Ocular Dominance and Functional Asymmetry in Visual Attention Networks

PurposeThe dorsal attention network (DAN) and the ventral attention network (VAN) are known to support visual attention, but the influences of ocular dominance on the attention networks are unclear. We aimed to explore how visual cortical asymmetry of the attention networks correlate with neurophysiological oscillation and connectivity markers of attentional processes.MethodsAn oddball task with concentric circle stimuli of three different sizes (i.e., spot size of 5°, 20°, or 30° of visual angle) was used to vary task difficulty. Event-related oscillations and interareal communication were tested with an electroencephalogram-based visual evoked components as a function of ocular dominance in 30 healthy subjects.ResultsAccuracy rates were higher in the dominant eyes compared with the nondominant eyes. Compared with the nondominant eyes, the dominant eyes had higher theta, low-alpha, and low-beta powers and lower high-alpha powers within the nodes of VAN and DAN. Furthermore, visual information processed by the dominant and nondominant eye had different fates, that is, the dominant eyes mainly relied on theta and low-alpha connectivity within both the VAN and the DAN, whereas the nondominant eyes mainly relied on theta connectivity within the VAN and high-alpha connectivity within the DAN. The difference in accuracy rate between the two eyes was correlated with the low-alpha oscillations in the anterior DAN area and low-alpha connectivity of the left DAN.ConclusionsThe ocular dominance processing and interareal communication reveal a cortical asymmetry underlying attention, and this reflects a two-way modulatory mechanism within attention networks in the human brain.     

Impact of COVID-19 pandemic and national lockdown on ocular trauma at a tertiary eye care institute

Purpose:To evaluate the impact of the COVID-19 pandemic and the national lockdown on the demographic and clinical profile of patients presenting with ocular trauma.Methods:In this retrospective, hospital-based, comparative analysis, patients presenting to the emergency department with ocular trauma in the following COVID-19 period (March 25, 2020 to July 31, 2020) were compared with patients in the pre-COVID-19 period (March 25, 2019 to July 31, 2019).Results:Overall, 242 patients (COVID-19 period: 71 and pre-COVID-19 period: 171) presented with ocular trauma. The mean age of the patients in COVID-19 and pre-COVID-19 periods were 26.7 ± 17.3 and 34.1 ± 20.3 years, respectively (P = 0.008). A majority of patients (68.6%) in both groups were from the rural background. Home-related injuries were common in the COVID-19 period (78.8%) as compared to pre-COVID-19 period (36.4%) (P < 0.0001). Iron particles (29.5%) were the common inflicting agents in the COVID-19 period while it was plant leaves (25.5%) in the pre-COVID-19 period. The most common ocular diagnosis was open globe injury (40.8%) in the COVID-19 period and microbial keratitis (47.9%) in the pre-COVID-19 period. Surgical intervention was required in 46.4% of patients in the COVID-19 period and 32.1% of patients in the pre-COVID-19 period (P = 0.034).Conclusion:During the COVID-19 period, there was a significant decline in the number of patients presenting with ocular trauma. In this period, a majority of patients sustained ocular trauma in home-settings. About half the patients required surgical intervention which was most commonly rendered in the form of primary wound repair.     

Primary treatment of ocular surface squamous neoplasia with topical interferon alpha-2b: Comparative analysis of outcomes based on original tumor configuration

Purpose:The aim of this study was to evaluate tumor control of OSSN with topical IFNα2b alone based on tumor configuration (flat versus (vs.) dome-shaped).Methods:Retrospective, nonrandomized, interventional cohort study on 64 consecutive tumors in 63 patients with OSSN treated with topical IFNα2b. Topical IFNα2b (1 million international units/cc) was compounded and provided by the Thomas Jefferson University Hospital Pharmacy to be refrigerated and applied 4 times daily until biomicroscopic evidence of tumor resolution was observed.Results:The tumor configuration was flat (n = 15, 23%) or dome-shaped (n = 49, 77%). A comparison (flat vs. dome-shaped) revealed dome-shaped with older mean patient age at presentation (62 vs. 70 years, P = 0.04), greater patient history of smoking (13% vs. 42%, P = 0.04), greater corneal involvement (7% vs. 82%, P < 0.001), larger mean basal diameter (5.5 vs. 12.4 mm, P = 0.001) and mean thickness (1.9 vs. 4.3, P = 0.002), and longer mean duration IFNα2b therapy (3.7 vs. 6.3 months, P = 0.002). There was no difference in mean follow-up time (22.2 vs 23.1 months) or time to complete response (5.0 vs. 6.1 months). There was no difference in achievement of complete tumor control with IFNα2b alone (93% vs. 96%). There were no cases with metastasis or death.Conclusion:Topical IFNα2b alone shows excellent overall tumor control of 95% with no difference in efficacy based on tumor configuration.     

Retinal manifestations in patients following COVID-19 infection: A consecutive case series

Purpose:To describe retinal manifestations seen in patients associated with COVID-19 infection at a multi-specialty tertiary care hospital in Southern India.Methods:In this retrospective chart review, all consecutive cases presenting to the Retina-Uveitis service from May 2020 to January 2021 with retinal manifestations associated with COVID-19 infection or its sequelae or as a result of treatment given for COVID-19 were included.Results:Of the 7 patients, 3 were female, and 4 were male. Four patients had onset of symptoms during the active phase of COVID-19 infection. Four had bilateral and three had unilateral involvement. The manifestations ranged from mild to vision threatening. Vision threatening manifestations included infections: endogenous endophthalmitis, candida retinitis and tubercular choroidal abscess and bilateral pre-foveal hemorrhages. Milder manifestations included paracentral acute middle maculopathy, central serous chorio-retinopathy and voriconazole induced visual symptoms. Final visual acuity was 6/36 or better in the four severe cases and 6/9 or better in the mild cases.Conclusion:This study highlights the retinal manifestations associated with COVID-19 infection and its sequelae. As these patients presented with an association with COVID-19 (either during or after recovery), ophthalmologists should be vigilant and screen for such entities in case of complaints of visual symptoms or in the presence of systemic sepsis. The outcomes can be good with prompt and aggressive management.     

The anterior and posterior biometric characteristics in primary angle-closure disease: Data based on anterior segment optical coherence tomography and swept-source optical coherence tomography

Purpose:Obtaining a better understanding of the pathogenesis of primary angle-closure disease (PACD) still requires studies that provide measurements of anterior and posterior biometric characteristics together and that assess the relationship between them.Methods:In total, 201 eyes were enrolled in this cross-sectional study: 50 normal controls, 49 primary angle-closure suspect (PACS), 38 primary angle closure (PAC), and 64 primary angle-closure glaucoma (PACG) eyes. The anterior and posterior structural features were measured by anterior segment optical coherence tomography and swept-source optical coherence tomography.Results:All PACD groups had smaller anterior chamber depth (ACD), anterior chamber area (ACA), anterior chamber volume (ACV), angle opening distance at 750 μm from the scleral spur (AOD750), trabecular–iris space area at 750 μm from the scleral spur (TISA750), and angle recess area (ARA), as well as a larger lens vault (LV), than controls (all P < 0.001). The PACS and PAC groups had thicker iris thickness at 750 μm from the scleral spur (IT750) than controls (P = 0.017 and P = 0.002, respectively). Choroidal thickness (CT) was not statistically different among normal, PACS, PAC, and PACG eyes. Univariate and multivariate linear regression analysis revealed a significant association between thinner IT750 and increased CT in PACD eyes (P = 0.031, univariate analysis; P = 0.008, multivariate analysis).Conclusion:Thinner iris thickness was associated with increased CT in PACD eyes; however, the underlying mechanism needs further investigation.     

Ocular Leishmaniasis - A systematic review

The incidence of leishmaniasis is reported to be up to 1 million per year. To date, there has been no comprehensive review describing the diversity of clinical presentations of ocular leishmaniasis (OL) and its treatment. This systematic review aims to address this knowledge gap and provide a summary of the clinical presentation, natural course, and treatment options for OL. Our study identified a total of 57 published articles as describing cases of OL involving: adnexa (n = 26), orbit (n = 1), retina (n = 7), uvea (n = 18) and cornea (n = 6). Though well described and easily treated, palpebral leishmaniasis is often misdiagnosed and may lead to chronic issues if untreated. The retinal manifestations of Leishmaniasis consist of self-resolving hemorrhages secondary to thrombocytopenia. Two main uveitis etiologies have been identified: uveitis in the context of active Leishmanial infection (associated with immunosuppression) and uveitis occurring as an immune reconstitution syndrome. Corneal involvement in most geographic areas generally follows an aggressive course, most often ending in corneal perforation if left untreated. In the Americas, a chronic indolent interstitial keratitis may also occur. Topical steroids are of little use in keratitis (systemic antileishmanials being the cornerstone of treatment). However, these are essential in cases of uveitis, with or without concomitant systemic antileishmanial therapy. In conclusion, though ocular involvement in Leishmaniasis is rare, severe sight-threatening consequences follow if left untreated. Early diagnosis, enthusiastic follow-up and aggressive treatment are essential for good outcomes.     

婴儿期白内障摘除手术后眼轴长度、角膜屈光力及屈光状态的变化

目的探讨婴儿期白内障摘除手术后患儿眼轴长度、角膜屈光力、屈光度数变化情况及其发展规律。方法回顾性队列研究。选取2015年1月1日至2018年12月31日在温州医科大学附属眼视光医院杭州院区103例因先天性白内障婴儿期接受白内障摘除手术患儿的病历资料,男性61例,女性42例,行手术时月龄为(3.95±1.94)个月。双眼白内障患儿均双眼接受白内障摘除手术,选取左眼进行分析。入选患儿至少随访1年,患儿按白内障摘除手术时月龄分为<4月龄组和4~12月龄组,比较患儿白内障摘除手术前及手术后1年的眼轴长度、角膜屈光力、检影验光的等效球镜度数以及变化量,采用独立样本t检验、单因素方差分析和简单线性回归法进行统计学分析。结果双眼白内障患儿71例,<4月龄组33例,4~12月龄组38例;单眼白内障患儿32例,<4月龄组17例,4~12月龄组15例。<4月龄组双眼患儿术后1年眼轴长度变化量为(2.46±1.33)mm,大于4~12月龄组的(1.52±1.00)mm,差异有统计学意义(t=3.21;P<0.01)。相同手术月龄分组中,双眼患儿患眼、单眼患儿患眼及对侧眼,三者间术后1年眼轴长度变化量差异均无统计学意义(均P>0.05)。术后1年,双眼患儿患眼、单眼患儿患眼及对侧眼眼轴长度均与实际月龄的对数高度正相关(r=0.68,0.52,0.73;均P<0.01)。角膜屈光力随年龄增大总体呈减少趋势,<4月龄组双眼患儿术后1年角膜屈光力变化量为(1.43±2.87)D,大于4~12月龄组的(0.68±2.10)D,但差异无统计学意义(P>0.05)。<4月龄组双眼患儿术后1年屈光度数变化量为(2.02±2.60)D,大于4~12月龄组的(0.69±1.89)D,差异有统计学意义(t=2.15;P<0.05)。单眼患儿患眼4~12月龄组术后1年屈光度数变化量为(2.05±0.95)D,大于双眼患儿4~12月龄组的(0.69±1.89)D,差异有统计学意义(t=2.49;P<0.05)。术后1年,双眼及单眼患儿患眼屈光度数均与实际月龄成高度负相关(r=-0.51,-0.54;均P<0.01)。结论婴儿期白内障摘除手术后1年,患儿眼轴长度增长,角膜屈光力降低,屈光度数降低,且患儿手术年龄越小,眼轴长度、角膜屈光力、近视漂移变化量越大。     

SARS-CoV-2对眼部的影响及其经眼途径传播的可能性

SARS-CoV-2引起的新型冠状病毒肺炎（COVID-19）已对全球构成重大的公共卫生威胁。SARS-CoV-2和SARS-CoV均属于人冠状病毒（HCoVs）β属,两者的基因组相似性高达79.6%,且均通过血管紧张素转换酶2（ACE-2）感染宿主细胞。目前已有研究表明,SARS-CoV-2感染与结膜炎具有一定相关性,SARS-CoV-2是否能经眼感染或传播的问题也备受关注,但目前尚缺乏其通过眼部组织感染的临床确诊病例和实验室证据。本文就SARS-CoV-2的病原学特点、流行病学特征、眼部表现及结膜囊病毒感染率作一综述,并对SARS-CoV-2经眼途径传播的可能性进行探讨。     

双通道视觉分析系统评估白内障的眼表及视觉质量

目的:通过OQAS视觉质量分析系统对不同类型白内障的眼表和视觉质量进行评估。方法:横断面研究。收集2019-06/2020-06在武汉大学人民医院眼科中心的裸眼视力(UCVA)≤0.5的年龄相关性白内障患者30例30眼,平均年龄71.69±3.79岁;并发性白内障30例30眼,平均年龄61.00±4.56岁;正常对照组30例30眼,平均年龄65.34±4.06岁。由同一位医生对患者的视觉质量进行眼表和视觉质量检查,包括前房深度(ACD)、眼轴(AL)、眼压(IOP)、角膜曲率(K)、客观散射指数(OSI)、MTF截止频率(MTF cut off)、斯特尔比率(SR)、对比度视力检查VA100%、VA20%、VA9%等指标。结果:葡萄膜炎性白内障MTF cut off小于青光眼性白内障(P=0.025),大于眼底病性白内障(P=0.013),大于糖尿病性白内障(P=0.001);青光眼性白内障MTF cut off高于眼底病性白内障(P=0.013),高于糖尿病性白内障(P=0.007);眼底病性白内障MTF cut off高于糖尿病性白内障(P=0.010)。结论:各亚类并发性白内障眼表和视觉质量参数尤其是MTF cut off存在一定差异,临床上应在术前关注白内障类型。