Study of long-term visual function and plasma biomarkers in patients with epilepsy receiving Vigabatrin

Vigabatrin is a highly effective adjunctive treatment for adults with refractory epilepsy and for infantile spasms. After gaining its license in Europe in 1989, it was used widely with much success until 1997 when reports of permanent visual fields defects were observed in some patients. The use of Vigabatrin had fallen in Europe since, where significant number of patients were denied this treatment leading to inadequate seizure control, poorer quality of life and greater risk of death and injury. In the US, Vigabatrin was made available for their patients in 2009 involving costly and extensive monitoring programme of visual function. The result of long-term monitoring is varied, partly due to the mixed methods used for examination of visual function. Our centre previously completed one of the largest international studies investigating Vigabatrin associated retinal toxicity, differentiating the pathological from physiological effects of Vigabatrin on vision and to document pre-existing visual field defects in 25% of patients with epilepsy. More than 2 milliseconds timing delay on the peripheral retina on WF-mfERG was found to be a sensitive and specific indicator of Vigabatrin associated retinal toxicity. 28 subjects were examined in this study. The effect of Vigabatrin use (current versus previous) on their visual function and retinal structures with the Optical Coherence Tomography (OCT) was assessed. Subjects were also stratified based on the presence of >2ms peripheral timing delay to uncover specific patterns in their visual tests. The results showed a strong relationship between >2ms peripheral timing delay with higher volume of the inner retinal microstructures based on the OCT (p2ms peripheral timing delay. We propose that OCT macula volume analysis to be a promising method to detect and monitor for presence of VaRT. Development of a customised analytical algorithm involving retinal auto-segmentation could help us progress in developing a practical and reliable tool for the detection and monitoring of VaRT

The properties of the cornea based on hyperspectral imaging

Purpose : Hyperspectral Imaging (HSI) is a hybrid modality that combines imaging and spectroscopy. Here we investigate the ability of a hyperspectral device in extracting data from the layers in the porcine corneal tissue through the wavelength spectrum, in foreseeing its potential in clinical diagnostics by simplifying methods of examination by clinicians in detecting corneal injuries. Methods : Hyperspectral imaging using 400 to 1000nm visible wavelength camera was used to scan five porcine eyes, containing a mix of eyes with intact and unintact epithelial layer. Images were saved and analysed in three dimensional rows, columns and depth slices at 1200 to 1300 x 804 x 604 resolution. The Matlab image processing toolbox was utilised to process the images for inspection in grayscale, HSV format and reflectance spectrum. All laboratory works were performed in accordance with the general risk assessment of University of Strathclyde. Results : The obtained hyperspectral images were able to demonstrate distinct differences through the wavelength. Images at longer wavelength reveal distinct shapes in regular arrangements, and could be descriptive of the physical properties of the corneal tissue in particular layers. When comparing reflectance spectrum obtained from both eyes with intact and unintact epithelium, we were able to demonstrate distinct separation in reflectance values from 578 to 818nm wavelenghth. Conclusions : Our analysis was able to demonstrate a gap in the reflectance spectrum between the intact and unintact epithelium of a porcine’s cornea, illustrating its potential value in the assessment of corneal tissue integrity. Further image processing with grayscale slices reveal distinct tissue properties at varying wavelengths strongly suggests a novel role for hyperspectral image technology in the diagnostics of corneal tissues, alongside traditional methods such as microscopy. These findings support our proposition for the role of hyperspectral imaging in aiding the development of innovative, mobile devices

A New Paradigm for Muscle Contraction

For the past 60 years, muscle contraction had been thought to be governed exclusively by the contractile filaments, actin and myosin. This thinking explained most observations for concentric and isometric, but not for eccentric muscle contractions. Just over a decade ago, we discovered that eccentric contractions were associated with a force that could not be assigned to actin and myosin, but was at least in part associated with the filamentous protein titin. Titin was found to bind calcium upon activation, thereby increasing its structural stability, and thus its stiffness and force. Furthermore, there is increasing evidence that the proximal part of titin binds to actin in an activation- and force-dependent manner, thereby shortening its free length, thus increasing its stiffness and force. Therefore, we propose that muscle contraction involves three filaments, actin, myosin and titin, and that titin regulates force by binding calcium and by shortening its spring length by binding to actin

Hyperspectral Image Enhancement and Mixture Deep-Learning Classification of Corneal Epithelium Injuries

In our preliminary study, the reflectance signatures obtained from hyperspectral imaging (HSI) of normal and abnormal corneal epithelium tissues of porcine show similar morphology with subtle differences. Here we present image enhancement algorithms that can be used to improve the interpretability of data into clinically relevant information to facilitate diagnostics. A total of 25 corneal epithelium images without the application of eye staining were used. Three image feature extraction approaches were applied for image classification: (i) image feature classification from histogram using a support vector machine with a Gaussian radial basis function (SVM-GRBF); (ii) physical image feature classification using deep-learning Convolutional Neural Networks (CNNs) only; and (iii) the combined classification of CNNs and SVM-Linear. The performance results indicate that our chosen image features from the histogram and length-scale parameter were able to classify with up to 100% accuracy; particularly, at CNNs and CNNs-SVM, by employing 80% of the data sample for training and 20% for testing. Thus, in the assessment of corneal epithelium injuries, HSI has high potential as a method that could surpass current technologies regarding speed, objectivity, and reliability

Bimanual anterior segment revision surgery for anterior capsule contraction syndrome associated with anterior flexion of intraocular lens haptics

PURPOSE To report the incidence of anterior capsule contraction syndrome (ACCS) and to present a novel minimally invasive bimanual technique for anterior segment revision surgery associated with ACCS with anterior flexion of the intraocular lens haptics. METHODS A consecutive cohort of 268 eyes of 161 patients undergoing phacoemulsification and implantation of the same type of hydrophilic acrylic aspheric intraocular lens cohort were analysed and a novel technique of minimally invasive bimanual technique for anterior segment revision surgery is described. RESULTS We identified four eyes (1.5%) of three patients with advanced ACCS. Successful restoration of a clear visual axis with minimal induction of astigmatism and rapid visual rehabilitation was achieved in all four cases. CONCLUSION This technique is a safe and minimally invasive alternative to laser or vitrector-cut capsulotomy to restore a clear visual axis. In cases of advanced ACCS, it offers the option for haptic reposition or amputation