Glaucomatous vertical vessel density asymmetry of the temporal raphe detected with optical coherence tomography angiography.

Changes in retinal vasculature and ocular circulation may play an important role in the glaucoma development and progression. We evaluated the vertical asymmetry across the temporal raphe of the deep retinal layer vessel density, using swept-source optical coherence tomography angiography (SS-OCTA), and its relationship with the central visual field (VF) loss. Thirty-four eyes of 27 patients with open-angle glaucoma were included. SS-OCTA macular scanning was performed within a 3 × 3 mm (300 × 300 pixels) volume, centred on the fovea. The relationships between the vertical asymmetrical deep retinal vessel density reduction (ADRVD) across the temporal raphe and various ocular parameters were analysed. Twenty-two glaucomatous eyes with ADRVDs had central VF loss. Contrarily, ADRVDs were not found in any of the 12 eyes without central VF loss. Thirteen eyes (59.1%) with central VF loss had ADRVDs topographically corresponding to the central VF loss and macular ganglion cell complex thinning. The glaucomatous eyes with ADRVDs exhibited inferior rather than superior central VF loss (P = 0.032). Thus, ADRVD specifically indicates the glaucomatous central visual loss. Further analysis of ADRVD may improve our understanding on glaucoma pathogenesis, offering new treatment insights

Building a truster environment for e-business : a Malaysian perspective

Internet identify ‘security’ as a major concern for businesses. In general, the level of security in any network environment is closely linked to the level of trust assigned to a particular individual or organization within that environment. It is the trust element that is crucial in ensuring a secure environment. Besides physical security, security technology needs to be utilised to provide a trusted environment for e-business. Network security components for perimeter defense, i.e., Virtual Private Networks, firewalls and Intrusion Detection Systems, need to be complemented by security components at the applications and user level, e.g., authentication of user. ID or password security solution may be an option but now with the availability of legally binding digital certificates, security in e-business transactions can be further improved. Time and date stamping of e-business transactions are also of concern to prove at a later date that the transactions took place at the stipulated date and time. Digital certificates are part of a Public Key Infrastructure (PKI) scheme, which is an enabling technology for building a trusted epvironment. PIU comprise policies and procedures for establishing a secure method for exchanging information over a network environment. The Digital Signature Act 1997 (DSA 1997) facilitates the PKI implementation in Malaysia. Following the DSA 1997, Certification Authorities (CAs) were set up in Malaysia. This paper describes a trusted platform for spurring ebusiness and provides a Malaysian perspective of it

Structure and optics of the anterior segment of the cetacean eye : a thesis presented in fulfilment of the requirements for the degree of Master of Philosophy at Massey University

The anterior segment of the mammalian eye is concerned with the function and maintenance of its optical components, the most important of these being the maintenance of transparency and stable intraocular pressure. The structures of the eye change throughout life. Continuous growth occurs in the lens, and a number of other changes associated with aging also occur, many of which reduce visual capacity. Many of these manifest in humans because of their long life span but have very little relevance in terms of survival. However, other long lived animals such as some birds, reptiles and whales, could be severely compromised by complete or partial blindness associated with aging. The aims of this study were to evaluate the importance of vision as a sense in whales by observation of the structure and optics of the anterior segment, and compare the findings with other species whose visual functions are well known. Pathological changes were recorded where appropriate. The findings in this thesis are based on a three year survey of eyes from 45 whales in which i) differences between species in the size of the globe, lens, and cornea are described ii) the unique histological structure of the uveal tract is demonstrated and defined iii) evidence of emmetropia in both air and water from NMR images of two eyes is given iv) lens shape and capsular features which indicate that there could be a capacity for accommodation, are described, and v) lens pathology (four cataracts and one case of phacolysis) is described in five animals. The largest whales (baleen and sperm) had the largest eyes, but this was mainly due to the thickness of sclera. Internal dimensions showed little variation with respect to body size, suggesting that there is an upper limit on internal size which is dependant on the focal length of the lens, a structure which enlarges only slightly with age. Corneal and lens sizes were especially large in the baleen whales, and particularly small in the sperm whale. The uveal tract was found to be very vascular when compared to other species, and particularly well innervated with specialised nerve endings which are thought to be unique to cetaceans. Although the findings are not conclusive, evidence from this study suggests that the whales' unique uveal vasculature and aqueous drainage methods may be instrumental in modifying the dioptric strength of the eye. The abundance of specialised pressure-receptors in the ciliary body indirectly supports a proposed mechanism for this, whereby the engorged ciliary body raises intraocular pressure causing increased corneal curvature, and releases tension on the zonule to allow 'rounding up' of the lens. Optically, the study showed that eyes from two long-finned pilot whales were emmetropic by virtue of a cornea with only a very small amount of optical power in both air and water, and a very powerful lens (about 72D in water). Emmetropia was thus not affected unduly by transition from air to water as it is in most mammals, where the cornea is optically very significant in air but neutral in water. Lenses in both animals showed an unusual 'bump' on the central posterior : surface, and the increased radius of curvature in this area was responsible for the very high dioptric strength of the lenses. The prevalence of lens pathology, particularly cataracts in young animals, was high. but in all cases the cause was unknown

The impact of collarette region-based convolutional neural network for iris recognition

Iris recognition is a biometric technique that reliably and quickly recognizes a person by their iris based on unique biological characteristics. Iris has an exceptional structure and it provides very rich feature spaces as freckles, stripes, coronas, zigzag collarette area, etc. It has many features where its growing interest in biometric recognition lies. This paper proposes an improved iris recognition method for person identification based on Convolutional Neural Networks (CNN) with an improved recognition rate based on a contribution on zigzag collarette area - the area surrounding the pupil - recognition. Our work is in the field of biometrics especially iris recognition; the iris recognition rate using the full circle of the zigzag collarette was compared with the detection rate using the lower semicircle of the zigzag collarette. The classification of the collarette is based on the Alex-Net model to learn this feature, the use of the couple (collarette/CNN) allows for noiseless and more targeted characterization and also an automatic extraction of the lower semicircle of the collarette region, finally, the SVM training model is used for classification using grayscale eye image data taken from (CASIA-iris-V4) database. The experimental results show that our contribution proves to be the best accurate, because the CNN can effectively extract the image features with higher classification accuracy and because our new method, which uses the lower semicircle of the collarette region, achieved the highest recognition accuracy compared with the old methods that use the full circle of collarette region

Ear Symmetry Evaluation on Selected Feature Extraction Algorithms in Ear Biometrics

The human ear has an intriguing shape and like most parts of the human body, bilateral symmetry is observed between left and right.  Occlusions of the ear is a major problem in ear recognition, however, if ear symmetry is established, then reconstructing partially occluded ear images will be possible from the other ear, also the left ear of an individual’s test image can be matched against the right ear in the gallery database (or vice-versa). This paper presented an evaluation of the relationship between left and right ear using four selected feature extraction algorithms: Principal Component Analysis (PCA), Speeded Up Robust Features (SURF), Geometric feature extraction and Gabor wavelet based feature extraction techniques in terms of performance issues given by of False Acceptance Rate (FAR), False Rejection Rate (FRR), and Genuine Acceptance Rate (GAR).The approach was evaluated on non-public ear dataset and simulated in MATLAB Environment. For these selected feature extraction algorithms, the right ears of the subjects are used as the gallery, and the left ear as the probe. The experimental results suggest the existence of some degree of symmetry in the human ears but the ear are not exactly identical as the recognition accuracy of the system declined for three (PCA, SURF, and Gabor wavelet) of the feature extraction algorithms, FRR rising to over 84% for SURF. However, Geometric feature extraction reported relatively high recognition accuracy with FRR of 12.50% and GAR of 87.50%. Keywords: Ear symmetry, Gabor wavelet, Occlusion, Principal Component Analysis (PCA), Speeded Up Robust Features (SURF)