Significance: The main problem with phakometry is the low visibility of the third Purkinje image. We built a phakometer using Bessel beams, which have properties of being resistant to diffraction and the potential for self-reconstruction. This instrument had lenticular images three times brighter than those of a conventional phakometer.
Purpose: To investigate Purkinje image brightness, accuracy, and repeatability of a "Bessel" phakometer compared with those of a conventional phakometer.
Methods: Phakometers were developed with a telecentric imaging system focused at the pupil plane of the eye to capture anterior cornea, anterior lens (PIII), and posterior lens (PIV) Purkinje images. A Bessel beam was generated by a diode laser beam passing through a high-powered doublet with a central obstruction. Software was used to determine image sizes and estimate lens anterior and posterior surface radii of curvature (Ra, Rp), equivalent refractive index (RI), and equivalent power (F). The Bessel phakometer's accuracy was assessed using a model eye. Repeatability (interobserver and intraobserver) and Purkinje images brightnesses of Bessel and conventional phakometers were assessed with six participants.
Results: The lens parameters of the model eye determined by the Bessel phakometer were similar to those provided by the model eye's manufacturer with differences (manufacturer - Bessel) in Ra and Rp, RI, and F of +1.18 mm, 0.18 mm, +0.0053, and -0.55 D, respectively. The intraobserver repeatabilities for the Bessel and conventional phakometers were similar. The interobserver repeatabilities of Ra, Rp, and RI for the Bessel phakometer were almost half those (i.e., two times better) for the conventional phakometer. Brightnesses of PIII and PIV were approximately three times higher with the Bessel phakometer than with the conventional phakometer.
Conclusions: The Bessel beam phakometer provided accurate estimates of lens parameters of a model eye and produced brighter Purkinje images and better interobserver repeatability than that of a conventional phakometer.
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http://dx.doi.org/10.1097/OPX.0000000000001130 | DOI Listing |
Cureus
December 2024
Neurology, SRM Medical College Hospital and Research Centre, SRM Institute of Science and Technology, Chengalpattu, IND.
Introduction: This study discusses the various clinical profiles, investigatory findings, treatment responses, and prognosticating factors in seven cases of autoimmune encephalitis (AE).
Methods: The clinical records of seven AE patients admitted to the Neurology Department, SRM Medical College Hospital and Research Centre, Chennai, from July 2022 to December 2023 were retrospectively analyzed.
Results: The patients' ages ranged from 18 to 35, and all experienced seizures.
Retina
January 2025
Department of Ophthalmology and Vision Science, Eye and ENT Hospital, Fudan University, Shanghai 200031, People's Republic of China.
Purpose: To describe a simplified technique for correcting intraocular lens (IOL) decentration during scleral-sutured IOL fixation surgery.
Methods: During surgery, Purkinje images were utilized to assess IOL positioning. A straightforward IOL decentration adjustment technique was employed when necessary.
Nat Metab
January 2025
CECAD Excellence Center, University of Cologne, Cologne, Germany.
Dysfunctions in autophagy, a cellular mechanism for breaking down components within lysosomes, often lead to neurodegeneration. The specific mechanisms underlying neuronal vulnerability due to autophagy dysfunction remain elusive. Here we show that autophagy contributes to cerebellar Purkinje cell (PC) survival by safeguarding their glycolytic activity.
View Article and Find Full Text PDFJ Vis Exp
December 2024
The David and Inez Myers Laboratory for Cancer Genetics, Department of Human Molecular Genetics and Biochemistry, Faculty of Health and Medical Sciences, School of Medicine, Tel Aviv University;
Cerebellar Purkinje cells (PCs) exhibit a unique interplay of high metabolic rates, specific chromatin architecture, and extensive transcriptional activity, making them particularly vulnerable to DNA damage. This necessitates an efficient DNA damage response (DDR) to prevent cerebellar degeneration, often initiated by PC dysfunction or loss. A notable example is the genome instability syndrome, ataxia-telangiectasia (A-T), marked by progressive PC depletion and cerebellar deterioration.
View Article and Find Full Text PDFNat Cardiovasc Res
January 2025
Institute of Developmental and Regenerative Medicine, University of Oxford, Oxford, UK.
Arrhythmias are a hallmark of myocardial infarction (MI) and increase patient mortality. How insult to the cardiac conduction system causes arrhythmias following MI is poorly understood. Here, we demonstrate conduction system restoration during neonatal mouse heart regeneration versus pathological remodeling at non-regenerative stages.
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