Mechanical Disruption of the Inner Limiting Membrane In Vivo Enhances Targeting to the Inner Retina.

Purpose: To evaluate the effects of mechanical disruption of the inner limiting membrane (ILM) on the ability to target interventions to the inner neurosensory retina in a rodent model. Our study used an animal model to gain insight into the normal physiology of the ILM and advances our understanding of the effects of mechanical ILM removal on the viral transduction of retinal ganglion cells and retinal ganglion cell transplantation. Methods: The ILM in the in vivo rat eye was disrupted using mechanical forces applied to the vitreoretinal interface. Immunohistology and electron microscopy were used to verify the removal of the ILM in retina flatmounts and sections. To assess the degree to which ILM disruption enhanced transvitreal access to the retina, in vivo studies involving intravitreal injections of adeno-associated virus (AAV) to transduce retinal ganglion cells (RGCs) and ex vivo studies involving co-culture of human stem cell-derived RGCs (hRGCs) on retinal explants were performed. RGC transduction efficiency and transplanted hRGC integration with retinal explants were evaluated by immunohistology of the retinas. Results: Mechanical disruption of the ILM in the rodent eye was sufficient to remove the ILM from targeted retinal areas while preserving the underlying retinal nerve fiber layer and RGCs. Removal of the ILM enhanced the transduction efficiency of intravitreally delivered AAV threefold (1380.0 ± 290.1 vs. 442.0 ± 249.3 cells/mm2; N = 6; P = 0.034). Removal of the ILM was also sufficient to promote integration of transplanted RGCs within the inner retina. Conclusions: The ILM is a barrier to transvitreally delivered agents including viral vectors and cells. Mechanical removal of the ILM is sufficient to enhance access to the inner retina, improve viral transduction efficiencies of RGCs, and enhance cellular integration of transplanted RGCs with the retina.

Usability and Clinician Acceptance of a Deep Learning-Based Clinical Decision Support Tool for Predicting Glaucomatous Visual Field Progression.

PRCIS: We updated a clinical decision support tool integrating predicted visual field (VF) metrics from an artificial intelligence model and assessed clinician perceptions of the predicted VF metric in this usability study. PURPOSE: To evaluate clinician perceptions of a prototyped clinical decision support (CDS) tool that integrates visual field (VF) metric predictions from artificial intelligence (AI) models. METHODS: Ten ophthalmologists and optometrists from the University of California San Diego participated in 6 cases from 6 patients, consisting of 11 eyes, uploaded to a CDS tool ("GLANCE", designed to help clinicians "at a glance"). For each case, clinicians answered questions about management recommendations and attitudes towards GLANCE, particularly regarding the utility and trustworthiness of the AI-predicted VF metrics and willingness to decrease VF testing frequency. MAIN OUTCOMES AND MEASURES: Mean counts of management recommendations and mean Likert scale scores were calculated to assess overall management trends and attitudes towards the CDS tool for each case. In addition, system usability scale scores were calculated. RESULTS: The mean Likert scores for trust in and utility of the predicted VF metric and clinician willingness to decrease VF testing frequency were 3.27, 3.42, and 2.64, respectively (1=strongly disagree, 5=strongly agree). When stratified by glaucoma severity, all mean Likert scores decreased as severity increased. The system usability scale score across all responders was 66.1±16.0 (43rd percentile). CONCLUSIONS: A CDS tool can be designed to present AI model outputs in a useful, trustworthy manner that clinicians are generally willing to integrate into their clinical decision-making. Future work is needed to understand how to best develop explainable and trustworthy CDS tools integrating AI before clinical deployment.

Detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) RNA in the Human Eye.

PURPOSE: To determine the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in postmortem ocular specimens of patients with severe COVID-19 disease. PATIENTS AND METHODS: Postmortem conjunctival (28 samples), aqueous humor (30 samples) and vitreous humor (30 samples) specimens were obtained bilaterally from the eyes of 15 deceased COVID-19 patients within one hour of death. The presence of viral RNA was evaluated in samples using Real-time reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: Positive RT-PCR SARS-COV-2 results were found in one conjunctival and 2 vitreous humor samples. All aqueous humor samples tested negative for the presence of SARS-COV-2 RNA. Of note, three positive samples were obtained from three different patients. The overall prevalence of positive RT-PCR ocular samples was 3.4% among all samples and 20% at the patient level. CONCLUSION: SARS-CoV-2 RNA is detectable in postmortem conjunctival and vitreous humor samples of patients with severe COVID-19.

Comparison of the Effects of Latanoprostene Bunod and Timolol on Retinal Blood Vessel Density: A Randomized Clinical Trial.

PURPOSE: To compare the differences in retinal vessel density (VD) between topical administration of latanoprostene bunod (LBN) ophthalmic solution 0.024% and timolol maleate 0.5% in patients with open-angle glaucoma (OAG) or ocular hypertension (OHT) and normal subjects. DESIGN: Randomized, single center, crossover clinical trial. METHODS: Eligible subjects were examined during 6 study visits over 12 weeks. All subjects were randomized in a 1:1 ratio to LBN dosed once daily or timolol dosed twice daily in both eyes (OU) for a duration of 4 weeks each, separated by a 2-week washout period. A comprehensive eye examination OU was performed at each visit. Testing was performed with optical coherence tomography and optical coherence tomography angiography (optic nerve and macula), as well as visual field examination, on the study eye at baseline and before and after each treatment. RESULTS: One eye from each of 50 patients was enrolled (10 healthy patients, 26 patients with OHT, and 14 patients with OAG). After administration of LBN there was significantly increased macular VD (0.76% [0.20%-1.33%], P = 0.009) and a trend in increasing peripapillary VD in patients with OAG and patients with OHT. In contrast, after administration of timolol, there were no differences in macular VD, and a decrease in peripapillary VD only was observed in the nasal inferior sector (-0.56% [-1.08% to -0.03%], P = .04) in patients with OAG and patients with OHT. No change in peripapillary or macular VD was observed in the normal subjects (P > .05 for all). CONCLUSIONS: Topical administration of LBN enhanced macular VD in patients with OAG or patients with OHT. In contrast, timolol administration did not have any effect on VD.

Polymorphous low-grade adenocarcinoma with cavernous sinus involvement presenting as third nerve palsy.

Purpose: Polymorphous low-grade adenocarcinoma is a tumor of the salivary glands that typically localizes within the oral cavity. We present a case of isolated third cranial nerve palsy as the initial presentation of polymorphous low-grade adenocarcinoma involving the left cavernous sinus in a patient status post glaucoma surgery. Observations: A 68-year-old woman status post glaucoma drainage device implantation in her left eye presented with an isolated left third nerve palsy ten weeks postoperatively. Differential diagnoses included microvascular ischemic neuropathy, postoperative ptosis, and compressive mass. MRI revealed a left cavernous sinus mass, and subsequent excisional biopsy revealed a diagnosis of polymorphous low-grade adenocarcinoma. Conclusions: There are few cases reporting polymorphous low-grade adenocarcinoma originating from and extending beyond the nasopharynx. This report emphasizes an unexpected neuro-ophthalmic manifestation of this salivary gland tumor.

Optic Nerve Engraftment of Neural Stem Cells.

Purpose: To evaluate the integrative potential of neural stem cells (NSCs) with the visual system and characterize effects on the survival and axonal regeneration of axotomized retinal ganglion cells (RGCs). Methods: For in vitro studies, primary, postnatal rat RGCs were directly cocultured with human NSCs or cultured in NSC-conditioned media before their survival and neurite outgrowth were assessed. For in vivo studies, human NSCs were transplanted into the transected rat optic nerve, and immunohistology of the retina and optic nerve was performed to evaluate RGC survival, RGC axon regeneration, and NSC integration with the injured visual system. Results: Increased neurite outgrowth was observed in RGCs directly cocultured with NSCs. NSC-conditioned media demonstrated a dose-dependent effect on RGC survival and neurite outgrowth in culture. NSCs grafted into the lesioned optic nerve modestly improved RGC survival following an optic nerve transection (593 ± 164 RGCs/mm2 vs. 199 ± 58 RGCs/mm2; P < 0.01). Additionally, RGC axonal regeneration following an optic nerve transection was modestly enhanced by NSCs transplanted at the lesion site (61.6 ± 8.5 axons vs. 40.3 ± 9.1 axons, P < 0.05). Transplanted NSCs also differentiated into neurons, received synaptic inputs from regenerating RGC axons, and extended axons along the transected optic nerve to incorporate with the visual system. Conclusions: Human NSCs promote the modest survival and axonal regeneration of axotomized RGCs that is partially mediated by diffusible NSC-derived factors. Additionally, NSCs integrate with the injured optic nerve and have the potential to form neuronal relays to restore retinofugal connections.

Characteristics of Central Visual Field Progression in Eyes with Optic Disc Hemorrhage.

PURPOSE: To investigate the characteristics and rate of central visual field loss after optic disc hemorrhage (DH). DESIGN: Prospective cohort study. METHODS: Three hundred forty-three eyes of 220 subjects who had ≥3 years of follow-up with a minimum of 5 visits with 10-2 and 24-2 visual field (VF) were recruited. Rates of 10-2 mean deviation (MD) loss in each hemifield and predefined zones were compared using linear mixed-effects models in DH and non-DH eyes. Clustered pointwise regression analysis was also used to define central VF progressors and compared with 24-2 VF loss using guided progression analysis. RESULTS: Thirty-nine eyes with DH and 304 eyes without DH had a mean follow-up of 5.2 years. Eyes with DH had rates of 10-2 MD loss that were 3 times faster than non-DH eyes (mean difference -0.36 dB/year [95% confidence interval 0.54-0.18]; P < .001) and were 3.7 times more likely to progress (P = .002). A larger proportion of glaucomatous eyes showed central VF progression rather than peripheral VF progression in the DH group (30.8% vs. 20.5%) compared with the non-DH group (10.9% vs. 9.2%). In early glaucoma, the rate of 10-2 MD loss was 5.5 times faster in DH eyes than in non-DH eyes (P < .001). Superonasal and superotemporal central VF regions progressed more rapidly than other regions, especially in DH eyes. CONCLUSION: Central VF loss is accelerated in glaucoma eyes with DH and it corresponds topographically to the DH location. In patients with glaucoma with DH, one should consider supplementing 10-2 VFs with 24-2 VFS to monitor the disease.

Rates of Retinal Nerve Fiber Layer Thinning in Distinct Glaucomatous Optic Disc Phenotypes in Early Glaucoma.

PURPOSE: To compare spectral-domain optical coherence tomography (SDOCT) measured circumpapillary retinal nerve fiber layer (cpRNFL) among 4 glaucomatous optic disc phenotypes in early glaucoma. DESIGN: Clinical cohort study METHODS: In this study, 218 early glaucoma eyes that had at least 3 years of follow-up and a minimum of 4 SDOCT scans were recruited. The optic discs were classified into 4 types based on appearance: 76 generalized cup enlargement (GE), 53 focal ischemic (FI), 22 myopic glaucomatous (MY), and 67 senile sclerotic (SS). A linear mixed effects model was used to compare the rates of global and regional cpRNFL thinning among optic disc phenotypes. RESULTS: After adjusting for confounders, the SS group (mean [95% CI]: -1.01 [-1.30, -0.73] µm/y) had the fastest mean rate of global cpRNFL thinning followed by FI (-0.77 [-0.97, -0.57] µm/y), MY (0.59 [-0.81, -0.36] µm/y), and GE (-0.58 [-0.75, -0.40] µm/y) at P < .001. The inferior temporal sector had the fastest rate of cpRNFL thinning among the regional measurements except for the MY group (-0.68 [-1.10, -0.26] µm/y, P = .002). In the multivariable analysis, GE (P = .002) and MY (P = .010) phenotypes were associated with significantly slower global rates of cpRNFL thinning compared with the SS phenotype. CONCLUSIONS: Rates of cpRNFL thinning were different among the 4 glaucomatous optic disc phenotypes. Those patients with early glaucoma with SS phenotype have the fastest cpRNFL thinning. These patients may benefit from more frequent monitoring and the need to advance therapy if cpRNFL thinning is detected.

Central Visual Field Defects in Patients with Distinct Glaucomatous Optic Disc Phenotypes.

PURPOSE: To investigate central visual field (VF) defects among 4 phenotypes of glaucomatous optic discs. DESIGN: Cross-sectional study. METHODS: Optic disc phenotypes were determined in eyes with definite or suspected glaucoma that had a 24-2 VF with mean deviation (MD) better than -12 dB and a 10-2 VF. 10-2 VFs were classified as abnormal based on a cluster criterion. Additionally, the average of the total deviation values at each 10-2 test point was compared by optic disc phenotype. RESULTS: The following 4 glaucomatous optic disc phenotypes were identified in 448 eyes of 309 patients: focal ischemic (FI) (n = 121); generalized cup enlargement (GE) (n = 109); myopic glaucoma (MY) (n = 66); and senile sclerotic (SS) (n = 152). Although 24-2 VF MD values were similar among optic disc phenotypes, GE eyes had higher 10-2 VF MD (P = .004), as well as lower 24-2 VF pattern standard deviations (PSD) (P < .001) and VF 10-2 PSD (P < .001) than the other phenotypes. The prevalence of an abnormal VF 10-2 was highest in FI eyes (78.5%) and lowest in GE eyes (50.5%) (P < .001). In glaucoma suspects, the prevalence of an abnormal 10-2 VF was highest in the MY eyes (31.2%) and FI eyes (23.5%) and lowest in GE eyes (8.6%). In mild glaucoma, the prevalence of abnormal 10-2 VF test results was highest in FI eyes (79.2%) and lowest in GE eyes (44.4%) (P = .013). CONCLUSIONS: The severity and prevalence of central VF loss varied among different glaucomatous optic disc phenotypes. Glaucomatous eyes with FI and MY optic disc phenotypes are more likely to have 10-2 VF loss, particularly in early disease, and especially may benefit from testing with both 10-2 and 24-2 VF tests.

Sheath-Preserving Optic Nerve Transection in Rats to Assess Axon Regeneration and Interventions Targeting the Retinal Ganglion Cell Axon.

Retinal ganglion cell (RGC) axons converge at the optic nerve head to convey visual information from the retina to the brain. Pathologies such as glaucoma, trauma, and ischemic optic neuropathies injure RGC axons, disrupt transmission of visual stimuli, and cause vision loss. Animal models simulating RGC axon injury include optic nerve crush and transection paradigms. Each of these models has inherent advantages and disadvantages. An optic nerve crush is generally less severe than a transection and can be used to assay axon regeneration across the lesion site. However, differences in crush force and duration can affect tissue responses, resulting in variable reproducibility and lesion completeness. With optic nerve transection, there is a severe and reproducible injury that completely lesions all axons. However, transecting the optic nerve dramatically alters the blood brain barrier by violating the optic nerve sheath, exposing the optic nerve to the peripheral environment. Moreover, regeneration beyond a transection site cannot be assessed without reapposing the cut nerve ends. Furthermore, distinct degenerative changes and cellular pathways are activated by either a crush or transection injury. The method described here incorporates the advantages of both optic nerve crush and transection models while mitigating the disadvantages. Hydrostatic pressure delivered into the optic nerve by microinjection completely transects the optic nerve while maintaining the integrity of the optic nerve sheath. The transected optic nerve ends are reapposed to allow for axon regeneration assays. A potential limitation of this method is the inability to visualize the complete transection, a potential source of variability. However, visual confirmation that the visible portion of the optic nerve has been transected is indicative of a complete optic nerve transection with 90-95% success. This method could be applied to assess axon regeneration promoting strategies in a transection model or investigate interventions that target the axonal compartments.

Pseudophakic glaucoma and angle closure in a patient with an anterior chamber intraocular lens.

PURPOSE: To report use of ultrasound biomicroscopy (UBM) and anterior segment ocular coherence tomography (AS-OCT) in a case of pseudophakic glaucoma in a patient with an anterior chamber intraocular lens. OBSERVATIONS: UBM and AS-OCT were critical in determining a non-drug related etiology of angle closure. Images indicated anterior obstruction of the pupil secondary to anterior chamber intraocular lens, but also posterior obstruction of the pupil secondary to the anterior hyaloid face. CONCLUSIONS: When evaluating a patient with suspected angle closure, it is important to perform a full ophthalmologic examination, including gonioscopy, as well as a thorough review of past medical history and medications so as not to miss systemic-related etiologies. Imaging with B-scan, UBM, and, more recently in the last decade, AS-OCT is a key component of evaluation of a patient in angle closure, especially one with a complex medical and ocular history.

A Randomized Controlled Trial Comparing Subconjunctival Injection to Direct Scleral Application of Mitomycin C in Trabeculectomy.

PURPOSE: To compare the efficacy of intraoperative scleral application with subconjunctival injection of mitomycin C (MMC) in trabeculectomy. DESIGN: Prospective, randomized, interventional study. METHODS: This study took place in a single clinical practice in an academic setting. Patients had medically uncontrolled glaucoma as indicated by high intraocular pressure (IOP), worsening visual field, or optic nerve head changes in whom primary trabeculectomy was indicated. Patients were older than 18 years with medically uncontrolled glaucoma and no history of incisional glaucoma surgery. Patients were randomized to MMC delivered by preoperative subconjunctival injection or by intraoperative direct scleral application using surgical sponges during trabeculectomy. Comprehensive eye examinations were conducted at 1 day, 1 week, 6 weeks, 3 months, and 6 months postoperatively. Subconjunctival 5-fluorouracil injections were given postoperatively, as needed. The primary outcome was the proportion of patients who demonstrated IOP of <21 mm Hg and ≥30% reduction in IOP from baseline. Secondary outcome measures included the number of IOP-lowering medications, bleb morphology using the Indiana Bleb Appearance Grading Scale, and complication rates. RESULTS: Participants (n = 100) were randomized into groups matched for baseline demographics, glaucoma status, and baseline IOP. At 6 months, there were no significant differences between the injection (n = 38) and sponge (n = 40) groups in surgical success (P = .357), mean IOP (P = .707), number of glaucoma medications (P = 1.000), bleb height (P = .625), bleb extension (P = .216), bleb vascularity (P = .672), or complications rates. CONCLUSION: Both techniques of MMC delivery (subconjunctival injection and direct scleral application) resulted in comparable surgical outcomes and bleb morphologies.

Fluorescein Aqueous Angiography in Live Normal Human Eyes.

PURPOSE: To evaluate aqueous humor outflow (AHO) in intact eyes of live human subjects during cataract surgery using fluorescein aqueous angiography. METHODS: Aqueous angiography was performed in 8 live human subjects (56 to 86 y old; 2 men and 6 women). After anesthesia, fluorescein (2%) was introduced into the eye [either alone or after indocyanine green (ICG; 0.4%)] from a sterile, gravity-driven constant-pressure reservoir. Aqueous angiographic images were obtained with a Spectralis HRA+OCT and FLEX module (Heidelberg Engineering). Using the same device, anterior-segment optical coherence tomography (OCT) and infrared images were also concurrently taken with aqueous angiography. RESULTS: Fluorescein aqueous angiography in the live human eye showed segmental AHO patterns. Initial angiographic signal was seen on average by 14.0±3.0 seconds (mean±SE). Using multimodal imaging, angiographically positive signal colocalized with episcleral veins (infrared imaging) and intrascleral lumens (anterior-segment OCT). Sequential aqueous angiography with ICG followed by fluorescein showed similar segmental angiographic patterns. DISCUSSION: Fluorescein aqueous angiography in live humans was similar to that reported in nonhuman primates and to ICG aqueous angiography in live humans. As segmental patterns with sequential angiography using ICG followed by fluorescein were similar, these tracers can now be used sequentially, before and after trabecular outflow interventions, to assess their effects on AHO in live human subjects.

Atypical chronic central serous chorioretinopathy with cystoid macular edema: Therapeutic response to medical and laser therapy.

PURPOSE: To describe an atypical case of chronic central serous chorioretinopathy (CSCR). METHODS: A 58-year-old man with longstanding, bilateral visual impairment was self-referred for a second opinion. RESULTS: Findings by direct ophthalmoscopy, optical coherence tomography, fluorescein angiography, and fundus autofluorescence (FAF) were suggestive of atypical, chronic CSCR. Treatment with oral anti-mineralocorticoids resulted in moderate improvement, and photodynamic therapy (PDT) had minimal effect. CONCLUSION: Chronic CSCR may lack cardinal features of CSCR. Once retinal degenerative changes ensue, current treatments may not be effective in improving anatomical and visual outcomes in patients with chronic CSCR.

SnoN facilitates axonal regeneration after spinal cord injury.

Adult CNS neurons exhibit a reduced capacity for growth compared to developing neurons, due in part to downregulation of growth-associated genes as development is completed. We tested the hypothesis that SnoN, an embryonically regulated transcription factor that specifies growth of the axonal compartment, can enhance growth in injured adult neurons. In vitro, SnoN overexpression in dissociated adult DRG neuronal cultures significantly enhanced neurite outgrowth. Moreover, TGF-ß1, a negative regulator of SnoN, inhibited neurite outgrowth, and SnoN over-expression overcame this inhibition. We then examined whether SnoN influenced axonal regeneration in vivo: indeed, expression of a mutant form of SnoN resistant to degradation significantly enhanced axonal regeneration following cervical spinal cord injury, despite peri-lesional upregulation of TGF-ß1. Thus, a developmental mechanism that specifies extension of the axonal compartment also promotes axonal regeneration after adult CNS injury.