Do poor environmental conditions drive trachoma transmission in Burundi? A mathematical modelling study

Trachoma is an infectious disease and it is the leading cause of preventable blindness worldwide. To achieve its elimination, the World Health Organization set a goal of reducing the prevalence in endemic areas to less than 55% by 2020, utilizing the SAFE (surgery, antibiotics, facial cleanliness, environmental improvement) strategy. However, in Burundi, trachoma prevalences of greater than 55% are still reported in 11 districts and it is hypothesized that this is due to the poor implementation of the environmental improvement factor of the SAFE strategy. In this paper, a model based on an ordinary differential equation, which includes an environmental transmission component, is developed and analysed. The model is calibrated to recent field data and is used to estimate the reductions in trachoma that would have occurred if adequate environmental improvements were implemented in Burundi. Given the assumptions in the model, it is clear that environmental improvement should be considered as a key component of the SAFE strategy and, hence, it is crucial for eliminating trachoma in Burundi. doi:10.1017/S1446181121000389

DO POOR ENVIRONMENTAL CONDITIONS DRIVE TRACHOMA TRANSMISSION IN BURUNDI? A MATHEMATICAL MODELLING STUDY

Trachoma is an infectious disease and it is the leading cause of preventable blindness worldwide. To achieve its elimination, the World Health Organization set a goal of reducing the prevalence in endemic areas to less than $5$ % by 2020, utilizing the SAFE (surgery, antibiotics, facial cleanliness, environmental improvement) strategy. However, in Burundi, trachoma prevalences of greater than $5$ % are still reported in 11 districts and it is hypothesized that this is due to the poor implementation of the environmental improvement factor of the SAFE strategy. In this paper, a model based on an ordinary differential equation, which includes an environmental transmission component, is developed and analysed. The model is calibrated to recent field data and is used to estimate the reductions in trachoma that would have occurred if adequate environmental improvements were implemented in Burundi. Given the assumptions in the model, it is clear that environmental improvement should be considered as a key component of the SAFE strategy and, hence, it is crucial for eliminating trachoma in Burundi.

Association between FVL G1691A, MTHFR C677T and A1298C Polymorphisms with Risk for Retinopathy of PrematurityAssociation between FVL G1691A, MTHFR C677T and A1298C Polymorphisms with Risk for Retinopathy of Prematurity

Background: Retinopathy of prematurity (ROP) is an important cause of preventable blindness in children. The aim of this study was to examine the association of the polymorphisms at Factor V Leiden (FVL) and methylene tetrahydrofolate reductase (MTHFR) gene with risk of ROP. Methods: A total of 106 neonates with ROP and 110 healthy neonates were enrolled. The FVL G1691A and MTHFR C677T and A1298C polymorphisms were genotyped by PCR-RFLP assay. Results: There was a significant association between FVL G1691A polymorphism and an increased risk of ROP. However, the MTHFR C677T and A1298C polymorphisms were not associated with risk of ROP. Conclusion: FVL G1691A polymorphism may be risk factor for development of ROP in neonates. However, there was no significant association between MTHFR C677T and A1298C polymorphisms and risk of ROP. However, it is critical that larger and well-designed studies in different ethnicities are needed to confirm our conclusions.

1338 Bariatric Surgery as a Viable Treatment for Idiopathic Intracranial Hypertension: A Case Series

Introduction Idiopathic Intracranial Hypertension (IIH) is a significant cause of preventable blindness. Patients also suffer from debilitating headaches, pulsatile tinnitus, nausea, vomiting, photophobia, and radicular pain. If IIH continues to rise as predicted, treatment cost will increase to 462.7 million GBP annually by 2030. Weight loss is the only proven disease-modifying therapy for reversal of IIH. Bariatric surgery is an attractive treatment option due to superlative weight loss and reversal of related comorbidities. The case series aims to raise awareness of bariatric surgery as a safe and effective treatment modality for IIH. Method The case series consists of a retrospective analysis of four patients with a pre-operative diagnosis of IIH. They were referred to our department for bariatric surgery between January to December 2018. They were followed up for a total of two years. Results In our case series, all four patients were females with a mean age of 34 years. Mean BMI reduced from 47.3 kg/m2 before surgery to 30 kg/m2 with an EWL of 76.4% at the end of two years after surgery. They all showed significant improvement or resolution in their symptoms related to IIH, and none of them required further CSF pressure reducing procedures afterwards. Conclusions Bariatric surgery is a safe and effective method of treating IIH. It is superior compared to medical management and CSF pressure reducing procedures which have high rates of recurrence.

Recent Advancements in the Medical Treatment of Diabetic Retinal Disease

Diabetic retinal disease remains one of the most common complications of diabetes mellitus (DM) and a leading cause of preventable blindness. The mainstay of management involves glycemic control, intravitreal, and laser therapy. However, intravitreal therapy commonly requires frequent hospital visits and some patients fail to achieve a significant improvement in vision. Novel and long-acting therapies targeting a range of pathways are warranted, while evidence to support optimal combinations of treatments is currently insufficient. Improved understanding of the molecular pathways involved in pathogenesis is driving the development of therapeutic agents not only targeting visible microvascular disease and metabolic derangements, but also inflammation and accelerated retinal neurodegeneration. This review summarizes the current and emerging treatments of diabetic retinal diseases and provides an insight into the future of managing this important condition.

Identification of a GrgA-Euo-HrcA Transcriptional Regulatory Network in Chlamydia

Chlamydia trachomatis is the most prevalent sexually transmitted bacterial pathogen worldwide and is a leading cause of preventable blindness in underdeveloped areas as well as some developed countries. Chlamydia carries genes that encode a limited number of known transcription factors. While Euo is thought to be critical for early chlamydial development, the functions of GrgA and HrcA in the developmental cycle are unclear.

Conventional glaucoma implants and the new MIGS devices: a comprehensive review of current options and future directions

Glaucoma is a progressive optic neuropathy that is the second leading cause of preventable blindness worldwide, after cataract formation. A rise in the intraocular pressure (IOP) is considered to be a major risk factor for glaucoma and is associated with an abnormal increase of resistance to aqueous humour outflow from the anterior chamber. Glaucoma drainage devices have been developed to provide an alternative pathway through which aqueous humour can effectively exit the anterior chamber, thereby reducing IOP. These devices include the traditional aqueous shunts with tube-plate design, as well as more recent implants, such as the trabeculectomy-modifying EX-PRESS® implant and the new minimally invasive glaucoma surgery (MIGS) devices. In this review, we will describe each implant in detail, focusing on their efficacy in reducing IOP and safety profile. Additionally, a critical and evidence-based comparison between these implants will be provided. Finally, we will propose potential developments that may help to improve the performance of current devices.

Restarting cataract surgery during the COVID-19 pandemic; a prospective study analysing 30 day outcomes after elective cataract surgery in the United Kingdom

Background Cataract is a significant cause of preventable blindness in the United Kingdom and worldwide. Prior to the COVID-19 pandemic, cataract surgery was the most commonly performed operation by the National Health Service in the United Kingdom. The aim of this study is to evaluate the safety of elective cataract surgery performed in the United Kingdom in a COVID-19 free hospital during the COVID-19 pandemic. Methods Single centre prospective observational cohort study of consecutive patients undergoing elective cataract surgery in the United Kingdom over a 3 month period from May to August 2020. Electronic medical records were reviewed and patients were contacted at 30 days post-operatively. Data collection included symptoms suggestive of COVID-19 infection, hospital admission, mortality, intra-operative and post-operative surgical complications. Results A total of 649 elective cataract surgeries were performed. Two patients (0.3%) developed worsening dyspnoea during the 30 day post-operative period, but tested negative for COVID-19 infection. Three patients (0.5%) were hospitalised, unrelated to COVID-19 infection, of which one patient (0.2%) passed. Four patients (0.6%) suffered posterior capsular rupture. 601 (93.2%) had no post-operative complications. Conclusion This study demonstrates a safe model for the resumption of elective cataract surgery during the COVID-19 pandemic, providing strict infection control measures are in place.

MYOPIA INDIAN EYES: COMPARING CALCULATED AND MEASURED AXIAL LENGTH IN YOUNG PATIENTS

Myopia is the leading cause of preventable blindness in children and young adults in the world. As age increases axial length increasing risks of myopia for causing ocular morbidity including retinal detachment, glaucoma, myopic macular degeneration, and cataracts. In India, much patient eye examination done at primary eye clinic, where to estimate axial length is difficult. Our aim of the study was to assess the reliability of formula by comparing Predicted Axial Length (AL) uses corneal radius and Spherical equivalent (SE) to the measured AL using Ocular Biometry. Method: 96 myopic eyes were included, Comprehensive eye examination with Auto-refractokeratometer using TOPCON-800 and Axial length with Ocular Biometry (IOL Master-500) Calculated Axial length with formula by using AVE-K and SE which is obtained from original Gullstrand simplified Schematic eye: AL= (24.00×AVE-K/7.80–SE×0.40) for both K-reading. Result: Mean Calculated AL(mm) was 24.67 ± .90 and Measured AL (mm) which was 24.28 ± .96mm in 9-25yr age (P<0.001) with Mean difference 0.3±0.4. All groups show statistically significant correlation between Calculate AL and Mean AL (p<0.01, r>0.9). The coefficient of determination (R2) was 82% in 9-25yr age group. Conclusion: Study provides strong agreement between Measured AL and Calculated AL. Alternate method of AL measurement with a calculated formula can be implemented in all primary eye care for predicting Axial length and managing myopic patients for monitoring myopia control.

Study of preventable causes of blindness in a tertiary care institute in Lucknow

<p class="abstract"><strong>Background:</strong> World Health Organization (WHO) in 2019, released the estimates which show that approximately 80% of the causes of blindness and severely reduced visual acuity are preventable and avoidable. The aim of the study was to assess the prevalence of preventable causes of blindness in an OPD setup in the city of Lucknow.</p><p class="abstract"><strong>Methods:</strong> Descriptive cross-sectional study was done from January, 2019 to March, 2019 at the ophthalmology department OPD, Dr Ram Manohar lohia hospital, Lucknow. Patient presenting with complains of Blurring of vision or blindness during the defined OPD days at the study place, sample size- 550. Convenience sampling, all the eligible patients who were attending the OPD on defined days during the study period. </p><p class="abstract"><strong>Results:</strong> The current study found the prevalence of blindness in the OPD based patients to be 13.5% and 25% (WHO and NPCB standards) respectively which is higher than the other reported statistics and found cataract to be the single most contributor of cause of blindness in accordance with other literature.</p><p class="abstract"><strong>Conclusions:</strong> The study demonstrates that even after the implementation of a national program (NPCB), the prevalence of blindness continues to be on the higher side and cataract remains to the most common cause of preventable blindness.</p>