12 research outputs found
Estimating retinal vessel diameter change from the vessel cross-section
No full textWe have developed a methodology to estimate small change in the retinal vessel diameter. This technique does not rely on the segmentation of the vessel which is prone to error when the fitted profile does not exactly represent the expected model. Using the newly proposed method, we have identified an inverse linear relationship (p<0.0001, r 2 = 0.965) between the proposed technique with the narrowing of the simulated vessels. The immediate application of this technique is in the caliber change estimation of the time-series retinal vessels, gated with the electrocardiogram
A systematic review on prevalence, risk factors, clinical diagnosis and medical management of dry eye disease in the Arab population
Get PDFBackground: Dry eye (DE) is a multifactorial disorder that can influence tear production,functional visual acuity and ultimately increase the osmolarity of the tear film. The prevalence of DE ranges from 7% to 33% across the world. However, to the best of our knowledge, the prevalence range of DE in Arab countries is not precisely documented in the literature.Aim: The aim of this article was to determine the prevalence range of DE, investigate the major risk factors of DE and identify the clinical diagnosis and medical management of DE.Method: In this study, only English language articles from 2017 to 2020 were selected. There were 52 articles on prevalence, risk factors, clinical diagnosis and medical management of DE in the Arab population.Results: The prevalence of DE in the Arab population varies in reports, from 10% in the UnitedArab Emirates (Dubai) to 69% in Palestine (West Bank). Gender difference (DE more in women), wearing of contact lenses, diabetes mellitus and glaucoma were all known to intensify the symptoms of DE. Lastly, there are two approaches to reduce DE in the Arab population, namely, pharmacologic and non-pharmacologic methods.Conclusion: The prevalence of DE in the Arab population was relatively high. In addition, the ocular surface disease index is one of the most common tools for the diagnosis of DE, whilst tear break-up time test is the common clinical test used in the Arab reports. Lastly, the most common treatment for DE is artificial tears
Prevalence and Risk Factors of Dry Eye Disease in Kuantan, Malaysia
Get PDFBackground: To determine the prevalence of dry eye disease (DED) at Jalan Hospital Eye Care, International Islamic University Malaysia (IIUM), Kuantan, Malaysia. Methods: The dry eye symptoms and tear breakup time test (TBUT) values retrieved from the medical records of 643 patients were retrospectively analysed. Dry eye cases with one or more symptom were included. ‘Yes’ or ‘no’ responses were used in discriminant analysis of tear abnormality (TBUT < 5 seconds). Results: The crude prevalence of DED was 48.5%, the age-adjusted prevalence was 43% in women <50 years of age, and 68.4% in those ≥50 years of age. Contact lens wear and low TBUT values were associated with DED risk in men. Age of ≥50 years and a low tear meniscus height (TMH) score were associated with risk of DED symptoms in women. Conclusions: The prevalence of DED in optometric outpatients at IIUM was relatively high, especially in the elderly population. Symptoms and signs were poorly associated with DED. TBUT performed well in diagnosing dry eye and may be useful to improve the assessment of patients with dry eye problems in this region
Changes in Contrast Sensitivity in Young Adults with Diabetes
Get PDFBackground: This study compared contrast sensitivity and visual acuity of young adults with diabetes to that of controls and attempted to identify predictors of dry eye symptoms in patients with diabetes. Methods: This cross-sectional study, which included 37 patients with diabetes and 37 age-matched controls, was conducted in the Optometry Clinic of Kulliyyah Allied Health Science. All participants were aged between 19 and 39 years. Inclusion criteria were a diagnosis of diabetes without any evidence of ocular disease, abnormalities in colour vision or media opacity. Results: The contrast sensitivity significantly differed between patients and controls (p = 0.045). A multiple regression analysis showed that contrast sensitivity was a significant predictor of ocular symptoms in patients with diabetes, and this was statistically significant (p = 0.002). Conclusions: Contrast sensitivity may be affected during early ocular changes among young adults with diabetes. It may also predict the occurrence of dry eye symptoms in such patients
Grey matter volume differences of textual memorization: a voxel based morphometry study
No full textTextual memorization involves intensive memorization techniques and processes, including repetition, rehearsal, and retrieval. Yet, little is known about the possible effects of this robust memorization training on brain structures. Therefore, this study was designed to investigate the presence of structural plasticity in the brain, which may develop after long-term practice of textual memorization techniques. The subjects are a group of huffaz who underwent one year of textual memory training. Twenty-eight volunteers (14 males) were enrolled in this study. Brain images of the subjects were obtained by employing 1.5 Tesla MRI and 3D-MPRAGE imaging sequence. Voxel-based morphometry was applied to assess the gray matter volume differences in the memorizers and the control subjects. The current study found that gray matter volume in the anterior cingulate gyrus, orbitofrontal cortex, left inferior temporal gyrus, right occipitotemporal gyrus, left inferior parietal gyrus, right perirhenal cortex, superior parietal cortex, posterior cingulate cortex and anterior cingulate cortex of the memorizers were significantly increased as compared with the control subjects. The results suggest textual memorization involves with extensive connection across the brain
Peek acuity as an alternative method for visual acuity measurement for vision screening in children
No full textIntroduction: Accurate and reliable clinical measurement of visual acuity (VA) is necessary to establish the needs for further clinical investigations. A simpler option for VA measurement is the use of smartphones, in which the measurement method is programmed in an application that enables automated and self-administered VA testing. Aims: This study aimed to investigate the validity of PEEK Acuity (PA), a smartphone’s application for VA measurement, in testing children’s vision, especially for vision screening programs. Methodology: Data were obtained from a vision screening program involving children aged 3–13 years. One hundred thirteen participants were included in the study (mean age 7.47±2.33 years old, 59 boys). The participants’ VA was measured using the PA and Snellen chart in random order. Both eyes were tested, with 226 data points used in the statistical analysis. The Kolmogorov-Smirnov test revealed non-normal data. The VA between the PA and Snellen tests was compared using the Wilcoxon signed rank test. Test-retest variability was calculated for both tests using intraclass correlation (ICC) analysis. Spearman’s rank correlation and the Bland-Altmann test were plotted to evaluate the agreement between tests. Results: The mean VA recorded using PA was 0.066±0.007 logMAR, while that recorded using Snellen was 0.103±0.009 logMAR (z=-4.119, p<0.0005, Wilcoxon signed rank test; ? two-letter differences). The ICC between the PA and Snellen was 0.641. Spearman’s rank correlation revealed a significant correlation between PA and Snellen (r=0.508, p<0.001). Conclusion: There was a moderate correlation between the PA and Snellen scores. The PA application showed good agreement with conventional Snellen. Thus, smartphone applications such as PA may serve as an alternative to measure VA in children, especially in vision screening programs
Peek acuity as an alternative method for visual acuity measurement for vision screening in children
Get PDFIntroduction: Accurate and reliable clinical measurement of visual acuity (VA) is necessary to establish the needs for further clinical investigations. A simpler option for VA measurement is the use of smartphones, in which the measurement method is programmed in an application that enables automated and self-administered VA testing.
Aims: This study aimed to investigate the validity of PEEK Acuity (PA), a smartphone’s application for VA measurement, in testing children’s vision, especially for vision screening programs.
Methodology: Data were obtained from a vision screening program involving children aged 3–13 years. One hundred thirteen participants were included in the study (mean age 7.47±2.33years old, 59 boys). The participants’ VA was measured using the PA and Snellen chart in random order. Both eyes were tested, with 226 data points used in the statistical analysis. The Kolmogorov-Smirnov test revealed non-normal data. The VA between the PA and Snellen tests was compared using the Wilcoxon signed rank test. Test-retest variability was calculated for both tests using intraclass correlation (ICC) analysis. Spearman’s rank correlation and the Bland-Altmann test were plotted to evaluate the agreement between tests.
Results: The mean VA recorded using PA was 0.066±0.007 logMAR, while that recorded using Snellen was 0.103±0.009 logMAR (z=-4.119, p<0.0005, Wilcoxon signed rank test; ≈ two-letter differences). The ICC between the PA and Snellen was 0.641.Spearman’s rank correlation revealed a significant correlation between PA and Snellen (r=0.508, p<0.001).
Conclusion: There was a moderate correlation between the PA and Snellen scores. The PA application showed good agreement with conventional Snellen. Thus, smartphone applications such as PA may serve as an alternative to measure VA in children, especially in vision screening programs
2D and 3D Complexity Analysis on MRI Images using Fractal Dimension
Get PDFThe brain, which is the most complex structure in the human body, has attracted attention of many researchers to study the possible fractal analysis application upon it. Current interest is seen directed more towards the utilization of complexity analysis as measured by fractal dimension in determining the pathologies effect and degenerative factor on the brain structure volume. In this paper, we used two boxcounting methods: average 2D Fractal Dimension and 3D Fractal Dimension. 47 subjects (19 males, 28 females), aged ranging from 21 to 25 years, were recruited. Brain MRI images were acquired by using 3T MRI system. The images were then thresholded according to Otsu’s method. The processed images were then calculated using fractal analysis, and the values obtained were statistically evaluated using Pearson’s correlation test (r2 = -0.106, p = 0.477). In conclusion, no correlation was seen between average 2D FD and 3D FD
Robust methodology for fractal analysis of the retinal vasculature
No full text10.1109/TMI.2010.2076322IEEE Transactions on Medical Imaging302243-250ITMI
Fractal dimension of the retinal vasculature and risk of stroke : a nested case-control study
No full textRecent studies show associations between retinal vascular changes and small infarcts detected on brain imaging, or clinical stroke. Fractal dimension has been used as a global measure of the geometric pattern of the retinal vasculature potentially representing the complex branching pattern of the microvasculature, including the cerebral microvasculature. We have developed an automatic method to assess spectrum fractal dimension (SFD) of the retinal microvasculature using Fourier-transformed images.
Two previous studies have reported cross-sectional associations between retinal fractal dimension and lacunar stroke. In this study, we aimed to examine the association between baseline SFD and stroke incidence using a case-control sample nested in the Blue Mountains Eye Study (BMES)
