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in category ophthalmology

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1: Ocular manifestations and clinical characteristics of 534 cases of COVID-19 in China: A cross-sectional study
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Posted 16 Mar 2020

Ocular manifestations and clinical characteristics of 534 cases of COVID-19 in China: A cross-sectional study
7,108 downloads medRxiv ophthalmology

Liwen Chen, Chaohua Deng, Xuhui Chen, Xian Zhang, Bo Chen, Huimin Yu, Yuanjun Qin, Ke Xiao, Hong Zhang, Xufang Sun

ObjectiveThe novel coronavirus disease (COVID-19) was first reported in Wuhan, China in December 2019 and is now pandemic all over the world. Previous study has reported several COVID-19 cases with conjunctivitis. However, the complete profiling of COVID-19 related ocular symptoms and diseases are still missing. We aim to investigate the ocular manifestations and clinical characteristics of COVID-19 patients. MethodsA total of five hundred and thirty-four patients were recruited at Mobile Cabin Hospital and Tongji Hospital. We collected information on demographic characteristics, exposure history, ocular symptoms, systemic concomitant symptoms, eye drop medication, eye protections, radiologic findings, and SARS-CoV-2 detection in nasopharyngeal swabs by RT-PCR from questionnaires and electronic medical records. ResultsThe median age of patients was 40 and 50 years at Mobile Cabin Hospital and Tongji Hospital, respectively. Of 534 COVID-19 patients, 25 patients (4.68%) presented with conjunctival congestion and 3 patients had conjunctival congestion as the initial symptom. The average duration of conjunctival congestion was 4.9 {+/-} 2.6 days (mean [SD]), ranging from 2 to 10 days. Dry eye (112, 20.97%), blurred vision (68, 12.73%), and foreign body sensation (63, 11.80%) ranked as the top three COVID-19 related ocular symptoms. Notably, a total of 332 COVID-19 patients (62%) had a hand-eye contact history. We also found that some COVID-19 patients had a history of eye disease, including conjunctivitis (33, 6.18%), dry eye (24, 4.49%), keratitis (14, 2.62%), cataract (9, 1.69%), and diabetic retinopathy (5, 0.94%). In consistent with previous studies, the most common clinical symptoms were fever, cough, and fatigue. Patients, 60.5% in Mobile Cabin Hospital and 67.5% in Tongji Hospital, respectively were confirmed with positive SARS-CoV-2 detection. ConclusionsConjunctival congestion was one of the COVID-19 related ocular symptoms, which may have clinical diagnostic significance. It is essential to provide eye-care equipment and strengthen education on eye protection, as dirty hand-eye contact might be a high risk factor of COVID-19. Further detailed and comprehensive ophthalmological guidance is needed for COVID-19 control.

2: Ophthalmologic evidence against the interpersonal transmission of 2019 novel coronavirus through conjunctiva
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Posted 12 Feb 2020

Ophthalmologic evidence against the interpersonal transmission of 2019 novel coronavirus through conjunctiva
5,262 downloads medRxiv ophthalmology

Yunyun Zhou, Yuyang Zeng, Yongqing Tong, Changzheng Chen

BackgroundThe emerging 2019 novel coronavirus (2019-nCoV) has pushed several countries into state of emergency all over the world. The possible transmission of 2019-nCoV by conjunctiva is controversial and has substantial public health implications. MethodsA retrospective cohort study was initiated to investigate the possible transmission of 2019-nCoV through aerosol contact with conjunctiva. We enrolled 67 cases of confirmed or suspected cases of novel coronavirus pneumonia (NCP) during 17-28 Jan 2020. Nasopharyngeal and conjunctival swabs were collected for real time RT-PCR analysis to detect 2019-nCoV. Results63 patients were identified as laboratory-confirmed NCP and the remaining four were suspected NCP. Conjunctival swab samples from one NCP patient yielded positive PCR results and two NCP patients yielded probable positive PCR results. None of the three patients had ocular symptoms. The only one NCP patient with conjunctivitis as the first symptom had negative conjunctival sac 2019-nCoV test. Conjunctival swab samples from the four suspected cases of NCIP were negative. Conclusion2019-nCoV can be detected in the conjunctival sac of patients with NCP. Through clinical analysis, viral transmission via the conjunctival route was not supported by the data. Good clinical protection can effectively cut off the transmission path.

3: Prevalence of SARS-CoV-2 in human post-mortem ocular tissues
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Posted 06 Oct 2020

Prevalence of SARS-CoV-2 in human post-mortem ocular tissues
4,637 downloads medRxiv ophthalmology

Onkar B. Sawant, Sneha Singh, Robert Emery Wright, Kayla M. Jones, Michael S. Titus, Eugene Dennis, Eric Hicks, Parag A. Majmudar, Ashok Kumar, Shahzad I. Mian

BackgroundSARS-CoV-2 is found in conjunctival swabs and tears of COVID-19 patients. However, the presence of SARS-CoV-2 has not been detected in the human eye to date. We undertook this study to analyze the prevalence of SARS-CoV-2 in human post-mortem ocular tissues. MethodsThe expression of SARS-CoV-2 RNA was assessed by RT-PCR in corneal and scleral tissues from 33 surgical-intended donors who were eliminated from a surgical use per Eye Bank Association of America (EBAA) donor screening guidelines or medical director review or positive COVID-19 test. Ocular levels of SARS-CoV-2 RNA (RT-PCR), Envelope and Spike proteins (immunohistochemistry) and anti-SARS-CoV-2 IgG and IgM antibodies (ELISA) in blood were evaluated in 10 COVID-19 donors. FindingsOf 132 ocular tissues from 33 surgical-intended donors, the positivity rate for SARS-CoV-2 RNA was [~]13% (17/132). Of 10 COVID-19 donors, six had PCR positive post-mortem nasopharyngeal swabs whereas eight exhibited positive post-mortem anti-SARS-CoV-2 IgG levels. Among 20 eyes recovered from 10 COVID-19 donors: three conjunctival, one anterior corneal, five posterior corneal, and three vitreous swabs tested positive for SARS-CoV-2 RNA. SARS-CoV-2 spike and envelope proteins were detected in epithelial layer of the corneas that were procured without Povidone-Iodine (PVP-I) disinfection. InterpretationsOur study showed a small but noteworthy prevalence of SARS-CoV-2 in ocular tissues from COVID-19 donors. These findings underscore the criticality of donor screening guidelines, post-mortem nasopharyngeal PCR testing and PVP-I disinfection protocol to eliminate any tissue harboring SARS-CoV-2 being used for corneal transplantation. FundingResearch grant from EBAA and National Institutes of Health.

4: Improvement in Inner Retinal Function in Glaucoma in Response to Nicotinamide (Vitamin B3 Supplementation: A Crossover Randomized Clinical Trial
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Posted 29 Jan 2020

Improvement in Inner Retinal Function in Glaucoma in Response to Nicotinamide (Vitamin B3 Supplementation: A Crossover Randomized Clinical Trial
2,147 downloads medRxiv ophthalmology

Flora Hui, Jessica Tang, Pete A Williams, Myra B McGuinness, Xavier Hadoux, Robert J Casson, Michael Coote, Ian A Trounce, Keith R Martin, Peter van Wijngaarden, Jonathan G Crowston

ImportanceRetinal ganglion cells endure significant metabolic stress with ageing and glaucoma-related stressors. Injured cells require increased energy for repair but maintain capacity to recover function despite periods of functional loss. Nicotinamide, a precursor of redox co-factor and metabolite, NAD+, is low in serum of patients with primary open-angle glaucoma and its supplementation provides robust protection of retinal ganglion cells by targeting mitochondrial health in glaucoma models. However, the potential of nicotinamide to improve retinal ganglion cell function in humans with glaucoma is yet unknown. ObjectiveTo determine whether nicotinamide supplementation taken in conjunction with conventional IOP-lowering therapy leads to early improvement in retinal ganglion cell function in people with glaucoma. DesignCrossover, double-masked, randomized clinical trial conducted between October 2017 to January 2019. SettingStudy participants recruited from two tertiary care centers in Melbourne, Australia. ParticipantsAdults diagnosed and treated for primary glaucoma. Ninety-four participants assessed for study eligibility. InterventionParticipants randomized to first receive oral placebo or nicotinamide and reviewed six-weekly. Accelerated dosing method utilized; participants commenced 6-week course of 1.5 grams/day followed by 6 weeks of 3.0 grams/day. After 12 weeks, participants crossed over to other intervention for 12 weeks without washout. At each visit, visual function measured using full-field flash electroretinography and white-on-white perimetry. Main outcome measuresPrimary endpoint was change in inner retinal function determined a-priori as change in photopic negative response (PhNR) parameters: saturated PhNR amplitude (Vmax), ratio of PhNR/b-wave amplitude (Vmax ratio). ResultsFifty-seven participants (65.5{+/-}10.0 years, 39% female) enrolled. PhNR Vmax improved beyond 95% coefficient of repeatability (COR) in 23% of participants following 12 weeks of nicotinamide versus 9% on placebo. Conversely, PhNR Vmax deteriorated in 9% on placebo and 7% on nicotinamide. Overall, Vmax improved by 14.8% [95% CI: 2.8%, 26.9%], (p=0.02) on nicotinamide and 5.2% [-4.2%, 14.6%], (p=0.27) on placebo. Vmax ratio improved on average by 12.6% [5.0%, 20.2%], (p=0.002) following nicotinamide and 3.6% [-3.4%, 10.5%], (p=0.30) on placebo. A concomitant trend for improved visual field mean deviation was observed with 27% improving [≥]1dB on nicotinamide and fewer deteriorating [≥]1dB (4%) compared to placebo (p=0.02). Moderate correlation was observed between PhNR and visual field change with treatment. Participants demonstrated excellent treatment adherence rates (>94%) and nicotinamide was well tolerated with minimal side effects. Conclusions and RelevanceNicotinamide supplementation can improve inner retinal function in patients receiving concurrent IOP-lowering glaucoma therapy. Further studies are underway to elucidate the effects of long-term nicotinamide supplementation on glaucoma progression. Trial RegistrationANZCTR trial ID: ACTRN12617000809336 https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=373001

5: Risk of Corona virus disease 2019 (COVID-19) among spectacles wearing population of Northern India
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Posted 15 Feb 2021

Risk of Corona virus disease 2019 (COVID-19) among spectacles wearing population of Northern India
2,120 downloads medRxiv ophthalmology

Amit Kumar Saxena

IntroductionSevere Acute Respiratory Syndrome Corona virus-2 (SARS-CoV-2) spread mainly through respiratory droplets and contact routes. Long term use of spectacles may prevent repeated touching and rubbing of the eyes. Aim of the study is to compare the risk of COVID-19 in long term spectacles wearers with the risk in persons not using spectacles. ObjectivesTo know the association between infection with SARSCoV-2 and wearing of spectacles. Materials and methodsIn this study, 304 patients of Corona virus disease 2019 (COVID-19) were selected. Their spectacles wearing behaviour was assessed through a questionnaire. Spectacles wearing behaviour of general population was obtained from older studies (for comparison). Risk of COVID-19 was calculated in long term spectacles wearers as well as in persons not using spectacles. Chi-Square test was used for statistical analysis. ResultsIn this study, total 58 patients showed the behavior of using spectacles continuously during day time and always on outdoor activities. The risk of COVID-19 was found 0.48 in spectacles wearing population as compared to 1.35 in population not using spectacles. The calculated risk ratio was 0.36. The protective effectiveness of the spectacles was found statistically significant (p-value .00113). ConclusionThe present study showed that the risk of Covid-19 was about 2-3 times less in spectacles wearing population than the population not wearing those. The nasolacrimal duct may be a route of virus transmission from conjunctival sac to the nasopharynx.

6: Exposure to glucagon-like peptide 1 receptor (GLP-1R) agonists reduces glaucoma risk.
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Posted 20 Jan 2021

Exposure to glucagon-like peptide 1 receptor (GLP-1R) agonists reduces glaucoma risk.
1,821 downloads medRxiv ophthalmology

Jacob Sterling, Peiying Hua, Joshua L Dunaief, Qi N Cui, Brian L. VanderBeek

Importance: Glucagon-like peptide-1 receptor (GLP-1R) agonists regulate blood glucose and are commonly used to treat Type II Diabetes Mellitus. Recent work has shown that treatment with the novel GLP-1R agonist, NLY01, decreased retinal neuroinflammation and glial activation to rescue retinal ganglion cells in an animal model of glaucoma. Objective: In this study, we used an insurance claims database to examine whether GLP-1R agonist exposure impacts glaucoma risk. Design, Setting, and Participants: A retrospective cohort of adult patients who initiated a new GLP-1R agonist (i.e., exenatide, liraglutide, albiglutide, dulaglutide, semaglutide, or lixisenatide) was 1:3 age, gender, race, active diabetes medication classes, and year of index date matched to a cohort of patients who initiated a different class of oral diabetic medication during their time in the database. Exclusion occurred for <2 years in the database, age <18 years old, no visit to an eyecare provider prior to the index date, a prior diagnosis of glaucoma, glaucoma suspect, or ocular hypertension, or prior glaucoma medication, procedure, or surgery. Diabetes severity was assessed using hemoglobin A1c and the Diabetes Complications Severity Index (DCSI), a validated metric based on six categories of diabetic complications. Inverse probability of treatment weighting (IPTW) was used within a multivariable Cox proportional hazard regression model to test the association between GLP-1R agonist exposure and the primary outcome. IPTW was derived from a propensity score model based on the DCSI, HbA1c, demographic factors and other systemic health conditions. Exposure: Glucagon-like peptide 1 receptor agonist. Main Outcomes and Measures: New diagnosis of primary open angle glaucoma, glaucoma suspect, or low tension glaucoma. Results: Cohorts were comprised of 1,961 new users of GLP-1R agonists matched to 4,371 unexposed controls. After IPTW, age was the only covariate imbalanced (SMD >0.1) between cohorts. Ten new diagnoses of glaucoma (0.51%) were present in the GLP-1R agonist cohort compared to 58 (1.33%) in the unexposed controls. After adjustment, GLP-1R exposure conferred a reduced hazard of 0.54 (95%CI: 0.35-0.85, P =0.007), suggesting that GLP-1R agonists reduce the risk for glaucoma. Conclusions and Relevance: GLP-1R agonist use was associated with a statistically significant hazard reduction for a new glaucoma diagnosis. Our findings support further investigations into the use of GLP-1R agonists in glaucoma prevention.

7: Expert-validated estimation of diagnostic uncertainty for deep neural networks in diabetic retinopathy detection
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Posted 15 Jul 2019

Expert-validated estimation of diagnostic uncertainty for deep neural networks in diabetic retinopathy detection
1,692 downloads medRxiv ophthalmology

Murat Seçkin Ayhan, Laura Kühlewein, Gulnar Aliyeva, Werner Inhoffen, Focke Ziemssen, Philipp Berens

Deep learning-based systems can achieve a diagnostic performance comparable to physicians in a variety of medical use cases including the diagnosis of diabetic retinopathy. To be useful in clinical practise, it is necessary to have well calibrated measures of the uncertainty with which these systems report their decisions. However, deep neural networks (DNNs) are being often overconfident in their predictions, and are not amenable to a straightforward probabilistic treatment. Here, we describe an intuitive framework based on test-time data augmentation for quantifying the diagnostic uncertainty of a state-of-the-art DNN for diagnosing diabetic retinopathy. We show that the derived measure of uncertainty is well-calibrated and that experienced physicians likewise find cases with uncertain diagnosis difficult to evaluate. This paves the way for an integrated treatment of uncertainty in DNN-based diagnostic systems.

8: Deep-learning-based Prediction of Late Age-Related Macular Degeneration Progression
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Posted 16 Sep 2019

Deep-learning-based Prediction of Late Age-Related Macular Degeneration Progression
1,296 downloads medRxiv ophthalmology

Qi Yan, Daniel E. Weeks, Hongyi Xin, Anand Swaroop, Emily Y. Chew, Heng Huang, Ying Ding, Wei Chen

Both genetic and environmental factors influence the etiology of age-related macular degeneration (AMD), a leading cause of blindness. AMD severity is primarily measured by fundus images and recently developed machine learning methods can successfully predict AMD progression using image data. However, none of these methods have utilized both genetic and image data for predicting AMD progression. Here we jointly used genotypes and fundus images to predict an eye as having progressed to late AMD with a modified deep convolutional neural network (CNN). In total, we used 31,262 fundus images and 52 AMD-associated genetic variants from 1,351 subjects from the Age-Related Eye Disease Study (AREDS) with disease severity phenotypes and fundus images available at baseline and follow-up visits over a period of 12 years. Our results showed that fundus images coupled with genotypes could predict late AMD progression with an averaged area under the curve (AUC) value of 0.85 (95%CI: 0.83-0.86). The results using fundus images alone showed an averaged AUC of 0.81 (95%CI: 0.80-0.83). We implemented our model in a cloud-based application for individual risk assessment.

9: COVID-19 receptor ACE2 is expressed in human conjunctival tissue, expecially in diseased conjunctival tissue
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Posted 23 May 2020

COVID-19 receptor ACE2 is expressed in human conjunctival tissue, expecially in diseased conjunctival tissue
1,292 downloads medRxiv ophthalmology

Shengjie Li, Danhui Li, Jianchen Fang, Qiang Liu, Wenjun Cao, Xinghuai Sun, Gezhi Xu

COVID-19 virus has currently caused major outbreaks worldwide. ACE2 is a major cellular-entry receptor for the COVID-19 virus. Although ACE2 is known to be expressed in many organs, whether it is expressed by the conjunctival tissue is largely unknown. Human conjunctival tissues from 68 subjects were obtained, which included 10 subjects with conjunctival nevi, 20 subjects with conjunctivitis, 9 subjects with conjunctival papilloma, 16 subjects with conjunctival cyst, 7 subjects with conjunctival polyps, and 6 ocular traumas as normal subjects. Expression of ACE2 was evaluated by immunohistochemistry, immunofluorescence, reverse transcriptase-quantitative polymerase chain reaction, and western blot assay. We observed the expression of ACE2 by conjunctival tissues, expecially in conjunctival epithelial cells. ACE2 was significantly (p<0.001) overexpressed in conjunctival cells obtained from subjects with conjunctivitis, conjunctival nevi, conjunctival papilloma, conjunctival cyst, and conjunctival polyps epithelial cells when compared to that in conjunctival epithelial cells obtained from control subjects. Collectively, clinical features of reported COVID-19 patients combined with our results indicate that COVID-19 is likely to be transmitted through the conjunctiva.

10: Relevance of brain MRI in patients with uveitis: retrospective cohort on 402 patients
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Posted 23 Mar 2020

Relevance of brain MRI in patients with uveitis: retrospective cohort on 402 patients
1,198 downloads medRxiv ophthalmology

N. Chirpaz, S. Kerever, A. Gavoille, L. Kodjikian, R. Bernier, M. Gerfaud-Valentin, P. Denis, T. Mathis, Y. Jamilloux, P. Sève

AimTo assess the diagnostic value of brain magnetic resonance imaging (bMRI) for the etiological diagnosis of uveitis and to establish predictive factors associated with its advantageous use. MethodsRetrospective study on all patients with de novo uveitis who were referred to our tertiary hospital and who underwent a bMRI between 2003 and 2018. The bMRI was considered useful if it served to confirm a diagnosis or correct a misdiagnosis. We also collected characteristics of uveitis and associated ophthalmological and neurological clinical signs. ResultsBrain MRI was contributive in 19 out of 402 cases (5%): 10 multiple sclerosis, 5 radiologically isolated syndromes, and 4 oculocerebral lymphomas. A total of 34 (8%) had neurological signs and 13 (38%) of those patients had a contributive bMRI. Meanwhile, in the absence of neurological signs, 1% of bMRIs were contributive, and none of them resulted in specific treatment. Among patients with a contributive bMRI, 68% had neurological signs. Univariate analysis established that neurological signs (p<0.001), granulomatous uveitis (p=0.003), retinal vasculitis (p=0.002), and intermediate uveitis (p<0.001) were all significantly associated with a contributive bMRI. Multivariate analysis confirms the significant association of neurological signs (p<0.001) and intermediate uveitis (p=0.01). Patients with oculocerebral lymphoma were significantly older (p<0.001) and all were above 40 years of age. ConclusionBrain MRI appears to be a relevant and contributive exam, but it should be performed in cases of intermediate/posterior uveitis or panuveitis accompanied by neurological signs, retinal vasculitis, or in patients older than 40, to rule out an oculocerebral lymphoma.

11: Conjunctival polymerase chain reaction-tests of 2019 novel coronavirus in patients in Shenyang,China
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Posted 25 Feb 2020

Conjunctival polymerase chain reaction-tests of 2019 novel coronavirus in patients in Shenyang,China
1,176 downloads medRxiv ophthalmology

Li Xu, Xinyue Zhang, Wei Song, Baijun Sun, Jinping Mu, Bing Wang, Zhiqian Wang, Yehong Cao, Xue Dong

PurposeThe 2019 novel coronavirus(COVID-19) mainly transmitted by person-to-person through inhalation of respiratory droplets. We report the laboratory results of conjunctival PCR-tests and some clinical features of these patients in shenyang China. DesignThis is a cross-sectional non-randomized study SubjectsThe study include 14 confirmly diagnosed cases, 16 suspected cases and some medical observed patients. MethodsAll patients with diagnosed and suspected COVID-19 were admitted to a designated hospital in Shenyang, China. We collected conjunctival samples of these patients to do the laboratory tests by real time RT-PCR. Medical observed patients were enrolled if they had clinical symptoms. Then we analysed the PCR results and clinical data from eletronic medical records in order to find some relationships. Main Outcome MeasuresClinical condition and PCR results. of conjunctival swabs compared with other specimens ResultsOne of the identified case coverted from suspected case without typical clinical symptoms. Twenty-two medical observed cases were removed because none of them converted to identified cases. One of the suspected converted to identified case recently. The included cases in our study are imported cases with less underlying diseases and the severity of their infection was relatively moderate. All the conjunctival results of PCR-test were negative. Two cases had typical clinical symptoms but were finally confirmed by repeated pharynxswabtests. ConclusionConjunctiva may be a transmission way of COVID-19. And ocular conjunctival swabs in combination with PCR test could be a non-invasive, convenient and feasible diagnostic method for identifying the infection of COVID-19. Emphasis on the false-negative results is vital.

12: Reducing visible aerosol generation during phacoemulsification in the era of Covid-19
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Posted 18 May 2020

Reducing visible aerosol generation during phacoemulsification in the era of Covid-19
1,146 downloads medRxiv ophthalmology

Kieren Darcy, Omar Elhaddad, Asaf Achiron, Johannes Keller, Duncan Leadbetter, Derek Tole, Sidath E. Liyanage

Objective: To assess potential methods of reducing visible aerosol generation during clear corneal phacoemulsification surgery in the era of Covid-19. Methods: Aerosol generation during phacoemulsification was assessed using a model comprising a human cadaveric corneoscleral rim mounted on an artificial anterior chamber. Typical phacoemulsification settings were used and visible aerosol production was recorded using high speed 4K camera. Aerosolisation was evaluated under various experimental settings: Two different phacoemulsification tip sizes (2.2mm, 2.75mm), varying levels of corneal moisture, the use of suction and blowing air in the surgical field, the use of hydroxypropyl methylcellulose (HPMC) coating of the cornea with a static and moving tip. Results: This model demonstrates visible aerosol generation during phacoemulsification with a 2.75mm phacoemulsification tip. No visible aerosol was noted with a 2.2mm tip. The presence of visible aerosol is unrelated to corneal wetting. Suction in close proximity to the aerosol plume did not impact on its dispersion. Blowing air redirected the aerosol plume towards the ocular surface. Visible aerosol production was abolished when HPMC was used to coat the cornea. This effect lasted for an average of 67{+/-}8 seconds in the static model. Visible aerosol generation was discerned during movement of the 2.2mm tip towards the corneal wound. Conclusions: We demonstrate visible aerosol production in the setting of a model of a clear cornea phacoemulsification. Visible aerosol can be reduced using a 2.2mm phacoemulsification tip and reapplying HPMC every minute during phacoemulsification.

13: Post-COVID-19 syndrome: retinal microcirculation as a potential marker for chronic fatigue
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Posted 23 Sep 2022

Post-COVID-19 syndrome: retinal microcirculation as a potential marker for chronic fatigue
1,141 downloads medRxiv ophthalmology

Sarah Schlick, Marianna Lucio, Alexander Johannes Bartsch, Adam Skornia, Jakob Hoffmanns, Charlotte Szewczykowski, Thora Schroeder, Franzi Raith, Lennart Rogge, Felix Heltmann, Michael Moritz, Lorenz Beitlich, Julia Schottenhamml, Martin Herrmann, Thomas Harrer, Marion Ganslmayer, Friedrich E. Kruse, Robert Laemmer, Christian Mardin, Bettina Hohberger

Post-COVID-19 syndrome (PCS) summarizes persisting sequelae after infection with the severe-acute-respiratory-syndrome-Coronavirus-2 (SARS-CoV-2). PCS can affect patients of all covid-19 disease severities. As previous studies revealed impaired blood flow as a provoking factor for triggering PCS, it was the aim of the present study to investigate a potential association of self-reported chronic fatigue and retinal microcirculation in patients with PCS, potentially indicating an objective biomarker. A prospective study was performed, including 201 subjects: 173 patients with PCS and 28 controls. Retinal microcirculation was visualized by OCT-Angiography (OCT-A) and quantified by the Erlangen-Angio-Tool as macula and peripapillary vessel density (VD). Chronic Fatigue (CF) was assessed with the variables Bell score, age and gender. The VD in the superficial vascular plexus (SVP), intermediate capillary plexus (ICP) and deep capillary plexus (DCP) were analyzed considering the repetitions (12 times). Taking in account of such repetitions a mixed model was performed to detect possible differences in the least square means between different groups of analysis. An age effect on VD was observed between patients and controls (p<0.0001). Gender analysis yielded that women with PCS showed lower VD levels in SVP compared to male patients (p=0.0015). The PCS patients showed significantly lower VD of ICP as compared to the controls (p=0.0001, [CI: 0.32; 1]). Moreover, considering PCS patients, the mixed model reveals a significant difference between chronic fatigue (CF) and without CF in VD of SVP (p=0.0033, [CI: -4.5; -0.92]). The model included age, gender and the variable Bell score, representing a subjective marker for CF. Consequently, the retinal microcirculation might be an objective biomarker in subjective-reported chronic fatigue of patients with PCS.

14: Consequences of Mismatch, Misalignment and Rotation of Toric Intraocular Lenses in Refractive Cataract Surgery. Part 1. It Ain't 30. The True 'Angle of Doom'.
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Posted 16 Jun 2020

Consequences of Mismatch, Misalignment and Rotation of Toric Intraocular Lenses in Refractive Cataract Surgery. Part 1. It Ain't 30. The True 'Angle of Doom'.
1,100 downloads medRxiv ophthalmology

Samir Sayegh

Purpose: To demonstrate that the total loss of astigmatism as a consequence of misalignment or rotation of a toric intraocular lens (tIOL) can occur much earlier than the widely believed and taught 30 degrees. To give a precise surgically useful estimate of that value. To clarify the role of mismatch and misalignment of toric intraocular lenses in cataract surgery beyond what is commonly recognized in the literature and make corresponding surgical recommendations. Setting: Private Practice and Research Center. The EYE Center. Champaign, IL, USA. Design: Formal Analytical Study Methods: The astigmatism addition approach is used in its simplest form along with analytical tools to derive new results concerning mismatch, misalignment and rotation of toric intraocular lenses. Results: The often stated results of total loss of astigmatic correction by 30-degree rotation and 3.3 % loss per degree represent a usually poor approximation to realistic surgical cases. We show how they constitute a very special case in the context of a more general framework relevant to procedures performed by refractive cataract surgeons dealing with the surgical correction of astigmatism with tIOLs. Total loss of astigmatic correction can occur with as little as 20 degrees of misalignment and less than 10 degrees of tIOL rotation. A practical approximation for that angle of doom, {Delta}, in the surgically relevant range can be expressed by {Delta} {approx} 30 - 15 {omega} degrees, where {omega} = (L - A) / A is the fractional overcorrection of L, the cylinder of the tIOL, and A, the astigmatism to be corrected. Similarly for undercorrection we show that {Delta} {approx} 30 + 15 degrees where = (A - L) / A represents the corresponding fractional undercorrection. That is to say the angle of doom is extended beyond the 30 degrees for cases of undercorrection of the astigmatism. We also demonstrate that overcorrection of astigmatism results in a significantly faster decline in astigmatism correction per degree of misalignment/rotation. The significant clinical implications and surgical recommendations, including for optimal degree of overcorrection, are a natural consequence of these novel results. Conclusions: Total loss of astigmatism correction can occur at a significantly smaller angle than commonly believed and overcorrected astigmatism residual rises with tIOL misalignment or rotation significantly faster than undercorrected astigmatism. We provide the methodology and explicit solution for determining this behavior.

15: Current practice and challenges in screening for visual perception deficits after stroke: a qualitative study
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Posted 29 Nov 2019

Current practice and challenges in screening for visual perception deficits after stroke: a qualitative study
1,081 downloads medRxiv ophthalmology

Kathleen Vancleef, Michael J Colwell, Olivia Hewitt, Nele Demeyere

AIMWe aimed to document current clinical practice and needs in screening for visual perception problems after stroke to inform development of new screening tools. METHODSWe interviewed 25 health care professionals (12 occupational therapists, 13 orthoptists) from 16 organisations in England. Interviews were transcribed and coded in NVivo Software. Data were thematically analysed using the Value Proposition Canvas, a model which establishes what people want to achieve, the challenges they face and what facilitates their jobs. RESULTSParticipants understanding of visual perception varied and often included sensory and cognitive deficits. Occupational therapists commonly screened for visual field deficits and hemispatial neglect, while other aspects of visual cognition were rarely assessed. They decided on referrals to orthoptists for further assessment. Screening generally occurred during functional assessments and/or with in-house developed tools. Challenges to practice were: lack of time, lack of training, environmental and stroke survivor factors (e.g. aphasia), insufficient continuation of care, and test characteristics (e.g. not evidence-based). Facilitators to practice were: quick and practical tools, experienced staff or tools with minimal training requirements, a streamlined care pathway between a stroke unit and eye hospital supported by occupational therapists and orthoptists. CONCLUSIONScreening employs non-standardised assessments and rarely covers visual perceptual deficits in higher order perception. Our service evaluation demonstrates the need for a standardised visual perception screen, which should ideally be 15 minutes or less, be portable, and require minimal equipment. The screen should be suitable for bedside testing in noisy environments, inclusive for participants with aphasia and evidence-based.

16: Private Equity Acquisition in Ophthalmology and Optometry: A Time Series Analysis of the Pre-COVID, COVID Pre-Vaccine, and COVID Post-Vaccine Eras
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Posted 03 Feb 2022

Private Equity Acquisition in Ophthalmology and Optometry: A Time Series Analysis of the Pre-COVID, COVID Pre-Vaccine, and COVID Post-Vaccine Eras
1,064 downloads medRxiv ophthalmology

Sachi A Patil, Daniel Garrett Vail, Jacob Tanner Cox, Evan M Chen, Prithvi Mruthyunjaya, James C Tsai, Ravi Parikh

Objective: To identify temporal and geographic trends in private equity (PE) backed acquisitions of ophthalmology and optometry practices in the United States from 2012 to 2021. Design: Cross-sectional time series analysis using acquisition data from 10/21/2019 to 9/1/2021 compared to previously published data from 1/1/2012-10/20/2019. Acquisition data was compiled from 6 financial databases, 5 industry news outlets, and publicly available press releases. Linear regression models were used to compare rates of acquisition. Subjects: 245 PE acquisitions of ophthalmology and optometry practices in the United States between 10/21/2019 and 9/1/2021. Measures: Number of total acquisitions, practice type, locations, provider details, and geographic footprint. Results: 245 practices associated with 614 clinical locations and 948 ophthalmologists or optometrists were acquired by 30 PE-backed platform companies. 18 of 30 platform companies were new compared to our prior study. Of these acquisitions from 10/21/2019 - 9/1/2021, 127, 29, and 89 were comprehensive, retina, and optometry practices, respectively. From 2012 to 2021, monthly acquisitions increased by 0.947 acquisitions per year (p<0.001*). Texas, Florida, Michigan, and New Jersey were the states with the greatest number of PE acquisitions with 55, 48, 29, 28 clinic acquisitions, respectively. Average monthly PE acquisitions were 5.71 per month from 1/1/2019 - 2/29/2020 (pre-COVID), 5.30 per month 3/1/2020-12/31/2020 (COVID pre-vaccine, p=0.8072), and were 8.78/month 1/1/2021-9/1/2021 (COVID post-vaccine, p=0.1971). Conclusion: PE acquisitions increased from 2012-2021 as companies continue to utilize both regionally focused and multi-state models of add-on acquisitions.

17: Estimating excess visual loss in people with neovascular age-related macular degeneration during the COVID-19 pandemic
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Posted 05 Jun 2020

Estimating excess visual loss in people with neovascular age-related macular degeneration during the COVID-19 pandemic
1,050 downloads medRxiv ophthalmology

Darren S Thomas, Alasdair Warwick, Abraham Olvera-Barrios, Catherine Egan, Roy Schwartz, Sudeshna Patra, Haralabos Eleftheriadis, Anthony P. Khawaja, Andrew Lotery, Philipp L Mueller, Robin Hamilton, Ella Preston, Paul Taylor, Adnan Tufail, UK EMR Users Group

Objectives: To report the reduction in new neovascular age-related macular degeneration (nAMD) referrals during the COVID-19 pandemic and estimate the impact of delayed treatment on visual outcomes at one year. Design: Retrospective clinical audit and simulation model. Setting: Multiple UK NHS ophthalmology centres. Participants: Data on the reduction in new nAMD referrals was obtained from four NHS Trusts in England comparing April 2020 to April 2019. To estimate the potential impact on one-year visual outcomes, a stratified bootstrap simulation model was developed drawing on an electronic medical records dataset of 20,825 nAMD eyes from 27 NHS Trusts. Main outcome measures: Simulated mean visual acuity and proportions of eyes with vision [&le;]6/60, [&le;]6/24 and [&ge;]6/12 at one year under four hypothetical scenarios: no treatment delay, 3, 6 and 9-month treatment delays. Estimated additional number of eyes with vision [&le;]6/60 at one year nationally. Results: The number of nAMD referrals at four major eye treatment hospital groups based in England dropped on average by 72% (range 65 to 87%) in April 2020 compared to April 2019. Simulated one-year visual outcomes for 1000 nAMD eyes with a 3-month treatment delay suggested an increase in the proportion of eyes with vision [&le;]6/60 from 15.5% (13.2 to 17.9) to 23.3% (20.7 to25.9), and a decrease in the proportion of eyes with vision [&ge;]6/12 (driving vision) from 35.1% (32.1 to 38.1) to 26.4% (23.8 to29.2). Outcomes worsened incrementally with longer modelled delays. Assuming nAMD referrals are reduced to this level at the national level for only one month, these simulated results suggest an additional 186-365 eyes with vision [&le;]6/60 at one-year with even a short treatment delay. Conclusions: We report a large decrease in nAMD referrals during the first month of COVID-19 lockdown and provide an important public health message regarding the risk of delayed treatment. As a conservative estimate, a treatment delay of 3 months could lead to a >50% relative increase in the number of eyes with vision [&le;]6/60 and 25% relative decrease in the number of eyes with driving vision at one year.

18: Prevalence of Strabismus in Individuals on the Autism Spectrum: A Meta-analysis
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Posted 16 Jul 2021

Prevalence of Strabismus in Individuals on the Autism Spectrum: A Meta-analysis
1,034 downloads medRxiv ophthalmology

Zachary J Williams

Background and Objectives: Strabismus, a misalignment of the eyes, is an important risk factor for amblyopia and visual impairment in the pediatric population. Several studies have reported an increased likelihood of strabismus in persons on the autism spectrum, but prevalence estimates in this group vary greatly. Methods: We searched multiple databases to identify peer-reviewed articles published in English through November 1, 2020 that provided estimates of strabismus prevalence in autistic individuals. Prevalence estimates were synthesized using Bayesian random-effects meta-analysis, and sensitivity analysis was also performed using only the subset of studies that recruited participants from non-ophthalmologic settings and identified strabismus using structured ocular exams. Bayesian meta-regression was used to assess potential moderators of prevalence across studies. Results: A total of 151 nonduplicate articles were screened, of which 22 were included in the meta-analysis (k=28 samples, nAUT=113,227). The meta-analytic point prevalence of strabismus in autistic individuals was 13.4% (95% CrI [8.3, 19.4]), and sensitivity analysis produced a very similar estimate (14.0% [7.0, 22.0], nAUT=581). Esotropia was the predominant subtype of strabismus reported, accounting for approximately 55% of cases. Reported prevalence rates were higher in younger samples (BF10=13.43, R2Het=0.273) and samples recruited from optometry/ophthalmology clinics (BF10=11.47, R2Het=0.238). Conclusion: This meta-analysis found a high prevalence of strabismus in autistic individuals, with rates 3-10 times that of the general population. As untreated strabismus is a major risk factor for amblyopia in young children, these findings underscore the importance of timely screening and assessment of ocular problems in persons on the autism spectrum. What's Known on This Subject: Strabismus has been reported to be more prevalent in individuals on the autism spectrum, but estimates have been very imprecise, ranging from 3-84% across studies. What This Study Adds: This study performs the first quantitative synthesis of strabismus prevalence in over 100,000 autistic individuals, generating more precise estimates of the prevalence of strabismus in the autistic population. Factors contributing to the large differences between studies are also examined using meta-regression.

19: Automated measurement of the foveal avascular zone in healthy eyes on Heidelberg Spectralis Optical Coherence Tomography Angiography
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Posted 07 Aug 2020

Automated measurement of the foveal avascular zone in healthy eyes on Heidelberg Spectralis Optical Coherence Tomography Angiography
1,026 downloads medRxiv ophthalmology

Laura Gutierrez-Benitez, Yolanda Palomino, Noe Casas, Mouafk Asaad

PurposeTo develop and evaluate an automated method to measure the foveal avascular zone (FAZ) area in healthy eyes on Heidelberg Spectralis Optical Coherence Tomography Angiography (HS-OCTA). This method is referred to as the modified Kanno-Saitama macro (mKSM). MethodsThis cross-sectional study included 29 eyes of 25 healthy volunteers who underwent HS-OCTA at the macular area twice at the same time. Regardless of the quality of the images, all of them were included. Macular data on the superficial vascular plexus, intermediate capillary plexus and deep capillary plexus were processed by mKSM. The FAZ area was measured twice automatically using the mKSM and twice manually by two independent examiners. ResultsIntrascan intraclass coefficient ranged from 0,948 to 0,993 for manual measurements and was 1 for mKSM method. Interscan intraclass coefficients ranged from 0,925 to 0,973 for manual measurements and from 0,770 to 0,902 for mKSM method. Despite that the difference between human examiners is smaller than between human examiners and mKSM according to Bland-Altman plots, the scatterplots show a strong correlation between human and automatic measurements. The best results are obtained in intermediate capillary plexus. ConclusionsAutomated determination of the FAZ area in HS-OCTA is feasible and less human- dependent by mKSM even if the image is not perfectly centred or has artefacts. The mKSM processing could contribute to our understanding of the three vascular plexuses.

20: Knowledge about benefits and risks of undergoing cataract surgery among cataract patients in Southern China
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Posted 11 Dec 2019

Knowledge about benefits and risks of undergoing cataract surgery among cataract patients in Southern China
1,007 downloads medRxiv ophthalmology

Guofang Ye, Bo Qu, Wen Shi, Xin Chen, Pengjuan Ma, Yuxin Zhong, Shida Chen, Ecosse Lamoureux, Yingfeng Zheng

ObjectiveTo develop a theoretical framework for assessing knowledge about the possible outcomes of undergoing cataract surgery, and explore the association of knowledge level with psychological status and decision quality among patients with cataract in Southern China. MethodsThe details of the knowledge scale were based on the health education information booklet provided by National Eye Institute, NIH. We used a theory-based approach to assess gist knowledge, which comprises conceptual and numeric questions related to knowledge of the possible surgical outcomes. The scale was then used in a cross-sectional study to assess the association of knowledge score with psychological status and decision quality of cataract patients, including worry, anxiety, attitudes, intentions, decisional conflict, confidence in decision making, anticipated regret and temporal orientation. ResultsA total of 489 participants with age-related cataract were included in this study, and 10.2% (50/489) of them had adequate level of knowledge. The knowledge scale was significantly associated to the levels of worry (Odds Ratio (OR) = 0.36, 95%CI: 0.18, 0.70; P = 0.003), anxiety (beta coefficient = -5.36, 95%CI: -8.88,-1.84; P = 0.003), inaction regret (OR = 0.49, 95%CI : 0.28, 0.88; P = 0.016) and decision conflict (beta coefficient = -7.93, 95%CI: -12.81, -3.04; P = 0.002) in multivariate analyses adjusted for age, sex, education level and literacy level. ConclusionThe level of knowledge adequacy with cataract surgery outcomes is high in China and was associated with psychological status and decision quality. These findings suggest that strategies targeting knowledge of possible surgical outcomes may reduce psychological stress and improve decision quality among patients with age-related cataract.

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