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- Tear meniscus height agreement and reproducibility between two corneal topographers and spectral-domain optical coherence tomographyPublication . Soares, Ivo; Ramalho, Eva; Brardo, Francisco M.; Nunes, Amélia FernandesClinical relevance: Tear meniscus height (TMH) is an important clinical marker in dry eye diagnosis and management. Purpose: To evaluate the reproducibility and agreement of TMH measurements in non-clinical participants using the Oculus Keratograph 5 M, Medmont Meridia, and Spectral-domain optical coherence tomography (Spectralis SD-OCT). Methods: Fifty-six participants (mean 43.8 ± 22.4 years) were recruited for this cross-sectional study. Image acquisitions were performed on the three devices, sequentially and randomized. The repeatability and reproducibility of inter-observer and inter-device analysis were performed. Repeated measures ANOVA and Bland-Altman Plots were used to evaluate the agreement between devices. Results: The mean TMH with the Oculus Keratograph 5 M, Medmont Meridia and Spectralis SD-OCT were 0.29 ± 0.16 mm, 0.24 ± 0.09 mm and 0.27 ± 0.16 mm, respectively. There were no significant inter-observer differences (paired t-tests, p < 0.001). All the devices exhibited good inter-observer reliability (ICC ≥ 0.877), and good repeatability (CV ≤ 16.53%). Inter-device reliability is moderate (ICC = 0.621, p < 0.001). Repeated measures ANOVA revealed that TMH measurements given by the Spectralis SD-OCT are not significantly different from the Oculus Keratograph 5 M (p = 0.19) and the Medmont Meridia (p = 0.38). TMH measurements from Oculus Keratograph 5 M were significantly higher than those from Medmont Meridia (p = 0.02). Correlations between the mean TMH and the difference in the TMH measurements were positive for Oculus Keratograph 5 M and Medmont Meridia (r2 = 0.62, p < 0.001), negative for Medmont Meridia and Spectralis SD-OCT (r2 = -0.59, p < 0.001), and not significant for Oculus Keratograph 5 M and Spectralis SD-OCT (r2 = 0.05, p = 0.74). A strong correlation was found for TMH measured with all devices (r2 = 0.55 to 0.81, p < 0.001). Conclusions The Oculus Keratograph 5 M, Medmont Meridia, and Spectralis SD-OCT provide reliable and reproducible inter-observer TMH measurements. Inter-device reliability is moderate, with a close correlation between Spectralis SD-OCT and the Oculus Keratograph 5 M. Oculus Keratograph 5 M and Medmont Meridia are repeatable devices appropriate for the measurement of TMH, but they are not interchangeable in clinical practice.
- Diffusion of the Laser Radiation to Characterise the Paper Fibre Orientation and the Paper Sheet FormationPublication . Pereira, Mário; Fiadeiro, Paulo; Brardo, FranciscoThis work concerns the determination of fiber orientation in the paper sheet and possibly the mass density distribution. Both parameters strongly influence the quality of the paper for end uses in printing and converting. The measurement of such parameters is done using different approaches, most commonly indirectly from the determination of the paper's physical properties. The measurement and analysis of the microscopic features of the paper sheet structure, using optical methods based on the laser radiation retro-diffusion and transmission, are the main aims of this work. The proposed method only uses laser light scattered by retro-diffusion from the paper surfaces for surface analysis and the laser light transmitted through the paper for analysis in the bulk. The system can analyze through a scanning procedure point-by-point, one paper sheet to produce a map of both paper surfaces with the selected results.
- Convergence insufficiency and accommodative insufficiency in childrenPublication . Nunes, Amélia; Monteiro, Pedro; Brardo, Francisco M.; Nunes, AntónioPurpose: Convergence and accommodative insufficiency represent the main cause of complaints during close visual work and can reduce visual performance and comfort. Knowing their prevalence among schoolchildren is fundamental to define strategies for action. The purpose of this study was to estimate the frequency of these conditions in children in 5th and 6th school years in inland Portugal and to assess the impact that each visual condition has on their quality of life, based on the level of visual symptoms. Methods: a cross-sectional study was carried out with children enrolled in the 5th and 6th school years. 372 children (192 girls) were assessed, with average ages of 10.9 ± 0.9 years. Refractive error and binocular vision assessment, integrating accommodative parameters, were used to analyse the visual condition. Symptoms were quantified using the Portuguese version of the CISS (Convergence Insufficiency Symptom Survey). Results: The prevalence of definite Convergence Insufficiency (CI) in the children assessed was 2%. A prevalence of 6,8% could be considered if clinically significant CI (high suspect and definite categories) cases are accounted. In relation to Accommodative Insufficiency (AI), a frequency rate of 10% was recorded, with 3% of the evaluated children presenting AI and CI simultaneously. The symptoms score was higher in AI than in CI. Conclusions: A frequency of approximately 10% was found for each one of the visual syndromes, and it was verified that visual discomfort is common among teenagers who carry these conditions. In cases of asthenopia, such as headaches and loss of concentration, associated with near vision activities, there is a requirement to evaluate the quality of binocular vision.
- Transcranial Magnetic Stimulation in Adults With AmblyopiaPublication . Tuna, Ana Rita; Pinto, Nuno; Brardo, Francisco M.; Fernandes, Andresa; Nunes, Amélia; Patto, Maria Da Assunção VazThrough transcranial magnetic stimulation (TMS) it is possible to change cortical excitability of the visual cortex, and to influence binocular balance. The main goal of our study is to assess the effect of transcranial magnetic stimulation, specifically theta burst stimulation (TBS), in a group of amblyopic volunteers measuring several visual parameters: visual acuity, suppressive imbalance, and stereoacuity.