Purpose: The guarded light pipe is a recently described alternative endoillumination technique to chandelier illumination. We sought to compare the outcomes of scleral buckling (SB) under indirect ophthalmoscopy (ID) to heads-up three-dimensional visualization with a guarded light pipe (3DGLP). Methods: A retrospective comparative study was performed, including 47 eyes that underwent SB for rhegmatogenous retinal detachment (RRD) repair with either traditional ID (n = 31) or 3DGLP (n = 16). Results: The single surgery anatomic success rate was 87.0% in the ID group and 87.5% in the 3DGLP group. The final anatomic success rate was 100% in both groups. The median (interquartile range) post-operative logMAR was 0.10 (0.0-0.20) in the ID group and 0.08 (0.02-0.69) in the 3DGLP group (p = 0.51). The median operative time was 107 (94-123) minutes in the ID group and 100 (90-111) minutes in the 3DGLP group (p = 0.25). Among eyes that underwent subretinal fluid drainage, the operative time was significantly longer in the ID group compared to the 3DGLP group, 113 (100-135) minutes vs 93 (85-111) minutes (p = 0.035). There were no post-operative complications in the ID group and one complication of self-resolving vitreous hemorrhage associated with a malfunctioning cryoprobe in the 3DGLP group (p = 0.34). There were no cases of post-operative cataract progression in either group. Conclusion: Compared to traditional SB, 3DGLP improves ergonomics and educational value with similar anatomical, visual, intra and post-operative outcomes and may result in shorter operative time in cases requiring subretinal fluid drainage.

Single cell RNA sequencing studies identified novel neurodegeneration-associated microglial (MGnD/DAM) subtypes activated around cerebral amyloid plaques. Micro-RNA (miR)-155 of the TREM2-APOE pathway was shown to be a key transcriptional regulator of MGnD microglial phenotype. Despite growing interest in studying manifestations of Alzheimer's disease (AD) in the retina, a CNS organ accessible to noninvasive high-resolution imaging, to date MGnD microglia have not been studied in the AD retina. Here, we discovered the presence and increased populations of Clec7a+ and Galectin-3+ MGnD microglia in retinas of transgenic APPSWE/PS1L166P AD-model mice. Conditionally targeting MGnD microglia by miR-155 ablation via the tamoxifen-inducible CreERT2 system in APPSWE/PS1L166P mice diminished retinal Clec7a+ and Galectin-3+ microglial populations while increasing homeostatic P2ry12+ microglia. Retinal MGnD microglia were often adhering to microvessels; their depletion protected the inner blood-retina barrier and reduced vascular amyloidosis. Microglial miR-155 depletion further limits retinal inflammation. Mass spectrometry analysis revealed enhanced retinal PI3K-Akt signaling and predicted IL-8 and Spp1 decreases in mice with microglia-specific miR-155 knockout. Overall, this study identified MGnD microglia in APPSWE/PS1L166P mouse retina. Transcriptional regulation of these dysfunctional microglia mitigated retinal inflammation and vasculopathy. The protective effects of microglial miR-155 ablation should shed light on potential treatments for retinal inflammation and vascular damage during AD and other ocular diseases.

BACKGROUND: Human-induced pluripotent stem cell-derived retinal organoids are a valuable tool for disease modelling and therapeutic development. Many efforts have been made over the last decade to optimise protocols for the generation of organoids that correctly mimic the human retina. Most protocols use common media supplements; however, protocol-dependent variability impacts data interpretation. To date, the lack of a systematic comparison of a given protocol with or without supplements makes it difficult to determine how they influence the differentiation process and morphology of the retinal organoids. METHODS: A 2D-3D differentiation method was used to generate retinal organoids, which were cultured with or without the most commonly used media supplements, notably retinoic acid. Gene expression was assayed using qPCR analysis, protein expression using immunofluorescence studies, ultrastructure using electron microscopy and 3D morphology using confocal and biphoton microscopy of whole organoids. RESULTS: Retinoic acid delayed the initial stages of differentiation by modulating photoreceptor gene expression. At later stages, the presence of retinoic acid led to the generation of mature retinal organoids with a well-structured stratified photoreceptor layer containing a predominant rod population. By contrast, the absence of retinoic acid led to cone-rich organoids with a less organised and non-stratified photoreceptor layer. CONCLUSIONS: This study proves the importance of supplemented media for culturing retinal organoids. More importantly, we demonstrate for the first time that the role of retinoic acid goes beyond inducing a rod cell fate to enhancing the organisation of the photoreceptor layer of the mature organoid.

Background: To characterize contrast sensitivity function (CSF) in cataractous and pseudophakic eyes compared to healthy control eyes using a novel quantitative CSF test with active learning algorithms. Methods: This is a prospective observational study at an academic medical center. CSF was measured in eyes with visually significant cataract, at least 2+ nuclear sclerosis (NS) and visual acuity (VA) ≥ 20/50, in pseudophakic eyes and in healthy controls with no more than 1+ NS and no visual complaints, using the Manifold Contrast Vision Meter. Outcomes included Area under the Log CSF (AULCSF) and CS thresholds at 1, 1.5, 3, 6, 12, and 18 cycles per degree (cpd). A subgroup analysis as performed on cataract eyes with VA ≥ 20/25. Results: A total of 167 eyes were included, 58 eyes in the cataract group, 77 controls, and 32 pseudophakic eyes with respective median AULCSF of 1.053 (0.352) vs 1.228 (0.318) vs 1.256 (0.360). In our multivariate regression model, cataract was associated with significantly reduced AULCSF (P= 0.04, β= -0.11) and contrast threshold at 6 cpd (P= 0.01, β= -0.16) compared to controls. Contrast threshold at 6 cpd was significantly reduced even in the subgroup of cataractous eyes with VA ≥ 20/25 (P=0.02, β=-0.16). Conclusion: The novel qCSF test detected disproportionate significant contrast deficits at 6 cpd in cataract eyes; this remained significant even in the cataractous eyes with VA ≥ 20/25. CSF testing may enhance cataract evaluation and surgical decision-making, particularly in patients with subjective visual complaints despite good VA.

A 49-year-old man presented with acute unilateral blurred vision one week after SARS-CoV-2 vaccination. A unilateral serous detachment of the macula, intraretinal hemorrhages, vitritis, and anterior chamber cell was found. Diagnostic testing was negative for infectious and inflammatory causes, and a diagnosis of acute idiopathic maculopathy (AIM) was made. Symptoms and serous detachment resolved over 12 weeks, with residual retinal pigment epithelial changes consistent with the disease course. AIM is a rare diagnosis that presented in close proximity to SARS-CoV-2 vaccination without evidence of coxsackievirus infection. Further research is necessary to clarify an association between this vaccine and uveitis.