Collective production of hydrogen sulfide gas enables budding yeast lacking MET17 to overcome their metabolic defect.

Assimilation of sulfur is vital to all organisms. In S. cerevisiae, inorganic sulfate is first reduced to sulfide, which is then affixed to an organic carbon backbone by the Met17 enzyme. The resulting homocysteine can then be converted to all other essential organosulfurs such as methionine, cysteine, and glutathione. This pathway has been known for nearly half a century, and met17 mutants have long been classified as organosulfur auxotrophs, which are unable to grow on sulfate as their sole sulfur source. Surprisingly, we found that met17Δ could grow on sulfate, albeit only at sufficiently high cell densities. We show that the accumulation of hydrogen sulfide gas underpins this density-dependent growth of met17Δ on sulfate and that the locus YLL058W (HSU1) enables met17Δ cells to assimilate hydrogen sulfide. Hsu1 protein is induced during sulfur starvation and under exposure to high sulfide concentrations in wild-type cells, and the gene has a pleiotropic role in sulfur assimilation. In a mathematical model, the low efficiency of sulfide assimilation in met17Δ can explain the observed density-dependent growth of met17Δ on sulfate. Thus, having uncovered and explained the paradoxical growth of a commonly used "auxotroph," our findings may impact the design of future studies in yeast genetics, metabolism, and volatile-mediated microbial interactions.

Extracellular vesicle biomarkers in ocular fluids associated with ophthalmic diseases.

Extracellular vesicles (EVs) are released as highly stable lipid bilayer particles carrying proteins, lipids, glycans and miRNAs. The contents of EVs vary based on the cellular origin, biogenesis route and the functional state of the cell suggesting certain diseased conditions. A growing body of evidence show that EVs carry important molecules implicated in the development and progression of ophthalmic diseases. EVs associated with ophthalmic diseases are mainly carried by one of the three ocular biofluids which include tears, aqueous humor and vitreous humor. This review summarizes the list of EV derived biomarkers identified thus far in ocular fluids for ophthalmic disease diagnosis. Further, the methods used for sample collection, sample volume and the sample numbers used in these studies have been highlighted. Emphasis has been given to describe the EV isolation and the characterization methods used, EV size profiled and the EV concentrations analyzed by these studies, thus providing a roadmap for future EV biomarker studies in ocular fluids.

RaacFold: a webserver for 3D visualization and analysis of protein structure by using reduced amino acid alphabets.

Protein structure exhibits greater complexity and diversity than DNA structure, and usually affects the interpretation of the function, interactions and biological annotations. Reduced amino acid alphabets (Raaa) exhibit a powerful ability to decrease protein complexity and identify functional conserved regions, which motivated us to create RaacFold. The RaacFold provides 687 reduced amino acid clusters (Raac) based on 58 reduction methods and offers three analysis tools: Protein Analysis, Align Analysis, and Multi Analysis. The Protein Analysis and Align Analysis provide reduced representations of sequence-structure according to physicochemical similarities and computational biology strategies. With the simplified representations, the protein structure can be viewed more concise and clearer to capture biological insight than the unreduced structure. Thus, the design of artificial protein will be more convenient, and redundant interference is avoided. In addition, Multi Analysis allows users to explore biophysical variation and conservation in the evolution of protein structure and function. This supplies important information for the identification and exploration of the nonhomologous functions of paralogs. Simultaneously, RaacFold provides powerful 2D and 3D rendering performance with advanced parameters for sequences, structures, and related annotations. RaacFold is freely available at http://bioinfor.imu.edu.cn/raacfold.

Simulations reveal challenges to artificial community selection and possible strategies for success.

Multispecies microbial communities often display "community functions" arising from interactions of member species. Interactions are often difficult to decipher, making it challenging to design communities with desired functions. Alternatively, similar to artificial selection for individuals in agriculture and industry, one could repeatedly choose communities with the highest community functions to reproduce by randomly partitioning each into multiple "Newborn" communities for the next cycle. However, previous efforts in selecting complex communities have generated mixed outcomes that are difficult to interpret. To understand how to effectively enact community selection, we simulated community selection to improve a community function that requires 2 species and imposes a fitness cost on one or both species. Our simulations predict that improvement could be easily stalled unless various aspects of selection are carefully considered. These aspects include promoting species coexistence, suppressing noncontributors, choosing additional communities besides the highest functioning ones to reproduce, and reducing stochastic fluctuations in the biomass of each member species in Newborn communities. These considerations can be addressed experimentally. When executed effectively, community selection is predicted to improve costly community function, and may even force species to evolve slow growth to achieve species coexistence. Our conclusions hold under various alternative model assumptions and are therefore applicable to a variety of communities.

Suppression of electromagnetic interference in electroretinography from a patient with an implanted left ventricular assist device (LVAD).

PURPOSE: A left ventricular assist device (LVAD) is an implantable cardiac pump that uses a magnetically-levitating rotor to pump blood into circulation for patients with congestive heart failure. The continuous high-frequency motion of the pump can cause significant interference in electroretinography (ERG) recordings. We evaluate filtering methods to improve ERG quality in the presence of LVAD interference. METHODS: A patient with an implanted LVAD was referred to our clinic for ERG testing on suspicion of a retinal dystrophy. Full-field ERG (ffERG) and pattern ERG (pERG) were performed according to ISCEV standards. Recordings were acquired once in full-bandwidth mode and again in low-bandwidth mode. Digital low-pass and band-stop filtering were performed to mitigate ERG interference. Post-processing was also evaluated in a control subject with no implanted device. RESULTS: High-frequency interference was present in all ERG recordings and corresponded to the speed settings of the pump. When applied in post-processing, both low-pass and band-stop filters suppressed the interference and presented readable ERGs without affecting peak times or amplitudes. By contrast, when recording in low-bandwidth mode, the filter drop-off was not steep enough to completely remove the interference and peak delays were introduced that could not be readily corrected. CONCLUSIONS: LVAD interference in ERG waveforms can be successfully removed using simple digital filters. If post hoc data processing capabilities are unavailable, a large amount of interference can be removed by narrowing the acquisition bandwidth and averaging additional repeats of each stimulus response.

Preparing a Single Cell Suspension from Zebrafish Retinal Tissue for Flow Cytometric Cell Sorting of Müller Glia.

Preparation of a single cell suspension from solid tissue is vital for a successful flow cytometry experiment. We report a detailed and reproducible method to produce a quality cell suspension from the zebrafish retina. Zebrafish retinas, especially their Müller glia cells, are of particular interest for their inherent regenerative capacity, making them a useful model for regenerative medicine and cell therapy research. Here, we detail a papain-based dissociation that is gentle enough to keep cells intact, but strong enough to disrupt cell-cell and cell-matrix interactions to yield a cell suspension that produces clean and reliable flow cytometric cell sorting results. This procedure consistently results in over 90% viability and three populations of cells based on GFP expression. The dissociation procedure described herein has been optimized for the collection of Müller glia from Tg(apoe:gfp) zebrafish retinas; however, the overall process may be applicable to other cell types in the fish retina, additional flow cytometric techniques, or preparing cell suspensions from similar tissues. © 2019 International Society for Advancement of Cytometry.

Retinal artery occlusion does not portend an increased risk of stroke.

OBJECTIVE: The aim of this study was to determine the subsequent risk of stroke after a diagnosis of retinal artery occlusion (RAO). We hypothesized that the risk would be low and comparable to that of the general population. RAO is relatively rare and often incorrectly diagnosed. We believe our institution is in a unique position to investigate this relationship with both a high-volume eye center and vascular laboratory. METHODS: This was a retrospective, single-institution review of 221 patients diagnosed with RAO from 2004 to 2018, confirmed with fluorescein angiography. Demographics, comorbidities, imaging of the carotid arteries, and prospective events, such as stroke, myocardial infarction (MI), and death, were recorded. Time to first stroke, first MI, and death was estimated using Kaplan-Meier estimation separately and as a composite end point. RESULTS: There were 221 patients identified with a confirmed diagnosis of RAO. The mean age in the cohort was 66.1 years; 53% of patients were male, and 29% were diabetic. Median length of follow-up was 2.2 years. Five patients (2.3%) had a documented stroke; four of the five strokes occurred at the time of RAO, with one that was contralateral occurring at 1.2 years. There were eight MIs (3.6%) in the cohort, two of which resulted in death. Twenty-two patients (10%) experienced a stroke, MI, or death. There were 141 (63.8%) patients who had carotid imaging performed, of whom 20 (14.2%) were found to have >50% stenosis. CONCLUSIONS: The rate of stroke in patients with confirmed RAO was 2.3%; however, excluding concurrent ischemic events, the risk was <1%. The incidence of carotid artery stenosis >50% was 14.2%. The authors conclude that the risk of stroke after confirmed RAO is lower than previously reported and comparable to prior population-based studies of all at-risk adults.

ADVERSE EVENTS OF THE ARGUS II RETINAL PROSTHESIS: Incidence, Causes, and Best Practices for Managing and Preventing Conjunctival Erosion.

PURPOSE: To analyze and provide an overview of the incidence, management, and prevention of conjunctival erosion in Argus II clinical trial subjects and postapproval patients. METHODS: This retrospective analysis followed the results of 274 patients treated with the Argus II Retinal Prosthesis System between June 2007 and November 2017, including 30 subjects from the US and European clinical trials, and 244 patients in the postapproval phase. Results were gathered for incidence of a serious adverse event, incidence of conjunctival erosion, occurrence sites, rates of erosion, and erosion timing. RESULTS: Overall, 60% of subjects in the clinical trial subjects versus 83% of patients in the postapproval phase did not experience device- or surgery-related serious adverse events. In the postapproval phase, conjunctival erosion had an incidence rate of 6.2% over 5 years and 11 months. In 55% of conjunctival erosion cases, erosion occurred in the inferotemporal quadrant, 25% in the superotemporal quadrant, and 20% in both. Sixty percent of the erosion events occurred in the first 15 months after implantation, and 85% within the first 2.5 years. CONCLUSION: Reducing occurrence of conjunctival erosion in patients with the Argus II Retinal Prosthesis requires identification and minimization of risk factors before and during implantation. Implementing inverted sutures at the implant tabs, use of graft material at these locations as well as Mersilene rather than nylon sutures, and accurate Tenon's and conjunctiva closure are recommended for consideration in all patients.

Animal models of radiation retinopathy - From teletherapy to brachytherapy.

Radiation retinopathy is a serious vision-impairing complication of radiation therapy used to treat ocular tumors. Characterized by retinal vasculopathy and subsequent retinal damage, the first sign of radiation retinopathy is the preferential loss of vascular endothelial cells. Ensuing ischemia leads to retinal degradation and late stage neovascularization. Despite the established disease progression, the pathophysiology and cellular mechanisms contributing to radiation retinopathy remain unclear. Clinical experience and basic research for other retinal vasculopathies, such as diabetic retinopathy and retinopathy of prematurity, can inform our understanding of radiation retinopathy; however, the literature investigating the fundamental mechanisms in radiation retinopathy is limited. Treatment trials have shown modest success but, ultimately, fail to address the cellular events that initiate radiation retinopathy. Animal models of radiation retinopathy could provide means to identify effective therapies. Here, we review the literature for all animal models of radiation retinopathy, summarize anatomical highlights pertaining to animal models, identify additional physiological factors to consider when investigating radiation retinopathy, and explore the use of clinically relevant tests for studying in vivo models of radiation retinopathy. We encourage further investigation into the mechanistic characterization of radiation retinopathy in the hope of discovering novel treatments.

Heterogeneity of cultured melanocyte elongation and proliferation factor in bilateral diffuse uveal melanocytic proliferation.

A patient with bilateral diffuse uveal melanocytic proliferation (BDUMP) associated with endometrial cancer was treated with plasmapheresis, but failed therapy with progressive serous retinal detachment. We collected plasma before and after plasmapheresis therapy. Our goal was to determine if the cultured melanocyte elongation and proliferation (CMEP) factor and hepatocyte growth factor (HGF) was present in the IgG enriched fraction and understand why our patient failed plasmapheresis therapy. Melanocytes were cultured for 3-5 days in the presence of control medium, unfractionated pre-plasmapheresis BDUMP medium, IgG enriched or IgG depleted BDUMP medium, or unfractionated post-plasmapheresis BDUMP medium. Subretinal fluid was collected from patients with BDUMP and control retinal detachments and analyzed by electropheresis with immunoblotting. Medium with unfractionated BDUMP plasma stimulated melanocyte growth 1.4-1.5 fold compared to control medium on days 3-5 (p < 0.001 for all). Both IgG enriched and IgG depleted BDUMP medium mildly increased melanocyte growth 1.3 fold (p < 0.05 for enriched, p < 0.01 for depleted) compared to control. In comparison, unfractionated BDUMP medium caused a 1.7-fold increase in melanocyte growth, which was significantly more than the enriched (p < 0.01) and depleted (p < 0.05) fractions. Pre-plasmapheresis and post-plasmapheresis unfractionated BDUMP medium equally stimulated melanocyte growth 1.7-fold (p < 0.05) compared to control. HGF was present in IgG depleted, pre-plasmapheresis, and post-plasmapheresis samples, but absent in the IgG enriched fraction. There was no enrichment of IgG in the subretinal fluid from eyes with BDUMP. In conclusion, CMEP factor is not concentrated in the IgG enriched plasma fraction in our patient who failed plasmapheresis therapy. HGF levels have no correlation with melanocyte growth. Because plasmapheresis preferentially removes immunoglobulins from the plasma, our patient responded poorly to plasmapheresis treatment with worsening retinal detachment.

The DISCOVER Study 3-Year Results: Feasibility and Usefulness of Microscope-Integrated Intraoperative OCT during Ophthalmic Surgery.

PURPOSE: To report the 3-year assessment of feasibility and usefulness of microscope-integrated intraoperative OCT (iOCT) during ophthalmic surgery. DESIGN: Prospective, consecutive case series. PARTICIPANTS: Adult participants undergoing incisional ophthalmic surgery with iOCT imaging who consented to be enrolled in the Determination of Feasibility of Intraoperative Spectral-Domain Microscope Combined/Integrated OCT Visualization during En Face Retinal and Ophthalmic Surgery (DISCOVER) study. METHODS: The DISCOVER study is a single-site, multisurgeon, institutional review board-approved investigational device prospective study. Participants included patients undergoing anterior or posterior segment surgery who underwent iOCT imaging with 1 of 3 prototype microscope-integrated iOCT systems (i.e., Zeiss Rescan 700, Leica EnFocus, or Cole Eye iOCT systems). Clinical characteristics were documented, iOCT was directed by the operating surgeon at predetermined surgical time points, and each surgeon completed a questionnaire after surgery to evaluate the usefulness of iOCT during surgery. MAIN OUTCOME MEASURES: Feasibility of iOCT based ability to obtain an OCT image during surgery and usefulness of iOCT based on surgeon reporting during surgery. RESULTS: Eight hundred thirty-seven eyes (244 anterior segment cases and 593 posterior segment cases) were enrolled in the DISCOVER study. Intraoperative OCT demonstrated feasibility with successful image acquisition in 820 eyes (98.0%; 95% confidence interval [CI], 96.8%-98.8%). In 106 anterior segment cases (43.4%; 95% CI, 37.1%-49.9%), the surgeons indicated that the iOCT information impacted their surgical decision making and altered the procedure. In posterior segment procedures, surgeons reported that iOCT enabled altered surgical decision making during the procedure in 173 cases (29.2%; 95% CI, 25.5%-33.0%). CONCLUSIONS: The DISCOVER iOCT study demonstrated both generalized feasibility and usefulness based on the surgeon-reported impact on surgical decision making. This large-scale study confirmed similar findings from other studies on the potential value and impact of iOCT on ophthalmic surgery.

FACTORS ASSOCIATED WITH DEVELOPMENT OF DISSOCIATED OPTIC NERVE FIBER LAYER APPEARANCE IN THE PIONEER INTRAOPERATIVE OPTICAL COHERENCE TOMOGRAPHY STUDY.

PURPOSE: To assess the relationship of dissociated optic nerve fiber layer (DONFL) and intraoperative membrane-peeling dynamics as visualized using intraoperative optical coherence tomography (OCT), and to evaluate the functional implications of DONFL. METHODS: This was a post hoc analysis of eyes undergoing membrane peeling for vitreomacular interface disorders in the prospective PIONEER intraoperative OCT study. Retinal layer measurements in preincision and postpeel intraoperative OCT images were obtained. The primary outcome was development of DONFL appearance on spectral domain OCT at 6-month follow-up. Secondary outcomes included correlation of DONFL with surgical technique, surgical indication, intraoperative OCT findings, and retinal sensitivity. RESULTS: Ninety-five eyes were included. The prevalence of DONFL at 6 months was 36%. Increased inner retinal layer thickness on intraoperative OCT immediately after membrane peeling was associated with development of DONFL (P < 0.01). Macular hole repair was significantly associated with DONFL appearance. Peel technique (forceps vs. diamond-dusted membrane scraper) was not associated with DONFL. There was no difference in retinal sensitivity or visual acuity between eyes with or without DONFL. CONCLUSION: Acute postpeel increase in inner retinal thickness and macular hole repair were associated with development of DONFL appearance. However, it is unclear whether the surgical indication (e.g., macular hole) or the surgical manipulations performed (e.g., internal limiting membrane peeling) is the major factor that has an impact on DONFL appearance. Overall, these findings suggest that one mechanism in the development of DONFL appearance may be intraoperative trauma to the inner retina, potentially during internal limiting membrane peeling (e.g., macular hole repair).

The adult zebrafish retina: In vivo optical sectioning with Confocal Scanning Laser Ophthalmoscopy and Spectral-Domain Optical Coherence Tomography.

Non-invasive imaging is an invaluable diagnostic tool in ophthalmology. Two imaging devices, the scanning laser ophthalmoscope (SLO) and spectral domain optical coherence tomography (SDOCT), emerged from the clinical realm to provide research scientists with a real-time view of ocular morphology in living animals. We utilized these two independent imaging modalities in a complementary manner to perform in vivo optical sectioning of the adult zebrafish retina. Due to the very high optical power of the zebrafish lens, the confocal depth of field is narrow, allowing for detailed en face views of specific retinal layers, including the cone mosaic. Moreover, we demonstrate that both native reflectance, as well as fluorescent features observed by SLO, can be combined with axial in-depth information obtained by SDOCT. These imaging approaches can be used to screen for ocular phenotypes and monitor retinal pathology in a non-invasive manner.

Retinal vasculature of adult zebrafish: in vivo imaging using confocal scanning laser ophthalmoscopy.

Over the past 3 decades the zebrafish (Danio rerio) has become an important biomedical research species. As their use continues to grow additional techniques and tools will be required to keep pace with ongoing research using this species. In this paper we describe a novel method for in vivo imaging of the retinal vasculature in adult animals using a commercially available confocal scanning laser ophthalmoscope (SLO). With this instrumentation, we demonstrate the ability to distinguish diverse vascular phenotypes in different transgenic GFP lines. In addition this technology allows repeated visualization of the vasculature in individual zebrafish over time to document vascular leakage progression and recovery induced by intraocular delivery of proteins that induce vascular permeability. SLO of the retinal vasculature was found to be highly informative, providing images of high contrast and resolution that were capable of resolving individual vascular endothelial cells. Finally, the procedures required to acquire SLO images from zebrafish are non-invasive, simple to perform and can be achieved with low animal mortality, allowing repeated imaging of individual fish.

Demographics, Presenting Features, and Outcomes of Adult Patients with Ocular Trauma.

Introduction: Ocular trauma is a common cause of permanent vision loss in adults. The combination of an accurate clinical examination and imaging offers the best prognostic indicators for patients and helps to navigate treatment modalities. This is a retrospective chart review of examination and imaging findings for ocular trauma and how they correlate with treatment course and visual acuity (VA) outcomes. Methods: Adult patients with ocular trauma presenting to a single institution between January 2013 and December 2020 were evaluated. Initial examination and imaging findings were compared for associations with each other and with VA outcomes. Results: 136 ocular traumas on 134 patients were included. The median presenting logMAR VA was 2.7 (interquartile range (IQR) 1.2-3.7) with 62% open globe injuries. The most commonly reported finding on initial CT scan was globe deformity (30%), on B-scan was choroidal detachment (20%), and on ultrasound biomicroscopy was intraocular foreign body, ciliochoroidal effusions, or angle recession (21% each). Worse vision was observed for patients positive for retinal detachment on initial B-scan compared to those negative for this finding at 6-month (median logMAR 2.7 vs. 0.5; P < 0.0001) and at final post-injury evaluation (median logMAR 3.7 vs. 0.4; P < 0.0001). Similarly, worse VA was observed for patients with choroidal detachment on initial B-scan compared to those without this finding at 6-month (median logMAR 1.4 vs. 0.5; P = 0.002) and at final post-injury evaluation (median logMAR 2.0 vs. 0.4; P < 0.0001). If positive conjunctiva/sclera examination findings were identified, 66% had positive findings on B-scan, whereas if the conjunctiva/sclera examination findings were absent, 41% had positive findings on B-scan (P = 0.005). If anterior chamber (AC) examination findings were positive, 59% had positive findings on B-scan, whereas if the AC examination findings were absent, 37% had positive findings on B-scan (P = 0.03). Discussion. The predictive value of examination findings in this study may offer insight as to long-term visual prognosis. Positive B-scan or CT findings should increase suspicion for open globe injuries.

Short-Term Outcomes of Faricimab in Patients with Neovascular Age-Related Macular Degeneration on Prior Anti-VEGF Therapy.

PURPOSE: A subset of patients with neovascular age-related macular degeneration (nAMD) experience treatment burden and suboptimal response with anti-VEGF therapy. The aim of this study was to investigate the effect of switching to a novel, bispecific agent, faricimab, in patients with nAMD currently treated with anti-VEGF. DESIGN: Retrospective, noncomparative cohort study. SUBJECTS: Patients with nAMD previously treated with anti-VEGF and switched to intravitreal faricimab injection (IFI) at the Cleveland Clinic's Cole Eye Institute. METHODS: Switching and administration schedule of IFI was at the discretion of the clinician. Visual acuity (VA) and macular OCT parameters, including central subfield thickness (CST), maximum pigment epithelial detachment (PED) height, and presence of subretinal (SRF) or intraretinal fluid (IRF), were assessed at baseline (day of first IFI) and after each IFI. MAIN OUTCOME MEASURES: Central subfield thickness and presence of IRF or SRF after ≥ 3 IFIs. RESULTS: One hundred twenty-six eyes of 106 patients were included in the analysis with a mean follow-up time of 24.3 ± 5.2 weeks. Before switching to IFI, patients received a mean of either aflibercept (20.0 ± 8.4, mean ± standard deviation), bevacizumab (7 ± 8.9), ranibizumab (1.9 ± 8.5), or brolucizumab (0.3 ± 1.6) injections. The most common agent used before switching to IFI was aflibercept (n = 110, 87%), and the mean treatment interval with any anti-VEGF was 5.6 ± 1.6 weeks before switching. Central subfield thickness was reduced from baseline after the first IFI (266.8 ± 64.7 vs. 249.8 ± 58.6 µm, P = 0.02) and persisted over the 3 IFIs (P = 0.01). Pigment epithelial detachment height was reduced after the third IFI (249.6 ± 179.0 vs. 206.9 ± 130.0 µm, P = 0.01). The mean VA (62.9 vs. 62.7 approximate ETDRS letters, P = 0.42) and interval between injections (6.3 vs. 5.7 weeks, P = 0.16) was similar after the third IFI compared with baseline. Eleven (8.7%) eyes were switched back to their previous anti-VEGF, including 2 (1.6%) eyes from 1 patient with intraocular inflammation requiring cessation of IFI. There were no other adverse events from switching. CONCLUSIONS: Switching to faricimab resulted in a reduction in mean CST (-11.6 µm, P = 0.01) and PED height (-44.2 µm, P = 0.01) after 3 injections, with stable VA and at a similar treatment interval to prior anti-VEGF therapy. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Comparing Three-Dimensional Digitally Enabled Intraoperative OCT With Conventional Microscope-Integrated OCT in Vitreoretinal Surgery: A Post Hoc Analysis of the DISCOVER Study.

BACKGROUND AND OBJECTIVE: This study compared the surgeon experience between conventional microscope-integrated intraoperative optical coherence tomography (iOCT) and digitally enabled microscope-integrated iOCT in vitreoretinal surgery. PATIENTS AND METHODS: This is a post hoc case-control analysis of the DISCOVER study. Conventional microscope-integrated iOCT (Rescan 700, Zeiss) was compared with digitally enabled iOCT (Artevo 800, Zeiss). Compared variables included surgical field-based visualization (ie, ocular heads-up display in the conventional group; three-dimensional screen-based visualization in the digital iOCT group) and non-surgical field-based visualization (ie, review on the external two-dimensional monitor). RESULTS: A total of 200 patients were included. Surgical field-based visualization of iOCT was significantly higher in the digitally enabled group (P < 0.0001). Required endoillumination level was significantly lower in the digital iOCT group (P < 0.0001). Surgeons reported "significant" back discomfort and headache more frequently when using conventional iOCT (P = 0.003 and P = 0.001, respectively). CONCLUSIONS: Digitally enabled iOCT resulted in greater surgical visualization efficiency, appeared to require a lower illumination level, and may provide advantages for ergonomic-related discomfort. [Ophthalmic Surg Lasers Imaging Retina 2024;55:270-277.].

Trans-tamponade optical coherence tomography: postoperative imaging in gas-filled eyes.

PURPOSE: To investigate the feasibility of trans-tamponade optical coherence tomography and evaluate factors contributing to image quality and acquisition success. METHODS: Retrospective case series of eyes receiving Postoperative Day 1 optical coherence tomography imaging after vitrectomy and gas tamponade. The quality of the scans was graded by three independent expert readers. Clinical and surgical variables were recorded and correlated with scan quality. RESULTS: Eighty eyes were included in the study. An image quality classification scheme was developed (0-4, 0 = no image and 4 = comparable quality to trans-fluid optical coherence tomography). In 51 scans (64%), visualization of the inner retina and retinal pigment epithelium was achieved (Grades 2-4) but with variable image quality of the retinal layers. Twenty-nine scans (36%) achieved visualization of all retinal layers (Grades 3-4). Only 9 scans (11%) were of comparable quality to fluid-filled eyes (Grade 4). Pseudophakia (P = 0.0001), shorter operative times (P = 0.007), and macular surgery (P = 0.002) correlated with scan quality. An optimum scan protocol was developed to facilitate maximum quality images. CONCLUSION: Successful trans-tamponade optical coherence tomography through gas on Postoperative Day 1 is possible but significant variability exists in scan quality.