Optimization of biometry for best refractive outcome in cataract surgery.

High-precision biometry and accurate intraocular lens (IOL) power calculation have become essential components of cataract surgery. In clinical practice, IOL power calculation involves measuring parameters such as corneal power and axial length and then applying a power calculation formula. The importance of posterior corneal curvature in determining the true power of the cornea is increasingly being recognized, and newer investigative modalities that can estimate both the anterior and posterior corneal power are becoming the standard of care. Optical biometry, especially using swept-source biometers, with an accuracy of 0.01-0.02 mm, has become the state-of-the-art method in biometry. With the evolution of IOL formulas, the ultimate goal of achieving a given target refraction has also moved closer to accuracy. However, despite these technological efforts to standardize and calibrate methods of IOL power calculation, achieving a mean absolute error of zero for every patient undergoing cataract surgery may not be possible. This is due to inherent consistent bias and systematic errors in the measurement devices, IOL formulas, and the individual bias of the surgeon. Optimization and personalization of lens constants allow for the incorporation of these systematic errors as well as individual bias, thereby further improving IOL power prediction accuracy. Our review provides a comprehensive overview of parameters for accurate biometry, along with considerations to enhance IOL power prediction accuracy through optimization and personalization. We conducted a detailed search in PubMed and Google Scholar by using a combination of MeSH terms and specific keywords such as "ocular biometry," "IOL power calculations," "prediction accuracy of refractive outcome in cataract surgery," "effective lens position," "intraocular lens calculation formulas," and "optimization of A-constants" to find relevant literature. We identified and analyzed 121 relevant articles, and their findings were included.

Central Retinal Artery Occlusion With Triple Cilioretinal Artery Sparing.

We report a rare case of central retinal artery occlusion (CRAO) with triple cilioretinal artery sparing in a 76-year-old male with hypertension who presented with sudden diminution of vision in the left eye (OS) for one day. Optical coherence tomography angiography (OCTA) demonstrated the presence of three cilioretinal arteries and the absence of flow signals in the rest of the macula. Primary ophthalmic treatment was instituted immediately in the form of ocular massage, and acetazolamide 500 mg per oral (PO) stat was given. Systemic investigations revealed a significant blockage in coronary circulation on coronary angiography and an atheromatous plaque at the origin of the left internal carotid artery with 50% stenosis on digital subtraction angiography. Systemic anticoagulants and lipid-lowering agents (statins) were initiated by the cardiologist. Percutaneous transluminal coronary angioplasty was subsequently performed. At the eight-week follow-up visit, best-corrected visual acuity had improved to 2/60 OS. Fundus examination of the OS revealed optic disc pallor with normal retinal background. Spectral-domain optical coherence tomography showed diffuse retinal thinning except in the area supplied by the three patent cilioretinal arteries. En face OCTA OS showed restoration of retinal flow signal in the macula. Non-invasive imaging (OCTA) is critical in establishing early diagnosis and initiating prompt treatment in this ocular emergency with underlying potentially life-threatening systemic associations.

Pediatric Lupus Retinopathy: A Rare Manifestation of a Grave Systemic Disorder.

We describe a rare case of pediatric systemic lupus erythematosus (pSLE) and its successful management. A nine-year-old female presented with bilateral diminution of vision, fever, and rash in the malar region, chest, abdomen, back, and arms for three months. Clinical examination and multimodal imaging revealed bilateral extensive retinal vasculitis with macular edema. Laboratory investigations revealed anemia, leucopenia, positive serum antinuclear antibody (ANA), and anti-extractable nuclear antigen (ENA) antibodies. A diagnosis of pediatric lupus retinopathy was made. Ocular and systemic manifestations responded well to intense systemic immunosuppression (pulse intravenous {IV} methylprednisolone, oral prednisolone and hydroxychloroquine {HCQ}, six cycles of IV cyclophosphamide, and oral azathioprine) along with topical steroids and laser photocoagulation, over the next 10 months. Though ocular manifestations are not a part of the diagnostic criteria for SLE, they may be markers of active systemic disease. Ophthalmologists and rheumatologists must treat this complex disease in tandem in order to provide optimum patient care.

Multimodal Imaging in a Case of Chronic Sympathetic Ophthalmia.

We report a case of chronic sympathetic ophthalmia (SO) in a one-eyed patient who was successfully managed with systemic immunosuppression therapy. A 77-year-old one-eyed female presented with progressive diminution of vision in the left eye (OS) for one month. She had previously undergone a right eye (OD) pars plana vitrectomy elsewhere for exogenous post-operative endophthalmitis (after manual small incision cataract surgery five months ago), following which she developed phthisis. Granulomatous panuveitis and advanced cataract were noted in the OS. Findings on multimodal imaging, including spectral domain optical coherence tomography (SD-OCT), fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA), and B-scan ultrasonography, were consistent with those of chronic SO. Promptly, oral steroids and systemic immunosuppressants were initiated under the supervision of a rheumatologist. At the three-week follow-up, complete resolution of clinical signs was observed on multimodal imaging. Chronic SO may present with ambiguous clinical signs, leading to a diagnostic dilemma. This may cause a delay in initiating treatment, which can prove to be highly detrimental, especially in one-eyed patients. Multimodal imaging is critical in excluding differential diagnoses and proves to be indispensable in the timely management of this sight-threatening condition.

A Systematic Review of the Risk of Non-alcoholic Fatty Liver Disease in Women With Polycystic Ovary Syndrome.

Polycystic ovary syndrome (PCOS) is a complex hormonal disorder associated with complications throughout various body organs. Previous studies have shown evidence of liver disease in some women with PCOS. In this study, we attempted to explore the risk of non-alcoholic fatty liver disease (NAFLD) in PCOS women and the specific factors involved in its development. We searched PubMed, PubMed Central, Medline, and ScienceDirect for articles related to the topic, screened those articles according to our inclusion/exclusion criteria, and conducted a thorough quality check using various quality appraisal tools to select articles relevant to our research. The process was conducted according to Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) Checklist 2020. We selected 11 high-quality observational studies for our review. Studies from various countries were included, and all studies demonstrated an increased prevalence of NAFLD in PCOS patients compared to healthy controls. Although insulin resistance, obesity, and increased androgens contribute to the increase in the risk of NAFLD in these patients, hyperandrogenism was the most influential risk factor in four of these studies. Two studies explored the degree of NAFLD in these patients using transient elastography (TE). They concluded that PCOS was significantly associated with hepatic steatosis (HS) rather than hepatic fibrosis in most patients. PCOS patients have an increased risk of developing NAFLD, particularly HS, and hyperandrogenism seems to be the main determinant. Therefore, effort should be put into screening and monitoring these patients to manage the disease. TE may be a useful method for monitoring the natural history of NAFLD in these patients, which requires further exploration.

Central retinal vein occlusion post ChAdOx1 nCoV-19 vaccination - can it be explained by the two-hit hypothesis?

PURPOSE: To report a case of central retinal vein occlusion (CRVO) seven days following the first dose of ChAdOx1 nCoV-19 vaccine and propose a hypothesis for the possible underlying pathogenesis. OBSERVATION: A 31-year-old male presented with CRVO with cystoid macular edema, one week after receiving his first ChAdOx1 nCoV-19 vaccine dose. Apart from mild hyperhomocysteinemia, no major thrombophilic or systemic risk factors were found. Anti-platelet factor 4 antibodies, specific for vaccine-induced immune thrombotic thrombocytopenia, were also negative. However, he tested strongly positive (> 250 U/mL) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG spike antibodies, 2 weeks post the first dose - suggestive of a prior subclinical infection. CONCLUSION: COVID-19 is known to be associated with an altered host one-carbon metabolism resulting in hyperhomocysteinemia. We hypothesize that a prior subclinical infection with COVID-19, the first hit, may have led to hyperhomocysteinemia in our patient and vaccination must have been the second hit that triggered the thrombotic event. Further studies, including correlation of thrombotic complications with IgG antibody titres post-vaccination, are essential in order to better understand the pathogenesis of such events.

Exploring the Efficacy of Alirocumab and Evolocumab in Reducing Low-Density Lipoprotein (LDL) Cholesterol Levels in Patients With Familial Hypercholesterolemia: A Systematic Review.

Patients with familial hypercholesterolemia (FH) have an increased risk of having abnormally high low-density lipoprotein cholesterol (LDL-C) levels. One of the main groups of drugs used for FH is statins. However, even with statins, most patients with FH do not achieve their pre-defined therapeutic LDL-C goals. Therefore, proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) serve to decrease LDL-C levels in that population. A total of 838 articles were found after searching the databases of PubMed, MEDLINE, and Cochrane Library. After including only full-text peer-reviewed articles published in the last 10 years, 67 articles remained. Thirteen articles were put through the Cochrane bias assessment tool to screen for bias. After a strict quality assessment based on the criteria, eight articles were extracted and included in this systematic review. The data extraction from these studies showed that alirocumab and evolocumab were efficacious in decreasing LDL-C levels and achieving the pre-defined LDL-C goals. Many parameters influenced the strength of the LDL-C reduction: sample size of the population, genetic structure of the patients affected by FH, length of the trial, or baseline lipid-lowering therapy used. Therefore, one must consider several other factors while evaluating the percent reduction of PCSK9i. This review is limited because it did not comment on these drugs' cardiovascular outcomes or mortality benefits. In addition, some of the articles used in this systematic review have small sample sizes and short trial times, limiting the long-term evaluation of these drugs.

Efficacy of Dengue Vaccines in the Prevention of Severe Dengue in Children: A Systematic Review.

Dengue is a vector-borne disease caused by the dengue virus (DENV) and is a major health concern worldwide, particularly in regions of endemic disease. Dengue usually presents as a self-limited febrile illness. In some cases, more severe forms with hemorrhage and shock can occur, and children are especially prone to develop it. These forms can be lethal without appropriate management, and no antiviral treatment exists today. In the absence of a curative treatment for dengue, its clinical prevention remains essential. One vaccine - the chimeric yellow fever-dengue-tetravalent dengue vaccine (CYD-TDV) - has been approved for use in some populations, and several others are currently in development, including Takeda's tetravalent dengue vaccine candidate (TAK-003). This study is a systematic review of the current literature realized to evaluate the efficacy of the dengue vaccines in preventing severe dengue in children. This review focuses on the vaccines CYD-TDV and TAK-003. This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, PubMed Central (PMC), Medical Literature Analysis and Retrieval System Online (MEDLINE), Cochrane Library, and Google Scholar were the databases used to find the relevant data. The articles were selected using specific inclusion and exclusion criteria, and quality appraisal was realized with standardized quality assessment tools. Overall, our study shows that the dengue vaccines CYD-TDV and TAK-003 confer protection against severe dengue in children. Some distinctions exist depending on the vaccine type, the age, and the dengue serostatus of patients. While demonstrating encouraging results, this review also emphasizes the need for more in-depth studies about the safety and efficacy of dengue vaccines.

Role of Vitamin D Deficiency in Increased Susceptibility to Respiratory Infections Among Children: A Systematic Review.

Vitamin D has several roles in the immune system besides its effects on bone metabolism. Acute respiratory infections are common infections in children. Severe lower respiratory tract infections (LRTIs) even cause death in children, especially in those less than five years of age. Our study aims to examine whether children with vitamin D deficiency are susceptible to respiratory infections and to study the association between vitamin D deficiency and the severity of respiratory infections. We comprehensively searched research articles in PubMed, ScienceDirect, and Cochrane library databases. The main keywords were vitamin D deficiency, respiratory infections, and children. We used Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines to conduct this systematic review. The initial search showed 16,120 papers. A meticulous screening of research articles using the eligibility criteria and quality appraisal tools was done. Finally, 10 research articles qualified for this systematic review, including eight case-control studies, one randomized controlled trial (RCT), and one cohort study. Seven of 10 research studies reviewed found that children with low vitamin D levels are susceptible to respiratory infections. Five studies discussed the severity of respiratory infections and low vitamin D levels. This systematic review concluded that children with low vitamin D levels are prone to developing respiratory infections. But we could not find a conclusive association between the severity of respiratory infections and low vitamin D levels.

Association Between Helicobacter pylori Infection and the Risk of Pancreatic Cancer: A Systematic Review Based on Observational Studies.

Helicobacter pylori (H. pylori) bacterial infection has long been scrutinized as one of the potential risk factors for the development of pancreatic cancer with quite inconsistent and unequivocal data. Little is known about the risk factors involved with this malignancy. In this systematic review, we aimed to examine the relationship between H. pylori infection and pancreatic cancer based on the evidence from the existing observational studies across the world. We searched major electronic databases such as PubMed, MEDLINE, Science Direct, and Cochrane Library. After a careful and thorough screening process, we selected 15 observation studies for this systematic review. Six of 15 studies found a significant association between H. pylori infection and pancreatic cancer. Additionally, four of these studies found a significant relationship between the cytotoxin-associated gene A strain of H. pylori and pancreatic cancer. Based on the evidence from the selected studies, a weak association was observed between H. pylori infection and cancer of the pancreas, especially in European and Asian populations compared to the North American population. The cross-sectional evidence from the case-control studies only suggests the existence of an association but does not provide substantial evidence of the causative relationship. Further large-scale, prospective cohort studies are warranted in the future to understand this contradictory relationship better.

The Impact of the COVID-19 Pandemic on Myopia Progression in Children: A Systematic Review.

Myopia is the most common refractive error among children. The coronavirus disease 2019 (COVID-19) pandemic has affected children's health in many ways. Policy changes due to the COVID-19 pandemic, such as home quarantine and online schooling, have been proposed as causes for the increased risk of myopia progression. During strict home quarantine, children spend less time outdoors and more time using electronic devices which are important risk factors associated with myopia. Our systematic review aims to assess the relationship between myopia progression and these risk factors in children. We did the literature search from PubMed, Google Scholar, and ScienceDirect. A total of 10 research papers were selected for final review using the Preferred Reporting Item for Systematic Review and Meta-Analyses (PRISMA) guidelines. The research articles used had a quality of more than 70%. The quality of these articles was determined using the Joanna Briggs Institute (JBI) tool. Our review included eight cross-sectional and two cohort studies. Most of these studies used questionnaires to assess the risk factors of myopia. Standardized ocular examinations were done in most studies to measure visual acuity, spherical equivalent, and axial lengths. Our study found that the progression of myopia was affected by the reduced time spent outdoors and increased screen time during the pandemic. We also found that children's increased use of electronic devices, such as mobile phones and tablets, has significantly affected myopia progression during the pandemic.

A Systematic Review on Whether an Association Exists Between Adolescent Obesity and Idiopathic Intracranial Hypertension.

Pseudotumor cerebri syndrome (PTCS)/idiopathic intracranial hypertension (IIH) is a clinical presentation appertaining to signs/symptoms of raised intracranial pressure, like headache and papilledema. It is an uncommon but clinically significant cause of morbidity such as permanent vision loss. It is crucial to understand if idiopathic intracranial hypertension (IIH) is on the rise in adolescents, it is probably due to the rising prevalence of obesity worldwide. Our study aimed to find an association between obesity and IIH in adolescents. We utilized Preferred Reporting Items for Systematic Review and Meta-Analysis 2020 (PRISMA) guidelines to run this systematic review. Many publications related to the topic in the discussion were scrutinized through a comprehensive database search. We filtered them down to a final count of 10 articles after utilizing our inclusion/exclusion criteria and assessing the quality of work. In these final papers, we identified several possibilities to explain the link between obesity and IIH in adolescents. Overweight and obese adolescents were found to have a significantly increased risk of IIH development, with a more severe clinical picture seen in morbidly obese female patients.

Regression of choroidal metastasis from breast carcinoma with palbociclib.

BACKGROUND: Uveal metastasis is reported to be the most common intraocular malignancy. The most common site of origin of ocular metastases in females is the breast. In some cases, uveal metastatic lesions respond to systemic chemotherapy. We report a case of a patient who developed choroidal metastasis, while on endocrine therapy with selective estrogen receptor modulator (SERM), tamoxifen, for estrogen receptor (ER) positive, progesterone receptor (PR) positive and (human epidermal growth factor receptor 2) HER2 negative primary breast carcinoma, which then regressed following systemic chemotherapy with palbociclib. CASE DESCRIPTION: An 83-year-old female, with a history of modified radical mastectomy, chemotherapy and radiation therapy for infiltrating duct carcinoma of the breast, presented with a choroidal metastatic lesion in the left eye along with liver and lung metastases, 3 years after the primary carcinoma was treated. At the time of presentation, she was on tamoxifen. The choroidal tumor showed regression after the introduction of palbociclib, a cyclin-dependent kinase 4/6 (CDK4/6) inhibitor. CONCLUSION: This report highlights the use of palbociclib, in the palliative treatment of choroidal metastasis from primary breast cancer. The use of chemotherapy for choroidal metastasis can help avoid external beam radiation therapy and its concurrent side effects. Although there are a few reports involving the use of palbociclib for metastatic breast carcinoma, all of those have been in conjunction with and/or following non-response to other treatment modalities. Ours is the first report wherein palbociclib has been used as the first-line palliative chemotherapy and helped in regression of choroidal metastasis.

Utility of N-terminal (NT)-Brain Natriuretic Peptide (proBNP) in the Diagnosis and Prognosis of Pregnancy Associated Cardiovascular Conditions: A Systematic Review.

Cardiovascular disease includes many diseases such as heart failure, cardiomyopathy, valvular disease, pericardial disease, peripheral vascular disease, rheumatic heart disease, and vascular disease to name a few. Cardiovascular disease in pregnancy is on the rise especially with women being pregnant at an older age. Brain natriuretic peptide (BNP) could be a factor in determining the severity. BNP is elevated in heart failure. This study will attempt to determine the relationship between BNP and pregnancy outcomes in women with heart failure. A keyword combination search was performed using varying databases. Inclusion and exclusion criteria were implemented and relevant articles were obtained to formulate ideas to support the topic. BNP, the amino acid peptide, is secreted by both atrial and ventricular monocytes. BNP and N-terminal (NT)-pro hormone BNP (NT-proBNP) are elevated in heart failure and seen in pregnant women alike. Within six to 12 weeks it returns to normal levels. Normal levels were shown to have good pregnancy outcomes in that the baby is healthy with normal birth weight and the mother is free of cardiovascular complications, whereas at elevated levels the pregnancy outcome was not favorable. NT-proBNP, when elevated in the pregnant patient, is a predictor of poor pregnancy outcomes, especially in patients with precursors. Testing for this peptide in pregnant women during the early stages of pregnancy could help determine the best course of action for a better outcome.

Preferred practice patterns for photorefractive keratectomy surgery.

Over the past two decades, excimer laser-based refractive surgery procedures have been successfully established for their safety and satisfactory visual outcomes. Surface ablation procedures or photorefractive keratectomy (PRK) are practised commonly for the correction of refractive errors including myopia, astigmatism and hyperopia. Satisfactory visual outcomes are achieved in majority of cases, although a very small percentage have issues related to corneal haze, regression, and its associated visual disturbances. To ensure optimal outcomes and to minimize complications, certain keys to success have been designed on the basis of the current review of literature on surface ablation procedures.

A new normal with cataract surgery during COVID-19 pandemic.

Cataract is the second leading cause of preventable blindness on the globe. Several programs across the country have been running efficiently to increase the cataract surgical rates and decrease blindness due to cataract. The current COVID-19 pandemic has led to a complete halt of these programs and thus accumulating all the elective cataract procedures. At present with the better understanding of the safety precautions among the health care workers and general population the Government of India (GoI) has given clearance for functioning of eye care facilities. In order to facilitate smooth functioning of every clinic, in this paper, we prepared preferred practice pattern based on consensus discussions between leading ophthalmologists in India including representatives from major governmental and private institutions as well as the All India Ophthalmological Society leadership. These guidelines will be applicable to all practice settings including tertiary institutions, corporate and group practices and individual eye clinics. The guidelines include triage, use of personal protective equipment, precautions to be taken in the OPD and operating room as well for elective cataract screening and surgery. These guidelines have been prepared based on current situation but are expected to evolve over a period of time based on the ongoing pandemic and guidelines from GoI.

Diagnostic dilemma in a neglected case of fetus-in-fetu solved with Magnetic Resonance Imaging and MDCT--a case report and review of literature.

Fetus-in-fetu (FIF) is a rare anomaly in which a vertebrate fetus is enclosed within the body of its twin in diamniotic monochorionic pregnancy. To the best of our knowledge, fewer than 100 cases have been reported in literature. Although a wide variety of presentations have been described in clinical reports, the characteristic features on MRI which distinguish FIF from teratoma have not been well delineated. Here we present a case of fetus-in-fetu in which characteristic MDCT and MR findings were used to diagnose FIF preoperatively and successfully differentiate it from teratoma. Although both CT and MRI can be used for definitive preoperative diagnosis of FIF, MRI is an ideal imaging modality due to inherent high tissue contrast and spatial resolution. Furthermore, MRI obviates the need for iodine contrast and eliminates the risk of ionizing radiation. We emphasize that MRI is an ideal valuable diagnostic tool for definite preoperative diagnosis of FIF and surgical planning.