Longitudinal In Vivo Imaging of Retinal Cells with Tailored Adeno-Associated Virus Serotypes via Confocal Scanning Laser Ophthalmoscopy.

The dynamic nature of retinal cellular processes necessitates advancements in gene delivery and live monitoring techniques to enhance the understanding and treatment of ocular diseases. This study introduces an optimized adeno-associated virus (AAV) approach, utilizing specific serotypes and promoters to achieve optimal transfection efficiency in targeted retinal cells, including retinal ganglion cells (RGCs) and Müller glia. Leveraging the precision of confocal scanning laser ophthalmoscopy (CSLO), this work presents a non-invasive method for in vivo imaging that captures the longitudinal expression of AAV-mediated green fluorescent protein (GFP). This approach eliminates the need for terminal procedures, preserving the continuity of observation and the well-being of the subject. Furthermore, the GFP signal can be traced in AAV-infected RGCs along the visual pathway to the superior colliculus (SC) and lateral geniculate nucleus (LGN), enabling the potential for direct visual pathway mapping. These findings provide a detailed protocol and demonstrate the application of this powerful tool for real-time studies of retinal cell behavior, disease pathogenesis, and the efficacy of gene therapy interventions, offering valuable insights into the living retina and its connections.

MENISCUS MICROPYON: An Ophthalmoscopic Sign Possibly Associated With Epiretinal Proliferation After Retinal Surgery With Gas Tamponade.

PURPOSE: To describe an ophthalmoscopic sign, termed a meniscus micropyon, and its possible association with proliferative vitreoretinopathy/epiretinal membrane (ERM) formation after retinal surgery with gas tamponade. METHODS: Patients with intravitreal gas were examined postoperatively by one of six vitreoretinal surgeons from four institutions. A micropyon was defined as a white-yellow, solid-appearing consolidation along the meniscus (i.e., the fluid-gas interface). RESULTS: A micropyon was visualized and photographed in 49 patients who received intravitreal gas. Preoperatively, retinal breaks were present in all 49 eyes and rhegmatogenous retinal detachment in 45 (92%). Postoperatively, 39 eyes (80%) developed epiretinal proliferation: 16 eyes (33%) developed recurrent rhegmatogenous retinal detachment from proliferative vitreoretinopathy, 6 eyes (12%) re-detached without frank proliferative vitreoretinopathy, 9 eyes (18%) developed postoperative ERM/worsening, and 8 eyes (16%) had postoperative ERM but no preoperative optical coherence tomography to determine if the postoperative ERM was new or worsening. The single-operation anatomical success in eyes with a micropyon was 51%, which was lower than that of a contemporaneous rhegmatogenous retinal detachment control group (91%) in which no micropyon was detected. In two patients, micropyons were biopsied during pars plana vitrectomy and examined histopathologically; they consist predominantly of white blood cells. CONCLUSION: The meniscus micropyon is an ophthalmoscopic sign that can occur after retinal surgery with gas tamponade. Features that distinguish a micropyon from postvitrectomy fibrin/fibrinoid syndrome include delayed appearance, hyperautofluorescence, absence of translucent strands or sheets in the anterior chamber or vitreous cavity, and the histopathologic identification of white blood cells. A clinically detectable micropyon may be a biomarker of proliferative vitreoretinopathy/ERM formation.

Eyesi direct ophthalmoscope simulator: an effective training tool for medical undergraduates.

INTRODUCTION: Non-ophthalmologists often lack sufficient operational training to use a direct ophthalmoscope proficiently, resulting in a global deficit of basic ophthalmological skills among general practitioners. This deficiency hampers the timely diagnosis, referral, and intervention of patients. Consequently, the optimization of teaching tools and methods to enhance teaching efficiency is imperative. This study explores the effectiveness of the Eyesi Direct Ophthalmoscope Simulator (Eyesi) as an innovative tool for fundus examination training. METHODS: Medical undergraduates were randomly assigned to Group A or B (n = 168). All participants completed a pre-training questionnaire. Group A received Eyesi training, while Group B underwent traditional direct ophthalmoscope (TDO) training. Subsequently, participants answered questionnaires relevant to their respective training methods. Both groups exchanged training tools and completed a summary questionnaire. RESULTS: After training, 54.17% of participants believed that images presented by the Eyesi were consistent with the real fundus. Group A scored significantly higher than Group B in fundus structure recognition and self-confidence in examination. The degree of mastery over fundus theory score increased from 6.10 ± 0.13 to 7.74 ± 0.16 (P < 0.001) in Group A, but Group B did not demonstrate a significant difference. We also compared undergraduates' tendencies for different learning purposes, 75.59% of participants preferred the Eyesi to TDO as a training tool, and 88.41% of participants were receptive to introducing the Eyesi in training. CONCLUSION: According to subjective participant feedback, Eyesi outperformed TDO in fundus observation, operational practice, and theoretical learning. It effectively equips undergraduates with fundus examination skills, potentially promoting the use of direct ophthalmoscopes in primary medical institutions.

Smartphone fundoscopy with 20 dioptres lens: our experience.

Objective: Assessment of the utility of smartphone fundoscopy in diagnosing posterior pole pathologies. Methods: An iPhone 12 and a 20D Volk lens were used for smartphone fundoscopy. Patients needing bedside consultation were examined with direct ophthalmoscopy and smartphone fundoscopy. Some patients were examined with this technique after slit lamp examination. Results: Over one year 23 bedside fundus examinations were performed and 2 papilledema were diagnosed. After initial slit lamp examination, photos of various pathologies were taken: age-related macular degeneration, branch retinal artery occlusion, arterial embolus, branch retinal vein occlusion, non-arteritic anterior ischemic optic neuropathy, myelinated retinal nerve fiber layer, choroidal naevus. Discussion: With the 20D lens, the image is overturned, magnified 3,13X, and the field of view is 46°. The utility was demonstrated in literature by teaching students this technique and using it in screening for retinopathy of prematurity. The weighted retinal irradiance was measured in two studies. It was 4,6 mW/cm2 in one and from 0,58 to 2,30 mW/cm2 in the other, within safe limits. Conclusions: Smartphone fundoscopy is a fast, accessible, and safe technique for fundus examinations. Other departments could use it for the diagnosis of papilledema.

The Versatile Teaching Eye: an affordable, 3D-printed model eye for simulating ophthalmic examination.

Purpose: To describe the Versatile Teaching Eye (VT Eye), a 3D-printed model eye designed to provide an affordable examination simulator, and to report the results of a pilot program introducing the VT Eye and an ophthalmic training curriculum at a teaching hospital in Ghana. Methods: TinkerCAD was used to design the VT Eye, which was printed with ABS plastic. The design features an adapter that permits use of a smartphone as a digital fundus. We developed a set of digital flashcards allowing for an interactive review of a range of retinal pathologies. An analog fundus was developed for practicing traditional slit lamp and indirect examinations as well as retinal laser practice. The model was used for a period of 2 weeks by ophthalmic trainees at Komfo Anokye Teaching Hospital, Kumasi, Ghana, to practice indirect ophthalmoscopy, slit lamp biomicroscopy, smartphone funduscopy, and retinal image drawing. Results were assessed at by means of a pre-/post-training survey of 6 residents. Results: The VT Eye accommodates diverse fundus examination techniques. Its 3D-printed design ensures cost-effective, high-quality replication. When paired with a 20 D practice examination lens, the digital fundus provides a comprehensive, interactive training environment for <$30.00 (USD). This device allows for indirect examination practice without requiring an indirect headset, which may increase the amount of available practice for trainees early in their careers. In the Ghana pilot program, the model's use in indirect examination training sessions significantly boosted residents' confidence in various examination techniques. Comparing pre- and post-session ratings, average reported confidence levels rose by 30% for acquiring clear views of the posterior pole, 42% for visualizing the periphery, and 141% for capturing important pathology using personal smartphones combined with a 20 D lens (all P < 0.05). Conclusions: The VT Eye is readily reproducible and can be easily integrated into ophthalmic training curricula, even in regions with limited resources. It offers an effective and affordable training solution, underscoring its potential for global adoption and the benefits of incorporating innovative technologies in medical education.

Retinal peri-arteriolar versus peri-venular amyloidosis, hippocampal atrophy, and cognitive impairment: exploratory trial.

The relationship between amyloidosis and vasculature in cognitive impairment and Alzheimer's disease (AD) pathogenesis is increasingly acknowledged. We conducted a quantitative and topographic assessment of retinal perivascular amyloid plaque (AP) distribution in individuals with both normal and impaired cognition. Using a retrospective dataset of scanning laser ophthalmoscopy fluorescence images from twenty-eight subjects with varying cognitive states, we developed a novel image processing method to examine retinal peri-arteriolar and peri-venular curcumin-positive AP burden. We further correlated retinal perivascular amyloidosis with neuroimaging measures and neurocognitive scores. Our study unveiled that peri-arteriolar AP counts surpassed peri-venular counts throughout the entire cohort (P < 0.0001), irrespective of the primary, secondary, or tertiary vascular branch location, with a notable increase among cognitively impaired individuals. Moreover, secondary branch peri-venular AP count was elevated in the cognitively impaired (P < 0.01). Significantly, peri-venular AP count, particularly in secondary and tertiary venules, exhibited a strong correlation with clinical dementia rating, Montreal cognitive assessment score, hippocampal volume, and white matter hyperintensity count. In conclusion, our exploratory analysis detected greater peri-arteriolar versus peri-venular amyloidosis and a marked elevation of amyloid deposition in secondary branch peri-venular regions among cognitively impaired subjects. These findings underscore the potential feasibility of retinal perivascular amyloid imaging in predicting cognitive decline and AD progression. Larger longitudinal studies encompassing diverse populations and AD-biomarker confirmation are warranted to delineate the temporal-spatial dynamics of retinal perivascular amyloid deposition in cognitive impairment and the AD continuum.

Fluorescence Lifetime Imaging of Human Retinal Pigment Epithelium in Pentosan Polysulfate Toxicity Using Adaptive Optics Scanning Light Ophthalmoscopy.

Purpose: Fluorescence lifetime ophthalmoscopy (FLIO) is an emerging clinical modality that could provide biomarkers of retinal health beyond fluorescence intensity. Adaptive optics (AO) ophthalmoscopy provides the confocality to measure fluorescence lifetime (FL) primarily from the retinal pigment epithelium (RPE) whereas clinical FLIO has greater influence from fluorophores in the inner retina and lens. Adaptive optics fluorescence lifetime ophthalmoscopy (AOFLIO) measures of FL in vivo could provide insight into RPE health at different stages of disease. In this study, we assess changes in pentosan polysulfate sodium (PPS) toxicity, a recently described toxicity that has clinical findings similar to advanced age-related macular degeneration. Methods: AOFLIO was performed on three subjects with PPS toxicity (57-67 years old) and six age-matched controls (50-64 years old). FL was analyzed with a double exponential decay curve fit and with phasor analysis. Regions of interest (ROIs) were subcategorized based on retinal features on optical coherence tomography (OCT) and compared to age-matched controls. Results: Twelve ROIs from PPS toxicity subjects met the threshold for analysis by curve fitting and 15 ROIs met the threshold for phasor analysis. Subjects with PPS toxicity had prolonged FL compared to age-matched controls. ROIs of RPE degeneration had the longest FLs, with individual pixels extending longer than 900 ps. Conclusions: Our study shows evidence that AOFLIO can provide meaningful information in outer retinal disease beyond what is obtainable from fluorescence intensity alone. More studies are needed to determine the prognostic value of AOFLIO.

Multimodal Imaging of Choroidal Nodules in Neurofibromatosis Type I.

AIM: To clarify the possibilities and role of posterior segment imaging in patients with neurofibromatosis type I (NF1), and to show the prevalence of this disease in the pediatric population in Slovakia. MATERIAL AND METHODS: Until recently, ophthalmologic consultations in patients with NF1 were limited mainly to the observation of Lisch nodules of the iris and the presence of optic nerve glioma. However, advances in imaging capabilities have made it possible to investigate and describe new f indings concerning the ocular manifestations of this disease. Between October 2020 and November 2021, we examined the anterior and posterior segment of 76 eyes (38 children ­ 12 boys and 26 girls) with genetically confirmed NF1 gene mutation at our clinic. The age of the patients ranged from 4 to 18 years. The anterior segment was checked for the presence of Lisch nodules biomicroscopically with a slit lamp. On the posterior segment, the presence of choroidal nodules was checked by various imaging methods ­ fundus camera, infrared confocal selective laser ophthalmoscopy, MultiColor imaging, OCT, and OCT angiography. All the patients had magnetic resonance imaging performed in order to detect potential optic nerve gliomas for the purpose of diagnosis. We observed the correlation between the patients' age, presence of Lisch nodules and the presence of choroidal nodules. Eight patients also had other manifestations of the disease ­ optic nerve gliomas or microvascular changes (so-called "corkscrew" vessels). RESULTS: Out of 38 patients, Lisch iris nodules were present in 20 patients (53%) and choroidal nodules in 24 patients (63%). There was no positive correlation between the presence of these two manifestations within the same patient or eye, but there is a clear correlation between the presence of choroidal nodules and patient age. CONCLUSION: The results suggest that a previously unknown ocular manifestation of neurofibromatosis type I, namely choroidal nodules, has a higher prevalence than Lisch nodules also in the pediatric population and can be easily visualized using various imaging modalities. It will be important to include follow-up observation of this finding among the standard controls for ocular findings in NF1, and it will be very interesting to correlate this f inding with the exact NF1 mutation

Diagnóstico da retinopatia diabética por inteligência artificial por meio de smartphone / Diagnosis of diabetic retinopathy by artificial intelligence using smartphone

RESUMO Objetivo: Obter imagens de fundoscopia por meio de equipamento portátil e de baixo custo e, usando inteligência artificial, avaliar a presença de retinopatia diabética. Métodos: Por meio de um smartphone acoplado a um dispositivo com lente de 20D, foram obtidas imagens de fundo de olhos de pacientes diabéticos; usando a inteligência artificial, a presença de retinopatia diabética foi classificada por algoritmo binário. Resultados: Foram avaliadas 97 imagens da fundoscopia ocular (45 normais e 52 com retinopatia diabética). Com auxílio da inteligência artificial, houve acurácia diagnóstica em torno de 70 a 100% na classificação da presença de retinopatia diabética. Conclusão: A abordagem usando dispositivo portátil de baixo custo apresentou eficácia satisfatória na triagem de pacientes diabéticos com ou sem retinopatia diabética, sendo útil para locais sem condições de infraestrutura.

ABSTRACT Introduction: To obtain fundoscopy images through portable and low-cost equipment using artificial intelligence to assess the presence of DR. Methods: Fundus images of diabetic patients' eyes were obtained by using a smartphone coupled to a device with a 20D lens. By using artificial intelligence (AI), the presence of DR was classified by a binary algorithm. Results: 97 ocular fundoscopy images were evaluated (45 normal and 52 with DR). Through AI diagnostic accuracy around was 70% to 100% in the classification of the presence of DR. Conclusion: The approach using a low-cost portable device showed satisfactory efficacy in the screening of diabetic patients with or without diabetic retinopathy, being useful for places without infrastructure conditions.

Impact of cigarette smoking on fluorescence lifetime of ocular fundus.

Cigarette smoking is known to adversely affect cellular metabolism and is a risk factor for various retinal diseases. Fluorescence lifetime imaging ophthalmoscopy (FLIO) has the potential to detect metabolic changes in the ocular fundus. Aim of this study was to analyze the influence of cigarette smoking on fluorescence lifetime (FLT) of healthy eyes using FLIO. Twenty-six non-smokers and 28 smokers aged between 20 and 37 years without systemic and ocular diseases were investigated by FLIO (excitation: 473 nm, emission: short spectral channel (SSC) 498-560 nm, long spectral channel (LSC) 560-720 nm). The FLT at the ETDRS grid regions were analyzed and compared. In SSC, the mean FLT (τm) of smokers was significantly longer in the ETDRS inner ring region, whereas the τm in LSC was significantly shorter in the outer ring. For the long component (τ2), smokers with pack year < 7.11 showed significantly shorter τ2 in SSC than non-smokers and the smokers with pack year ≥ 7.11. There were no significant differences in retinal thickness. The lack of obvious structural differences implies that the observed FLT changes are likely related to smoking-induced metabolic changes. These results suggest that FLIO may be useful in assessing retinal conditions related to lifestyle and systemic metabolic status.

Efficacy of Smartphone-Based Telescreening for Retinopathy of Prematurity With and Without Artificial Intelligence in India.

Importance: Retinopathy of prematurity (ROP) telemedicine screening programs have been found to be effective, but they rely on widefield digital fundus imaging (WDFI) cameras, which are expensive, making them less accessible in low- to middle-income countries. Cheaper, smartphone-based fundus imaging (SBFI) systems have been described, but these have a narrower field of view (FOV) and have not been tested in a real-world, operational telemedicine setting. Objective: To assess the efficacy of SBFI systems compared with WDFI when used by technicians for ROP screening with both artificial intelligence (AI) and human graders. Design, Setting, and Participants: This prospective cross-sectional comparison study took place as a single-center ROP teleophthalmology program in India from January 2021 to April 2022. Premature infants who met normal ROP screening criteria and enrolled in the teleophthalmology screening program were included. Those who had already been treated for ROP were excluded. Exposures: All participants had WDFI images and from 1 of 2 SBFI devices, the Make-In-India (MII) Retcam or Keeler Monocular Indirect Ophthalmoscope (MIO) devices. Two masked readers evaluated zone, stage, plus, and vascular severity scores (VSS, from 1-9) in all images. Smartphone images were then stratified by patient into training (70%), validation (10%), and test (20%) data sets and used to train a ResNet18 deep learning architecture for binary classification of normal vs preplus or plus disease, which was then used for patient-level predictions of referral warranted (RW)- and treatment requiring (TR)-ROP. Main Outcome and Measures: Sensitivity and specificity of detection of RW-ROP, and TR-ROP by both human graders and an AI system and area under the receiver operating characteristic curve (AUC) of grader-assigned VSS. Sensitivity and specificity were compared between the 2 SBFI systems using Pearson χ2testing. Results: A total of 156 infants (312 eyes; mean [SD] gestational age, 33.0 [3.0] weeks; 75 [48%] female) were included with paired examinations. Sensitivity and specificity were not found to be statistically different between the 2 SBFI systems. Human graders were effective with SBFI at detecting TR-ROP with a sensitivity of 100% and specificity of 83.49%. The AUCs with grader-assigned VSS only were 0.95 (95% CI, 0.91-0.99) and 0.96 (95% CI, 0.93-0.99) for RW-ROP and TR-ROP, respectively. For the AI system, the sensitivity of detecting TR-ROP sensitivity was 100% with specificity of 58.6%, and RW-ROP sensitivity was 80.0% with specificity of 59.3%. Conclusions and Relevance: In this cross-sectional study, 2 different SBFI systems used by technicians in an ROP screening program were highly sensitive for TR-ROP. SBFI systems with AI may be a cost-effective method to improve the global capacity for ROP screening.

Blue-light fundus autofluorescence imaging of pigment epithelial detachments.

BACKGROUND: Pigment epithelial detachments (PEDs) occur in association with various chorioretinal diseases. With respect to the broad clinical spectrum of PEDs we describe fundus autofluorescence (FAF) characteristics of PEDs. METHODS: Ninety-three eyes of 66 patients (mean age 71.9 ± 11.1) with uni- or bilateral PED ( ≥ 350 µm) were included in a retrospective cross-sectional study. PEDs were secondary to age-related macular degeneration (n = 79), central serous chorioretinopathy (n = 7), polypoidal choroidal vasculopathy (n = 2), pattern dystrophy (n = 3) or idiopathic PED (n = 2). FAF images were recorded using confocal scanning laser ophthalmoscopy (488 nm excitation wavelength, detection of emission >500 nm). Diagnosis of PED was confirmed using spectral-domain optical coherence tomography. A qualitative FAF grading system was established, and grading was performed by two independent readers. RESULTS: PEDs showed highly variable characteristics on FAF imaging. FAF within the area of PED was found to be irregular/granular (n = 59, 63.4%), increased (n = 28, 30.1%), decreased (n = 3, 3.2 %), or normal (n = 3, 3.2%). Accompanying FAF changes included condensation of macular pigment (n = 67, 72.0%), focally increased FAF at the PED apex (n = 14, 15.1%) or elsewhere (n = 52, 55.9%), focally decreased FAF (n = 23, 24.7%), a cartwheel-like pattern (n = 10, 10.8%), a doughnut sign (n = 6, 6.5%), and a halo of decreased FAF encircling the PED (completely n = 20, 21.5% or incompletely n = 20, 21.5%). CONCLUSIONS: PEDs show a variety of abnormal patterns on FAF imaging. These changes in FAF signals may be secondary to morphological and metabolic alterations within corresponding retinal layers and do not necessarily correspond with the underlying PED subtype or a specific pathology.

Feasibility of Dynamic Video Scanning Laser Ophthalmoscopy for Evaluation of Vitreous Opacities.

To explore the feasibility of confocal scanning laser ophthalmoscope video for evaluation and quantification of vitreous opacities. Descriptive study outlining the utilization of dynamic confocal scanning laser ophthalmoscope video technology to capture movement of vitreous opacities. By having the patient perform a saccade followed by refixation, the vitreous gel was set in motion and the shadowing and movement of the vitreous opacities was easily visualized. The whole process of recording the images took less than a minute. Qualitative analysis showed dense shadowing from the vitreous opacities tracking over the central visual axis in some patients. Video scanning laser ophthalmo-scope can be a useful tool in documenting the presence and degree of vitreous opacities. This technology can be applied for clinical decision-making as well as educating patients. [Ophthalmic Surg Lasers Imaging Retina 2022;53:714-716.].

Ultra-wide-field fundus photography compared to ophthalmoscopy in diagnosing and classifying major retinal diseases.

To analyze the performance of ultra-wide-field (UWF) fundus photography compared with ophthalmoscopy in identifying and classifying retinal diseases. Patients examined for presumed major retinal disorders were consecutively enrolled. Each patient underwent indirect ophthalmoscopic evaluation, with scleral depression and/or fundus biomicroscopy, when clinically indicated, and mydriatic UWF fundus imaging by means of CLARUS 500™ fundus camera. Each eye was classified by a clinical grader and two image graders in the following groups: normal retina, diabetic retinopathy, vascular abnormalities, macular degenerations and dystrophies, retinal and choroidal tumors, peripheral degenerative lesions and retinal detachment and myopic alterations. 7024 eyes of new patients were included. The inter-grader agreement for images classification was perfect (kappa = 0.998, 95% Confidence Interval (95%CI) = 0.997-0.999), as the two methods concordance for retinal diseases diagnosis (kappa = 0.997, 95%CI = 0.996-0.999) without statistically significant difference. UWF fundus imaging might be an alternative to ophthalmoscopy, since it allows to accurately classify major retinal diseases, widening the range of disorders possibly diagnosed with teleophthalmology. Although the clinician should be aware of the possibility that a minority of the most peripheral lesions may be not entirely visualized, it might be considered a first line diagnostic modality, in the context of a full ophthalmological examination.

Morphological Features of Full-Thickness Macular Holes Using Retromode Scanning Laser Ophthalmoscopy.

BACKGROUND AND OBJECTIVE: Retromode scanning laser ophthalmoscopy (RM-SLO) is a new imaging modality displaying pseudo-3D retinal images. We assessed the correlation between the morphological features of full-thickness macular holes (FTMHs) when using spectral domain-optical coherence tomography (SD-OCT) and when using RM-SLO. MATERIALS AND METHODS: This is a prospective observational case series in which patients were examined through SD-OCT and RM-SLO after informed consent was obtained. Intraclass correlation coefficient (ICC) and Pearson correlation coefficient (PCC) were used to assess interobserver agreement and the correlation between the diameters measured with the two techniques. RESULTS: We enrolled 20 patients (20 eyes) with an average hole aperture size of 426 µm (140-890 µm) on SD-OCT and 56 pixels (19-102 pixels) on RM-SLO. ICC and PCC were 0.999 and 0.992, respectively. "Standard" and "double-ring" FTMH patterns were described on RM-SLO and related well with SD-OCT findings. CONCLUSIONS: RM-SLO is a reliable method for FTMH-diameter evaluation and identifies unique pseudo-3D morphological features consistent with their B-scan counterparts. [Ophthalmic Surg Lasers Imaging Retina 2022; 53:368-373.].

Non-mydriatic fundus photography as an alternative to indirect ophthalmoscopy for screening of diabetic retinopathy in community settings: a comparative pilot study in rural and tribal India.

OBJECTIVES: The impending and increasing prevalence of diabetic retinopathy (DR) in India has necessitated a need for affordable and valid community outreach screening programme for DR, especially in rural and far to reach indigenous local communities. The present study is a pilot study aimed to compare non-mydriatic fundus photography with indirect ophthalmoscopy for its utilisation as a feasible and logistically convenient screening modality for DR in an older age, rural, tribal population in Western India. DESIGN AND SETTING: This community-based, cross-sectional, prospective population study was a part of a module using Rapid Assessment of Avoidable Blindness and DR methodology in 8340 sampled participants with ≥50 years age. In this study, the diabetics identified were screened for DR using two methods: non-mydriatic fundus photography on the field by trained professionals, that were then graded by a retina specialist at the base hospital and indirect ophthalmoscopy by expert ophthalmologists in the field with masking of each other's findings for its utility and comparison. RESULTS: The prevalence of DR, sight threatening DR and maculopathy using indirect ophthalmoscopy was found to be 12.1%, 2.1% and 6.6%, respectively. A fair agreement (κ=0.48 for DR and 0.59 for maculopathy) was observed between both the detection methods. The sensitivity and specificity of fundus photographic evaluation compared with indirect ophthalmoscopy were found to be 54.8% and 92.1% (for DR), 60.7% and 90.8% (for any DR) and 84.2% and 94.8% (for only maculopathy), respectively. CONCLUSION: Non-mydriatic fundus photography has the potential to identify DR (any retinopathy or maculopathy) in community settings in Indian population. Its utility as an affordable and logistically convenient cum practical modality is demonstrable. The sensitivity of this screening modality can be further increased by investing in better resolution cameras, capturing quality images and training and validation of imagers. TRIAL REGISTRATION NUMBER: CTRI/2020/01/023025; Clinical Trial Registry, India (CTRI).

Short-term Assessment of Subfoveal Injection of Adeno-Associated Virus-Mediated hCHM Gene Augmentation in Choroideremia Using Adaptive Optics Ophthalmoscopy.

Importance: Subretinal injection for gene augmentation in retinal degenerations forcefully detaches the neural retina from the retinal pigment epithelium, potentially damaging photoreceptors and/or retinal pigment epithelium cells. Objective: To use adaptive optics scanning light ophthalmoscopy (AOSLO) to assess the short-term integrity of the cone mosaic following subretinal injections of adeno-associated virus vector designed to deliver a functional version of the CHM gene (AAV2-hCHM) in patients with choroideremia. Design, Setting, and Participants: This longitudinal case series study enrolled adult patients with choroideremia from February 2015 to January 2016 in the US. To be included in the study, study participants must have received uniocular subfoveal injections of low-dose (5 × 1010 vector genome per eye) or high-dose (1 × 1011 vector genome per eye) AAV2-hCHM. Analysis began February 2015. Main Outcomes and Measures: The macular regions of both eyes were imaged before and 1 month after injection using a custom-built multimodal AOSLO. Postinjection cone inner segment mosaics were compared with preinjection mosaics at multiple regions of interest. Colocalized spectral-domain optical coherence tomography and dark-adapted cone sensitivity was also acquired at each time point. Results: Nine study participants ranged in age from 26 to 50 years at the time of enrollment, and all were White men. Postinjection AOSLO images showed preservation of the cone mosaic in all 9 AAV2-hCHM-injected eyes. Mosaics appeared intact and contiguous 1 month postinjection, with the exception of foveal disruption in 1 patient. Optical coherence tomography showed foveal cone outer segment shortening postinjection. Cone-mediated sensitivities were unchanged in 8 of 9 injected and 9 of 9 uninjected eyes. One participant showed acute loss of foveal optical coherence tomography cone outer segment-related signals along with cone sensitivity loss that colocalized with disruption of the mosaic on AOSLO. Conclusions and Relevance: Integrity of the cone mosaic is maintained following subretinal delivery of AAV2-hCHM, providing strong evidence in support of the safety of the injections. Minor foveal thinning observed following surgery corresponds with short-term cone outer segment shortening rather than cone cell loss. Foveal cone loss in 1 participant raises the possibility of individual vulnerability to the subretinal injection.

Application of a 3D-printed eye model for teaching direct ophthalmoscopy to undergraduates.

PURPOSE: This study aims to design an eye model that can simulate the fundus for teaching direct ophthalmoscopy and to evaluate its effectiveness. METHODS: We first used 3D printing materials to make an eye model and then randomly assigned 92 undergraduates into group A (model-assisted training group) and group B (traditional training group) to test our model. After the same training time, real patients were used to test the students, with 120 s as the examination time limit. We recorded the students' ability to clearly see the optic disk, the time to determine the cup-to-disk ratio, and whether they were correct. RESULTS: Forty-three students in group A (93.48%) successfully saw the fundus, while 21 in group B (45.65%) succeeded. The difference between the two groups was 47.83% (95% confidence interval, 29.59-66.07%, P < 0.0001). The median time to see the fundus was 29s (95% confidence interval 23-45 s) in group A, while an estimated minimum time in group B was 80 s, indicating that group A was significantly faster than group B (P < 0.0001). CONCLUSIONS: This 3D-printed eye model significantly improved the students' study interest, study efficiency, and study results and is worthy of being promoted.

Retinal structural and microvascular abnormalities in retinal dysplasia imaged by OCT and OCT angiography.

OBJECTIVE: To describe the in vivo structural characteristics of multifocal and geographic retinal dysplasia visualized with advanced retinal imaging including confocal scanning laser ophthalmoscopy (cSLO), optical coherence tomography (OCT), en face OCT, and the novel vascular imaging technique OCT angiography (OCTA). DOGS STUDIED AND PROCEDURES: Two dogs were diagnosed with unilateral multifocal or geographic retinal dysplasia and underwent advanced retinal imaging under general anesthesia at the Retinal Disease Studies Facility of the University of Pennsylvania. RESULTS: In both cases, the morphological pattern of the lesions was similar including outer retinal folds that invaginated and formed tubular retinal rosettes, surrounding a central inner retinal thickening (multifocal) or plaque (geographic). The two dogs had multiple vascular anomalies in the lesions such as increased tortuosity, abnormal change of vessel diameter including aneurysms and capillary network disruption. We also identified increased autofluorescence by AF cSLO with short wavelength light source (488 nm and barrier filter at 500 nm), and several areas of photoreceptor loss associated with the lesions. CONCLUSION: The use of OCTA allowed the identification of microvascular abnormalities associated with multifocal and geographic retinal dysplasia in two dogs. To our knowledge, this is the first report where the dye-free OCTA technique is used to study vascular lesions in canine retinas.

Near infrared autofluorescence imaging of retinal pigmented epithelial cells using 663 nm excitation.

PURPOSE: Fundus autofluorescence (AF) using adaptive optics scanning laser ophthalmoscopy (AOSLO) enables morphometric analysis of individual retinal pigmented epithelial (RPE) cells. However, only a few excitation wavelengths in the visible and near-infrared have been evaluated. Visible light excitation (<600 nm) presents additional safety hazards and is uncomfortable for patients. Near-infrared excitation (>700 nm) overcomes those problems but introduces others, including decreased AF signal and cone signatures that obscure RPE structure. Here we investigated the use of an intermediate wavelength, 663 nm, for excitation and compared it to 795 nm. METHODS: Subjects were imaged using AOSLO equipped with a detection channel to collect AF emission between 814 and 850 nm. Two light sources (663 and 795 nm) were used to excite the retinal fluorophores. We recorded 90 s videos and registered them with custom software to integrate AF images for analysis. RESULTS: We imaged healthy eyes and an eye with pattern dystrophy. Similar AF microstructures were detected with each excitation source, despite ~4 times lower excitation power with 663 nm. The signal-to-noise values showed no meaningful difference between 663 nm and 795 nm excitation and a similar trend was observed for image contrast between the two excitation wavelengths. CONCLUSIONS: Lower light levels can be used with shorter wavelength excitation to achieve comparable images of the microstructure of the RPE as have been obtained using higher light levels at longer wavelengths. Further experiments are needed to fully characterize AF across spectrum and determine the optimal excitation and emission bandwidths that balance efficiency, patient comfort, and efficacy.