Ahmad Samir Alfaar

Dr. Ahmad Samir Alfaar

Ophthalmology, Royal Liverpool University Hospital, Liverpool, UK
orcid

Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 February 2021 in The Lancet Global Health
Verified
Journal Article
Open access
RBRupert Bourne
Rupert Bourne
JSJaimie D Steinmetz
Jaimie D Steinmetz
SFSeth Flaxman
Seth Flaxman
PBPaul Svitil Briant
Paul Svitil Briant
HTHugh R Taylor
Hugh R Taylor
TVTheo Vos
Theo Vos
To contribute to the WHO initiative, VISION 2020: The Right to Sight, an assessment of global vision impairment in 2020 and temporal change is needed. We aimed to extensively update estimates of global vision loss burden, presenting estimates for 2020, temporal change over three decades between 1990-2020, and forecasts for 2050. We did a systematic review and meta-analysis of population-based surveys of eye disease from January, 1980, to October, 2018. Only studies with samples representative of the population and with clearly defined visual acuity testing protocols were included. We fitted hierarchical models to estimate 2020 prevalence (with 95% uncertainty intervals [UIs]) of mild vision impairment (presenting visual acuity ≥6/18 and <6/12), moderate and severe vision impairment (<6/18 to 3/60), and blindness (<3/60 or less than 10° visual field around central fixation); and vision impairment from uncorrected presbyopia (presenting near vision

7 January 2019 in Cancer
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Journal Article
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ASAnas M. Saad
Anas M. Saad
MGMohamed M. Gad
Mohamed M. Gad
MAMuneer J. Al‐Husseini
Muneer J. Al‐Husseini
MAMohamad A. AlKhayat
Mohamad A. AlKhayat
ARAhmad Rachid
Ahmad Rachid
HHHesham M. Hamoda
Hesham M. Hamoda

3 January 2025 in PLOS ONE
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Journal Article
Open access
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ISIyad Sultan
Iyad Sultan
Ahmad Samir AlfaarAhmad Samir Alfaar
Ahmad Samir Alfaar
YSYaseen Sultan
Yaseen Sultan
ZSZeena Salman
Zeena Salman
IQIbrahim Qaddoumi
Ibrahim Qaddoumi
Background: The SEER Registry contains U.S. cancer statistics. To assess trends in incidence and survival and the impact of demographic factors among pediatric patients with cancer, we assessed nearly 5 decades (1975–2019) of data. Methods: All patients below the age of 20 with histology-confirmed malignancy were studied. Kaplan-Meier survival curves were generated to evaluate survival trends across treatment periods and ICCC classes. JoinPoint analysis was conducted to identify changes in incidence and survival. Results: The incidence of childhood cancer increased from 14.23 cases per 100,000 children in 1975–1979 to 18.89 in 2010–2019, with an average annual percent change of 0.73. This rise was more pronounced in several cancers, including leukemias, lymphomas, brain tumors, hepatic tumors, and gonadal germ cell tumors. Age-adjusted cancer mortality decreased from 4.9 to 2.3 per 100,000. Cancer-related mortality was consistently higher in boys than in girls, and in Black children than in White children. Survival significantly improved, with 5- and 10-year survival rates rising from 63.1% to 85.2% and from 58.8% to 82.7%, respectively. Leukemias showed a substantial increase in 5-year survival from 48.2% ± 1.7% to 85.1% ± 0.4% in 2010–2019. Lymphomas also showed significant improvement, with survival increasing from 72.9% ± 1.7% to 94.2% ± 0.3%. Despite these improvements, the survival of CNS tumors, bone tumors, and sarcomas remained suboptimal, with 5-year survival estimates of approximately 60%. Our joinpoint analysis confirmed our findings but revealed an interesting increase in the incidence of lymphomas limited to the years between 2005 and 2014. Conclusion: This research elucidates advancements in survival among pediatric patients with cancer. The results offer critical perspectives on pediatric oncology, highlighting the imperative for ongoing innovation in therapeutics. Although the increase in incidence may partially stem from enhanced diagnostic capabilities and more comprehensive registration processes, the underlying causes remain unclear.

27 June 2024 in Eye
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VSVision Loss Expert Group of the Global Burden of Disease Study
Vision Loss Expert Group of the Global Burden of Disease Study
KCKatie Curran
Katie Curran
TPTunde Peto
Tunde Peto
JJJost B. Jonas
Jost B. Jonas
DFDavid Friedman
David Friedman
PZPeng Zheng
Peng Zheng
Objectives: To estimate global and regional trends from 2000 to 2020 of the number of persons visually impaired by diabetic retinopathy and their proportion of the total number of vision-impaired individuals. Methods: Data from population-based studies on eye diseases between 1980 to 2018 were compiled. Meta-regression models were performed to estimate the prevalence of blindness (presenting visual acuity <3/60) and moderate or severe vision impairment (MSVI; <6/18 to ≥3/60) attributed to DR. The estimates, with 95% uncertainty intervals [UIs], were stratified by age, sex, year, and region. Results: In 2020, 1.07 million (95% UI: 0.76, 1.51) people were blind due to DR, with nearly 3.28 million (95% UI: 2.41, 4.34) experiencing MSVI. The GBD super-regions with the highest percentage of all DR-related blindness and MSVI were Latin America and the Caribbean (6.95% [95% UI: 5.08, 9.51]) and North Africa and the Middle East (2.12% [95% UI: 1.55, 2.79]), respectively. Between 2000 and 2020, changes in DR-related blindness and MSVI were greater among females than males, predominantly in the super-regions of South Asia (blindness) and Southeast Asia, East Asia, and Oceania (MSVI). Conclusions: Given the rapid global rise in diabetes and increased life expectancy, DR is anticipated to persist as a significant public health challenge. The findings emphasise the need for gender-specific interventions and region-specific DR healthcare policies to mitigate disparities and prevent avoidable blindness. This study contributes to the expanding body of literature on the burden of DR, highlighting the need for increased global attention and investment in this research area.

18 December 2016 in International Journal of Ophthalmology
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Journal Article
Open access
WHWaleed M. Hassan
Waleed M. Hassan
MBMohamed S. Bakry
Mohamed S. Bakry
HHHousam M. Hassan
Housam M. Hassan
Ahmad Samir AlfaarAhmad Samir Alfaar
Ahmad Samir Alfaar
To determine the types and incidence of tumors affecting the orbit, conjunctiva and lacrimal glands and to study the trend line of these tumors in the United States from 1973 to 2009. We used the publicly available Surveillance, Epidemiology and End Results (SEER) database registries to determine the incidence rates. Age was adjusted to the 2000 US Standard Population. Patients were stratified according to age group, gender, race and histological grouping of tumor lesions. Three age groups were defined: 0-19, 20-49 and ≥50y. Annual percentage changes were calculated to examine trends. The overall age adjusted incidence rate was 3.39 (95%CI: 3.27-3.52) per million person-years. The tumors were more prevalent in age group ≥50 counting 9.51 (95%CI: 9.11-9.92) per million person-years. Most of the soft tissue sarcomas occurred in the young age with incidence rate of 0.35 (95%CI: 0.28-0.42) per million person-years. Lymphomas were the dominant subtype in the adult population with incidence rate of 5.74 (95%CI: 5.43-6.06) per million person-years. Incidence rates were higher in males than females with an overall rate ratio of 1.31 (95%CI: 1.21-1.41) mainly caused by the increase in carcinoma subtypes. White race had a higher tumor incidence with a rate ratio of 1.47(95%CI: 1.25-1.73) driven by the higher incidence of most histological subtypes. Orbital tumors showed a higher incidence rate followed by conjunctival and lacrimal gland tumors with incidence rates of 1.59, 1.37 and 0.43 per million person-years respectively. The trend line of overall incidence of tumors showed a significant increase (APC=3.11, 95%CI: 2.61-3.61) mainly due to increase of lymphomas. This increase was higher than the increase of lymphomas at other sites. Orbital, conjunctival and lacrimal gland malignant tumors differ among children and adults. Over the years there has been a noticeable increase in incidence rates of orbital and lacrimal gland tumors mainly caused by an increase in lymphomas and an apparent increase due to advances in diagnostic techniques. ICD-O-3 topographical coding should be improved to consider the different orbital bones and ocular structures.

19 February 2019 in Scientific Reports
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NRNadine Reichhart
Nadine Reichhart
SSSimon Schöberl
Simon Schöberl
SKSusanne Keckeis
Susanne Keckeis
Ahmad Samir AlfaarAhmad Samir Alfaar
Ahmad Samir Alfaar
CRChristophe Roubeix
Christophe Roubeix
OSOlaf Strauß
Olaf Strauß
Changes in cell function occur by specific patterns of intracellular Ca2+, activating Ca2+-sensitive proteins. The anoctamin (TMEM16) protein family has Ca2+-dependent ion channel activity, which provides transmembrane ion transport, and/or Ca2+-dependent phosphatidyl-scramblase activity. Using amino acid sequence analysis combined with measurements of ion channel function, we clarified the so far unknown Ano4 function as Ca2+-dependent, non-selective monovalent cation channel; heterologous Ano4 expression in HEK293 cells elicits Ca2+ activated conductance with weak selectivity of K+ > Na+ > Li+. Endogenously expressed Ca2+-dependent cation channels in the retinal pigment epithelium were identified as Ano4 by KO mouse-derived primary RPE cells and siRNA against Ano4. Exchanging a negatively charged amino acid in the putative pore region (AA702–855) into a positive one (E775K) turns Ano4-elicited currents into Cl− currents evidencing its importance for ion selectivity. The molecular identification of Ano4 as a Ca2+-activated cation channel advances the understanding of its role in Ca2+ signaling.