Purpose To report the outcomes of secondary Descemet Membrane Endothelial Keratoplasty (DMEK) performed for failed primary DMEK. Methods The medical records of all patients undergoing secondary DMEK due to failure of primary DMEK were reviewed. Reasons for failure were sought and best-corrected visual acuity (BCVA), endothelial cell density (ECD) and complications of secondary DMEK were evaluated. Results A total of 10 cases undergoing secondary DMEK following failed primary DMEK were identified. Presumed reasons for failure included donor ECD B 2300 cells/mm 2 (n = 4), difficulty during graft preparation (n = 2), graft detachment (n = 2), acute angle closure due to retroiridal air dislocation (n = 1), inverse graft positioning (n = 1) and phacoemulsification (n = 1). Eyes with low visual potential were not excluded from the study group. We should note that one patient (case no7) had both low ECD and graft detachment as reasons for failure and as a result he is counted twice.Median BCVA (decimal fraction) increased from 0.1 (range, 0.01; 0.3) to 0.5 (0.05; 1.0) at one month and remained stable thereafter. A BCVA of 0.5 or higher was achieved in 7 cases at the final follow-up. Mean ECD fell from 2628 ± 284 cells/mm 2 to 1391 ± 252cells/mm 2 at 6 months (47% reduction) and 959 ± 225cells/mm 2 at 24 months (64% reduction) (P B 0.028). Complications included the incomplete removal of the primary graft and mild iris bleeding, decompensation of a preexisting primary open-angle glaucoma and retroiridal air dislocation. Conclusions Apart from low donor ECD, surgical challenges, i.e., difficulty with graft preparation, inverse graft positioning, and retroiridal air dislocation, were main reasons for failure of primary DMEK. Secondary DMEK showed a good safety profile and reasonable visual outcomes.

Purpose To report a 71-year-old male patient diagnosed with epiretinal membrane-induced intraretinal neovascularization. Observations The presence of an epiretinal membrane (ERM) was confirmed by Optical Coherence Tomography (OCT), fluorescein and indocyanine angiography. Optical coherence tomography angiography (OCT-A) revealed a neovascular membrane within the ERM. Intravitreal ranibizumab injections were administered three times at four-week intervals. Imaging revealed a stable membrane with no leakage. Five months after the third injection, OCT revealed intraretinal fluid. OCT-A showed a new branch of the neo-vascular membrane at the superficial capillary plexus. Following an additional ranibizumab injection, the membrane stabilized. Conclusions and importance It is conceivable that neovascularization developed due to, or in close conjunction with an epiretinal membranes already in place.

Natural Language Understanding is a major aspect of the intelligence of robotic systems. A main goal of improving their artificial intelligence is to allow a robot to ask questions, whenever the given instructions are not complete, and also by using implicit information. These enhanced communicational abilities can be based on the voids of an output data structure that corresponds to a systemic-semantic model of language communication, as grammar formalism. In addition, the enhancing process also improves the learning abilities of a robot. Accordingly, the presented herein experimental project was conducted by using a simulated (by a plain PC) robot and a simple constructed language that facilitated semantic orientation.

To describe the off-label use of lyophilized equine pericardium for tectonic enhancement of the sclera in a case of progressive scleromalacia perforans.Methods: An 82-year-old woman with a history of varicella zoster virus sclerokeratitis presented with a progressively expanding scleral thinning at the superonasal quadrant of the anterior sclera of her left eye. The eye was blind because of intractable glaucoma. To avoid perforation of the exposed choroid, a single layer of lyophilized equine pericardium was sutured over the scleral perforation. After performing a conjunctival peritomy in the involved superonasal area, the pericardium was trimmed, fixated on the anterior sclera with 4 Nylon 9 to 0 interrupted sutures, and tucked underneath the conjunctival pocket. The conjunctiva was adapted with 6 Vicryl 8 to 0 interrupted sutures. Results:The postoperative course was uneventful. At 12 months after surgery, slit-lamp biomicroscopy showed a stable subconjunctival sheet covering the staphyloma, whereas anterior segment optical coherence tomography demonstrated thickening of the ocular wall, suggesting successful integration of the pericardium.Conclusions: Suturing of equine pericardium over a scleral defect was feasible allowing successful reinforcement of the staphyloma in a case of severe scleromalacia perforans.

This paper attempts to approach the interface of a robot from the perspective of virtual assistants. Virtual assistants can also be characterized as the mind of a robot, since they manage communication and action with the rest of the world they exist in. Therefore, virtual assistants can also be described as the brain of a robot and they include a Natural Language Processing (NLP) module for conducting communication in their human-robot interface. This work is focused on inquiring and enhancing the capabilities of this module. The problem is that nothing much is revealed about the nature of the human-robot interface of commercial virtual assistants. Therefore, any new attempt of developing such a capability has to start from scratch. Accordingly, to include corresponding capabilities to a developing NLP system of a virtual assistant, a method of systemic semantic modelling is proposed and applied. For this purpose, the paper briefly reviews the evolution of virtual assistants from the first assistant, in the form of a game, to the latest assistant that has significantly elevated their standards. Then there is a reference to the evolution of their services and their continued offerings, as well as future expectations. The paper presents their structure and the technologies used, according to the data provided by the development companies to the public, while an attempt is made to classify virtual assistants, based on their characteristics and capabilities. Consequently, a robotic NLP interface is being developed, based on the communicative power of a proposed systemic conceptual model that may enhance the NLP capabilities of virtual assistants, being tested through a small natural language dictionary in Greek.

No abstract

The objective of this study is to perform a systematic review and meta-analysis of the published studies on limbal stem cell transplantation (LSCT) combined with penetrating keratoplasty (PK) performed either simultaneously or sequentially.Methods: An extensive search was conducted in the MEDLINE and Google Scholar databases. Prospective and retrospective trials and case series reporting on the outcomes of LSCT with PK were included. Primary outcomes were the stability of the ocular surface and the rejection and/or failure of the corneal graft.Results: A total of 209 eyes from 13 studies were included in the simultaneous group and 489 eyes from 33 studies in the sequential group. Ocular surface stability was 88% [95% confidence interval (CI), 79%-96%] for sequential cases and 64% (95% CI, 43%-82%) for simultaneous cases (P = 0.001). The graft failure rate was 15% (95% CI, 6%-26%) for sequential cases and 44% (95% CI, 31%-58%) for simultaneous cases (P , 0.001). For cases performed sequentially, subgroup analysis revealed a stable ocular surface in 97% (95% CI, 91%-100%) of autograft cases and 63% (95% CI, 45%-80%) of allograft cases (P , 0.001). The graft failure rate in sequential cases was 7% (95% CI, 0%-18%) for autografts and 34% (95% CI, 18%-52%) for allografts (P , 0.001).Conclusions: Sequential LSCT followed by PK demonstrated superior results in terms of ocular surface stability and graft retention compared with simultaneous LSCT and PK. Limbal stem cells of autologous origin fare better than allogeneic ones in sequential cases.

An unusual case of nitroglycerin-induced Paracentral Acute Middle Maculopathy (PAMM) is presented. A 50-year-old patient with sudden vision loss and scotoma was followed up with swept-source optical coherence tomography (SS-OCT), optical coherence tomography-angiography (OCT-A), and fluorescein angiography (FA). An anal fissure treated with glyceryl trinitrate (GTN) 0.2% ointment with headache and dizziness after application was reported. Fundoscopy OS revealed mild retinal venous dilatation and tortuosity with scattered blot hemorrhages and subtle, parafoveal, whitish lesions in the outer retina. SS-OCT revealed diffuse, hyperreflective lesions in the inner plexiform (IPL), inner nuclear (INL), and outer plexiform layers (OPL). OCT-A revealed focal dropout in the deep capillary plexus. FA showed masking due to blot hemorrhages and early punctuate leakage in the inner retina. This entity was identified as nitroglycerin-induced PAMM. Over the following 8 months, after discontinuation of the ointment application, the patient was symptom-free with stable visual acuity. OCT revealed INL/OPL thinning and confirmed complete lesion resolution. This first report of retinal vascular abnormalities due to nitrite ointment provides an insight into an unknown side effect of nitroglycerin ointment use. A dose-dependent correlation between GTN application and retinal vascular abnormalities remains to be confirmed.