Publications

2022

The optic nerve, like most pathways in the mature central nervous system, cannot regenerate if injured, and within days, retinal ganglion cells (RGCs), the neurons that extend axons through the optic nerve, begin to die. Thus, there are few clinical options to improve vision after traumatic or ischemic optic nerve injury or in neurodegenerative diseases such as glaucoma, dominant optic neuropathy, or optic pathway gliomas. Research over the past two decades has identified several strategies to enable RGCs to regenerate axons the entire length of the optic nerve, in some cases leading to modest reinnervation of di- and mesencephalic visual relay centers. This review primarily focuses on the role of the innate immune system in improving RGC survival and axon regeneration, and its synergy with manipulations of signal transduction pathways, transcription factors, and cell-extrinsic suppressors of axon growth. Research in this field provides hope that clinically effective strategies to improve vision in patients with currently untreatable losses could become a reality in 5-10 years.
Lennikov A, Yang M, Chang K, Pan L, Saddala MS, Lee C, Ashok A, Cho KS, Utheim TP, Chen DF. Direct modulation of microglial function by electrical field. Front Cell Dev Biol. 2022;10:980775.
Non-invasive electric stimulation (ES) employing a low-intensity electric current presents a potential therapeutic modality that can be applied for treating retinal and brain neurodegenerative disorders. As neurons are known to respond directly to ES, the effects of ES on glia cells are poorly studied. A key question is if ES directly mediates microglial function or modulates their activity merely via neuron-glial signaling. Here, we demonstrated the direct effects of ES on microglia in the BV-2 cells-an immortalized murine microglial cell line. The low current ES in a biphasic ramp waveform, but not that of rectangular or sine waveforms, significantly suppressed the motility and migration of BV-2 microglia in culture without causing cytotoxicity. This was associated with diminished cytoskeleton reorganization and microvilli formation in BV-2 cultures, as demonstrated by immunostaining of cytoskeletal proteins, F-actin and β-tubulin, and scanning electron microscopy. Moreover, ES of a ramp waveform reduced microglial phagocytosis of fluorescent zymosan particles and suppressed lipopolysaccharide (LPS)-induced pro-inflammatory cytokine expression in BV-2 cells as shown by Proteome Profiler Mouse Cytokine Array. The results of quantitative PCR and immunostaining for cyclooxygenase-2, Interleukin 6, and Tumor Necrosis Factor-α corroborated the direct suppression of LPS-induced microglial responses by a ramp ES. Transcriptome profiling further demonstrated that ramp ES effectively suppressed nearly half of the LPS-induced genes, primarily relating to cellular motility, energy metabolism, and calcium signaling. Our results reveal a direct modulatory effect of ES on previously thought electrically "non-responsive" microglia and suggest a new avenue of employing ES for anti-inflammatory therapy.
The COVID-19 pandemic necessitated a virtual annual meeting of the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) in 2021, thus eliminating carbon emissions from travel to and from the planned meeting venue in Boston, Massachusetts. We found that the reduced carbon footprint of the virtual meeting saved 1,282 metric tonnes of CO2 emissions compared with estimated CO2 emissions for travel if the meeting had taken place in person, or 880 metric tonnes relative to the projected emissions associated with the in-person 2022 annual meeting in Scottsdale, Arizona. An entirely virtual or hybrid AAPOS meeting would reduce its environmental footprint and increase the opportunity for national and international participation and education.
Marmamula S, Barrenkala NR, Kumbham TR, Modepalli SB, Yellapragada R, Khanna R, Friedman D. Impact of an intervention for avoidable vision loss on visual function in the elderly-The Hyderabad Ocular Morbidity in Elderly Study (HOMES). Eye (Lond). 2022;
BACKGROUND/OBJECTIVES: To report the impact of interventions for avoidable vision impairment (VI) on the visual function of elderly residents in 'homes for the aged' in India. METHODS: Participants aged ≥60 years were recruited. A comprehensive eye examination was conducted by trained examiners and interventions were provided. Trained social investigators administered the Indian Vision Function questionnaire (INDVFQ) to assess visual function before and after the intervention (spectacles, cataract surgery or laser capsulotomy). Lower scores on IVFQ imply better visual function. VI was defined as presenting visual acuity worse than 6/18 in the better eye. VI due to cataract, uncorrected refractive errors, and posterior capsular opacification after cataract surgery were considered avoidable VI. RESULTS: The mean age of the participants (n = 613) was 73.8 years (standard deviation: 8.1 years) and 378 (62.2%) were women. 64/103 (62.1%) participants who had avoidable VI at baseline were evaluated after the intervention. Significant gains were observed in all four domains of visual function. There was a 14.9% improvement in mobility scores (33.8 versus 28.8; p = 0.03), a 19.9% improvement in the activity limitations score (36.8 versus 29.5; p < 0.01), a 10.9% improvement in the psychosocial impact score (41.1 versus 36.6; p < 0.01) and a 13.6% improvement in the visual symptoms score (49.2 versus 42.5 p < 0.01). Overall, the mean IVFQ score improved by 16.4% (47.6 versus 39.8; p < 0.01). CONCLUSION: Elderly individuals in residential care with avoidable VI had a significant improvement in visual function after relatively low-cost interventions such as spectacles and cataract surgery. Strategies are needed to provide these interventions for the elderly in 'homes for the aged' in India.
Hoogsteen K, Szpiro S, Kreiman G, Peli E. Beyond the Cane: Describing Urban Scenes to Blind People for Mobility Tasks. ACM Trans Access Comput. 2022;15(3).
Blind people face difficulties with independent mobility, impacting employment prospects, social inclusion, and quality of life. Given the advancements in computer vision, with more efficient and effective automated information extraction from visual scenes, it is important to determine what information is worth conveying to blind travelers, especially since people have a limited capacity to receive and process sensory information. We aimed to investigate which objects in a street scene are useful to describe and how those objects should be described. Thirteen cane-using participants, five of whom were early blind, took part in two urban walking experiments. In the first experiment, participants were asked to voice their information needs in the form of questions to the experimenter. In the second experiment, participants were asked to score scene descriptions and navigation instructions, provided by the experimenter, in terms of their usefulness. The descriptions included a variety of objects with various annotations per object. Additionally, we asked participants to rank order the objects and the different descriptions per object in terms of priority and explain why the provided information is or is not useful to them. The results reveal differences between early and late blind participants. Late blind participants requested information more frequently and prioritized information about objects' locations. Our results illustrate how different factors, such as the level of detail, relative position, and what type of information is provided when describing an object, affected the usefulness of scene descriptions. Participants explained how they (indirectly) used information, but they were frequently unable to explain their ratings. The results distinguish between various types of travel information, underscore the importance of featuring these types at multiple levels of abstraction, and highlight gaps in current understanding of travel information needs. Elucidating the information needs of blind travelers is critical for the development of more useful assistive technologies.
Botten N, Hodges R, Bair J, Utheim T, Serhan C, Yang M, Dartt DA. Resolvin D2 uses multiple Ca2+ -dependent signaling pathways to stimulate mucin secretion in rat and human conjunctival goblet cells. J Cell Physiol. 2022;237(10):3816–3833.
The mucin layer of the tear film is produced by goblet cells in the conjunctiva to protect the ocular surface and maintain homeostasis. The pro-resolving lipid mediator resolvin D2 (RvD2) biosynthesized from an omega 3 fatty acid actively terminates inflammation and regulates mucin secretion from conjunctival goblet cells. Our objective was to determine which Ca2+ -dependent signaling pathways RvD2 uses to stimulate conjunctival goblet cell function (CGC). We hypothesize that RvD2 activates multiple intracellular Ca2+ signaling pathways to stimulate CGC secretion. Rat and human CGCs were cultured from conjunctival explants. The amount of RvD2 receptor GPR18/DRV2 message and protein were determined. The intracellular concentration of Ca2+ ([Ca2+ ]i ) was measured in CGCs using a fluorescent Ca2+ dye and mucin secretion was determined by measuring protein secretion enzymatically with a lectin. Goblet cells were incubated with signaling pathway inhibitors before stimulation with RvD2 and [Ca2+ ]i or secretion was measured. In rat and human CGCs RvD2 receptor and in rat CGCs IP3 (a molecule that releases Ca2+ from intracellular organelles) receptors 1-3 were detected. In both species of CGC RvD2 increased [Ca2+ ]i similarly to RvD1. In rat CGCs, the increase in [Ca2+ ]i and secretion stimulated by RvD2 was significantly blocked by inhibitors to phospholipase (PL-) C and IP3 -receptor, but not protein kinase C. Increase in [Ca2+ ]i was blocked by the PLD inhibitor, but not the PLA2 inhibitor. Secretion was blocked by PLA2 inhibitor, but not the PLD inhibitor. An inhibitor of the epidermal growth factor receptor blocked the increase in [Ca2+ ]i by RvD2 in both species of CGCs. In CGCs RvD2 activates multiple intracellular signaling pathways that are Ca2+ -dependent, along with one Ca2+ -independent and one cAMP/protein kinase A-dependent pathway. Activation of these pathways stimulate mucin secretion from rat and human CGCs into the tear film contributing to ocular surface homeostasis and health.
Vingopoulos F, Kasetty M, Garg I, Silverman R, Katz R, Vasan R, Lorch A, Luo Z, Miller J. Active Learning to Characterize the Full Contrast Sensitivity Function in Cataracts. Clin Ophthalmol. 2022;16:3109–3118.
Background: To characterize contrast sensitivity function (CSF) in cataractous and pseudophakic eyes compared to healthy control eyes using a novel quantitative CSF test with active learning algorithms. Methods: This is a prospective observational study at an academic medical center. CSF was measured in eyes with visually significant cataract, at least 2+ nuclear sclerosis (NS) and visual acuity (VA) ≥ 20/50, in pseudophakic eyes and in healthy controls with no more than 1+ NS and no visual complaints, using the Manifold Contrast Vision Meter. Outcomes included Area under the Log CSF (AULCSF) and CS thresholds at 1, 1.5, 3, 6, 12, and 18 cycles per degree (cpd). A subgroup analysis as performed on cataract eyes with VA ≥ 20/25. Results: A total of 167 eyes were included, 58 eyes in the cataract group, 77 controls, and 32 pseudophakic eyes with respective median AULCSF of 1.053 (0.352) vs 1.228 (0.318) vs 1.256 (0.360). In our multivariate regression model, cataract was associated with significantly reduced AULCSF (P= 0.04, β= -0.11) and contrast threshold at 6 cpd (P= 0.01, β= -0.16) compared to controls. Contrast threshold at 6 cpd was significantly reduced even in the subgroup of cataractous eyes with VA ≥ 20/25 (P=0.02, β=-0.16). Conclusion: The novel qCSF test detected disproportionate significant contrast deficits at 6 cpd in cataract eyes; this remained significant even in the cataractous eyes with VA ≥ 20/25. CSF testing may enhance cataract evaluation and surgical decision-making, particularly in patients with subjective visual complaints despite good VA.
Maleki A, Fernandez C, Philip A, Manhapra A, Chang P, Foster S. Acute macular neuroretinopathy in a patient with birdshot chorioretinopathy after intravitreal triamcinolone suspension injection. Eur J Ophthalmol. 2022;:11206721221124653.
PURPOSE: To report a case of acute macular neuroretinopathy (AMN) after intravitreal triamcinolone acetonide (TRIESENCE®) injection for cystoid macular edema secondary to birdshot chorioretinopathy. METHOD: A case report. PATIENT: A 62-year-old female. RESULTS: The patient presented with acutely decreased vision and a ring scotoma around her central vision three days after intravitreal triamcinolone acetonide (TRIESENCE®) injection for cystoid macular edema in her right eye (OD) secondary to birdshot chorioretinopathy. She had undergone pars plana vitrectomy, cataract extraction, and secondary intraocular lens implantation OD three months prior to the recent injection. Best-corrected visual acuity (BCVA) was 20/1000 OD and 20/50 OS. Intraocular pressure was 21 mmHg OD and 12 mmHg OS. Fluorescein angiography demonstrated a hypofluorescent area in the perifoveal zone OD. Optical coherence tomography OD depicted hyperreflective areas in the outer nuclear layer, outer plexiform layer, and retinal pigment epithelium. We diagnosed her with AMN OD and started her on brimonidine three times a day OD. She came back a week later with resolved scotoma and her vision improved to 20/60 OD. Five weeks later, BCVA was 20/40 and Intraocular pressures (IOP) was 12 mmHg OD. CONCLUSIONS AND IMPORTANCE: Intravitreal triamcinolone injection may be a cause of AMN with cystoid macular edema (CME) and borderline-high intraocular pressure. Brimonidine may be an effective treatment for these patients in the early course of the disease.
Zeng R, Vingopoulos F, Wang M, Bannerman A, Wescott H, Baldwin G, Katz R, Koch T, Elze T, Kim L, Vavvas D, Husain D, Miller J. Structure-function association between contrast sensitivity and retinal thickness (total, regional, and individual retinal layer) in patients with idiopathic epiretinal membrane. Graefes Arch Clin Exp Ophthalmol. 2022;
PURPOSE: To investigate structure-function associations between retinal thickness, visual acuity (VA), and contrast sensitivity (CS), using the quantitative contrast sensitivity function (qCSF) method in patients with idiopathic epiretinal membrane (ERM). METHODS: Retrospective, cross-sectional observational study. Patients with a diagnosis of idiopathic ERM were included. Patients underwent complete ophthalmic examination, spectral-domain optical coherence tomography imaging (SD-OCT) (SPECTRALIS® Heidelberg), and CS testing using the qCSF method. Outcomes included area under the log CSF (AULCSF), contrast acuity (CA), and CS thresholds at 1, 1.5, 3, 6, 12, and 18 cycles per degree (cpd). RESULTS: A total of 102 eyes of 79 patients were included. Comparing standardized regression coefficients, retinal thickness in most ETDRS sectors was associated with larger reductions in AULCSF, CA, and CS thresholds at 3 and 6 cpd than those in logMAR VA. These differences in effect on VA and CS metrics were more pronounced in the central subfield and inner ETDRS sectors. Among the retinal layers, increased INL thickness had the most detrimental effect on visual function, being significantly associated with reductions in logMAR VA, AULCSF, CA, and CS thresholds at 3 and 6 cpd (all p < .01), as well as at 1.5 and 12 cpd (p < .05). CONCLUSION: Retinal thickness seems to be associated with larger reductions in contrast sensitivity than VA in patients with ERM. Measured with the qCSF method, contrast sensitivity may serve as a valuable adjunct visual function metric for patients with ERM.
Guzman Aparicio M, Liebman D, Chodosh J, Freitag S, Kazlas M, Mai D, Marando C, Mukai S, Wu A, Chen T. Two pediatric cases of reticular corneal epithelial edema associated with netarsudil. Am J Ophthalmol Case Rep. 2022;27:101638.
Purpose: To report two pediatric cases of reticular corneal epithelial edema associated with the use of netarsudil ophthalmic solution 0.02%. Observations: In Case 1, a six-year-old male with glaucoma following cataract surgery was treated with netarsudil for thirteen months and developed diffuse reticular corneal epithelial edema on post-operative day one after undergoing transscleral diode cyclophotocoagulation for persistently elevated intraocular pressures. In Case 2, a three-month-old male with bilateral ocular hypertension developed unilateral inferior reticular corneal epithelial edema five weeks after initiation of netarsudil, which had been discontinued in the fellow eye two weeks prior. In both cases, the reticular epithelial edema resolved following cessation of netarsudil. Conclusions and Importance: Netarsudil-associated reticular corneal epithelial edema can occur in infants and young children.