Optometry Commons^™

The Effect Of Transverse Ocular Magnification Adjustment On Macular Thickness Profile In Different Refractive Errors In Community-Based Adults, Hamed Niyazmand, Gareth Lingham, Paul G. Sanfilippo, Magdalena Blaszkowska, Maria Franchina, Seyhan Yazar, David Alonso-Caneiro, David Mackey, Samantha Sze-Yee Lee

Articles

Purpose Changes in retinal thickness are common in various ocular diseases. Transverse magnification due to differing ocular biometrics, in particular axial length, affects measurement of retinal thickness in different regions. This study evaluated the effect of axial length and refractive error on measured macular thickness in two community-based cohorts of healthy young adults.

Methods A total of 2160 eyes of 1247 community-based participants (18–30 years; 23.4% myopes, mean axial length = 23.6mm) were included in this analysis. Macular thickness measurements were obtained using a spectral-domain optical coherence tomography (which assumes an axial length of 24.385mm). Using a custom program, retinal …

Normative Data On The Foveal Avascular Zone In A Young Healthy Irish Population Using Optical Coherence Tomography Angiography, Susan M. O'Shea, Veronica O'Dwyer, Grainne Scanlon

Articles

Purpose: To establish normative data on the size, shape and vascular profile of the foveal avascular zone (FAZ) in a young, healthy, Irish population, using the Cirrus 5000 HD-OCT. Certain diseases may alter FAZ appearance. Normative databases provide normal baseline values for comparison, thus improving diagnostic ability.

Methods: One hundred and fifty-four subjects aged 18–35 years old were recruited. Superficial FAZ area, diameter, circularity, ganglion cell layer, central macular thickness (CMT), vascular perfusion and density were measured using the Cirrus 5000. Axial length was measured with the IOL Master and blood pressure was measured using the Omron sphygmomanometer. …

Regional Variations And Temporal Trends Of Childhood Myopia Prevalence In Africa: A Systematic Review And Meta-Analysis, Emmnuel Kobia Acquah, Daniel Ian Flitcroft, Prince Kwaku Akowuah, Gareth Lingham, James Loughman

Articles

Purpose: To provide contemporary and future estimates of childhood myopia prevalence in Africa.

Methods: A systematic online literature search was conducted for articles on childhood (≤18 years) myopia (spherical equivalent [SE] ≤ −0.50D; high myopia: SE ≤ −6.00D) in Africa. Population-or school-based cross-sectional studies published from 1 Jan 2000 to 30 May 2021 were included. Meta-analysis using Freeman–Tukey double arcsine transformation was performed to estimate the prevalence of childhood myopia and high myopia. Myopia prevalence from subgroup analyses for age groups and settings were used as baseline for generating a prediction model using linear regression.

Results: Forty-two studies from 19 …

Will Treating Progressive Myopia Overwhelm The Eye Care Workforce? A Workforce Modelling Study, Gareth Lingham, James Loughman, Stella Kuzmenko, Matilda Biba, Daniel Ian Flitcroft

Articles

Purpose

Treatments for myopia progression are now available, but implementing these into clinical practice will place a burden on the eye care workforce. This study estimated the full-time equivalent (FTE) workforce required to implement myopia control treatments in the UK and Ireland.

Methods

To estimate the number of 6- to 21-year-olds with myopia, two models utilising separate data sources were developed. The examination-based model used: (1) the number of primary care eye examinations conducted annually and (2) the proportion of these that are for myopic young people. The prevalence-based model used epidemiological data on the age-specific prevalence of myopia. The …

Investigation Of The Suitability Of A Commercial Radiation Sensor For Pretherapy Dosimetry Of Radioiodine Treatment Patients, Janet O'Callaghan, Dervil Cody, Jennie Cody

Articles

Radioiodine (I-131) therapy is routinely used to treat conditions of the thyroid. Dosimetry planning in advance of I-131 therapy has been shown to improve patient treatment outcomes. However, this pretherapy dosimetry step requires multiple outpatient appointments and is not feasible for patients living at greater distances. Here, the feasibility of a commercially available smartphone-operated radiation sensor (Smart Geiger Pro, Technonia) for at-home patient pretherapy dosimetry has been investigated. The influence of both treatment-specific parameters (radioisotope activity, gamma photon energy, patient size) and external factors (sensor placement and motion) on the ability of the radiation sensor to accurately quantify radiation dose …

Characterisation Of Holographic Recording In Environmentally Stable Photopolymerisable Glass, Tatsiana Mikulchyk, Pamela Stoeva, Alicja Kaworek, Mohamed Oubaha, Brian Rogers, Suzanne Martin, Dervil Cody, Izabela Naydenova

Articles

Photopolymerisable glasses are holographic recording materials which provide good recording capability, improved dimensional stability, and negligible shrinkage. Recently, a novel photopolymerisable hybrid sol-gel (PHSG) for holographic recording of volume gratings has been reported. The PHSG has significantly improved gelation time and high water resistance, both of which make it an attractive material for mass production of holographic optical elements (HOEs) with no sensitivity to ambient humidity. In order to achieve full control over the performance of the material and further improve its properties, a study of grating formation under holographic patterning is essential. This paper reports characterisation of the grating …

A Magnetic Nanoparticle-Doped Photopolymer For Holographic Recording, Muhammad Irfan, Suzanne Martin, Muhammad Ahmed Obeidi, Scott Miller, Frank Kuster, Dermot Brabazon, Izabela Naydenova

Articles

Functionalised holograms are important for applications utilising smart diffractive optical elements for light redirection, shaping and in the development of sensors/indicators. This paper reports on holographic recording in novel magnetic nanocomposites and the observed temperature change in dry layers and liquid samples exposed to alternating magnetic field (AMF). The nanocomposite consists of N-isopropylacrylamide (NIPA)-based polymer doped with magnetic nanoparticles (MNPs), and local heating is achieved through magnetic induction. Here, volume transmission holographic gratings (VTHGs) are recorded with up to 24% diffraction efficiency (DE) in the dry layers of magnetic nanocomposites. The dry layers and liquid samples are then exposed to …

Application Of Big-Data For Epidemiological Studies Of Refractive Error, Michael Moore, James Loughman, John Butler, Arne Ohlendorf, Siegfried Wahl, Daniel Ian Flitcroft

Articles

Purpose

To examine whether data sourced from electronic medical records (EMR) and a large industrial spectacle lens manufacturing database can estimate refractive error distribution within large populations as an alternative to typical population surveys of refractive error.

Subjects

A total of 555,528 patient visits from 28 Irish primary care optometry practices between the years 1980 and 2019 and 141,547,436 spectacle lens sales records from an international European lens manufacturer between the years 1998 and 2016.

Methods

Anonymized EMR data included demographic, refractive and visual acuity values. Anonymized spectacle lens data included refractive data. Spectacle lens data was separated into lenses …

Praseodymium Mid-Infrared Emission In Alf3-Based Glass Sensitized By Ytterbium, Jiquan Zhang, Mo Liu, Jin Yu, Ruicong Wang, Shijie Jia, Zijun Liu, Gerald Farrell, Shunbin Wang, Pengfei Wang

Articles

Broadband emission was obtained over 2.6 to 4.1 μm (Pr3+: 1G4→3F4, 3F3) in AlF3-based glass samples doped with different concentrations of praseodymium and 1 mol% ytterbium using a 976 nm laser pump. An efficient energy transfer process from Yb3+: 2F5/2 to Pr3+: 1G4 was analyzed through emission spectra and fluorescence lifetime values. The absorption and emission cross-sections were calculated by Füchtbauer-Ladenburg and McCumber theories and a positive gain can be obtained when P>0.3. To the best of the authors’ knowledge, this work represents the first report of broadband mid-infrared emission of Pr3+ in an AlF3-based glass. The results show …

Application Of Big-Data For Epidemiological Studies Of Refractive Error, James Loughman

Articles

To examine whether data sourced from electronic medical records (EMR) and a large industrial spectacle lens manufacturing database can estimate refractive error distribution within large populations as an alternative to typical population surveys of refractive error.

Job Satisfaction And Its Associated Factors Among Optometrists In Ghana: A Cross-Sectional Study, Kwadwo Owusu Akufo, Eldad Agyei-Manu, David Ben Kumah, Anthony Danso-Appiah, Abubakar Sadik Mohammed, Akosua Kesewah Asare, Emmanuel Kofi Addo

Articles

Job satisfaction describes an employee’s motivation and/or feeling of satisfaction towards his/her work. Globally, healthcare professionals’ turnover and retention play a critical role in the delivery of essential health services. In Ghana, however, little has been done to ascertain job satisfaction levels among human resources for eyehealth. The objective of this study therefore was to assess job satisfaction and its associated factors among optom‑ etrists in Ghana.

The Risks And Benefits Of Myopia Control, Mark A. Bullimore, Eric R. Ritchey, Sunil Shah,, Nicolas Leveziel, Rupert Bourne, Daniel Ian Flitcroft

Articles

The prevalence of myopia is increasing around the world, stimulating interest in 3 methods to slow its progression. The primary justification for slowing myopia progression is to 4 reduce the risk of vision loss through sight-threatening ocular pathology in later life. The paper 5 analyzes whether the potential benefits of slowing myopia progression by one diopter justify the 6 potential risks associated with treatments.

School Performance And Undetected And Untreated Visual Problems In Schoolchildren In Ireland; A Population-Based Cross-Sectional Study, Síofra Harrington, Peter Davison, Veronica O'Dwyer

Articles

This study explored the association between children’s vision and their school academic progress as reported by parents/guardians. Participants were 1,612 schoolchildren (722 6-7-year-olds, 890 12-13-year-olds) in randomly selected schools in Ireland. In advance of data collection, parents/guardians reported school performance as (a) much better than classmates (high-performance) (b) about the same as classmates (average-performance) (c) not as well as classmates (low-performance). Measurements included logMAR monocular visual acuities (with spectacles if worn, and pinhole) in the distance (3 m) and near (40 cm); the amplitude of accommodation; stereoacuity, colour vision assessment, and cyclopleged autorefraction. Controlling for confounders, children presenting with visual …

Prevalence And Associated Risk Factors Of Symptomatic Dry Eye In Ghana: A Cross-Sectional Population-Based Study, Emmnuel Kobia Acquah, Stephen Ankamah-Lomotey, Ebenezer Owusu, Sedinam Forfoe, Joseph Bannor, Joana Abokoma Koomson, Martin Opoku, Daniel Mensah Dzikpo, Derrick Nii Okaikwei Mensah, Jedidiah N. Amonoo, Prince Kwaku Akowuah

Articles

Purpose This study sought to estimate the prevalence and associated risk factors of symptomatic dry eye in the general non-clinical Ghanaian population.

Methods This was a cross-sectional population-based study conducted from November 2019 to February 2020. A stratified, multistage, random sampling technique was used to select participants aged 18 years and above from the capital cities of eight administrative regions in Ghana. Symptomatic dry eye was assessed using the Ocular Surface Disease Index questionnaire (OSDI). A study specific structured questionnaire was administered to collect information on participants’ demographics and self-reported risk factors of dry eye disease such as smoking, diabetes, …

Cantilever-Based Sensor Utilizing A Diffractive Optical Element With High Sensitivity To Relative Humidity, Catherine M. Grogan, Faolan Radford Mcgovern, Rory Staines, George Amarandei, Izabela Naydenova

Articles

High-sensitivity and simple, low-cost readout are desirable features for sensors independent of the application area. Micro-cantilever sensors use the deflection induced by the analyte presence to achieve high-sensitivity but possess complex electronic readouts. Current holographic sensors probe the analyte presence by measuring changes in their optical properties, have a simpler low-cost readout, but their sensitivity can be further improved. Here, the two working principles were combined to obtain a new hybrid sensor with enhanced sensitivity. The diffractive element, a holographically patterned thin photopolymer layer, was placed on a polymer (polydimethylsiloxane) layer forming a bi-layer macro-cantilever. The different responses of the …

Investigation Of Surrogate Biomarkers Associated With Macular Pigment Status In A Group Of Older Irish Adults, Grainne Scanlon, John S. Butler, Daniel Mccartney, Ekaterina Lostutova, Rose Anne Kenny, James Loughman

Articles

SIGNIFICANCE: Macular pigment (MP) confers potent antioxidant and anti-inflammatory effects at the macula; however, its optical density in the eye is not routinely measured in clinical practice.

PURPOSE: This study explored a range of surrogate biomarkers including anthropometric, clinical, and plasma measures that may be associated with lower MP optical density (MPOD).

METHODS: Two thousand five hundred ninety-four subjects completed a full MP assessment as part of wave 1 of The Irish Longitudinal Study of Aging. Macular pigment optical density was measured using customized heterochromatic flicker photometry. Clinical (blood pressure), plasma (lipoproteins, inflammatory markers), and anthropometric (waist, hip, height, weight) …

The Relationship Between Serum Zinc Levels And Myopia, Niamh Burke, John Butler, Daniel Ian Flitcroft, James Loughman

Articles

Clinical significance: Myopia is inherently associated with eye growth and thereby possibly amenable to nutritional influence. However, little attention has been given to possible die- tary influences. This study demonstrates that serum zinc does not play a role in myopia development. Background: Myopia is inherently associated with eye growth and thereby possibly amena- ble to nutritional influence. A number of Asian studies have reported lower levels of serum zinc in myopic children. This study was designed to assess the relationship between serum zinc and myopia in the Korean population – using a subsample of participants from nation- ally representative data.

Optimising Subjective Anterior Eye Grading Precision, Marta Vianya-Estopa, Manbir Nagra, Arnold Cochrane Arnold Cochrane, Neil Retallic Neil Retallic, Dean Dunning, Louise Terry Louise Terry, Aoife Lloyd, James Wolffsohn

Articles

To establish the optimum grading increment which ensured parity between practitioners while maximising clinical precision.

The Spatial Frequency Content Of Urban And Indoor Environments As A Potential Risk Factor For Myopia Development, Daniel Ian Flitcroft, Elise Harb, Christine F Wildsoet

Articles

To examine the hypothesis that the spatial frequency spectra of urban and indoor environments differ from the natural environment in ways that may promote the development of myopia. Methods: A total of 814 images were analyzed from three datasets; University of California Berkeley (UCB), University of Texas (UT), and Botswana (UPenn). Images were processed in Matlab (Mathworks Inc) to map the camera color characteristics to human cone sensitivities. From the photopic luminance images generated, two-dimensional spatial frequency (SF) spectra were calculated and converted to one-dimensional spectra by rotational averaging. The spatial filtering profile of a 0.4 Bangerter foil, which has …

Macular Pigment Optical Density Fluctuation As A Function Of Pupillary Mydriasis: Methodological Considerations For Dual-Wavelength Autofluorescence, Ekaterina Loskutova, John Butler, Gabriela Hernandez-Martinez, Daniel Ian Flitcroft, James Loughman

Articles

Macular pigment (MP), comprising the dietary carotenoids lutein, zeaxanthin and meso-zeaxanthin, is believed to benefit eye health and vision. Numerous clinical and research devices and techniques are currently available to facilitate MP optical density (MPOD) measurement. One of those techniques, dual-wavelength fundus autofluorescence (AF) is being increasingly used for measurement of MP in the eye. There is substantial methodological variation across the published studies that have employed this technique, including in relation to the use of mydriasis, the possible influence of which does not appear to have been addressed in the literature. This prospective cross-sectional study was designed to investigate …

Willingness To Pay For Improved Vision In Mozambique, Stephen Thompson, Kovin Naidoo, Carmen Gonzalez-Alvarez, Geoff Harris, James Loughman

Articles

The burden of vision impairment due to uncorrected refractive error (needing spectacles) in Mozambique is known to be significant. To improve the planning and provision of eye health services, a better understanding of how vision is valued by patients is needed. The willingness to pay (WTP) for improved vision through correcting refractive error was investigated in Nampula, Mozambique, using stated choice and bidding game methodologies. The mean WTP values were found to be 388.92 Meticals (US$13) for stated choice and 469.89 Meticals (US$16) for the bidding game. The mean WTP values for rural dwellers were found to be lower than …

The Efficacy Of Warm Compresses In The Treatment Of Meibomian Gland Dysfunction And Demodex Folliculorum Blepharitis, Orla Murphy, Veronica O'Dwyer, Aoife Lloyd-Mckernan

Articles

Purpose: To investigate and compare the effect of warm compresses on meibomian gland dysfunction and Demodex folliculorum blepharitis.

Methods: Forty-two subjects (13 males, 29 females; mean age of 56.45 years) enrolled and completed the two-month warm compress treatment study. Three warm compress therapies were compared: Warm face cloth, MGDRx EyeBag® and OPTASETM Moist Heat Mask. Subjects attended for four visits: baseline, two weeks, four weeks, and eight weeks. Subjective symptoms, osmolarity, non-invasive tear break-up time, ocular surface staining, Schirmer I test, meibum expressibility and clarity, and eyelash manipulation and epilation to assess for the presence of Demodex folliculorum, …

Prevalence Of Colour Vision Deficiency In The Republic Of Ireland Schoolchildren And Associated Socio-Demographic Factors, Síofra Harrington, Peter Davison, Veronica O'Dwyer

Articles

Clinical relevance: Early screening is essential to counsel schoolchildren with congenital colour vision deficiency (CVD) in determining their future career path and to advise teachers of the impact of CVD on classroom difficulties.

Background: Congenital CVD is an X-linked genetic abnormality relatively commonplace in humans. This study aimed to determine the prevalence of congenital CVD in the Republic of Ireland schoolchildren and associated socio-demographic factors.

Methods: A total of 1,626 schoolchildren (882 boys and 744 girls), in two age groups (728 aged 6–7 years and 898 aged 12–13 years) were examined from randomly selected schools. Colour vision …

Flash Vep In Clinically Stable Pre-Term And Full-Term Infants, Anish Kharal, Safal Khanal, Jyoti Baba Shrestha, Gauri Shankar Shrestha, Nabin Paudel

Articles

Purpose

Pre-term infants are at risk of abnormal visual development that can range from subtle to severe. The aim of this study was to compare flash VEPs in clinically stable pre-term and full-term infants at 6 months of age.

Methods

Twenty-five pre-term and 25 full-term infants underwent flash VEP testing at the age of 6 months. Monocular VEPs were recorded using flash goggles on a RETIscan system under normal sleeping conditions. Amplitude and peak time responses of the P2 component in the two eyes were averaged and compared between the two groups. Multiple regression analyses were performed to assess the …

Can Protanopia Be Correctly Diagnosed In Clinical Practice? An Evaluation Of Diagnosis By Four Screening Tests, Peter Davison, Grainne Scanlon

Articles

SIGNIFICANCE

Protanopia is a color vision deficiency (CVD) that is unacceptable for certain occupations. This study compares simultaneously for the first time the ability of three recently revised or developed clinical tests of color vision with the Ishihara test to diagnose protanopia from other color vision deficiencies.

PURPOSE

The objectives were to examine the ability of four clinical tests to differentiate (1) between protan and deutan CVDs in patients with protanopia and deuteranopia, and (2) protanopes and deuteranopes as “strong” deficiencies.

METHODS

The Hardy-Rand-Rittler (4th ed.), City University (3rd ed.), Ishihara, and Mollon-Reffin tests were evaluated against the Oculus Heidelberg …

Herpes Simplex Virus 1 Targets Irf7 Via Icp0 To Limit Type I Ifn Induction, David Shahnazaryan, Rana Khalil, Claire Wynne, Caroline A Jefferies, Joan Ní Gabhann-Dromgoole, Conor C Murphy

Articles

Herpes simplex keratitis (HSK), caused by herpes simplex virus type 1 (HSV‑1) infection, is the commonest cause of infectious blindness in the developed world. Following infection the virus is initially suspended in the tear film, where it encounters a multi‑pronged immune response comprising enzymes, complement, immunoglobulins and crucially, a range of anti‑viral and pro‑inflammatory cytokines. However, given that HSV‑1 can overcome innate immune responses to establish lifelong latency throughout a susceptible individual’s lifetime, there is significant interest in understanding the mechanisms employed by HSV‑1 to downregulate the anti‑viral type I interferon (IFN) mediated immune responses. This study aimed to investigate …

Low-Dose (0.01%) Atropine Eye Drops To Reduce Progression Of Myopia In Children: A Multi-Centre Placebo- Controlled Randomised Trial In The United Kingdom (Champ- Uk) – Study Protocol., Augusto Azuara-Blanco, Nicola Logan, Niall Strang, Peter Allen, Ruth Hogg, Ruth Weir, Paul Doherty, Catherine Adams, Margaret Mcfarland, Evie Gardner, Rejina Verghis, Jennifer Preston, James Loughman, Daniel I. Flintcroft, David Mackey, Samantha Lee, Christopher Hammond, Nathan Congdon, Mike Clarke

Articles

Background/aims To report the protocol of a trial designed to evaluate the efficacy, safety and mechanism of action of low-dose atropine (0.01%) eye-drops for reducing progression of myopia in UK children. Methods Multicentre, double-masked, superiority, placebo-controlled, randomised trial. We will enrol children aged 6–12 years with myopia of −0.50 dioptres or worse in both eyes. We will recruit 289 participants with an allocation ratio of 2:1 (193 atropine; 96 placebo) from five centres. Participants will instil one drop in each eye every day for 2 years and attend a research centre every 6 months. The vehicle and preservative will be …

Association Of Total Zinc Intake With Myopia In U.S. Children And Adolescents, Niamh Burke, John Butler, Daniel Ian Flitcroft, Daniel Mccartney, James Loughman

Articles

Significance: This present study advances our knowledge on the role of lifestyle factors in myopia (short-sightedness), specifically dietary factors. It has been suggested in previous studies that lower zinc status is associated with myopia; however, this article shows no relationship between dietary zinc intake and myopia in U.S. adolescents. Purpose: It has been suggested that low zinc levels may contribute to the development of myopia. The aim of the present study is to examine, for the first time in a Western population, the association of total dietary and supplement zinc intake with myopia. Methods: A total of 1095 children/adolescents aged …

Clinical Accuracy Of The Nidek Ark-1 Autorefractor, Nabin Paudel, Sameep Adhikari, Ajit Thakur, Bhairaja Shrestha, James Loughman

Articles

Autorefractors are commonly used by eye care practitioners worldwide as a starting point for clinical prescribing and by researchers as an instrument to study development of refractive errors and accommodation. This study demonstrates that the Nidek ARK-1 provides a reasonable and repeatable estimate of refractive error.

Consort Checklist, Myopia Outcome Study Of Atropine In Children (Mosaic): Design And Methodology, Saoirse Mccrann, Daniel Ian Flitcroft, John Butler, James Loughman

Articles

Purpose

The Myopia Outcome Study of Atropine in Children (MOSAIC) aims to explore the efficacy, safety, acceptability and mechanisms of action of 0.01% atropine for myopia control in a European population.

Methods

MOSAIC is an investigator-led, double-masked, placebo-controlled, randomised clinical trial (RCT) investigating the efficacy, safety and mechanisms of action of 0.01% atropine in myopia progression management. During Phase 1 of the trial, 250 children aged 6-16 years with progressive myopia apply eye drops once nightly in both eyes from randomisation to month 24. No treatment is given during Phase 2 from month 24 to 36 (washout period) for those …