FA4SANS-GAN: A Novel Machine Learning Generative Adversarial Network to Further Understand Ophthalmic Changes in Spaceflight Associated Neuro-Ocular Syndrome (SANS)

Purpose

To provide an automated system for synthesizing fluorescein angiography (FA) images from color fundus photographs for averting risks associated with fluorescein dye and extend its future application to spaceflight associated neuro-ocular syndrome (SANS) detection in spaceflight where resources are limited.

Design

Development and validation of a novel conditional generative adversarial network (GAN) trained on limited amount of FA and color fundus images with diabetic retinopathy and control cases.

Participants

Color fundus and FA paired images for unique patients were collected from a publicly available study.

Methods

FA4SANS-GAN was trained to generate FA images from color fundus photographs using 2 multiscale generators coupled with 2 patch-GAN discriminators. Eight hundred fifty color fundus and FA images were utilized for training by augmenting images from 17 unique patients. The model was evaluated on 56 fluorescein images collected from 14 unique patients. In addition, it was compared with 3 other GAN architectures trained on the same data set. Furthermore, we test the robustness of the models against acquisition noise and retaining structural information when introduced to artificially created biological markers.

Main Outcome Measures

For GAN synthesis, metric Fréchet Inception Distance (FID) and Kernel Inception Distance (KID). Also, two 1-sided tests (TOST) based on Welch's t test for measuring statistical significance.

Results

On test FA images, mean FID for FA4SANS-GAN was 39.8 (standard deviation, 9.9), which is better than GANgio model's mean of 43.2 (standard deviation, 13.7), Pix2PixHD's mean of 57.3 (standard deviation, 11.5) and Pix2Pix's mean of 67.5 (standard deviation, 11.7). Similarly for KID, FA4SANS-GAN achieved mean of 0.00278 (standard deviation, 0.00167) which is better than other 3 model's mean KID of 0.00303 (standard deviation, 0.00216), 0.00609 (standard deviation, 0.00238), 0.00784 (standard deviation, 0.00218). For TOST measurement, FA4SANS-GAN was proven to be statistically significant versus GANgio (P = 0.006); versus Pix2PixHD (P < 0.00001); and versus Pix2Pix (P < 0.00001).

Conclusions

Our study has shown FA4SANS-GAN to be statistically significant for 2 GAN synthesis metrics. Moreover, it is robust against acquisition noise, and can retain clear biological markers compared with the other 3 GAN architectures. This deployment of this model can be crucial in the International Space Station for detecting SANS.

Financial Disclosures

The authors have no proprietary or commercial interest in any materials discussed in this article.

Non-arteritic anterior ischemic optic neuropathy secondary to idiopathic intracranial hypertension

Purpose

Patients with increased intracranial pressure and underlying hypertensive emergency may present with optic disc edema. Papilledema in this setting may be a predisposing risk factor for superimposed non-arteritic anterior ischemic optic neuropathy (NAION). We highlight the role of neuroimaging including diffusion-weighted imaging in magnetic resonance imaging that can help to differentiate visual loss from NAION versus papilledema in fulminant IIH with and without hypertension.

Observations

A 46-year-old female presented with acute vision loss in the right eye and transient right hemiparesis. Neuro-ophthalmic examination revealed optic disc edema in both eyes. Magnetic resonance imaging (MRI) of the brain with diffusion-weighted imaging (DWI) sequences showed restricted diffusion in the optic nerve head of the affected eye. Lumbar puncture revealed an elevated opening pressure of 34.8 cm H2O confirming increased intracranial pressure. Additionally, literature searches were conducted in the PubMed, Google Scholar and Embase databases to uncover previous cases of patients with ischemic optic neuropathy and restricted diffusion on MRI.

Conclusions and importance

We highlight the shared pathophysiology between optic disc edema related visual loss in NAION and papilledema in IIH. We review the overlapping clinical and radiographic findings in these two conditions which may occur simultaneously. The presence of restricted diffusion in the optic nerve head versus in the optic nerve parenchyma may support a diagnosis of superimposed NAION and might influence the decision to perform surgery in cases of IIH with fulminant visual loss. Although restricted diffusion on MRI DWI sequences is often used to define cytotoxic edema related to ischemic infarction in the brain, this radiographic finding alone should not be used to determine the indication for surgery for papilledema related visual loss in fulminant IIH.

Transient Monocular Visual Loss (Amaurosis Fugax): How Does Age Impact Diagnosis?

Transient monocular visual loss (TMVL), also known as transient monocular blindness or amaurosis fugax ("fleeting blindness"), is a temporary loss of vision often due to ischemia to the retina. While acute TMVL should be considered an emergency that further requires exhaustive investigation, there are some cases in which TMVL arises secondary to benign causes. Age has a major impact in the diagnosis of ischemia and although the differential diagnosis of TMVL can be broad, timely and appropriate history, examination, diagnostic testing, and treatment can be vision- or life-saving. We review the causes of TMVL and the impact of age on the differential diagnoses and management.

Prioritizing open science in space medicine: perspectives following the NASA "Transform to Open Science (TOPS)" Curriculum

The National Aeronautics and Space Administration (NASA) has recently made a long-term commitment towards fostering open science. The NASA Transform to Open Science (TOPS) initiative provides recommendations, best practices, and tools related to open science. The principles of open science include the transparent sharing of data, findings, and methods and is designed to accelerate the pace of discovery and foster collaboration. The goal of open science is to allow data, publications, software, and physical samples to be accessible to all, regardless of being a professional or an amateur. In this paper, we summarize several key points open science that were presented as part of NASA's Open Science 101 Module 1 at an in-person training event in Washington, D.C., and include how open science can be beneficial for researchers and society as a whole.

Generative artificial intelligence in ophthalmology

Generative AI has revolutionized medicine over the past several years. A generative adversarial network (GAN) is a deep learning framework that has become a powerful technique in medicine, particularly in ophthalmology and image analysis. In this paper we review the current ophthalmic literature involving GANs, and highlight key contributions in the field. We briefly touch on ChatGPT, another application of generative AI, and its potential in ophthalmology. We also explore the potential uses for GANs in ocular imaging, with a specific emphasis on 3 primary domains: image enhancement, disease identification, and generating of synthetic data. PubMed, Ovid MEDLINE, Google Scholar were searched from inception to October 30, 2022 to identify applications of GAN in ophthalmology. A total of 40 papers were included in this review. We cover various applications of GANs in ophthalmic-related imaging including optical coherence tomography, orbital magnetic resonance imaging, fundus photography, and ultrasound; however, we also highlight several challenges, that resulted in the generation of inaccurate and atypical results during certain iterations. Finally, we examine future directions and considerations for generative AI in ophthalmology.

PARACENTRAL ACUTE MIDDLE MACULOPATHY IN GIANT CELL ARTERITIS

PURPOSE

To describe a representative case and review the literature on paracentral acute middle maculopathy (PAMM) and giant cell arteritis (GCA).

METHODS

A review of the English-language ophthalmic literature was performed using the search terms of PAMM, giant cell arteritis, and temporal arteritis.

RESULTS

A 72-year-old woman with PAMM as the presenting ophthalmic manifestation of GCA was described with a review of the prior cases from the literature. It was found that there were 26 cases of PAMM in GCA. In 19 of 26 cases, PAMM was associated with no other fundus abnormalities and was only seen on multimodal imaging including optical coherence tomography.

CONCLUSION

PAMM can cause acute paracentral visual loss, and GCA should be suspected in all cases of PAMM of the elderly patients, even when isolated and not associated with constitutional symptoms of GCA.

"Spaceflight-to-Eye Clinic": Terrestrial advances in ophthalmic healthcare delivery from space-based innovations

The phrase "Bench-to-Bedside" is a well-known phrase in medicine, highlighting scientific discoveries that directly translate to impacting patient care. Key examples of translational research include identification of key molecular targets in diseases and development of diagnostic laboratory tests for earlier disease detection. Bridging these scientific advances to the bedside/clinic has played a meaningful impact in numerous patient lives. The spaceflight environment poses a unique opportunity to also make this impact; the nature of harsh extraterrestrial conditions and medically austere and remote environments push for cutting-edge technology innovation. Many of these novel technologies built for the spaceflight environment also have numerous benefits for human health on Earth. In this manuscript, we focus on "Spaceflight-to-Eye Clinic" and discuss technologies built for the spaceflight environment that eventually helped to optimize ophthalmic health on Earth (e.g., LADAR for satellite docking now utilized in eye-tracking technology for LASIK). We also discuss current technology research for spaceflight associated neuro-ocular syndrome (SANS) that may also be applied to terrestrial ophthalmic health. Ultimately, various advances made to enable to the future of space exploration have also advanced the ophthalmic health of individuals on Earth.

Painful Eyes in Neurology Clinic: A Guide for Neurologists

Eye pain is a common complaint among patients presenting to the neurology clinic. It can be related to neurologic diseases, but it can also be a localized eye condition. Such disorders can be misleading, as their benign appearance might mask more grave underlying conditions, potentially leading to misdiagnoses or delayed treatment. Clinicians should be aware of the specific neurologic or systemic disorders (eg, demyelinating diseases or vascular abnormalities) that might first manifest as eye pain. Formal ophthalmic consultation is recommended for patients presenting with eye pain as the predominant complaint especially when red flags for more serious pathology are present.

National Football League Game Officials Self-Rating of Knowledge in Neuro-Ophthalmic Principles and Practice: A Pilot Program to Improve Precision and Accuracy of Game Official Calls

BACKGROUND

To determine whether a neuro-ophthalmic curriculum would improve National Football League (NFL) game officials' self-rated knowledge and interest in neuro-ophthalmic principles to improve precision and accuracy of NFL play-calling.

METHODS

The formalized and structured neuro-ophthalmic principles (NOP) curriculum was introduced to 121 NFL game officials, 17 replay officials, and 4 officiating staff who attended the NFL Official Training Camp in Irving, Texas, on September 8 and 9, 2023. Before and after the lecture and videos were introduced, participants completed an optional hard-copy feedback form pertaining to self-reported NOP knowledge, likelihood of using said terms, and interest in future content of NOP applicable NFL officiating. Paired 2-tailed t tests were used for statistical analysis to directly compare the self-reported knowledge before and after the neuro-ophthalmic curriculum introduction.

RESULTS

One hundred forty-two participants completed the prelecture and postlecture feedback forms self-reported knowledge after the NOP curriculum was given to the NFL officiating staff. All (142/142) participants completed a survey. There was a statistically significant improvement in the mean ratings of the prelecture vs. postlecture understanding of the specific neuro-ophthalmic terms pertinent to NFL game officials (2.6 [95% CI, 2.3-3.0] vs. 7.9 [95% CI, 7.6-8.2], P < 0.001) and 2.7 [95% CI, 2.3-3.0] vs. 7.7 [95% CI, 7.4-8.0]), respectively. There was a statistically significant greater likelihood of using said terms prelecture vs. postlecture (2.9 [95% CI, 2.4-3.4] vs. 7.5 [95% CI, 7.2-7.9], P < 0.001).

CONCLUSIONS

This study found a statistically significant improvement in neuro-ophthalmic knowledge and a greater likelihood of using NOP terms following the NOP curriculum. NFL game officials, replay officials, and staff are interested in expanding their knowledge in the vision science of neuro-ophthalmic concepts and applications involved in play-calling. We hope that our pilot data will lead to a model of education that will improve the precision and accuracy of NFL play-calls by officials on game days.

Ethical Considerations of Neuralink and Brain-Computer Interfaces

Neuralink is a neurotechnology company founded by Elon Musk in 2016, which has been quietly developing revolutionary technology allowing for ultra-high precision bidirectional communication between external devices and the brain. In this paper, we explore the multifaceted ethical considerations surrounding neural interfaces, analyzing potential societal impacts, risks, and call for a need for responsible innovation. Despite the technological, medical, medicolegal, and ethical challenges ahead, neural interface technology remains extremely promising and has the potential to create a new era of medicine.

Neuro-ophthalmic challenges and multi-morbidity in vasculitis among the older adults

INTRODUCTION

Vasculitides are a heterogeneous group of disorders producing inflammation of blood vessels (e.g. arteries or veins). All major vasculitides potentially have ophthalmological symptoms and signs including visual loss. Co-morbidity, multimorbidity, polypharmacy, and geriatric syndromes all play important roles in patient outcomes for these rheumatic conditions in the elderly. This monograph reviews the NCBI PubMed database (Feb 2023) literature on the neuro-ophthalmic and geriatric considerations in vasculitis.

AREAS COVERED

Cogan Syndrome, Granulomatosis with Polyangiitis, Giant Cell Arteritis, Polyarteritis Nodosa, Takayasu Arteritis, Vasculitis epidemiology, and neuro-ophthalmological symptoms.

EXPERT OPINION

Geriatric patient care for vasculitis with neuro-ophthalmological manifestations can be complicated by the interplay of multiple co-morbidities, polypharmacy, and specific geriatric syndromes. The valuation and treatment of vasculitis and the complications associated with the disease can negatively impact patient care. Advances in noninvasive imaging and updates in diagnostic criteria have enabled increased identification of patients at earlier stages with less severe disease burden. Novel therapeutic agents can be glucocorticoid sparing and might reduce the adverse effects of chronic steroid use. Holistic care models like the 5 M geriatric care model (mind, mobility, medications, multicomplexity, and matters most) allow patients' needs to be in the forefront with biopsychosocial aspects of a patient being addressed.

Concerns with OpenAI's Sora in Medicine

Open AI's Sora represents a ground-breaking innovation in AI that can generate lifelike and imaginative visual scenes based on text prompts. However, Sora has also produced some new concerns surrounding artificial video generation in medicine. While Sora is highly promising to enhance patient education, facilitate remote consultations and simulate surgical procedures, AI-generated videos also bring technical, legal, and ethical challenges. In this paper, we explore the clinical and ethical implications of Sora's AI-generated videos in the field of medicine.

SANS-CNN: An automated machine learning technique for spaceflight associated neuro-ocular syndrome with astronaut imaging data

Spaceflight associated neuro-ocular syndrome (SANS) is one of the largest physiologic barriers to spaceflight and requires evaluation and mitigation for future planetary missions. As the spaceflight environment is a clinically limited environment, the purpose of this research is to provide automated, early detection and prognosis of SANS with a machine learning model trained and validated on astronaut SANS optical coherence tomography (OCT) images. In this study, we present a lightweight convolutional neural network (CNN) incorporating an EfficientNet encoder for detecting SANS from OCT images titled "SANS-CNN." We used 6303 OCT B-scan images for training/validation (80%/20% split) and 945 for testing with a combination of terrestrial images and astronaut SANS images for both testing and validation. SANS-CNN was validated with SANS images labeled by NASA to evaluate accuracy, specificity, and sensitivity. To evaluate real-world outcomes, two state-of-the-art pre-trained architectures were also employed on this dataset. We use GRAD-CAM to visualize activation maps of intermediate layers to test the interpretability of SANS-CNN's prediction. SANS-CNN achieved 84.2% accuracy on the test set with an 85.6% specificity, 82.8% sensitivity, and 84.1% F1-score. Moreover, SANS-CNN outperforms two other state-of-the-art pre-trained architectures, ResNet50-v2 and MobileNet-v2, in accuracy by 21.4% and 13.1%, respectively. We also apply two class-activation map techniques to visualize critical SANS features perceived by the model. SANS-CNN represents a CNN model trained and validated with real astronaut OCT images, enabling fast and efficient prediction of SANS-like conditions for spaceflight missions beyond Earth's orbit in which clinical and computational resources are extremely limited.

Impact of COVID-19 on Neuro-Ophthalmology in the United States: A National Survey

PURPOSE

To evaluate the impacts of the COVID-19 on neuro-ophthalmology practice in the United States.

DESIGN

Cross-sectional study.

METHODS

The North American Neuro-ophthalmology Society distributed a survey on the impact of COVID-19 on neuro-ophthalmic practice to its members. The survey consisted of 15 questions regarding the impact of the pandemic on neuro-ophthalmic practice and perspectives.

RESULTS

Twenty-eight neuro-ophthalmologists practicing in the United States responded to our survey. In this survey, 64% of survey respondents were male (n = 18), while 36% were female (n = 10). The average age of a respondent was 55 years old. According to 77% of survey respondents, various neuro-ophthalmic diseases were reported to have worsened during the pandemic including idiopathic intracranial hypertension, compressive optic neuropathy, optic neuritis, and giant cell arteritis.

CONCLUSIONS

This survey represents one of the largest studies to describe the impact of the COVID-19 pandemic of neuro-ophthalmology. Given the underrepresentation of neuro-ophthalmology in the United States as described in the literature, this study strengthens the need for more neuro-ophthalmologists to provide timely care, particularly during the pandemic. Further interventions to incentivize the pursuit of neuro-ophthalmology training may help combat the effects of COVID-19 on neuro-ophthalmic conditions.