Polarization-Sensitive OCT Imaging of Scleral Abnormalities in Eyes With High Myopia and Dome-Shaped Macula.

Importance: The relevance of visualizing scleral fiber orientation may offer insights into the pathogenesis of pathologic myopia, including dome-shaped maculopathy (DSM). Objective: To investigate the orientation and density of scleral collagen fibers in highly myopic eyes with and without DSM by polarization-sensitive optical coherence tomography (PS-OCT). Design, Setting, and Participants: This case series included patients with highly myopic eyes (defined as a refractive error ≥6 diopters or an axial length ≥26.5 mm) with and without a DSM examined at a single site in May and June 2019. Analysis was performed from September 2019 to October 2023. Exposures: The PS-OCT was used to study the birefringence and optic axis of the scleral collagen fibers. Main Outcomes and Measures: The orientation and optic axis of scleral fibers in inner and outer layers of highly myopic eyes were assessed, and the results were compared between eyes with and without a DSM. Results: A total of 72 patients (51 [70.8%] female; mean [SD] age, 61.5 [12.8] years) were included, and 89 highly myopic eyes were examined (mean [SD] axial length, 30.4 [1.7] mm); 52 (58.4%) did not have a DSM and 37 (41.6%) had a DSM (10 bidirectional [27.0%] and 27 horizontal [73.0%]). Among the 52 eyes without DSM, the 13 eyes with simple high myopia had primarily inner sclera visible, displaying radially oriented fibers in optic axis images. In contrast, the entire thickness of the sclera was visible in 39 eyes with pathologic myopia. In these eyes, the optic axis images showed vertically oriented fibers within the outer sclera. Eyes presenting with both horizontal and bidirectional DSMs had clusters of fibers with low birefringence at the site of the DSM. In the optic axis images, horizontally or obliquely oriented scleral fibers were aggregated in the inner layer at the DSM. The vertical fibers located posterior to the inner fiber aggregation were not thickened and appeared thin compared with the surrounding areas. Conclusions and Relevance: This study using PS-OCT revealed inner scleral fiber aggregation without outer scleral thickening at the site of the DSM in highly myopic eyes. Given the common occurrence of scleral pathologies, such as DSM, and staphylomas in eyes with pathologic myopia, recognizing these fiber patterns could be important. These insights may be relevant to developing targeted therapies to address scleral abnormalities early and, thus, mitigate potential damage to the overlying neural tissue.

Simultaneous balancing of geometric transformation and linear polarizations using six-fold-mirror geometry over the visible region.

The presence of optical rotation due to the Berry phase and coating-induced linear polarizations across a set of rays deteriorate the form of a point spread function. In this Letter, we model an optical system with six aluminum coated fold mirrors, and we show how to balance geometric transformation, linear retardance, and linear diattenuation simultaneously. We minimize the linear polarizations by arranging the six fold mirrors in three pairs of crossed-fold-mirror geometry. In the same optical model, we also show that geometric transformation induced by the first set of three mirrors is canceled out by the second set of three mirrors by rotating the eigen-polarizations in opposite direction with the same amount. We perform experimental verification using a spectroscopic Mueller matrix polarimeter over the visible spectral range.

A study of distribution of ABO and Rh (D) blood groups amongst Sikkimese.

The objective of this study was to find out the distribution pattern of ABO and Rh (D) blood groups in Sikkimese population of Gangtok as there is not a single report regarding this so far. Blood groups were studied in 142 healthy MBBS Sikkimese students of SMIMS, Gangtok of age group 19 to 24 years. Blood grouping was carried out by rapid slide test. The predominant blood group in Sikkimese population is O followed by A, B and AB. This indicates that they might belong to the Paleo-Mongoloid group anthropologically.

5-N-Substituted-2-(substituted benzenesulphonyl) glutamines as antitumor agents. Part II: synthesis, biological activity and QSAR study.

Cancer is a major killer disease throughout human history. Thus, cancer becomes a major point of interest in life science. It was proved that cancer is a nitrogen trap and tumor cells are avid glutamine consumers. The non-essential amino acid glutamine, which is a glutamic acid derivative, supplies its amide nitrogen to tumor cells in the biosynthesis of purine and pyrimidine bases of nucleic acids as well as takes part in protein synthesis. Based on these and in continuation of our composite programme of development of new potential anticancer agents through rational drug design, 17 new 5-N-Substituted-2-(substituted benzenesulphonyl) glutamines were selected for synthesis. These compounds as well as 36 earlier synthesized glutamine analogues were screened for antitumor activity using percentage inhibition of tumor cell count as the activity parameter. QSAR study was performed with 53 compounds in order to design leads with increased effectiveness for antitumor activity using both physicochemical and topological parameters. QSAR study showed that steric effect on the aromatic ring is conducive to the activity. n-butyl substitution on aliphatic side chain and atom no 12 is important for antitumor activity of glutamine analogues.