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Introduction to optical imaging
Published in Ahmad Fadzil Mohamad Hani, Dileep Kumar, Optical Imaging for Biomedical and Clinical Applications, 2017
Dileep Kumar, Ahmad Fadzil Mohamad Hani
Lasers are light sources that can emit coherent and polarised light, which exhibit monochromatic (peaked) spectrum. Optical imaging techniques such as fluorescence and Raman spectroscopy most often use lasers. Lasers can couple effectively with the optical fibres because of their sharp and intense monochromatic type. Most commonly available lasers are gas or solid-state lasers obtained using He–Ne (helium–neon), CO2 (carbon dioxide), Ar+ (argon), nitrogen sapphire, Nd:YLF (neodymium–yttrium lithium fluoride) and Nd: YVO4 (neodymium–yttrium orthovanadate) solid states. The choice of lasers is made depending on the requirement of wavelength, size, power and cost [15]. Lasers are the prime source of light in the imaging techniques such as fluorescence imaging, optical tomography, etc. Lasers are used to excite the fluorescence signals in biological tissues in order to observe the abnormalities in the tissue through fluorescence imaging [13].
Sealing clear corneal incisions in cataract surgery
Published in Expert Review of Ophthalmology, 2018
Manpreet Kaur, Ankit Tomar, Farin Shaikh, Ruchita Falera, Lalit M. S. Bageshwar, Jeewan S. Titiyal
Experimental studies have demonstrated the feasibility of corneal welding using infrared lasers (1070-nm neodymium-doped yttrium lithium fluoride laser and 1980-nm thulium (Tm:YAP) laser) in bovine eyes with minimal histological damage [49]. An experimental study evaluated the wound-sealing properties of an ICG-containing tissue adhesive activated by infrared laser (808 nm), and observed a superior tensile strength as compared to sutures, with faster application time and biodegradability [50]. Menabuoni et al. did not observe wound leak in any case in a retrospective evaluation of cases undergoing phacoemulsification or extracapsular cataract extraction incision followed by corneal welding with ICG [48]. Minimal astigmatism changes were observed, and there was no significant endothelial cell loss or postoperative inflammation with the use of corneal welding [48]. A prospective study observed diode laser welding to be effective in sealing corneal wounds in pediatric cases undergoing keratoplasty or cataract surgery, with an absence of significant postoperative inflammation, wound leak, or astigmatism [51].