In optical coherence tomography (OCT), the axial resolution is directly linked to the coherence length of the employed light source. It is currently unclear if OCT allows measuring thicknesses below its axial resolution value. To investigate spectral-domain OCT imaging in the super-resolution regime, we derived a signal model and compared it with the experiment. Several island thin film samples of known refractive indices and thicknesses in the range 46 - 163 nm were fabricated and imaged. Reference thickness measurements were performed using a commercial atomic force microscope. In vivo measurements of the tear film were performed in 4 healthy subjects. Our results show that quantitative super-resolved thickness measurement can be performed using OCT. In addition, we report repeatable tear film lipid layer visualization. Our results provide a novel interpretation of the OCT axial resolution limit and open a perspective to deeper extraction of the information hidden in the coherence volume.
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http://dx.doi.org/10.1364/BOE.7.002650 | DOI Listing |
J Clin Med
January 2025
Department of Sciences, Section of Biomedical Sciences and Technologies, Roma Tre University, Viale Marconi 446, 00146 Rome, Italy.
: Diabetes is a well-recognised factor inducing a plethora of corneal alterations ranging from dry eye to reduced corneal sensibility, epithelial defects, and reduced cicatrisation. This cohort study aimed to assess the efficacy of a novel ophthalmic solution combining cross-linked hyaluronic acid (CHA), chondroitin sulfate (CS), and inositol (INS) in managing diabetes-induced corneal alterations. Specifically, it evaluated the solution's impact on the tear breakup time (TBUT), the ocular surface disease index (OSDI), and corneal sensitivity after three months of treatment.
View Article and Find Full Text PDFJ Clin Med
January 2025
Ocular Surface Unit, ISPRE Ophthalmics, 16129 Genoa, Italy.
Dry eye disease (DED) is a multifactorial, chronic, and often relapsing condition with a significant impact on patient quality of life (QoL). Symptoms such as ocular discomfort and visual disturbances are diverse and frequently misaligned with objective clinical signs, complicating diagnosis and management. DED not only interferes with daily activities like reading, driving, and computer use but also imposes a substantial economic burden due to direct healthcare costs and reduced work productivity.
View Article and Find Full Text PDFJ Clin Med
December 2024
Department of Neurology, National Institute of Medicine of the Ministry of Interior and Administration, 02-507 Warsaw, Poland.
Age-related changes to the orbicularis oculi muscle include impaired eyelid function, such as lagophthalmos, alterations in tear film dynamics, and aesthetic changes like wrinkles, festoons, and the descent of soft tissue. To date, the structural and functional changes that would comprehensively increase our understanding of orbicularis aging have not been analyzed. This study aims to investigate functional outcomes using surface electromyography and correlate them with ultrastructural changes in orbicularis during aging.
View Article and Find Full Text PDFSensors (Basel)
December 2024
State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China.
To avoid wear and tear of the slip ring due to electrical corrosion, the slip ring needs to undergo the running-in process under atmospheric conditions without current after assembly. To address the urgent demand for long-service capability space conductive slip rings in the aerospace field, the running-in behavior and failure mechanism between the AgCuNi alloy and Au-electroplated layer are investigated using a ball-on-disc tribometer in this paper. The results show that the transfer film composed of Au plays an important role in modifying the friction during the sliding process.
View Article and Find Full Text PDFOphthalmol Ther
January 2025
Santa Barbara Eye Care, Santa Barbara, CA, USA.
Perfluorohexyloctane ophthalmic solution (Miebo) and water-free cyclosporine ophthalmic solution 0.1% (Vevye) are recently approved treatments for dry eye disease (DED). Perfluorohexyloctane (PFHO) uses a novel approach to treat evaporative DED, whereas water-free cyclosporine (CsA 0.
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