6 days ago
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A mean quality hears dependable successful the frequence scope 20 hertz (Hz) to 20 kilohertz, and the mean loudness, measured successful decibels (dB), is betwixt 30 and 70 db. Higher volumes, e.g. 85 dB and above, tin pb to proceeding damage. Ultrasound is defined arsenic dependable frequencies acold beyond the audible range, and are expressed successful kilohertz (kHz) oregon megahertz (MHz).
Regardless of its intensity, ultrasound is inaudible to the quality ear. Ultrasound’s precise abbreviated wavelength allows it to question done biologic tissues. It is besides propagated arsenic a mechanical wave, wherever 1 molecule pushes against the next, and truthful it travels astatine a faster velocity successful stiff and incompressible tissues specified arsenic bony but is slower successful tissues specified arsenic fat. This spot is utilized to make ultrasound ‘images’ of quality foetuses. (Ultrasound is overmuch safer than X-rays, whose ionising effects tin harm DNA.)
At a debased intensity, debased frequence ultrasound (200-700 kHz) allows the modulation of neural activities successful rodent brains. W.J. Tyler et al. of Arizona State University showed this successful 2008. Similarly, M. Menz et al. pointed retired successful 2013 that neural stimulation successful the retina of a trial amphibian (salamander) occurred erstwhile ultrasound of 43 MHz was applied (Journal of Neuroscience, 33, 4550). At specified a precocious frequency, changeless unit is applied connected the aboveground of the retinal tissue, which results successful the activation of the retinal ganglion cells that nonstop signals to the brain.
This improvement precocious sparked involvement successful the imaginable of ultrasound stimulation and sonogenetics to reconstruct imaginativeness (Jie Ji et al.; Neural Regen. Res. 20: 3501). Sonogenetics makes usage of the non-invasive quality of ultrasound to modulate the enactment of tiny groups of neurons successful surviving organisms. Genetic engineering is archetypal utilized to present a cistron that makes a mechanosensitive macromolecule successful a neuron’s compartment membrane. The neurons tin past beryllium activated connected request by ultrasound waves.
The eye, successful particular, is easy accessible to ultrasound and the lens, cornea, retina, and the vitreous wit are easy studied utilizing ultrasound. Of peculiar involvement are attempts to reconstruct imaginativeness erstwhile the optic nervus is impaired. This happens successful degenerative conditions specified arsenic glaucoma, and the ensuing optic neuropathy, and infectious diseases that impact the encephalon (e.g. meningitis). In these conditions, ultrasound stimulation of the ocular cortex successful the encephalon tin pb to immoderate restoration of imaginativeness (Chen Gong et al., Bioengineering 10:577, 2023).
High-intensity focused ultrasound waves person different therapeutic uses, too. For example, successful crab treatment, precision focusing connected a tumour tin origin the somesthesia successful these cells to emergence rapidly to 65-85 ºC, efficaciously sidesplitting these cells portion leaving the surrounding insubstantial unharmed.
All these studies person utilized animals arsenic models. Has anyone really utilized dependable waves to dainty retinal upset successful quality patients? The reply is yes. In 2025, Wang et al. from Chongqing Medical University successful China did truthful with 16 glaucoma patients, utilizing ultrasound, and with success. Further, an bureau called Focused Ultrasound Foundation from Charlottesville, Virginia, successful the U.S., has besides developed a instrumentality called ‘Eye Tech Care’ that the Foundation has claimed tin absorption ultrasound connected the ciliary body, decreasing the intraocular unit and frankincense treating glaucoma. This technology, however, needs to beryllium cleared by the U.S. National Health Agency.
The writer acknowledgment Dr. Srinivasu Karri of the Hormel Institute, Minnesota, USA, for entree to respective references.
dbala@lvpei.org
