Cargo transport properties are enhanced by cylindrical microtubule geometry and elliptical contact zone on cargo surface.

Molecular motors are responsible for carrying cellular transport of various membranous vesicles or organelles along cytoskeletal tracks. Transport of cellular cargos require high forces that are generated by motors working in groups. Hence, the properties of cargo transport can be modulated by varying various parameters such as cargo size and shape, microtubule geometry, motor number and their arrangement on cargo surface. Only those motors which are present in the contact zone on cargo surface have potential to bind to microtubule. Although earlier studies revealed the importance of cargo size, total motors attached to microtubule and their arrangement on cargo transport, yet how the contact zone influences binding of motors to microtubule largely remains unexplored. Here, it has been shown that contact zone is elliptical in shape for a spherical cargo and increases with cargo size for Kinesin-1 motors. To further understand the combined effect of elliptical contact zone and microtubule geometry on cargo transport, 3D mean-field model with uniform and clustered arrangement of motors for different cargo sizes and motor number has been used. Our findings indicate that cylindrical microtubule geometry maximizes the microtubule-bound motors which enhances the runlength and velocity of cargo transport. Our results show that microtubule-bound motors decrease with cargo size for uniform arrangement of motors on cargo thus decreasing its runlength and velocity, whereas in clustered arrangement, the number of microtubule-bound motors increase with cargo size which leads to increase in runlength and velocity.

Sliding of motor tails on cargo surface due to drift and diffusion affects their team arrangement and collective transport.

Kinesin is a microtubule-associated motor protein which works in teams to carry the cellular cargo transport. Lipid rafts on membranous cargos reorganize, causing the motors present in these areas to physically cluster. Unregulated clustering of motors leads to diseases such as Leishmaniasis, Newmann-Pick disease, etc. Variousin-vitroand computational studies have reported improved cargo velocity and travel distance of a fluid cargo as compared to a rigid cargo. However, only cargo velocity increases with increase in membrane fluidity of a fluid cargo. Thermal and motor forces acting tangentially on a cargo generate random torque and motor torque respectively, leading to cargo rotation and motor tail sliding on cargo surface. However, it is unknown which of these forces/torques play a crucial role in improving the transport properties. Here, we use computational models that incorporate random torque, motor torque, and combination of both random and motor torques to understand how they influence the clustering of Kinesin motors on cargo surface due to drift and diffusion of their tails. These studies were performed at varying tail diffusivity to understand their effect on clustering of tails in dispersed and clustered arrangement. We find that in dispersed arrangement, random torque does not cause clustering, whereas motor torque is crucial for clustering of tails on cargo surface, and tails sliding due to both random and motor torques have fastest cargo transport and maximum cooperativity. In clustered arrangement, tails slide to form a broad and steady cluster whose size increases with tail diffusivity resulting in decreased cargo runlength, velocity and cooperativity. These findings suggest that increased tail diffusivity negatively impacts the cluster and cargo transport of tails in the clustered arrangement, whereas it aids physical clustering of tails and cargo transport in dispersed arrangement.

An unusual presentation of conjunctival aspergillosis as a polyp in an immunocompetent child.

Fungi are a part of normal ocular flora and usually do not cause clinical infection in the absence of predisposing factors. We report a 7-year-old healthy boy from a rural area of India, who presented with a gradually increasing mass in the left eye. Excisional biopsy of the mass was performed, and pathological examination revealed multiseptate hyphae with acute-angle branching consistent with aspergillosis.

Efficient Multi-Object Detection and Smart Navigation Using Artificial Intelligence for Visually Impaired People.

Visually impaired people face numerous difficulties in their daily life, and technological interventions may assist them to meet these challenges. This paper proposes an artificial intelligence-based fully automatic assistive technology to recognize different objects, and auditory inputs are provided to the user in real time, which gives better understanding to the visually impaired person about their surroundings. A deep-learning model is trained with multiple images of objects that are highly relevant to the visually impaired person. Training images are augmented and manually annotated to bring more robustness to the trained model. In addition to computer vision-based techniques for object recognition, a distance-measuring sensor is integrated to make the device more comprehensive by recognizing obstacles while navigating from one place to another. The auditory information that is conveyed to the user after scene segmentation and obstacle identification is optimized to obtain more information in less time for faster processing of video frames. The average accuracy of this proposed method is 95.19% and 99.69% for object detection and recognition, respectively. The time complexity is low, allowing a user to perceive the surrounding scene in real time.

Noninvasive ocular surface analyzer as an adjunct in diagnosis and estimating prevalence of meibomian gland dysfunction: Hospital-based comparative study.

Purpose: To assess the role of noninvasive ocular surface analyzer (OSA) in workup of meibomian gland dysfunction (MGD) and to estimate hospital-based prevalence of MGD using this objective device. Methods: The study recruited 113 consecutive participants attending the ophthalmology outpatient department of a tertiary care hospital. All participants were administered a symptom questionnaire. Participants underwent a comprehensive ocular examination, including slit-lamp biomicroscopy and meibomian gland expression. Lipid layer thickness (LLT), noninvasive tear breakup time (NIBUT), tear meniscus height (TMH), and meibomian gland loss (MGL) were assessed using OSA. The presence of either or both reduced/absent meibum secretion and cloudy to toothpaste-like secretion was diagnosed as MGD. Results: Prevalence of total MGD was 57.52% (95% confidence interval [95% CI]: 48.3%-66.8%) and that of symptomatic MGD was 42.5% (95% CI: 33.2%-51.7%). Prevalence of total and symptomatic MGD was highest in those aged ≥50 years (P < 0.001 and P = 0.004, respectively). Computer vision syndrome increased the odds of symptomatic MGD (odds ratio [OR]: 4.3). NIBUT and MGL significantly differed in MGD and non-MGD groups (P = 0.023 and P < 0.001, respectively). LLT significantly differed between asymptomatic and symptomatic cases (P = 0.033). MGL >25% increased the odds of having MGD (OR: 19.1). Significant negative correlations were observed between MGL and NIBUT (P = 0.04) and between MGL and LLT (P = 0.02). MGL demonstrated the highest diagnostic accuracy for MGD (AUC = 0.827, sensitivity = 75.4%, specificity = 85.4%, cut-off value: ≥26%). Conclusion: MGD is a common disorder in adults attending the ophthalmology outpatient services of a tertiary eye care hospital. Incorporating noninvasive OSA in clinical practice can aid in rapid and reliable measurements of MGD-related parameters.

Atypical Corneal Phenotype in Patients With Trachoma and Secondary Amyloidosis.

PURPOSE: To report clinical presentation, in vivo confocal microscopic features, and corneal phenotype in patients with trachomatous keratopathy (TK) and secondary amyloidosis. METHODS: Histopathological records of all patients undergoing keratoplasty at the Dr. Rajendra Prasad Centre for Ophthalmic Sciences over a 3-year period were scanned retrospectively for a diagnosis of TK and amyloidosis. Demographic profile and details of preoperative comprehensive ophthalmic assessment were extracted. The histopathology was freshly reviewed. RESULTS: Fifteen patients (29 eyes) with TK and atypical corneal involvement due to amyloid deposition were identified. Herbert's pits and upper palpebral conjunctival scarring were present in all cases. Central or total diffuse corneal scarring was present involving the anterior stroma in 5 (31%) and the full thickness of the cornea in 11 (69%) of the eyes. Eight (73%) of 11 patients with deep stromal amyloid deposits revealed bilateral, discrete, blue-white opacities at the level of deep stroma and Descemet membrane (DM). Endothelial cells were atrophic and flattened with gutta formation. Confoscans revealed hyperreflective, needle-shaped crystalline deposits of extracellular amyloid at various depths of the corneal stroma up to DM. All host corneal buttons demonstrated Congo red-positive amyloid deposits on histopathological examination. CONCLUSIONS: We describe a distinct form of TK unlike the usual presentation of dense, leucomatous, vascularized corneal scarring in trachoma. We believe that amyloid deposits in DM and the corneal endothelium have not previously been reported in patients with trachoma.

Surgical outcomes of concomitantly performed penetrating keratoplasty with intrascleral haptic fixation.

PURPOSE: : To describe the surgical results of concomitantly performed optical penetrating keratoplasty (PKP) with glued intrascleral haptic fixation (ISHF). METHODS: : Retrospective review of 18 patients (15-72 years) with best-corrected visual acuity (BCVA) of ≤1/60 subjected to unilateral concomitant optical PKP with ISHF and followed up for 13.11 ± 5.83 months (6-26 months) was undertaken. RESULTS: : The most common diagnoses were failed PKP (9/18, 50%) followed by aphakic bullous keratopathy (5/18, 27%). Preoperative glaucoma, peripheral anterior synechiae (PAS), and deep vascularization were present in 7/18 (38.88%), 12/18 (61.11%), and 5/18 (27.77%) patients, respectively. Intraoperatively, concomitant procedures such as pupilloplasty and intraocular lens explant were undertaken in 5/18 (27.277%) patients and 1/18 patients (5.55%) experienced suprachoroidal hemorrhage. At final follow-up, BCVA was ≥6/60 in 50% patients (mean astigmatism: 4.79 ± 1.68D), and 55.55% cases experienced graft failure (90% failed within one year of surgery). The most common causes of graft failure were glaucoma (50%), glaucoma with rejection (20%), rejection (10%), retinal detachment (10%), and suprachoroidal hemorrhage (10%). The ODDS ratio (OR) of having graft failure with the following factors was postoperative secondary interventions (OR: 6), postoperative complications (OR: 2.25), prior failed graft (OR: 1.8), preoperative PAS (OR: 1.75), intraoperative concomitant procedures (OR: 1.5), preoperative glaucoma (OR: 1.33), previous surgeries (OR: 1.24), and deep corneal vessels (OR: 0.66). CONCLUSION: : All patients underlying PKP combined with glued ISHF must be counseled about suboptimal surgical outcomes. Emphasis is laid on appropriate case selection and stringent follow-up during the first year after surgery. Secondary interventions should be undertaken cautiously and judiciously in these patients.

The association of sun exposure, ultraviolet radiation effects and other risk factors for pterygium (the SURE RISK for pterygium study) in geographically diverse adult (≥40 years) rural populations of India -3rd report of the ICMR-EYE SEE study group.

PURPOSE: To determine the prevalence and risk factors for pterygium in geographically diverse regions of India. METHODS: A population-based, cross-sectional multicentric study was conducted in adults aged ≥40 years in plains, hilly and coastal regions of India. All participants underwent a detailed questionnaire-based assessment for sun exposure, usage of sun protective measures, exposure to indoor smoke, and smoking. Detailed ocular and systemic examinations were performed. Pterygium was diagnosed and graded clinically by slit-lamp examination. Association of pterygium with sociodemographic, ophthalmological, and systemic parameters was assessed. Physical environmental parameters for the study period were estimated. RESULTS: Of the 12,021 eligible subjects, 9735 (81% response rate) participated in the study. The prevalence of pterygium in any eye was 13.2% (95% CI: 12.5%-13.9%), and bilateral pterygium was 6.7% (95% CI: 6.2-7.2). The prevalence increased with age (<0.001) irrespective of sex and was highest in those aged 60-69 years (15.8%). The prevalence was highest in coastal (20.3%), followed by plains (11.2%) and hilly regions (9.1%). On multi-logistic regression, pterygium was positively associated with coastal location (P<0.001), illiteracy (P = 0.037), increasing lifetime sun exposure (P<0.001), and negatively associated with BMI ≥25 kg/m2 (P = 0.009). CONCLUSION: Pterygium prevalence is high in the rural Indian population. The association of pterygium with several potentially modifiable risk factors reflects its multifactorial etiology and provides targets for preventive measures.

Blindness and visual impairment and their causes in India: Results of a nationally representative survey.

INTRODUCTION: Avoidable blindness is a significant public health problem in India. Nationally representative RAAB surveys (Rapid Assessment of Avoidable Blindness) are being conducted periodically in the country to know the current status of blindness in the country. The current study describes the findings from the RAAB survey conducted during 2015-19 in India. METHODOLOGY: A cross-sectional, population-based survey was conducted across the entire country among persons aged 50 years and above using RAAB version 6 methodology. Presenting and pinhole visual acuity was recorded followed by lens examination using a torchlight. In order to estimate the prevalence of blindness and visual impairment in overall population in India, district weights were assigned to each of the 31 surveyed districts and the prevalence was standardized using the RAAB software. RESULTS: The overall weighted, age-gender standardized, prevalence of blindness (presenting visual acuity <3/60 in better eye) in population aged ≥50 years was 1.99% (95% CI 1.94%, 2.13%) and of visual impairment (VI) (presenting visual acuity <6/12 in better eye) was 26.68% (95% CI 26.57-27.17%). On multivariate analysis, adjusted odds ratio showed that blindness was associated with age ≥ 80 years (OR = 20.3, 95% CI: 15.6-26.4) and being illiterate (OR = 5.6, 95% CI: 3.6-8.9). Blindness was not found to be significantly associated with either gender or locality. CONCLUSION: The results of the survey demonstrate that currently more than one fourth of persons aged 50 years and above are visually impaired (PVA<6/12 in better eye) in India. The prevalence of blindness among them is 1.99%, and older age and illiteracy are significantly associated with blindness. Major causes of blindness included cataract (66.2%), corneal opacity (CO) (8.2%), cataract surgical complications (7.2%), posterior segment disorders (5.9%) and glaucoma (5.5%). The proportion of blindness and visual impairment that is due to avoidable causes include 92.9% and 97.4% respectively.

Temperature-Dependent Activity of Motor Proteins: Energetics and Their Implications for Collective Behavior.

Molecular motor proteins are an extremely important component of the cellular transport system that harness chemical energy derived from ATP hydrolysis to carry out directed mechanical motion inside the cells. Transport properties of these motors such as processivity, velocity, and their load dependence have been well established through single-molecule experiments. Temperature dependent biophysical properties of molecular motors are now being probed using single-molecule experiments. Additionally, the temperature dependent biochemical properties of motors (ATPase activity) are probed to understand the underlying mechanisms and their possible implications on the enzymatic activity of motor proteins. These experiments in turn have revealed their activation energies and how they compare with the thermal energy available from the surrounding medium. In this review, we summarize such temperature dependent biophysical and biochemical properties of linear and rotary motor proteins and their implications for collective function during intracellular transport and cellular movement, respectively.

Intralenticular metallic foreign body 'locked-in' the posterior capsule and the utility of multimodal imaging.

Intraocular foreign bodies (FBs) are common ocular injuries reporting to the emergency services all over the world. The authors highlight the findings and surgical management of a case of intralenticular metallic FB following an injury while using chisel and hammer. The ocular path of the FB (2 mm) could be traced from a self-sealed corneal perforation, extending through the anterior capsule rupture, terminating at the posterior capsule, forming a posterior capsule tent with a part embedded in clear lens. Preoperative ultrasound biomicroscopy gave clues on posterior capsule integrity and the exact site of FB, and helped prognosticate and plan the surgical management of the case. The 'locked-in' FB was extracted after clear lens aspiration and posterior capsulorrhexis. The posterior capsule acted as a natural barrier between anterior and posterior segment, where the FB was found embedded.

Experimental evaluation of safety and efficacy of plasma-treated poly-ε-caprolactone membrane as a substitute for human amniotic membrane in treating corneal epithelial defects in rabbit eyes.

PURPOSE: To evaluate biocompatibility and safety of plasma-treated poly-ε-caprolactone (pPCL) membrane compared to the human amniotic membrane in the healing of corneal epithelial defects in an experimental model. METHODS: This is a prospective, randomized animal study including 12 rabbits. Circular epithelial injury measuring 6 mm in diameter was induced over the central cornea of one eye in twelve rabbits. The rabbits were randomized into two groups; in group A, the defect was covered with human amniotic membrane, while in group B, an artificial membrane made of bio-polymer plasma-treated poly-ε-caprolactone was grafted. Six rabbits were euthanized after 1 month and the other six after 3 months and the corneal epithelium was evaluated histopathologically and with immunohistochemistry. RESULTS: Light microscopy of the corneal tissue performed after 1 month and 3 months demonstrated similar findings with no significant complications in either group. Immunohistochemistry with anti-CK-3 antibody showed characteristic corneal phenotype in the healed epithelium. In eyes grafted with pPCL membrane, epithelial healing as estimated by a decrease in size of the defect was significantly better than the group treated with the human amniotic membrane at all time periods monitored (P < 0.05), except day 1 (P = 0.83). The percentage reduction in the size of the epithelial defect was also significantly more in the pPCL membrane group as compared to the human amniotic membrane at all time periods (P < 0.05 at all observations) post-implantation except day 1 (P = 0.73). CONCLUSION: Plasma-treated poly-ε-caprolactone membrane is safe, biocompatible, and effective in the healing of corneal epithelial defects in rabbits.

A deep learning-based COVID-19 automatic diagnostic framework using chest X-ray images.

The lethal novel coronavirus disease 2019 (COVID-19) pandemic is affecting the health of the global population severely, and a huge number of people may have to be screened in the future. There is a need for effective and reliable systems that perform automatic detection and mass screening of COVID-19 as a quick alternative diagnostic option to control its spread. A robust deep learning-based system is proposed to detect the COVID-19 using chest X-ray images. Infected patient's chest X-ray images reveal numerous opacities (denser, confluent, and more profuse) in comparison to healthy lungs images which are used by a deep learning algorithm to generate a model to facilitate an accurate diagnostics for multi-class classification (COVID vs. normal vs. bacterial pneumonia vs. viral pneumonia) and binary classification (COVID-19 vs. non-COVID). COVID-19 positive images have been used for training and model performance assessment from several hospitals of India and also from countries like Australia, Belgium, Canada, China, Egypt, Germany, Iran, Israel, Italy, Korea, Spain, Taiwan, USA, and Vietnam. The data were divided into training, validation and test sets. The average test accuracy of 97.11 ± 2.71% was achieved for multi-class (COVID vs. normal vs. pneumonia) and 99.81% for binary classification (COVID-19 vs. non-COVID). The proposed model performs rapid disease detection in 0.137 s per image in a system equipped with a GPU and can reduce the workload of radiologists by classifying thousands of images on a single click to generate a probabilistic report in real-time.

Intralenticular changes in eyes with mature senile cataract on modified posterior segment optical coherence tomography.

PURPOSE: To study the morphological changes within mature senile cataracts on modified posterior segment optical coherence tomography (OCT). METHODS: A cross-sectional observational study recruiting patients of mature cataracts admitted for elective cataract surgery in tertiary eye care. A modified OCT imaging of the lens was done and lenticular findings were noted by a single observer. Corresponding slit-lamp biomicroscopic findings and intraoperative experiences were also noted by a second observer and respective surgeons. RESULTS: Forty-four eyes of 44 patients were included. The mean age of patients was 65 ± 5.7 years. The intralenticular findings were uniform in groups of eyes, and they were characterized into three stages. First was a stage of early lamellar separation where small intralenticular clefts were noted superficially. Second was the stage of established lamellar separation where crescentic fluid clefts appeared interspersed between the lens fibers, and the depth increased as a function of severity. Both these stages did not show any distinct slit-lamp or intraoperative findings. A third stage of liquefaction identified as extensive lamellar separation with subcapsular fluid pockets. This was also reflected in slit-lamp biomicroscopy, showing the hydrated cortex with intraoperative challenges. Two cases showed peculiar changes, one of a hyperreflective subcapsular sheath and another of superficial nuclear lamellar separation. CONCLUSION: Mature cataracts may also show graded progression, which could be delineated on lenticular OCT. This could be of immense help in pre-operative planning and optimal management of these high-risk cases.

Role of Conjunctival Ultraviolet Autofluorescence in Ocular Surface Squamous Neoplasia.

OBJECTIVE: To evaluate the adjunctive role of conjunctival autofluorescence in the management of ocular surface squamous neoplasia (OSSN). MATERIALS AND METHODS: Seventeen patients with clinically diagnosed OSSN were included. Morphological characteristics, type of OSSN, and autofluorescence photographs of the lesion were captured. Presence and area of conjunctival ultraviolet autofluorescence (CUVAF) were the main outcome measures. RESULTS: Overall, 17 patients with 15 (88%) primary and 2 (12%) recurrent OSSN were included. Common locations were temporal (n = 10), nasal (n = 5), and diffuse variety (n = 2). Morphologically, there were 4 (22.2%) nodular, 4 (22.2%) leucoplakic, 3 (16.7%) gelatinous, and 1 (5.5%) each of papillary, nodulo-ulcerative, and diffuse variety. Mixed morphology was present in 4 eyes (22.2%). Sixteen of 18 eyes (88.9%) with OSSN displayed autofluorescence on CUVAF images. The mean area of CUVAF was 15.82 mm2 (10.77-19.59 mm2). Autofluorescence was reported in 8 eyes (44.4%) which had negative reports on impression cytology. CONCLUSIONS: Conjunctival autofluorescence was seen in the majority of cases with OSSN, in spite of negative cytology reports. Our study demonstrates that CUVAF may serve as an effective ancillary, non-invasive, and resource-friendly tool for supplementing the clinical diagnosis of OSSN, especially in diffuse and recurrent lesions that are not amenable to surgical intervention.

Preoperative assessment of posterior capsular integrity using a posterior segment OCT with a +20 D lens: The 'conical sign' to suggest capsular deficiency in posterior polar cataracts.

PURPOSE: To study the morphology of posterior polar cataracts and posterior lens capsules using modified posterior segment optical coherence tomography (m-OCT). SETTING: Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India. DESIGN: A prospective observational case series. METHODS: Patients with clinically diagnosed posterior polar cataracts were included. The routine posterior segment OCT was modified by placing an aspheric +20.00 diopter lens along its aperture, enabling it to visualize the anterior segment structures. Cases of posterior polar cataract were assessed preoperatively using this method to study the morphology of posterior lens cortex and the posterior capsule. All m-OCT observations were performed by 2 observers, and findings were recorded. RESULTS: A total of 26 eyes of 17 patients were included. The mean age of patients was 53 years. The morphology of the cataract appeared as hyperreflective opacity just anterior to the posterior capsule, subsequently involving it, and with variable hyporeflective spaces. An intact posterior capsule showed a regularly convex contour, whereas a loss in the tracing of posterior capsule at the paracentral region and disturbance in contour with a localized protrusion of lens matter (the conical sign) depicted a possible posterior capsule dehiscence. Four (15.38%) of 26 eyes showed the conical sign, and this posterior capsule defect was confirmed intraoperatively in all cases. CONCLUSIONS: In posterior polar cataracts, the conical sign could be a valuable clue to predict preexisting posterior capsule dehiscence and could be identified on a m-OCT.

Interplay between hereditary and environmental factors to establish an in vitro disease model of keratoconus.

Keratoconus (KC) is a bilateral corneal dystrophy and a multifactorial, multigenic disorder with an etiology involving a strong environmental component and complex inheritance patterns. The underlying pathophysiology of KC is poorly understood because of potential crosstalk between genetic-epigenetic variants possibly triggered by the environmental factors. Here, we decode the etiopathological basis of KC using genomic, transcriptomic, proteomic and metabolic approaches. The lack of relevant models that accurately imitate this condition has been particularly limiting in terms of the effective management of KC. Tissue-engineered in vitro models of KC could address this need and generate valuable insights into its etiopathology for the establishment of disease models to accelerate drug discovery.

Optimal refinement of residents' surgical skills by training on induced goat's eye corneoscleral perforation.

Surgical skill enhancement for the residents under training can be performed through various efforts. Here in this report, the authors describe a technique of corneoscleral perforation repair on goat's eye, as the tissue resemblance and the reality of experience while performing crucial steps are similar to human eyes. Beginning from tissue handling, optimal suture placement was taught with an intention to impart quality techniques of traumatic globe injury repair. Therefore, rather than training on expensive artificial eye model, training budding surgeons on goat's eye gives much more realistic tissue handling experiences in the presence of constant challenges almost similar to human eyes.