Treatment of experimental lens capsular tears with intense focused ultrasound.

Ultrasound Cycloplasty in Glaucoma – Mechanisms of Action and their Possible Impact on Intraocular Pressure

“…1 HIFU was later used in the 1990s in ophthalmological practice to treat intraocular pressure (IOP), traumatic capsular tears, glaucoma, retinal detachment and vitreous haemorrhage. [2][3][4][5][6][7] HIFU has been used to treat both benign and malignant lesions of various solid tumours, 8,9 and its potential has been recognised to transform treatment for a spectrum of other serious medical conditions. 10 Indeed, focused ultrasound is under research or has already received regulatory approval for over 50 medical conditions in Europe, the US and Asia.…”

High-Precision Thermotherapy for Small Lesions

“…They also describe additional phenomena that can significantly alter lesion shapes at very high intensities. An application that requires extremely small lesions is the production of small cataracts to 'seal' the anterior lens segments near traumatic ruptures of the lens capsule [6], In therapeutic animal experiments and earlier cataract experiments (9.8 MHz) [1], we found that suitable lesions (confined within 0.4-mm beam widths) could be pro duced by using pulse durations of 0.1 s or less, at focal point intensities above 2 kW/cm2; this result is consistent ening via thermal conduction. These exposures are still sufficiently brief to avoid blood flow cooling effects which can become significant after tenths of seconds; blood flow cooling introduces uncertainties because perfusion is dif ficult, if not impossible, to measure accurately, and it can be altered by temperature increase during exposures.…”

“…Over the past 20 years, our in vivo ani mal investigations have explored a broad variety of topics relevant to the safety of diagnostic ultrasound and to the development of specific therapeutic applications. We found that intense focused ultrasound could be used to treat glaucoma by focal ciliary-body lesions to suppress aqueous humor production and, in rabbits, overlying scleral lesions, which rendered the sclera semipermeable for aqueous humor outflow [5], We showed how matrices of small, ultrasonically induced lesions could 'seal' len ticular areas near traumatically ruptured lens capsules [6], thereby preventing the subsequent development of large cataracts, caused by aqueous-humor influx. We showed how focal chorioretinal lesions [7], like those induced with lasers, could produce retinal adhesions that can pre vent the spread of retinal tears; we also found that ultra sound could facilitate the reattachment of detached reti nal segments [8].…”

Clinical applications of high-intensity focused ultrasound

“…[1][2][3] In the 1990s, it was introduced to ophthalmology to treat raised intraocular pressure, traumatic capsular tears, glaucoma, retinal detachment, and vitreous haemorrhage. [4][5][6][7][8][9] This technique has a unique ability to target deepseated soft tissue tumours. Furthermore, as long as the lesions within solid organs can be clearly visualised on magnetic resonance imaging (MRI) or ultrasonography (USG)-that is, the presence of the acoustic window to allow the transmission of ultrasound energy-many lesions can be targeted such as those in the liver, kidney, pancreas and breast; and uterine fibroids, benign prostatic hypertrophy, and prostate cancer.…”