Long-acting nanoparticle-loaded bilayer microneedles for protein delivery to the posterior segment of the eye.

Treatment of neovascular ocular diseases involves intravitreal injections of therapeutic proteins using conventional hypodermic needles every 4-6 weeks. Due to the chronic nature of these diseases, these injections will be administrated to patients for the rest of their lives and their frequent nature can potentially pose a risk of sight-threatening complications and poor patient compliance. Therefore, we propose to develop nanoparticle (NP)-loaded bilayer dissolving microneedle (MN) arrays, to sustain delivery of protein drugs in a minimally invasive manner. In this research, a model protein, ovalbumin (OVA)-encapsulated PLGA NPs were prepared and optimised using a water-in-oil-in-water (W/O/W) double emulsion method. The impact of stabilisers and primary sonication time on the stability of encapsulated OVA was evaluated using an enzyme-linked immunosorbent assay (ELISA). Results showed that the lower primary sonication time was capable of sustaining release (77 days at 28.5% OVA loading) and improving the OVA bioactivity. The optimised NPs were then incorporated into a polymeric matrix to fabricate bilayer MNs and specifically concentrated into MN tips by high-speed centrifugation. Optimised bilayer MNs exhibited good mechanical and insertion properties and rapid dissolution kinetics (less than 3 min) in excised porcine sclera. Importantly, ex vivo transscleral distribution studies conducted using a multiphoton microscope confirmed the important function of MN arrays in the localisation of proteins and NPs in the scleral tissue. Furthermore, the polymers selected to prepare bilayer MNs and OVA NPs were determined to be biocompatible with retinal cells (ARPE-19). This delivery approach could potentially sustain the release of encapsulated proteins for more than two months and effectively bypass the scleral barrier, leading to a promising therapy for treating neovascular ocular diseases.

Quantitative measures of vortex veins in the posterior pole in eyes with pachychoroid spectrum diseases.

Pachychoroid spectrum diseases have attracted increasing attention, though their pathophysiology has yet to be fully elucidated. In this study, we assessed the vascular diameters of vortex veins in pachychoroid spectrum diseases such as central serous chorioretinopathy (CSC), pachychoroid neovasculopathy without polypoidal lesions (PNV), and pachychoroid neovasculopathy with polypoidal lesions (polypoidal choroidal vasculopathy: PCV). In a retrospective case series of 94 eyes with CSC, 60 eyes with PNV and 57 with PCV, we binarized en face optical coherence tomography (OCT) images of choroidal vortex veins and analyzed the mean diameter of vortex veins. The presence of anastomosis between the superior and inferior vortex veins and central choroidal thickness (CCT) were also evaluated using OCT images. CSC showed significantly larger mean diameter of vortex veins than PCV (P < 0.05). Anastomosis between superior and inferior vortex veins was observed in over 90% of eyes with each pachychoroid spectrum disease. The patients with CSC were the youngest, followed by PNV patients, and then patients with PCV. The largest CCT values were observed in CSC eyes, followed by PNV eyes, and then PCV eyes. CCT correlated with the mean diameter of vortex veins (rs = 0.51, P < 0.01). These findings suggest that congestion of vortex veins might show gradual amelioration corresponding to the development of anastomosis between the superior and inferior vortex veins during the course of progression of pachychoroid spectrum diseases. Moreover, the mean diameter of vortex veins can be used as a parameter indicating choroidal congestion.

Retinal imaging analysis based on vessel detection.

With an increase in the advancement of digital imaging and computing power, computationally intelligent technologies are in high demand to be used in ophthalmology cure and treatment. In current research, Retina Image Analysis (RIA) is developed for optometrist at Eye Care Center in Management and Science University. This research aims to analyze the retina through vessel detection. The RIA assists in the analysis of the retinal images and specialists are served with various options like saving, processing and analyzing retinal images through its advanced interface layout. Additionally, RIA assists in the selection process of vessel segment; processing these vessels by calculating its diameter, standard deviation, length, and displaying detected vessel on the retina. The Agile Unified Process is adopted as the methodology in developing this research. To conclude, Retina Image Analysis might help the optometrist to get better understanding in analyzing the patient's retina. Finally, the Retina Image Analysis procedure is developed using MATLAB (R2011b). Promising results are attained that are comparable in the state of art.