Importance This study assesses the interobserver agreement on dacryocystography (DCG) and dacryoscintigraphy (DSG) findings. Background There are no standard grading criteria to guide the interpretation of conventional DCG and DSG findings and therefore there may be a degree of subjectivity. This study evaluates the level of interobserver agreement in the interpretation of DCG and DSG findings. Design A retrospective observational study at the Royal Adelaide Hospital. Participants A total of 165 patients who presented with epiphora with 276 DCGs and 290 DSGs performed were included in this study. Methods DCG and DSG images were obtained, anonymized, randomized and interpreted by three independent oculoplastic surgeons. Standard grading criteria were set for both DCG and DSG images. Data from all observers were analysed for interobserver agreement using Kappa (κ) statistics, generated using a variation of Cohen's kappa for multiple observers. Main Outcome Measures Level of interobserver agreement (κ values) in the grading of DCG and DSG findings. Results There was an overall moderate interobserver agreement for DCG findings (κ = 0.55), with the highest agreement on interpreting canalicular obstruction (κ = 0.80), followed by proximal nasolacrimal duct obstruction (κ = 0.67) and normal patency (κ = 0.63). There was an overall fair interobserver agreement for DSG findings (κ = 0.36), with the best being moderate agreement (κ = 0.42‐0.50) for interpreting pre‐sac delay and post‐sac proximal delay. Conclusions and Relevance DCG offers good reliability in interpreting patent and obstructed systems. On the other hand, DSG has poor agreement and highlights some of the limitations in the ability to guide epiphora management.

The emerging field of quantum biology has led to a greater understanding of biological processes at the microscopic level. There is recent evidence to suggest that non-trivial quantum features such as entanglement, tunnelling and coherence have evolved in living systems. These quantum features are particularly evident in supersensitive light-harvesting systems such as in photosynthesis and photoreceptors. A biomimetic strategy utilizing biological quantum phenomena might allow new advances in the field of quantum engineering, particularly in quantum information systems. In addition, a better understanding of quantum biological features may lead to novel medical diagnostic and therapeutic developments. In the present review, we discuss the role of quantum physics in biological systems with an emphasis on the retina.

PURPOSE. Understanding the energetics of retinal neurons and glia is crucial for developing therapies for diseases that feature deficits in nutrient or oxygen availability. Herein, we performed a detailed characterization of the distribution and activity of mitochondrial proteins in the vascularized retinas of rat and marmoset, and the avascular retinas of rabbit and guinea pig. Further, we delineated expression of ubiquitous mitochondrial creatine kinase (uMtCK). METHODS. Expression of eight mitochondrial proteins was investigated using Western blotting, single-and double-labeling immunohistochemistry. Activities of cytochrome c oxidase, succinate dehydrgogenase, and isocitrate dehydrogenase were determined by enzyme histochemistry using unfixed tissue sections. RESULTS. In vascularized retinas, immunoreactivities were characterized by strong, punctate labeling in the plexiform layers, photoreceptor inner segments, somas of various cell types, notably retinal ganglion cells (RGCs), and the basolateral surface of the retinal pigment epithelium. In avascular retinas, immunoreactivities featured intense labeling of inner segments, together with weak, but unambiguous, staining of both plexiform layers. RGCs were relatively enriched. In Müller cells of avascular retinas, mitochondria were restricted to scleral-end processes. For each species, enzyme activity assays yielded similar results to the protein distributions. Labeling for uMtCK in vascular and avascular retinas was fundamentally similar, being restricted to neuronal populations, most notably inner segments and RGCs. Of all of the mitochondrial proteins, uMtCK displayed the strongest labeling in avascular retinas. uMtCK was not detectable in Müller cells in any species. CONCLUSIONS. The current findings advance our understanding of the metabolic similarities and differences between vascular and avascular retinas.