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Association of anthropometric measures across the life-course with refractive error and ocular biometry at age 15 yearsBruce, A., Ghorbani Mojarrad, Neema, Santorelli, G. 13 July 2020 (has links)
Yes / Background
A recent Genome-wide association meta-analysis (GWAS) of refractive error reported shared genetics with anthropometric traits such as height, BMI and obesity. To explore a potential relationship with refractive error and ocular structure we performed a life-course analysis including both maternal and child characteristics using data from the Avon Longitudinal Study of Parents and Children cohort.
Methods
Measures collected across the life-course were analysed to explore the association of height, weight, and BMI with refractive error and ocular biometric measures at age 15 years from 1613children. The outcome measures were the mean spherical equivalent (MSE) of refractive error (dioptres), axial length (AXL; mm), and radius of corneal curvature (RCC; mm). Potential confounding variables; maternal age at conception, maternal education level, parental socio-economic status, gestational age, breast-feeding, and gender were adjusted for within each multi-variable model.
Results
Maternal height was positively associated with teenage AXL (0.010 mm; 95% CI: 0.003, 0.017) and RCC (0.005 mm; 95% CI: 0.003, 0.007), increased maternal weight was positively associated with AXL (0.004 mm; 95% CI: 0.0001, 0.008). Birth length was associated with an increase in teenage AXL (0.067 mm; 95% CI: 0.032, 0.10) and flatter RCC (0.023 mm; 95% CI: 0.013, 0.034) and increasing birth weight was associated with flatter RCC (0.005 mm; 95% CI: 0.0003, 0.009). An increase in teenage height was associated with a lower MSE (− 0.007 D; 95% CI: − 0.013, − 0.001), an increase in AXL (0.021 mm; 95% CI: 0.015, 0.028) and flatter RCC (0.008 mm; 95% CI: 0.006, 0.010). Weight at 15 years was associated with an increase in AXL (0.005 mm; 95% CI: 0.001, 0.009).
Conclusions
At each life stage (pre-natal, birth, and teenage) height and weight, but not BMI, demonstrate an association with AXL and RCC measured at age 15 years. However, the negative association between refractive error and an increase in height was only present at the teenage life stage. Further research into the growth pattern of ocular structures and the development of refractive error over the life-course is required, particularly at the time of puberty.
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CLEAR - OrthokeratologyVincent, S.J., Cho, P., Chan, K.Y., Fadel, D., Ghorbani Mojarrad, Neema, González-Méijome, J.M., Johnson, L., Kang, P., Michaud, L., Simard, P., Jones, L. 10 November 2021 (has links)
No / Orthokeratology (ortho-k) is the process of deliberately reshaping the anterior cornea by utilising specialty contact lenses to temporarily and reversibly reduce refractive error after lens removal. Modern ortho-k utilises reverse geometry lens designs, made with highly oxygen permeable rigid materials, worn overnight to reshape the anterior cornea and provide temporary correction of refractive error. More recently, ortho-k has been extensively used to slow the progression of myopia in children. This report reviews the practice of ortho-k, including its history, mechanisms of refractive and ocular changes, current use in the correction of myopia, astigmatism, hyperopia, and presbyopia, and standard of care. Suitable candidates for ortho-k are described, along with the fitting process, factors impacting success, and the potential options for using newer lens designs. Ocular changes associated with ortho-k, such as alterations in corneal thickness, development of microcysts, pigmented arcs, and fibrillary lines are reviewed. The safety of ortho-k is extensively reviewed, along with an overview of non-compliant behaviours and appropriate disinfection regimens. Finally, the role of ortho-k in myopia management for children is discussed in terms of efficacy, safety, and potential mechanisms of myopia control, including the impact of factors such as initial fitting age, baseline refractive error, the role of peripheral defocus, higher order aberrations, pupil size, and treatment zone size. / The CLEAR initiative was facilitated by the BCLA, with financial support by way of Educational Grants for collaboration, publication and dissemination provided by Alcon and CooperVision.
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Refractive error, ocular biometry and oculomotor function: The prevalence of myopia and its potential risk factors in the Middle East, with an investigation of dynamic accommodation responses and axial length fluctuations in young myopic adults.Gammoh, Yazan S.S. January 2011 (has links)
The main experimental work of this thesis has been a cross-sectional study of the prevalence of refractive error and its biometric correlates in Middle Eastern adults. In addition dynamic accommodative responses and twenty-four hour axial length fluctuations were investigated in young myopic adults.
The prevalence of myopia in 3000 Middle Eastern adults (age range 17-40 years) was similar to previously reported levels of myopia in the West. Myopia was associated with a higher level of education, occupations with a high nearwork demand and positive family history of myopia; all of which have been identified as risk factors for myopia development and progression
Diurnal variations in axial length (AL) of similar magnitude to those previously reported in emmetropes were observed in myopes recruited in the current thesis. However, the pattern of the diurnal variation in AL was significantly different between early-onset myopes (EOMs) and late-onset myopes (LOMs).
There were no significant differences between EOMs and LOMs in the dynamic accommodative response to a sinusoidally oscillating target. The accommodative phase lag was increased following 30 minute adaptation to myopic defocus using +2.00 D lens. However, intense prolonged (30 minute) nearwork was found to have no effect on accommodative gain or phase lag.
A number of recommendations for further work on the prevalence of refractive error in the Middle East are suggested along with further research on diurnal AL variations and dynamic accommodative responses in EOMs and LOMs.
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Peripheral Refractive Error and its Association with Myopia Development and Progression. An examination of the role that peripheral retinal defocus may play in the origin and progression of myopiaJamal, Heshow January 2019 (has links)
Purpose: Currently there are attempts to slow myopia progression by manipulating peripheral refractive error. This study proposed to establish the distribution of peripheral refractive errors in hyperopic, emmetropic and myopic children and to test the hypothesis that relative peripheral hyperopia is a risk factor in the onset and progression of myopia.
Methods: Refraction was measured under non-cycloplegic conditions, at 0°, 10° (superior, inferior, temporal and nasal retina) and 30° (temporal and nasal retina), at distance and near. Central spherical equivalent refractive error (SER) was used to classify the eyes as myopic (≤ −0.75 D), emmetropic (−0.75 < SER < +0.75 D) or hyperopic (≥ +0.75 D). Relative peripheral refraction was calculated as the difference between the central (i.e. foveal) and peripheral refractive measurements. At baseline, measurements were taken from 554 children and in a subset of 300 of these same children at the follow-up visit. The time interval between initial and follow-up measurement was 9.71 ± 0.87 months.
Results: Results were analysed on 528 participants (10.21 ±0.94 years old) at baseline and 286 longitudinally. At baseline, myopic children (n=61) had relative peripheral hyperopia at all eccentricities at distance and near, except at 10°-superior retina where relative peripheral myopia was observed at near. Hyperopic eyes displayed relative peripheral myopia at all eccentricities, at distance and near. The emmetropes showed a shift from relative peripheral myopia at distance to relative peripheral hyperopia at near at all eccentricities, except at 10°-superior retina, where the relative peripheral myopia was maintained at near. In the longitudinal data analysis, myopes who became more myopic did not show greater relative peripheral hyperopia at baseline compared with myopic sub-groups whose central refraction remained stable.
Conclusions: The peripheral refractive profile differences between different refractive groups that are reported in other studies have been confirmed in this study. Relative peripheral hyperopia is not found to be a significant risk factor in the onset or progression of myopia in children.
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Commercialization of Software for the Prediction of Structural and Optical Consequences Resulting from Corneal Corrective TreatmentsLloyd, Joshua S. 26 January 2016 (has links)
No description available.
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Refractive error shift with continuous use (Rescu) lensesMerchea, Mohinder Mohan 01 October 2003 (has links)
No description available.
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Ciliary muscle, eye shape, and accommodation in adults with anisometropiaKuchem, Mallory Kuhlmann 25 June 2012 (has links)
No description available.
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Refractive error, ocular biometry and oculomotor function : the prevalence of myopia and its potential risk factors in the Middle East, with an investigation of dynamic accommodation responses and axial length fluctuations in young myopic adultsGammoh, Yazan Sultan Sa¿ad January 2011 (has links)
The main experimental work of this thesis has been a cross-sectional study of the prevalence of refractive error and its biometric correlates in Middle Eastern adults. In addition dynamic accommodative responses and twenty-four hour axial length fluctuations were investigated in young myopic adults. The prevalence of myopia in 3000 Middle Eastern adults (age range 17-40 years) was similar to previously reported levels of myopia in the West. Myopia was associated with a higher level of education, occupations with a high nearwork demand and positive family history of myopia; all of which have been identified as risk factors for myopia development and progression Diurnal variations in axial length (AL) of similar magnitude to those previously reported in emmetropes were observed in myopes recruited in the current thesis. However, the pattern of the diurnal variation in AL was significantly different between early-onset myopes (EOMs) and late-onset myopes (LOMs). There were no significant differences between EOMs and LOMs in the dynamic accommodative response to a sinusoidally oscillating target. The accommodative phase lag was increased following 30 minute adaptation to myopic defocus using +2.00 D lens. However, intense prolonged (30 minute) nearwork was found to have no effect on accommodative gain or phase lag. A number of recommendations for further work on the prevalence of refractive error in the Middle East are suggested along with further research on diurnal AL variations and dynamic accommodative responses in EOMs and LOMs.
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The Role of vision and refractive correction changes in dizzinessArmstrong, Deborah January 2018 (has links)
Dizziness is a common, multifactorial problem that causes reductions in
quality of life and is a major risk factor for falls, but the role of vision is a very
under-researched area. This study aimed to investigate any link between
dizziness and vision and to establish if changes in spectacle lens correction
could elicit dizziness symptoms.
A link between dizziness and self-reported poor vision was indicated in the
epidemiological literature as shown by a systematic review, provided lightheadedness
was not included in the definition of dizziness. Cases of
individuals who reported vision-related dizziness were investigated to
determine potential areas of research for this thesis and subsequently two
studies investigated the effects of refractive correction changes on dizziness
status. The first study was limited by logistical problems, although it
highlighted limitations in the short form of the Dizziness Handicap Inventory
that was used to quantify dizziness. Results of an optometry practice recheck
study found that oblique cylindrical changes were significantly more likely to
be associated with dizziness symptoms than other spectacle lens changes. It
also highlighted that optometrists do not ask/record about dizziness symptoms
with only 4% of records including “dizziness” as a problem when 38% of
patients reported dizziness symptoms when directly asked. All studies
highlighted a need for a patient-reported outcome measure to be designed to
assess vision-related dizziness. Literature review, interviews with experts and
patients and focus groups led to the development of a pilot questionnaire and
subsequently a 25-item Vision-Related Dizziness instrument, the VRD-25.
This was validated using responses from 223 respondents, with 79
participants completing the questionnaire a second time to provide test-retest
data. Two subscales of VRD-12-frequency (VRD-12f) and VRD-13-severity
(VRD-13s) were shown to be unidimensional and had good psychometric
properties, convergent validity and test-retest repeatability. The VRD-25 is the
only patient-reported outcome measure developed to date to assess vision related
dizziness and will hopefully provide the platform to further grow this
under-researched area that seems likely to provide important clinical
information. / College of Optometrists sponsored the research with a Postgraduate Research Scholarship
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The Effect of Refractive Error and Light Exposure on Red and Blue Light-Driven Pupil ResponsesOrr, Danielle Jean 28 July 2017 (has links)
No description available.
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