Long-Term Clinical Course and Treatment Outcomes in Occult and Overt Acute Zonal Outer Retinopathy.

PURPOSE: To report the longitudinal outcomes for AZOOR patients including treatment response, imaging evolution, and overlap with multiple evanescent white dot syndrome (MEWDS). METHODS: Visual acuity (VA) and visual field (VF) outcomes of occult and overt AZOOR patients were retrospectively compared between the first and final visits as well as between the two AZOOR subtypes. For treated patients, rates of VA change and fundus lesion area were compared before and after treatment. Analyses were performed using STATA 17. RESULTS: Seventeen eyes from 11 occult AZOOR patients and 45 eyes from 29 overt AZOOR patients were included. In a composite VA/VF primary outcome, clinical improvement was noted in five occult AZOOR and three overt AZOOR patients. The decline of logarithm of the Minimal Angle of Resolution (logMAR) VA was minimal in both groups: 0.00016 units/month in occult AZOOR patients and 0.009 units/month in overt AZOOR patients (p = 0.94). Occult AZOOR patients were more likely to have improved or stable VF than overt AZOOR patients (p = 0.04). One occult AZOOR and two overt AZOOR patients developed MEWDS at subsequent visits. Treatment with steroids or immunomodulatory therapy (IMT) was initiated in one occult AZOOR patient and nine overt AZOOR patients. Treated patients had overall VA stability. Fundus lesion area in treated patients changed by a mean of 0.2831 mm2/month, with 40% of patients showing decreased lesion area. CONCLUSION: AZOOR patients generally maintained their VA. Overt AZOOR patients were more likely to receive steroids or IMT; treatment was associated with stabilization of VA.

Histologic correlates of "Choroidal abnormalities" in Neurofibromatosis type 1 (NF1).

Neurofibromatosis type 1 (NF1) is a rare autosomal dominant disorder characterized by proliferation of cells from neural crest origin. The most common manifestations are cutaneous, neurologic, skeletal and ocular. The distinction of NF1 from other syndromes with multiple café-au-lait macules may be difficult in the pediatric age group, and ocular findings, especially Lisch nodules (i.e., melanocytic hamartomas on the irides), are a useful, early diagnostic tool. In recent years, novel ocular manifestations descriptively referred to as "choroidal abnormalities", choroidal "hyperpigmented spots" and "retinal vascular abnormalities" have been recognized in NF1. Choroidal abnormalities (CA) appear as bright patchy nodules that can be best detected with near-infrared ocular coherence tomography imaging (NIR-OCT). Because of their high specificity and sensitivity for NF1, CA have been added as an ocular diagnostic criterion of NF1 as an alternative to Lisch nodules. Although CA are important ocular diagnostic criteria for NF1, the histologic correlates are controversial. We present the postmortem ocular pathology findings of an NF1 patient for whom clinical notes and ocular imaging were available. Findings in this patient included choroidal hyperpigmented spots on funduscopy and retinal vascular abnormalities, both of which have been reported to be closely associated with CA. Histologic examination of the eyes showed multiple clusters of melanocytes of varying sizes in the choroid. Pathologic review of 12 additional postmortem eyes from 6 NF1 patients showed multiple, bilateral choroidal melanocytic aggregates in all eyes. These findings suggest that the CA seen on NIR-OCT and the hyperpigmented spots seen clinically in NF1 patients are manifestations of multifocal choroidal melanocytic clusters, consistent with choroidal melanocytic hamartomas. Lisch nodules, often multiple, were present in all eyes with morphology that differed from the choroidal hamartomas. As such, although CA and Lisch nodules are melanocytic hamartomas, there are clear phenotypical differences in their morphologies.

The Role of Epigenetics in Accelerated Aging: A Reconsideration of Later-Life Visual Loss After Early Optic Neuropathy.

BACKGROUND: In 2005, we reported 3 patients with bilateral optic nerve damage early in life. These patients had stable vision for decades but then experienced significant bilateral vision loss with no obvious cause. Our hypothesis, novel at that time, was that the late decline of vision was due to age-related attrition of retinal ganglion cells superimposed on a reduced neuronal population due to the earlier injury. EVIDENCE ACQUISITION: The field of epigenetics provides a new paradigm with which to consider the normal aging process and the impact of neuronal injury, which has been shown to accelerate aging. Late-in-life decline in function after early neuronal injury occurs in multiple sclerosis due to dysregulated inflammation and postpolio syndrome. Recent studies by our group in mice have also demonstrated the possibility of partial reversal of cellular aging and the potential to mitigate anatomical damage after injury and even improve visual function. RESULTS: The results in mice and nonhuman primates published elsewhere have shown enhanced neuronal survival and visual function after partial epigenetic reprogramming. CONCLUSIONS: Injury promotes epigenetic aging , and this finding can be observed in several clinically relevant scenarios. An understanding of the epigenetic mechanisms at play opens the opportunity to restore function in the nervous system and elsewhere with cellular rejuvenation therapies. Our earlier cases exemplify how reconsideration of previously established concepts can motivate inquiry of new paradigms.

Orbital Vasculopathy With Unexpected Finding of Calcium Oxalosis in the Context of a Clinical Diagnosis of Optic Neuropathy.

BACKGROUND: There are few reports of histopathology of any form of optic neuropathy. This article provides histopathologic findings of an adult-onset, nonprogressive optic neuropathy that was diagnosed clinically as nonacute, nonarteritic anterior ischemic optic neuropathy (NAION) but which was found by a pathological study to be associated with diffuse calcium oxalosis that was confined in the involved orbit. METHODS: This is a case report that includes results of a neuro-ophthalmologic examination and histopathology of a complete autopsy, including en bloc removal of both orbits and the brain. The unaffected orbit/optic nerve served as a control. The affected orbit was serially sectioned into 2,550 increments each separated by 10 µm; the uninvolved orbit was sectioned into 150 equally spaced sections. The main outcome measures were derived from the autopsy, especially from the thin-section histopathologic study of both orbits that focused on blood vessels and the site of neural damage within the optic nerve. RESULTS: The neuro-ophthalmologic examination revealed a unilateral optic neuropathy with pallor of the left optic nerve head that had been documented just before death. The general autopsy showed acute bacterial endocarditis and a recent cerebral hematoma that caused death. Histopathology revealed sectoral loss of optic nerve axons in the left eye. Numerous arterial walls in the left orbit, including short posterior ciliary arteries and the central retinal artery, contained hundreds of crystals with anisotropic, colorful birefringence consistent with calcium oxalosis. Crystals were not found in the right, control orbit or elsewhere in the body. CONCLUSIONS: The patient developed an optic neuropathy late in life that was diagnosed by an experienced neuro-ophthalmologist as being most consistent with nonacute, nonarteritic anterior ischemic optic neuropathy. The autopsy identified sectoral loss of optic nerve fibers consistent with that diagnosis. However, the unexpected discovery of calcium oxalate crystals in blood vessels of the involved orbit, which curiously were not present elsewhere in the body, raises a question of their etiological role in this particular optic neuropathy. Whether the crystals were causal, epiphenomenal, or purely incidental to the optic neuropathy cannot be answered by our study.

The Controversy of Chronotherapy: Emerging Evidence regarding Bedtime Dosing of Antihypertensive Medications in Non-Arteritic Anterior Ischemic Optic Neuropathy.

"Blindness upon awakening" occurs in a significant proportion of patients with non-arteritic anterior ischemic optic neuropathy (NAION). This observation has led to a notion that nocturnal hypotension is a significant contributor and, perhaps, the final insult in a multifactorial process leading to the development of NAION, as has been proposed in other ischemic events like strokes, myocardial infarction, and ischemic rest pain. An extension of this concept has led to the recommendation that patients who have experienced NAION avoid taking blood pressure medications at bedtime. However, mounting evidence in the cardiology literature suggests that nocturnal hypertension is associated with increased risk of cardiovascular morbidity. In two prospective blood pressure monitoring studies in 1994 and 1999, Hayreh observed an extreme dipping pattern in nocturnal systolic blood pressure in NAION patients compared to reported normal values. Yet, two subsequent ambulatory blood pressure studies found either normal or non-dipping patterns in NAION patients. The majority of clinical trials published since 1976 that have studied nocturnal administration of antihypertensives have reported enhanced blood pressure control and reduced cardiovascular risk. Most notably, the large, prospective 2020 Hygia Chronotherapy Trial reported a statistically-significant beneficial effect of nocturnal antihypertensive dosing on cardiovascular outcomes and mortality. The controversy regarding nocturnal hypotension and NAION is of increasing relevance as there is new evidence to suggest a beneficial effect of nocturnal antihypertensive dosing in cardiovascular risk. This new information should prompt a re-evaluation of the relevant risk-to-benefit of reducing the risk of NAION on one hand, and the potential increase of cardiovascular risk on the other. Definitive resolution of this question would require a prospective, randomized control study with input from both cardiology and ophthalmology.

Lamina cribrosa vessel and collagen beam networks are distinct.

Our goal was to analyze the spatial interrelation between vascular and collagen networks in the lamina cribrosa (LC). Specifically, we quantified the percentages of collagen beams with/without vessels and of vessels inside/outside of collagen beams. To do this, the vasculature of six normal monkey eyes was labeled by perfusion post-mortem. After enucleation, coronal cryosections through the LC were imaged using fluorescence and polarized light microscopy to visualize the blood vessels and collagen beams, respectively. The images were registered to form 3D volumes. Beams and vessels were segmented, and their spatial interrelationship was quantified in 3D. We found that 22% of the beams contained a vessel (range 14%-32%), and 21% of vessels were outside beams (13%-36%). Stated differently, 78% of beams did not contain a vessel (68%-86%), and 79% of vessels were inside a beam (64%-87%). Individual monkeys differed significantly in the fraction of vessels outside beams (p < 0.01 by linear mixed effect analysis), but not in the fraction of beams with vessels (p > 0.05). There were no significant differences between contralateral eyes in the percent of beams with vessels and of vessels outside beams (p > 0.05). Our results show that the vascular and collagenous networks of the LC in monkey are clearly distinct, and the historical notions that each LC beam contains a vessel and all vessels are within beams are inaccurate. We postulate that vessels outside beams may be relatively more vulnerable to mechanical compression by elevated IOP than are vessels shielded inside of beams.

Sectoral Sparing Associated With a Cilioretinal Artery in Arteritic Anterior Ischemic Optic Neuropathy.

ABSTRACT: Giant cell arteritis (GCA) is a life-threatening vasculitis occurring in older adults that can cause blindness by ischemia of the choroid, retina, and optic nerve. We report a case of a patient who presented with "occult" GCA with severe anterior ischemic optic neuropathy affecting both optic nerves, delayed choroidal filling, and a concomitant cilioretinal artery occlusion in the left eye. The retinal territory supplied by the affected cilioretinal artery was hypoperfused, yet this retinal territory at least partially corresponded to the only preserved visual field in that eye. The sector of the optic disc corresponding to the emergence of the cilioretinal artery was the only sector spared by pallid edema. This pattern of sectoral sparing associated with a cilioretinal artery has been observed in other patients with GCA and in animal models of posterior ciliary artery occlusion. This case serves as a clear example of an incompletely understood phenomenon in posterior pole circulation in vascular occlusive disease that deserves further study.

Advances in Neuroscience, Not Devices, Will Determine the Effectiveness of Visual Prostheses.

Background: Innovations in engineering and neuroscience have enabled the development of sophisticated visual prosthetic devices. In clinical trials, these devices have provided visual acuities as high as 20/460, enabled coarse navigation, and even allowed for reading of short words. However, long-term commercial viability arguably rests on attaining even better vision and more definitive improvements in tasks of daily living and quality of life. Purpose: Here we review technological and biological obstacles in the implementation of visual prosthetics. Conclusions: Research in the visual prosthetic field has tackled significant technical challenges, including biocompatibility, signal spread through neural tissue, and inadvertent activation of passing axons; however, significant gaps in knowledge remain in the realm of neuroscience, including the neural code of vision and visual plasticity. We assert that further optimization of prosthetic devices alone will not provide markedly improved visual outcomes without significant advances in our understanding of neuroscience.

Elevated Intracranial Pressure Associated With Exogenous Hormonal Therapy Used for Gender Affirmation.

BACKGROUND: Addison disease, corticosteroid withdrawal, and taking synthetic growth hormone have been linked with development of intracranial hypertension, but there is still debate on whether administration of other exogenous hormones plays a role in precipitating elevated pressure. The growing use of hormonal therapy for gender affirmation provides an opportunity to explore this possibility. METHODS: All transgender patients taking exogenous hormones for female-to-male (FTM) and male-to-female (MTF) transitions who were diagnosed with intracranial hypertension at Massachusetts Eye and Ear Infirmary, Massachusetts General Hospital and Beth Israel Deaconess Medical Center between August 2014 and November 2018 were included in a retrospective review. Visual acuity, type, and dose of exogenous hormone, visual field testing, clinical exam, results of neuroimaging and lumbar puncture, and treatment modalities were catalogued and analyzed. RESULTS: Six transgender individuals were identified. Five were FTM, with an average hormone treatment time of 18.4 months, and one was MTF who had been treated with hormones for 4 years. The average age of all patients was 23.5 years. The average time between onset of symptoms and presentation was 5 months. Fifty percent of the patients reported pulse-synchronous tinnitus, 83% reported positional headache, 33% reported transient visual obscurations, and 16% reported diplopia. Lumbar punctures performed on 4 of the patients revealed elevated opening pressures and normal cerebrospinal fluid constituents. MRI findings consistent with elevated intracranial pressure (ICP) were present in the other 2 patients in whom lumbar puncture was unsuccessful. Four patients were treated with acetazolamide and one was treated with topiramate, with an average follow-up time of 15.7 months. All patients demonstrated bilateral optic disc swelling, and all maintained normal acuity and color vision. Performance on visual field testing was not significantly affected in any patient. CONCLUSIONS: This is the largest reported series to date of gender-transitioning patients with intracranial hypertension, including one novel MTF conversion. These observations warrant further investigation into the possible link of exogenous hormonal therapy and elevated ICP and any mechanisms or confounders underlying this potential association.

Site of Origin of the Ophthalmic Artery Influences the Risk for Retinal Versus Cerebral Embolic Events.

BACKGROUND: Embolic events leading to retinal ischemia or cerebral ischemia share common risk factors; however, it has been well documented that the rate of concurrent cerebral infarction is higher in patients with a history of transient ischemic attack (TIA) than in those with monocular vision loss (MVL) due to retinal ischemia. Despite the fact that emboli to the ophthalmic artery (OA) and middle cerebral artery share the internal carotid artery (ICA) as a common origin or transit for emboli, the asymmetry in their final destination has not been fully explained. We hypothesize that the anatomic location of the OA takeoff from the ICA may contribute to the differential flow of small emboli to the retinal circulation vs the cerebral circulation. METHODS: We report a retrospective, comparative, case-control study on 28 patients with retinal ischemia and 26 patients with TIA or cerebral infarction caused by embolic events. All subjects underwent either computed tomography angiography or MRA. The location of the ipsilateral OA origin off the ICA was then graded in a blinded fashion and compared between cohorts. Vascular risk factors were collected for all patients, including age, sex, hypertension, hyperlipidemia, arrhythmia, diabetes, coronary artery disease, and smoking. RESULTS: We find that in patients with retinal ischemia of embolic etiology, the ipsilateral OA takeoff from the ICA is more proximal than in patients with cerebral infarcts or TIA (P = 0.0002). We found no statistically significant differences in demographic, vascular, or systemic risk factors. CONCLUSIONS: We find that the mean anatomical location of the OA takeoff from the ICA is significantly more proximal in patients with MVL due to retinal ischemia compared with patients with TIA or cerebral ischemia. This finding contributes significantly to our understanding of a long observed but poorly understood phenomenon that patients with MVL are less likely to have concurrent cerebral ischemia than are patients with TIA.

Lamina Cribrosa Capillaries Straighten as Intraocular Pressure Increases.

Purpose: The purpose of this study was to visualize the lamina cribrosa (LC) capillaries and collagenous beams, measure capillary tortuosity (path length over straight end-to-end length), and determine if capillary tortuosity changes when intraocular pressure (IOP) increases. Methods: Within 8 hours of sacrifice, 3 pig heads were cannulated via the external ophthalmic artery, perfused with PBS to remove blood, and then perfused with a fluorescent dye to label the capillaries. The posterior pole of each eye was mounted in a custom-made inflation chamber for control of IOP with simultaneous imaging. Capillaries and collagen beams were visualized with structured light illumination enhanced imaging at IOPs from 5 to 50 mm Hg at each 5 mm Hg increment. Capillary tortuosity was measured from the images and paired two-sample t-tests were used to assess for significant changes in relation to changes in IOP. Results: Capillaries were highly tortuous at 15 mm Hg (up to 1.45). In all but one eye, tortuosity decreased significantly as IOP increased from 15 to 25 mm Hg (P < 0.01), and tortuosity decreased significantly in every eye as IOP increased from 15 to 40 mm Hg (P < 0.01). In only 16% of capillaries, tortuosity increased with elevated IOP. Capillaries had a surprisingly different topology from the collagen beams. Conclusions: Although high capillary tortuosity is sometimes regarded as potentially problematic because it can reduce blood flow, LC capillary tortuosity may provide slack that mitigates against reduced flow and structural damage caused by excessive stretch under elevated IOP. We speculate that low capillary tortuosity could be a risk factor for damage under high IOP.

Micro-Fabrication of Components for a High-Density Sub-Retinal Visual Prosthesis.

We present a retrospective of unique micro-fabrication problems and solutions that were encountered through over 10 years of retinal prosthesis product development, first for the Boston Retinal Implant Project initiated at the Massachusetts Institute of Technology and at Harvard Medical School's teaching hospital, the Massachusetts Eye and Ear-and later at the startup company Bionic Eye Technologies, by some of the same personnel. These efforts culminated in the fabrication and assembly of 256+ channel visual prosthesis devices having flexible multi-electrode arrays that were successfully implanted sub-retinally in mini-pig animal models as part of our pre-clinical testing program. We report on the processing of the flexible multi-layered, planar and penetrating high-density electrode arrays, surgical tools for sub-retinal implantation, and other parts such as coil supports that facilitated the implantation of the peri-ocular device components. We begin with an overview of the implantable portion of our visual prosthesis system design, and describe in detail the micro-fabrication methods for creating the parts of our system that were assembled outside of our hermetically-sealed electronics package. We also note the unique surgical challenges that sub-retinal implantation of our micro-fabricated components presented, and how some of those issues were addressed through design, materials selection, and fabrication approaches.

Harmonization of Outcomes and Vision Endpoints in Vision Restoration Trials: Recommendations from the International HOVER Taskforce.

Translational research in vision prosthetics, gene therapy, optogenetics, stem cell and other forms of transplantation, and sensory substitution is creating new therapeutic options for patients with neural forms of blindness. The technical challenges faced by each of these disciplines differ considerably, but they all face the same challenge of how to assess vision in patients with ultra-low vision (ULV), who will be the earliest subjects to receive new therapies. Historically, there were few tests to assess vision in ULV patients. In the 1990s, the field of visual prosthetics expanded rapidly, and this activity led to a heightened need to develop better tests to quantify end points for clinical studies. Each group tended to develop novel tests, which made it difficult to compare outcomes across groups. The common lack of validation of the tests and the variable use of controls added to the challenge of interpreting the outcomes of these clinical studies. In 2014, at the bi-annual International "Eye and the Chip" meeting of experts in the field of visual prosthetics, a group of interested leaders agreed to work cooperatively to develop the International Harmonization of Outcomes and Vision Endpoints in Vision Restoration Trials (HOVER) Taskforce. Under this banner, more than 80 specialists across seven topic areas joined an effort to formulate guidelines for performing and reporting psychophysical tests in humans who participate in clinical trials for visual restoration. This document provides the complete version of the consensus opinions from the HOVER taskforce, which, together with its rules of governance, will be posted on the website of the Henry Ford Department of Ophthalmology (www.artificialvision.org). Research groups or companies that choose to follow these guidelines are encouraged to include a specific statement to that effect in their communications to the public. The Executive Committee of the HOVER Taskforce will maintain a list of all human psychophysical research in the relevant fields of research on the same website to provide an overview of methods and outcomes of all clinical work being performed in an attempt to restore vision to the blind. This website will also specify which scientific publications contain the statement of certification. The website will be updated every 2 years and continue to exist as a living document of worldwide efforts to restore vision to the blind. The HOVER consensus document has been written by over 80 of the world's experts in vision restoration and low vision and provides recommendations on the measurement and reporting of patient outcomes in vision restoration trials.

Implantation and Extraction of Penetrating Electrode Arrays in Minipig Retinas.

Purpose: This work was motivated by the goals of demonstrating methods to fabricate and implant large numbers of penetrating arrays into the retina and the feasibility of extraction. Methods: Arrays of inactive, three-dimensional (3D) SU-8 structures were microfabricated onto 13-µm polyimide substrates. Standard vitreoretinal surgical techniques were used with an ab externo approach for subretinal implantation of arrays in 12 mini-pigs. In the first three surgeries, different post-geometries were explored, while a preferred design (128-µm tall, 30-µm diameter, 200-µm spacing) was used for the remaining nine implantations. Two arrays were extracted. Funduscopy, optical coherence tomography (OCT) and immunohistochemistry of the retinae were performed. The unoperated eyes and tissue far from implantation served as controls. A thirteenth pig was implanted with a planar array. Results: Ten implant surgeries had no significant complication, and two arrays were successfully extracted. One retinal tear occurred after implantation due to too long posts in an early surgery. In "successful" cases, OCT showed close apposition of the arrays to the retina and integration of the posts, the tops of which were positioned at the junction of the inner plexiform and ganglion cells, without significant gliosis. Conclusions: These results provide a proof-of-concept that relatively large numbers of 3D posts can be implanted into, and extracted from, the retina of mini-pigs. Our surgical numbers were relatively small, especially for the extractions, and our conclusions must be viewed with that limitation. Our methods are applicable for human surgeries. Translational Relevance: This study provides results of implantation and extraction of relatively large numbers of 3D posts from the retina of minipig eyes. If similar technology were used in humans, a 3D array of this type should lower perceptual thresholds, provide safer long-term stimulation, and perhaps provide better perceptual outcomes.