibodies to retinal glial and epithelial cells. Results: Retinal holes below 1380 \ub5m in diameter closed spontaneously within four weeks, whereas larger holes remained open. Hole closure was mediated by central movement of the edges of the hole and in most cases the formation of a gliotic plug. Fluorescence microscopy revealed that the plug consisted of cells positive for glial fibrillary acidic protein, indicating the presence of macroglial cell types. Specifically, the plug was positive for S100 calcium-binding protein B, mainly representing astrocytes, while it was negative for anti-glutamine syntethase, representing M\ufcller glia. These findings suggest that astrocytes are the predominating cell type in the plug. Minimal glial reaction was seen in the retinal holes that did not close. Conclusions: We present a new porcine model for investigating large retinal holes. The retinal holes closed by approximation of hole edges, and the remnant retinal defect was closed with an astroglial plug