China
Africa
Explore chapters and articles related to this topic
Lasers in Medicine: Healing with Light
Published in Suzanne Amador Kane, Boris A. Gelman, Introduction to Physics in Modern Medicine, 2020
Suzanne Amador Kane, Boris A. Gelman
One use of the extremely rapid photovaporization made possible by pulsed lasers is a technique called photodisruption. Photodisruption effectively generates a small-scale explosion at the laser beam, sending forth shock waves that tear tissues apart and break up hard deposits. In laser lithotripsy, this effect is used to break up gallstones and stones in the urinary tract. The small pieces of the shattered stones can then either be passed by the patient or removed laparoscopically.
Nonlinear tissue processing in ophthalmic surgery
Published in Pablo Artal, Handbook of Visual Optics, 2017
Photodisruption is a nonlinear procedure of tissue processing, which is—in contrast, for example, to photoablation—independent from the wavelength of the laser radiation. Only nonlinear absorption enables 3D tissue processing inside the medium since the laser radiation is not absorbed at the tissue surface directly by linear absorption [Lub 00, Noa 99, Vog 05].
Neuro-Ophthalmic Literature Review
Published in Neuro-Ophthalmology, 2022
David A. Bellows, John J. Chen, Hui-Chen Cheng, Panitha Jindahra, Peter W. MacIntosh, Collin McClelland, Michael S. Vaphiades, Xiaojun Zhang
Autoantibody against CRX/CORD2, HSP60, and aldolase C were found in higher rates than in patients with RP and normal controls, while α-enolase and CAII were seen at equal rates. Antibodies against recoverin were found in three patients with autoimmune retinopathy, and not seen in normal controls or patients with RP. The area under the receiver operator characteristic curve was 0.531 for anti-recoverin, 0.479 for anti-α-enolase, 0.489 for anti-CAII, 0.737 for anti-CRX/CORD2, 0.637 for anti-HSP60, and 0.664 for anti-aldolase C. A higher number of retinal antibodies was associated with autoimmune retinopathy (≥4 antibodies were seen in 32.6% of patients with autoimmune retinopathy, 5% of patients with RP, and 3% of controls). A higher number of anti-retinal antibodies were slightly associated with photodisruption on optical coherence tomography and severe dysfunction on electroretinography.
Femtosecond Laser Assisted Cataract Surgery: A Review
Published in Seminars in Ophthalmology, 2021
On a molecular level, the FSL creates cavitation bubbles, ultimately leading to photodisruption of tissue. It uses precise near infrared scanning pulse energy, creating plasma within tissue, with treatment starting in the anterior planes of the lens and then progressing posteriorly. The free electrons and ionized molecules from the plasma expand as the plasma cools, creating cavitation bubbles separating the tissue.4 The infrared waves created by the laser are not absorbed by the adjacent cornea or lens, resulting in minimal localized trauma to surrounding tissues. The numerical aperture of the FSL affects the spot size and volume, subsequently treating either corneal or lens tissue. For corneal incisions, a larger numerical aperture is required allowing for precise localization of energy. The opposite, or smaller numerical aperture, is necessary when treating the lens.5
Small Incision Lenticule Extraction (SMILE): Myths and Realities
Published in Seminars in Ophthalmology, 2021
Small manual incision lenticule extraction (SMILE) has emerged in the last decade as an alternative for patients considering laser refractive surgery for myopia and myopic astigmatisms. It was first performed in Germany by Sekundo and Blum in 2008, with the first SMILE results published in 20085 and 2011.6 SMILE is a flapless laser refractive technique that uses a single femtosecond laser system. Photodisruption occurs at the laser’s focal point and creates a rapidly expanding cloud of free electrons and ionized plasma. Optical breakdown leads to a plasma state, and the vaporization of the tissue forms a series of small gas bubbles, cleaving the tissue plane.7 A femtosecond laser is used to create an intrastromal lenticule that can be removed through a small incision of three to four millimeters.8 This technique creates a smaller incision compared to the standard eight to nine millimeter diameter flap created by LASIK and avoids corneal flap creation and reduces its vulnerability to flap dislocation by mechanical trauma.