| 摘要 |
A method and instrument for thermal phacoemulsification includes, in one aspect, a process for introducing high temperature water into the lens capsule of the eye for emulsification purposes. The invention provides a mechanism for heating water to the desired temperature at the point of delivery, whereby the cannula that enters the eye is maintained at a temperature sufficiently low to avoid thermal damage to surrounding eye tissue. The invention provides an isenthalpic device for delivering heated water to the lens capsule for phacoemulsification. The device includes a intraocular cannula for delivering high pressure water, and a throttling mechanism at the point of delivery for converting the energy in the water stream from pressure to heat. The throttling mechanism may comprise a capillary passage, or a porous plug, or a micro-orifice which directs the fluid stream to strike a target in the cannula bore, after which the fluid is discharged from the cannula. In a further aspect, the invention comprises a fluid pressure intensifier generating high pressure fluid pulses that are delivered through the cannula to the throttling mechanism. The use of a fluid pressure intensifier minimizes the length of tubing that must carry high pressure fluid, and the use of a throttling mechanism to heat the fluid stream assures that the tubular cannula remains within a tolerable temperature range. Moreover, the risk of a catastrophic malfunction is held to an absolute minimum.
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