RHEGMATOGENOUS RETINAL DETACHMENT AFTER INJECTION OF TISSUE PLASMINOGEN ACTIVATOR AND GAS FOR SUBMACULAR HEMORRHAGE SECONDARY TO AGE-RELATED MACULAR DEGENERATION

PURPOSE

The purpose of this study was to describe the rate, clinical characteristics, and outcomes of rhegmatogenous retinal detachment (RRD) after injection of tissue plasminogen activator (TPA) and gas for submacular hemorrhage displacement.

METHODS

Retrospective analysis of consecutive cases developing RRD after TPA injection and gas for submacular hemorrhage displacement. The rate of RRD was calculated, and a description of RRD clinical characteristics was performed. Anatomic and visual outcomes after RRD repair were analyzed.

RESULTS

Ninety eyes of 90 patients were analyzed. Tissue plasminogen activator was given intravitreally in 53 eyes (59%) and subretinally in 37 eyes (41%). RRD occurred in 6 of 90 eyes (7%). Of these, one had intravitreal TPA and five had vitrectomy with subretinal TPA ( P = 0.04). The mean age was 75 (64-93) years. The median time of RRD occurrence was 42 (1-134) days. All cases had macular involvement. Two cases had PVR at presentation. Vitrectomy was performed in all cases and silicone oil used in five, all of which resulted in permanent silicone oil retention. One case (17%) achieved primary single surgery success. The median final visual acuity was 1.8 logMAR (20/1,260 Snellen).

CONCLUSION

The RRD rate after submacular hemorrhage displacement was 7% in our case series. Rhegmatogenous retinal detachment occurred more commonly after vitrectomy with subretinal TPA injection. The visual and anatomic outcomes were poor, with a high rate of retained silicone oil and recurrent RRD.

Role of HIF1α and HIF2α in Cre Recombinase-Induced Retinal Pigment Epithelium Pathology and Its Secondary Effect on Choroidal Neovascularization

CreTrp1 mice are widely used for conditional retinal pigment epithelium (RPE) gene function studies. Like other Cre/LoxP models, phenotypes in CreTrp1 mice can be affected by Cre-mediated cellular toxicity, leading to RPE dysfunction, altered morphology and atrophy, activation of innate immunity, and consequent impairment of photoreceptor function. These effects are common among the age-related alterations of RPE that feature in early/intermediate forms of age-related macular degeneration. This article characterizes Cre-mediated pathology in the CreTrp1 line to elucidate the impact of RPE degeneration on both developmental and pathologic choroidal neovascularization. Nonredundant roles of the two major components of the hypoxia-inducible factor (HIF) family of transcription regulators, HIF1α and HIF2α, were identified. Genetic ablation of Hif1a protected against Cre-induced degeneration of RPE and choroid, whereas ablation of Hif2a exacerbated this degeneration. Furthermore, HIF1α deficiency protected CreTrp1 mice against laser-induced choroidal neovascularization, whereas HIF2α deficiency exacerbated the phenotype. Cre-mediated degeneration of the RPE in CreTrp1 mice offers an opportunity to investigate the impact of hypoxia signaling in the context of RPE degeneration. These findings indicate that HIF1α promotes Cre recombinase-mediated RPE degeneration and laser-induced choroidal neovascularization, whereas HIF2α is protective.

Retinal detachment after post-operative endophthalmitis: clinical characteristics, outcomes and risk factors

PURPOSE

To describe clinical characteristics, risk factors, and outcomes of rhegmatogenous retinal detachment (RRD) following treatment of postoperative endophthalmitis (PE).

METHODS

Analysis of cross-referenced data from two service reviews of patients with RRD and bacterial PE treated between 01/01/2013 and 01/07/2020. The main outcome measure was final best-corrected visual acuity (BCVA). Secondary measures include proportion of patients with BCVA of ≤ 0.3 logMAR and ≥ 1.0 logMAR, rate of phthsis, and rate of eye removal.

RESULTS

Ninety-four cases of PE were analysed finding 21 cases of RRD (22%). Seven (35%) experienced recurrent RRD. Seven eyes (35%) were left with permanent silicone oil fill. All RRD cases had vitrectomy. After PE with RRD the median BCVA was 1.1 logMAR, compared with 0.4 logMAR for PE without RRD (p < 0.04). Fifty-seven percent (12/21) of RRD eyes attained BCVA of ≥ 1.0 logMAR vs. 29% (21/73) of PE without RRD (p = 0.01). Nineteen percent (4/21) of eyes with RRD attained BCVA of ≤ 0.3 logMAR, whereas those without RRD did so in 43% (31/73) of cases (p = 0.02). Five eyes with RRD (24%) and 2 eyes without RRD (3%) developed phthisis (p < 0.01). Three non-RRD cases required removal of the eye (4%, p = 0.46). Higher bacterial virulence was associated with worse final BCVA (2.1 logMAR vs. 0.3 logMAR; p < 0.01). RRD rate did not differ by bacterial virulence (OR 1.9; CI95: 0.6-6.9; p = 0.24).

CONCLUSIONS

RRD following PE leads to worse clinical outcomes. Eyes which developed RRD were more likely to have undergone vitrectomy. Final BCVA was worse in cases with more virulent micro-organisms.

Comparison of Perfluorodecalin and Silicone Oil as Initial Tamponade for Giant Retinal Tear-Associated Retinal Detachment

INTRODUCTION

To compare visual outcomes and complication rates of giant retinal tear-associated retinal detachment (GRT-RD) cases treated with short-term perfluorodecalin (PFD) tamponade versus silicone oil (SiO).

METHODS

Database analysis of patients with GRT-RD operated on in the period from 1 January 2014 to 31 December 2019.

RESULTS

Forty-five patients were operated for GRT-RD using PFD or SiO during this period. Two children, 7 patients receiving gas tamponade, and 2 lost to follow-up were excluded. Eighteen eyes (40%) received PFD and 27 (60%) received SiO. There were 15/18 (83%) macula-sparing cases in the PFD group and 18/27 (67%) in the SiO group (p = 0.13). The mean duration of oil tamponade was 91 days for SiO and 7.6 days for PFD (p < 0.0001). The mean length of follow-up was 274.5 days for PFD and 668.9 days for SiO. The mean BCVA was 6/18 (63.4 ± 26.0 ETDRS letters) for SiO and 6/12 (72.9 ± 12.7 ETDRS letters) for PFD (p = 0.42). Analysing macula-sparing pseudophakic eyes, the BCVA was 6/12 (67.4 ± 25.9 letters, n = 18) for SiO eyes and 6/9 (76.8 ± 9.9 letters, n = 11) for PFD eyes (p = 0.54). The recurrence rate was 22% (6/27) for SiO and 6% (1/18) for PFD (p = 0.12). The rate of cystoid macular oedema (CMO) was 22% for SiO and 22% for PFD. Epiretinal membrane (ERM) was found in 26% of SiO cases and 22% of PFD cases. Loss of vision after oil removal was not observed. Seven eyes (26%) receiving SiO and none receiving PFD developed chronic ocular hypertension (OHT) (p = 0.02).

CONCLUSIONS

Short-term tamponade with PFD for GRT-RD appears similar to tamponade with SiO in terms of the visual outcomes and complication rates.

Pathological Angiogenesis Requires Syndecan-4 for Efficient VEGFA-Induced VE-Cadherin Internalization

[Figure: see text].

Late neuroprogenitors contribute to normal retinal vascular development in a Hif2a-dependent manner

In the adult central nervous system, endothelial and neuronal cells engage in tight cross-talk as key components of the so-called neurovascular unit. Impairment of this important relationship adversely affects tissue homeostasis, as observed in neurodegenerative conditions including Alzheimer's and Parkinson's disease. In development, the influence of neuroprogenitor cells on angiogenesis is poorly understood. Here, we show in mouse that these cells interact intimately with the growing retinal vascular network, and we identify a novel regulatory mechanism of vasculature development mediated by hypoxia-inducible factor 2a (Hif2a). By Cre-lox gene excision, we show that Hif2a in retinal neuroprogenitor cells upregulates the expression of the pro-angiogenic mediators vascular endothelial growth factor and erythropoietin, whereas it locally downregulates the angiogenesis inhibitor endostatin. Importantly, absence of Hif2a in retinal neuroprogenitor cells causes a marked reduction of proliferating endothelial cells at the angiogenic front. This results in delayed retinal vascular development, fewer major retinal vessels and reduced density of the peripheral deep retinal vascular plexus. Our findings demonstrate that retinal neuroprogenitor cells are a crucial component of the developing neurovascular unit.

A Study of the Natural History of Vitreomacular Traction Syndrome by OCT

PURPOSE

To examine the natural history of vitreomacular traction syndrome (VMTS) in the absence of other ocular comorbidities.

DESIGN

Retrospective clinical case series.

PARTICIPANTS

A total of 183 eyes of 159 patients diagnosed with VMTS with no other ocular comorbidity.

METHODS

Patients with VMTS were identified from an OCT database at Moorfields Eye Hospital, London. Sequential OCT scans and patient notes were reviewed over a minimum period of 6 months. Data collected included patient demographics, best-corrected visual acuity, and OCT features of vitreomacular adhesion. Contingency tests and binary logistic modeling were used to identify baseline predictors of stability and progression.

MAIN OUTCOME MEASURES

The rates of spontaneous resolution (defined by release of traction), progression to full-thickness macular hole, and surgical intervention were analyzed.

RESULTS

Presenting visual acuity was 0.3±0.3 logMAR units. The mean length of follow-up was 17.4±12.1 months. During this period, VMTS persisted in 60% and resolved in 20% (occurring on average at 15 months). Of the remainder, 12% developed a macular hole and 8% elected to proceed with surgery for symptoms. Focal adhesion <1500 μm was present in 87%. A premacular membrane with macular pucker (PMM) was present in 20%. With persistent VMTS, vision and central foveal thickness remained unchanged. The relative risk of resolution increased in those cases with better presenting visual acuities, lesser foveal thicknesses, and no associated PMMs; vision significantly improved in those cases with resolution.

CONCLUSIONS

VMTS persists in the majority of patients but despite this, visual acuities did not deteriorate significantly over the study period unless patients developed a full-thickness macular hole or required surgical intervention for symptoms. Resolution spontaneously occurred in 20%, with an improvement in vision.

VEGF165-induced vascular permeability requires NRP1 for ABL-mediated SRC family kinase activation

Fantin et al. show that the VEGF isoform VEGF165 signals through a complex of VEGFR2 and NRP1, in which the NRP1 cytoplasmic domain promotes the ABL-mediated activation of SRC family kinases to evoke a hyperpermeability response, a known cause of pathological edema.

The vascular endothelial growth factor (VEGF) isoform VEGF165 stimulates vascular growth and hyperpermeability. Whereas blood vessel growth is essential to sustain organ health, chronic hyperpermeability causes damaging tissue edema. By combining in vivo and tissue culture models, we show here that VEGF165-induced vascular leakage requires both VEGFR2 and NRP1, including the VEGF164-binding site of NRP1 and the NRP1 cytoplasmic domain (NCD), but not the known NCD interactor GIPC1. In the VEGF165-bound receptor complex, the NCD promotes ABL kinase activation, which in turn is required to activate VEGFR2-recruited SRC family kinases (SFKs). These results elucidate the receptor complex and signaling hierarchy of downstream kinases that transduce the permeability response to VEGF165. In a mouse model with choroidal neovascularisation akin to age-related macular degeneration, NCD loss attenuated vessel leakage without affecting neovascularisation. These findings raise the possibility that targeting NRP1 or its NCD interactors may be a useful therapeutic strategy in neovascular disease to reduce VEGF165-induced edema without compromising vessel growth.

Pars Plana Vitrectomy for Vitreomacular Traction Syndrome: Analysing the Preoperative Prognostic Factors

PURPOSE

To identify the prognostic factors affecting the surgical outcomes in patients with vitreomacular traction syndrome undergoing pars plana vitrectomy.

METHODS

This was a retrospective clinical study of 67 eyes of 67 patients with vitreomacular traction syndrome who underwent pars plana vitrectomy. Demographic, clinical, and optical coherence tomography (OCT) characteristics were collected and analyzed. Univariate and multivariate linear regression analysis were used to examine the effect of parameters on change in best-corrected visual acuity (BCVA).

RESULTS

At a mean follow-up period of 15.9±12 months (mean±SD), the BCVA improved from 0.7±0.3 LogMAR (mean±SD) to 0.5±0.3. Seven patients developed full-thickness macular hole intraoperatively and tamponade (air, 20% SF6 or 12% C3F8) was used in 41 patients. Retinal breaks were identified intraoperatively in four patients. Regression analysis demonstrated that the preoperative BCVA was the only parameter affecting the postoperative visual outcome.

CONCLUSION

In the present study, the preoperative BCVA plays a predictive role in the surgical outcome of patients with VMT undergoing pars plana vitrectomy. No other preoperative OCT characteristics demonstrated prognostic potential. Further prospective studies are needed in order to examine the role of several factors that could potentially facilitate preoperative patient counselling.

Flow cytometric analysis of inflammatory and resident myeloid populations in mouse ocular inflammatory models

Myeloid cells make a pivotal contribution to tissue homeostasis during inflammation. Both tissue-specific resident populations and infiltrating myeloid cells can cause tissue injury through aberrant activation and/or dysregulated activity. Reliable identification and quantification of myeloid cells within diseased tissues is important to understand pathological inflammatory processes. Flow cytometry is a valuable technique for leukocyte analysis, but a standardized flow cytometric method for myeloid cell populations in the eye is lacking. Here, we validate a reproducible flow cytometry gating approach to characterize myeloid cells in several commonly used models of ocular inflammation. We profile and quantify myeloid subsets across these models, and highlight the value of this strategy in identifying phenotypic differences using Ccr2-deficient mice. This method will aid standardization in the field and facilitate future investigations into the roles of myeloid cells during ocular inflammation.

Multimodal analysis of ocular inflammation using the endotoxin-induced uveitis mouse model

Endotoxin-induced uveitis (EIU) in rodents is a model of acute Toll-like receptor 4 (TLR4)-mediated organ inflammation, and has been used to model human anterior uveitis, examine leukocyte trafficking and test novel anti-inflammatory therapeutics. Wider adoption has been limited by the requirement for manual, non-specific, cell-count scoring of histological sections from each eye as a measure of disease severity. Here, we describe a comprehensive and efficient technique that uses ocular dissection and multimodal tissue analysis. This allows matched disease scoring by multicolour flow cytometric analysis of the inflammatory infiltrate, protein analysis on ocular supernatants and qPCR on remnant tissues of the same eye. Dynamic changes in cell populations could be identified and mapped to chemokine and cytokine changes over the course of the model. To validate the technique, dose-responsive suppression of leukocyte infiltration by recombinant interleukin-10 was demonstrated, as well as selective suppression of the monocyte (CD11b+Ly6C+) infiltrate, in mice deficient for eitherCcl2orCcr2 Optical coherence tomography (OCT) was used for the first time in this model to allowin vivoimaging of infiltrating vitreous cells, and correlated with CD11b+Ly6G+ counts to provide another unique measure of cell populations in the ocular tissue. Multimodal tissue analysis of EIU is proposed as a new standard to improve and broaden the application of this model.

Myeloid-Derived Vascular Endothelial Growth Factor and Hypoxia-Inducible Factor Are Dispensable for Ocular Neovascularization--Brief Report

Supplemental Digital Content is available in the text.

Ocular neovascularization (ONV) is a pathological feature of sight-threatening human diseases, such as diabetic retinopathy and age-related macular degeneration. Macrophage depletion in mouse models of ONV reduces the formation of pathological blood vessels, and myeloid cells are widely considered an important source of the vascular endothelial growth factor A (VEGF). However, the importance of VEGF or its upstream regulators hypoxia-inducible factor-1α (HIF1α) and hypoxia-inducible factor-2α (HIF2α) as myeloid-derived regulators of ONV remains to be determined.

Cd59a deficiency in mice leads to preferential innate immune activation in the retinal pigment epithelium-choroid with age

Dysregulation of the complement system has been implicated in the pathogenesis of age-related macular degeneration. To investigate consequences of altered complement regulation in the eye with age, we examined Cd59a complement regulator deficient (Cd59a(-/-)) mice between 4 and 15 months. In vivo imaging revealed an increased age-related accumulation of autofluorescent spots in Cd59a(-/-) mice, a feature that reflects accumulation of subretinal macrophages and/or microglia. Despite this activation of myeloid cells in the eye, Cd59a(-/-) mice showed normal retinal histology and function as well as normal choroidal microvasculature. With age, they revealed increased expression of activators of the alternative complement pathway (C3, Cfb, Cfd), in particular in the retinal pigment epithelium (RPE)-choroid but less in the retina. This molecular response was not altered by moderately-enhanced light exposure. Cd59a deficiency therefore leads to a preferential age-related dysregulation of the complement system in the RPE-choroid, that alone or in combination with light as a trigger, is not sufficient to cause choroidal vascular changes or retinal degeneration and dysfunction. This data emphasizes the particular vulnerability of the RPE-choroidal complex to dysregulation of the alternative complement pathway during aging.

Assessment and in vivo scoring of murine experimental autoimmune uveoretinitis using optical coherence tomography

Despite advances in clinical imaging and grading our understanding of retinal immune responses and their morphological correlates in experimental autoimmune uveoretinitis (EAU), has been hindered by the requirement for post-mortem histology. To date, monitoring changes occurring during EAU disease progression and evaluating the effect of therapeutic intervention in real time has not been possible. We wanted to establish whether optical coherence tomography (OCT) could detect intraretinal changes during inflammation and to determine its utility as a tool for accurate scoring of EAU. EAU was induced in C57BL/6J mice and animals evaluated after 15, 26, 36 and 60 days. At each time-point, contemporaneous Spectralis-OCT scanning, topical endoscopic fundal imaging (TEFI), fundus fluorescein angiography (FFA) and CD45-immunolabelled histology were performed. OCT features were further characterised on retinal flat-mounts using immunohistochemistry and 3D reconstruction. Optic disc swelling and vitreous opacities detected by OCT corresponded to CD45+ cell infiltration on histology. Vasculitis identified by FFA and OCT matched perivascular myeloid and T-cell infiltrates and could be differentiated from unaffected vessels. Evolution of these changes could be followed over time in the same eye. Retinal folds were visible and found to encapsulate mixed populations of activated myeloid cells, T-cells and microglia. Using these features, an OCT-based EAU scoring system was developed, with significant correlation to validated histological (Pearson r² = 0.6392, P<0.0001, n = 31 eyes) and TEFI based scoring systems (r² = 0.6784, P<0.0001). OCT distinguishes the fundamental features of murine EAU in vivo, permits dynamic assessment of intraretinal changes and can be used to score disease severity. As a result, it allows tissue synchronisation with subsequent cellular and functional assessment and greater efficiency of animal usage. By relating OCT signals with immunohistochemistry in EAU, our findings offer the opportunity to inform the interpretation of OCT changes in human uveitis.

Airbag-induced corneal flap

PURPOSE

To describe a case of airbag-induced corneal flap in a previously normal cornea.

METHODS

Case report.

RESULTS

A 27-year-old woman presented with complete loss of vision in her left eye following a road traffic accident which involved airbag deployment. There was no previous ocular history. Examination revealed a large corneal flap of 6mm in diameter, extending to the depth of anterior stroma. This was accompanied by a traumatic optic neuropathy. One month follow-up revealed complete reattachment of the corneal flap.

CONCLUSIONS

This is the first reported case of a corneal flap induced by airbag deployment in a cornea with previously normal architecture.

Conjunctival sweeping with a squint hook to reduce chemosis

We describe a simple technique for reducing surgical chemosis. The conjunctival sweeping technique uses a squint hook and tissue scissors and can be used effectively by surgeons at all levels of experience.