December 2019

Agrawal R, Agarwal A, Jabs DA, Kee A, Testi I, Mahajan S, McCluskey PJ, Gupta A, Palestine A, Denniston A, Banker A, Invernizzi A, Fonollosa A, Sharma A, Kumar A, Curi A, Okada A, Schlaen A, Heiligenhaus A, Kumar A, Gurbaxani A, Bodaghi B, Islam Shah B, Lowder C, Tappeiner C, Muccioli C, Vasconcelos-Santos DV, Goldstein D, Behra D, Das D, Makhoul D, Baglivo E, Denisova E, Miserocchi E, Carreno E, Asyari F, Pichi F, Sen NH, Uy H, Nascimento H, Tugal-Tutkun I, Arevalo FJ, Davis J, Thorne J, Hisae Yamamoto J, Smith J, Garweg JG, Biswas J, Babu K, Aggarwal K, Cimino L, Kuffova L, Agarwal M, Zierhut M, Agarwal M, DeSmet M, Tognon MS, Errera M-H, Munk M, Westcott M, Soheilian M, Accorinti M, Khairallah M, Nguyen M, Kon OM, Mahendradas P, Yang P, Neri P, Ozdal P, Amer R, Lee R, Distia Nora RL, Chhabra R, Belfort R, Mehta S, Shoughy S, Luthra S, Mohamed SO, Chee S-P, Basu S, Teoh S, Ganesh S, Barisani-Asenbauer T, Guex-Crosier Y, Ozyazgan Y, Akova Y, Habot-Wilner Z, Kempen J, Nguyen QD, Pavesio C, Gupta V, Gupta V. Standardization of Nomenclature for Ocular Tuberculosis - Results of Collaborative Ocular Tuberculosis Study (COTS) Workshop. Ocul Immunol Inflamm 2019;:1-11.Abstract
: To standardize a nomenclature system for defining clinical phenotypes, and outcome measures for reporting clinical and research data in patients with ocular tuberculosis (OTB).: Uveitis experts initially administered and further deliberated the survey in an open meeting to determine and propose the preferred nomenclature for terms related to the OTB, terms describing the clinical phenotypes and treatment and reporting outcomes.: The group of experts reached a consensus on terming uveitis attributable to tuberculosis (TB) as tubercular uveitis. The working group introduced a SUN-compatible nomenclature that also defines disease "remission" and "cure", both of which are relevant for reporting treatment outcomes.: A consensus nomenclature system has been adopted by a large group of international uveitis experts for OTB. The working group recommends the use of standardized nomenclature to prevent ambiguity in communication and to achieve the goal of spreading awareness of this blinding uveitis entity.
Akula JD, Ambrosio L, Howard FI, Hansen RM, Fulton AB. Extracting the ON and OFF contributions to the full-field photopic flash electroretinogram using summed growth curves. Exp Eye Res 2019;189:107827.Abstract
Under cone-mediated (photopic) conditions, an "instantaneous" flash of light, including both stimulus onset and offset, will simultaneously activate both "ON" and "OFF" bipolar cells, which either depolarize (ON) or hyperpolarize (OFF) in response and, respectively, produce positive-going and negative-going deflections in the electroretinogram (ERG). The stimulus-response (SR) relationship of the photopic ON response demonstrates logistic growth, like that manifested in the rod-mediated (scotopic) b-wave, which is driven by a single class of depolarizing bipolar cell. However, the photopic b-wave SR function is importantly shaped by OFF responses, leading to a "photopic hill." Furthermore, both on and off stimuli elicit activity in both ON and OFF bipolar cells. This has made it difficult to produce meaningful parameters for ready interpretation of the photopic b-wave SR relationship. Therefore, we evaluated whether the sum of sigmoidal SR functions, as descriptors of the depolarizing and hyperpolarizing components of the photopic flash ERG, could be used to elucidate and quantitate the mechanisms that produce the photopic hill. We used a novel fitting routine to optimize a sum of simple sigmoidal curves to SR data in five groups of subjects: Healthy adult, 10-week-old infant, congenital stationary night blindness (CSNB), X-linked juvenile retinoschisis (XJR), and preterm-born, both without and with a history of retinopathy of prematurity (ROP). Differences in ON and OFF amplitude, sensitivity, and implicit time among the groups were then compared using parameters extracted from these fits. We found that our modeling procedure enabled plausible derivations of ON and OFF pathway contributions to the ERG, and that the parameters produced appeared to have physiological relevance. In adult subjects, the ON and OFF amplitudes were similar in magnitude with respectively longer and shorter implicit times. Infant, CSNB, and XJR subjects showed significant ON pathway deficits. History of preterm-birth, without or with a diagnosis of ROP, did not much affect cone responses.
Amamoto R, Garcia MD, West ER, Choi J, Lapan SW, Lane EA, Perrimon N, Cepko CL. Probe-Seq enables transcriptional profiling of specific cell types from heterogeneous tissue by RNA-based isolation. Elife 2019;8Abstract
Recent transcriptional profiling technologies are uncovering previously-undefined cell populations and molecular markers at an unprecedented pace. While single cell RNA (scRNA) sequencing is an attractive approach for unbiased transcriptional profiling of all cell types, a complementary method to isolate and sequence specific cell populations from heterogeneous tissue remains challenging. Here, we developed Probe-Seq, which allows deep transcriptional profiling of specific cell types isolated using RNA as the defining feature. Dissociated cells are labeled using fluorescent in situ hybridization (FISH) for RNA, and then isolated by fluorescent activated cell sorting (FACS). We used Probe-Seq to purify and profile specific cell types from mouse, human, and chick retinas, as well as from midguts. Probe-Seq is compatible with frozen nuclei, making cell types within archival tissue immediately accessible. As it can be multiplexed, combinations of markers can be used to create specificity. Multiplexing also allows for the isolation of multiple cell types from one cell preparation. Probe-Seq should enable RNA profiling of specific cell types from any organism.
Aminkhani A, Sharifi R, Dorosti R. Chemical Composition and Antimicrobial Activity of Achillea tenuifolia Lam. Essential Oil at Different Phenological Stages from Khoy. Chem Biodivers 2019;16(12):e1900289.Abstract
Achillea species and in particular Achillea tenuifolia Lam. is generally used as a food flavor and traditional remedies, especially in the initial developmental stage for medical conditions in the Mediterranean part of Iran. In this report, we extracted the essential oil from the aerial parts of A. tenuifolia (collected from Khoy), at various developmental stages (i. e., vegetative, flowering and fruiting), characterized them and studied their antibacterial activities. Of 46, 51 and 38 components found in the vegetative, flowering, and fruiting stages, respectively, 35 were present in all three stages, including oxygenated terpenes such as carvacrol (30.85-34.11), germacrene C (16.21-17.87), spathulenol (7.26-8.96), β-sesquiphellandrene (4.11-4.25), τ-muurolol (2.27-3.25) and α-cadinol (2.01-3.29). We witnessed that the composition of the essential oils varies with phenological stages and geographic regions. The essential oil demonstrated substantial antibacterial properties against both Gram-positive and Gram-negative bacteria, indicated by disk method, Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays. Except Pseudomonas aeruginosa, the essential oils of various phenological stages showed higher antibacterial activity against tested bacteria, with Bacillus anthracis as the most sensitive strain. Moreover, although antibacterial characteristics of the essential oil from the vegetative and flowering stages were similar (p=0.91), they were significantly different from those of fruiting stage (p<0.005 in both MIC and MBC tests). This emphasizes the importance of the developmental stage of the plant in the biological properties of its essential oil and justifies the widespread application of this plant in the vegetative stage.
Aronow ME, Wiley HE, Gaudric A, Krivosic V, Gorin MB, Shields CL, Shields JA, Jonasch EW, Singh AD, Chew EY. VON HIPPEL-LINDAU DISEASE: Update on Pathogenesis and Systemic Aspects. Retina 2019;39(12):2243-2253.Abstract
PURPOSE: To provide an update summarizing the biologic pathways governing von Hippel-Lindau (VHL) disease pathogenesis and to provide an overview of systemic manifestations as well as screening recommendations. METHODS: A PubMed search of the English language literature was reviewed using the following search terms: von Hippel-Lindau, von Hippel-Lindau disease, and VHL. Of 6,696 publications, the most current and pertinent information related to the pathogenesis and systemic aspects of VHL disease were included in this review. RESULTS: von Hippel-Lindau disease is one of the most frequently occurring multisystem familial cancer syndromes. The disease results from germline mutation in the VHL tumor suppressor gene on the short arm of chromosome 3. Mutation in the VHL gene affects multiple cellular processes including transcriptional regulation, extracellular matrix formation, apoptosis, and, in particular, the cellular adaptive response to hypoxia. As a result, there is widespread development of vascular tumors affecting the retina, brain, and spine, as well as a spectrum of benign and malignant tumors and/or cysts in visceral organs. CONCLUSION: The ophthalmologist plays a key role in VHL disease diagnosis, as retinal hemangioblastoma is frequently the first disease manifestation. Screening guidelines for individuals with known VHL disease, and those at risk of VHL disease, help to ensure early detection of potentially vision-threatening and life-threatening disease.
Bakaeva T, Mallery R, Prasad S. Emerging Treatments for Leber's Hereditary Optic Neuropathy and Other Genetic Causes of Visual Loss. Semin Neurol 2019;39(6):732-738.Abstract
Leber's hereditary optic neuropathy (LHON) and other genetic causes of visual loss are important clinical entities that can cause profound visual loss. To date, therapeutic options have been quite limited, but insights into the genetic basis of these diseases and advances in the ability to deliver effective and safe gene therapy have opened the door for new therapeutics that may revolutionize the approach to treating these conditions. This article reviews emerging gene therapies of LHON and other inherited ophthalmological diseases, addressing the technical, clinical, and ethical challenges that researchers and clinicians will encounter as new treatments become available for these conditions.
Brydon EM, Bronstein R, Buskin A, Lako M, Pierce EA, Fernandez-Godino R. AAV-Mediated Gene Augmentation Therapy Restores Critical Functions in Mutant PRPF31 iPSC-Derived RPE Cells. Mol Ther Methods Clin Dev 2019;15:392-402.Abstract
Retinitis pigmentosa (RP) is the most common form of inherited vision loss and is characterized by degeneration of retinal photoreceptor cells and the retinal pigment epithelium (RPE). Mutations in pre-mRNA processing factor 31 () cause dominant RP via haploinsufficiency with incomplete penetrance. There is good evidence that the diverse severity of this disease is a result of differing levels of expression of the wild-type allele among patients. Thus, we hypothesize that -related RP will be amenable to treatment by adeno-associated virus (AAV)-mediated gene augmentation therapy. To test this hypothesis, we used induced pluripotent stem cells (iPSCs) with mutations in and differentiated them into RPE cells. The mutant iPSC-RPE cells recapitulate the cellular phenotype associated with the PRPF31 pathology, including defective cell structure, diminished phagocytic function, defects in ciliogenesis, and compromised barrier function. Treatment of the mutant iPSC-RPE cells with AAV- restored normal phagocytosis and cilia formation, and it partially restored structure and barrier function. These results suggest that AAV-based gene therapy targeting RPE cells holds therapeutic promise for patients with -related RP.
Busch C, Fraser-Bell S, Iglicki M, Lupidi M, Couturier A, Chaikitmongkol V, Giancipoli E, Rodríguez-Valdés PJ, Gabrielle P-H, Laíns I, Santos AR, Cebeci Z, Amphornphruet A, Degenhardt V, Unterlauft J-D, Cagini C, Mané-Tauty V, Ricci GD'A, Hindi I, Agrawal K, Chhablani J, Loewenstein A, Zur D, Rehak M, Rehak M. Real-world outcomes of non-responding diabetic macular edema treated with continued anti-VEGF therapy versus early switch to dexamethasone implant: 2-year results. Acta Diabetol 2019;56(12):1341-1350.Abstract
AIMS: To provide 2-year follow-up data on eyes with diabetic macular edema (DME) that were non-responsive after three initial anti-vascular endothelial growth factor (VEGF) injections, comparing functional and anatomical outcomes under continued anti-VEGF therapy versus dexamethasone (DEX) implant. METHODS: Multicenter, retrospective chart review comparing eyes with treatment-naïve DME and a suboptimal response to a loading phase of anti-VEGF therapy (3 injections given monthly) which were then treated with (a) further anti-VEGF (n = 72) or (b) initially switched to DEX implant (n = 38). Main outcome measures were change in visual acuity (VA) and central subfield thickness (CST) from the end of the loading phase to 24 months. RESULTS: In 79% of the 12-month study population (87/110 eyes), 24-month data were available. One quarter of eyes in each group switched treatments during the second year. Eyes that were switched early to DEX implant maintained the functional and anatomical improvements at 24 months which were seen in the first year (from month 3: + 8.9 letters, - 214 µm). Eyes that were switched from anti-VEGF therapy to steroids in the second year improved VA and reduced CST at 24 months (from month 12: + 6.8 letters, p = 0.023; - 226 µm, p = 0.004). In eyes continued on anti-VEGF therapy, VA and CST were stable at 24 months (from month 3: + 2.8 letters, p = 0.254; - 24 µm, p = 0.243). Eyes that were non-responsive to anti-VEGF therapy for 12 months had similar chances to experience a VA gain from further therapy as eyes that were non-responsive for 3 months only (23.8 vs. 31.0%, p = 0.344). CONCLUSIONS: The beneficial effect of an early switch to DEX implant in DME non-responders seen at month 12 was maintained during the second year. A later switch from anti-VEGF to steroids still provided significant improvement. Eyes continued on anti-VEGF over a period of 24 months maintained vision. A quarter of eyes, which had not improved vision at 12 months, exhibited a delayed response to treatment.
Chekuri A, Zientara-Rytter K, Soto-Hermida A, Borooah S, Voronchikhina M, Biswas P, Kumar V, Goodsell D, Hayward C, Shaw P, Stanton C, Garland D, Subramani S, Ayyagari R. Late-onset retinal degeneration pathology due to mutations in CTRP5 is mediated through HTRA1. Aging Cell 2019;18(6):e13011.Abstract
Late-onset retinal degeneration (L-ORD) is an autosomal dominant macular degeneration characterized by the formation of sub-retinal pigment epithelium (RPE) deposits and neuroretinal atrophy. L-ORD results from mutations in the C1q-tumor necrosis factor-5 protein (CTRP5), encoded by the CTRP5/C1QTNF5 gene. To understand the mechanism underlying L-ORD pathology, we used a human cDNA library yeast two-hybrid screen to identify interacting partners of CTRP5. Additionally, we analyzed the Bruch's membrane/choroid (BM-Ch) from wild-type (Wt), heterozygous S163R Ctrp5 mutation knock-in (Ctrp5 ), and homozygous knock-in (Ctrp5 ) mice using mass spectrometry. Both approaches showed an association between CTRP5 and HTRA1 via its C-terminal PDZ-binding motif, stimulation of the HTRA1 protease activity by CTRP5, and CTRP5 serving as an HTRA1 substrate. The S163R-CTRP5 protein also binds to HTRA1 but is resistant to HTRA1-mediated cleavage. Immunohistochemistry and proteomic analysis showed significant accumulation of CTRP5 and HTRA1 in BM-Ch of Ctrp5 and Ctrp5 mice compared with Wt. Additional extracellular matrix (ECM) components that are HTRA1 substrates also accumulated in these mice. These results implicate HTRA1 and its interaction with CTRP5 in L-ORD pathology.
Chen X, Sullivan BD, Rahimi Darabad R, Liu S, Kam WR, Sullivan DA. Are BALB/c Mice Relevant Models for Understanding Sex-Related Differences in Gene Expression in the Human Meibomian Gland?. Cornea 2019;38(12):1554-1562.Abstract
BACKGROUND: A compelling feature of dry eye disease is that it occurs predominantly in women. We hypothesize that this female prevalence is linked to sex-related differences in the meibomian gland (MG). This gland plays a critical role in maintaining the tear film, and its dysfunction is a major cause of dry eye disease. To understand the factors that underlie MG sexual dimorphism and promote dry eye in women, we seek to identify an optimal model for the human MG. Our goal was to determine whether a murine MG is such a model. Toward that end, we examined whether sex differences in MG gene expression are the same in BALB/c mice and humans. METHODS: Eyelid tissues were collected from humans (n = 5-7/sex) and BALB/c mice (n = 9/sex). MGs were isolated and processed for the evaluation of gene expression by using microarrays and bioinformatics software. RESULTS: Our analysis of the 500 most highly expressed genes from human and mouse MGs showed that only 24.4% were the same. Our comparison of 100 genes with the greatest sex-associated differences in human and mouse MGs demonstrated that none were the same. Sex also exerted a significant impact on numerous ontologies, Kyoto Encyclopedia of Genes and Genomes pathways, and chromosomes, but these effects were primarily species-specific. CONCLUSIONS: Our results indicate that BALB/c mice are not optimal models for understanding sex-related differences in gene expression of the human MG.
Chen E, Parikh R. Re: Gong et al.: Comparison of United States and international ophthalmic drug pricing (Ophthalmology. 2019;126:1358-1365. Ophthalmology 2019;126(12):e94-e95.
Deng SX, Borderie V, Chan CC, Dana R, Figueiredo FC, Gomes JAP, Pellegrini G, Shimmura S, Kruse FE. Reply. Cornea 2019;38(12):e56-e57.
Dohlman TH, Lertsuwanroj B, D'Amico DJ, Ciralsky JB, Kiss S. Evaluation of signs and symptoms of ocular surface disease after intravitreal injection. Acta Ophthalmol 2019;97(8):e1154-e1156.
Elhusseiny AM, Huynh EM, Dagi LR. Evaluation and Management of V pattern Strabismus in Craniosynostosis. J Binocul Vis Ocul Motil 2019;:1-6.Abstract
V pattern strabismus is the most common ocular motor disorder reported in patients with craniosynostosis. Strabismus management may prove challenging, and few studies provide perspective on surgical approach. The purpose of this review is to discuss evaluation and surgical options for treating V pattern strabismus in patients with craniosynostosis. We provide a step-by-step approach to facilitate surgical planning.
Espinosa-Medina I, Garcia-Marques J, Cepko C, Lee T. High-throughput dense reconstruction of cell lineages. Open Biol 2019;9(12):190229.Abstract
The first meeting exclusively dedicated to the 'High-throughput dense reconstruction of cell lineages' took place at Janelia Research Campus (Howard Hughes Medical Institute) from 14 to 18 April 2019. Organized by Tzumin Lee, Connie Cepko, Jorge Garcia-Marques and Isabel Espinosa-Medina, this meeting echoed the recent eruption of new tools that allow the reconstruction of lineages based on the phylogenetic analysis of DNA mutations induced during development. Combined with single-cell RNA sequencing, these tools promise to solve the lineage of complex model organisms at single-cell resolution. Here, we compile the conference consensus on the technological and computational challenges emerging from the use of the new strategies, as well as potential solutions.
Frints SGM, Hennig F, Colombo R, Jacquemont S, Terhal P, Zimmerman HH, Hunt D, Mendelsohn BA, Kordaß U, Webster R, Sinnema M, Abdul-Rahman O, Suckow V, Fernández-Jaén A, van Roozendaal K, Stevens SJC, Macville MVE, Al-Nasiry S, van Gassen K, Utzig N, Koudijs SM, McGregor L, Maas SM, Baralle D, Dixit A, Wieacker P, Lee M, Lee AS, Engle EC, Houge G, Gradek GA, Douglas AGL, Longman C, Joss S, Velasco D, Hennekam RC, Hirata H, Kalscheuer VM. Deleterious de novo variants of X-linked ZC4H2 in females cause a variable phenotype with neurogenic arthrogryposis multiplex congenita. Hum Mutat 2019;40(12):2270-2285.Abstract
Pathogenic variants in the X-linked gene ZC4H2, which encodes a zinc-finger protein, cause an infrequently described syndromic form of arthrogryposis multiplex congenita (AMC) with central and peripheral nervous system involvement. We present genetic and detailed phenotypic information on 23 newly identified families and simplex cases that include 19 affected females from 18 families and 14 affected males from nine families. Of note, the 15 females with deleterious de novo ZC4H2 variants presented with phenotypes ranging from mild to severe, and their clinical features overlapped with those seen in affected males. By contrast, of the nine carrier females with inherited ZC4H2 missense variants that were deleterious in affected male relatives, four were symptomatic. We also compared clinical phenotypes with previously published cases of both sexes and provide an overview on 48 males and 57 females from 42 families. The spectrum of ZC4H2 defects comprises novel and recurrent mostly inherited missense variants in affected males, and de novo splicing, frameshift, nonsense, and partial ZC4H2 deletions in affected females. Pathogenicity of two newly identified missense variants was further supported by studies in zebrafish. We propose ZC4H2 as a good candidate for early genetic testing of males and females with a clinical suspicion of fetal hypo-/akinesia and/or (neurogenic) AMC.
Gaier ED, Heidary G. Pediatric Idiopathic Intracranial Hypertension. Semin Neurol 2019;39(6):704-710.Abstract
The presentation of idiopathic intracranial hypertension (IIH) in pediatric populations has several important distinctions from that in adults, especially among prepubertal patients, in which there is no apparent association with gender or obesity. Pediatric patients are more likely to be asymptomatic or present with atypical symptoms than their adult counterparts, posing a diagnostic challenge in some cases. It is important to be aware of the ways in which diagnostic criteria for IIH are modified from that of adults. Ideal treatment practices and the natural history of pediatric IIH remain unclear. Acetazolamide is the mainstay of medical treatment, but some patients with significant visual loss may require surgical intervention. Multicenter studies to accrue a large number of cases and future prospective studies will help to better define pediatric IIH and to formulate consensus guidelines for treatment and management of these patients.
Gangaputra SS, Newcomb CW, Joffe MM, Dreger K, Begum H, Artornsombudh P, Pujari SS, Daniel E, Sen NH, Suhler EB, Thorne JE, Bhatt NP, Foster SC, Jabs DA, Nussenblatt RB, Rosenbaum JT, Levy-Clarke GA, Kempen JH, Kempen JH. Comparison Between Methotrexate and Mycophenolate Mofetil Monotherapy for the Control of Noninfectious Ocular Inflammatory Diseases. Am J Ophthalmol 2019;208:68-75.Abstract
PURPOSE: To compare mycophenolate mofetil (MMF) to methotrexate (MTX) as corticosteroid-sparing therapy for ocular inflammatory diseases. DESIGN: Retrospective analysis of cohort study data. METHODS: Participants were identified from the Systemic Immunosuppressive Therapy for Eye Diseases Cohort Study. Demographic and clinical characteristics were obtained via medical record review. The study included 352 patients who were taking single-agent immunosuppression with MTX or MMF at 4 tertiary uveitis clinics. Marginal structural models (MSM)-derived statistical weighting created a virtual population with covariates and censoring patterns balanced across alternative treatments. With this methodological approach, the results estimate what would have happened had none of the patients stopped their treatment. Survival analysis with stabilized MSM-derived weights simulated a clinical trial comparing MMF vs MTX for noninfectious inflammatory eye disorders. The primary outcome was complete control of inflammation on prednisone ≤10 mg/day, sustained for ≥30 days. RESULTS: The time to success was shorter (more favorable) for MMF than MTX (hazard ratio = 0.68, 95% confidence interval: 0.46-0.99). Adjusting for covariates, the proportion achieving success was higher at every point in time for MMF than MTX from 2 to 8 months, then converges at 9 months. The onset of corticosteroid-sparing success took more than 3 months for most patients in both groups. Outcomes of treatment (MMF vs MTX) were similar across all anatomic sites of inflammation. The incidence of stopping therapy for toxicity was similar in both groups. CONCLUSIONS: Our results suggest that, on average, MMF may be faster than MTX in achieving corticosteroid-sparing success in ocular inflammatory diseases.
Ing EB, Miller NR, Ten Hove M, Torun N. Diplopia and Giant Cell Arteritis. J Neuroophthalmol 2019;39(4):546-547.
Jonas RA, Ung L, Rajaiya J, Chodosh J. Mystery Eye: Human Adenovirus and the Enigma of Epidemic Keratoconjunctivitis. Prog Retin Eye Res 2019;:100826.Abstract
Known to occur in widespread outbreaks, epidemic keratoconjunctivitis (EKC) is a severe ocular surface infection with a strong historical association with human adenovirus (HAdV). While the conjunctival manifestations can vary from mild follicular conjunctivitis to hyper-acute, exudative conjunctivitis with formation of conjunctival membranes, EKC is distinct as the only form of adenovirus conjunctivitis in which the cornea is also involved, likely due to specific corneal epithelial tropism of its causative viral agents. The initial development of a punctate or geographic epithelial keratitis may herald the later formation of stromal keratitis, and manifest as subepithelial infiltrates which often persist or recur for months to years after the acute infection has resolved. The chronic keratitis in EKC is associated with foreign body sensation, photophobia, glare, and reduced vision. However, over a century since the first clinical descriptions of EKC, and over 60 years since the first causative agent, human adenovirus type 8, was identified, our understanding of this disorder remains limited. This is underscored by a current lack of effective diagnostic tools and treatments. In part, stasis in our knowledge base has been encouraged by the continued acceptance, and indeed propagation of, inaccurate paradigms pertaining to disease etiology and pathogenesis, particularly with regard to mechanisms of innate and adaptive immunity within the cornea. Owing to its often persistent and medically refractory visual sequelae, reconsideration of key aspects of EKC disease biology is warranted to identify new treatment targets to curb its worldwide socioeconomic burden.