2 Nov Lecture: Phacodynamics – Introduction into the Basics. Cataract extraction using Phacoemulsification is the most precise way we currently have. In his 4th edition of Phacodynamics, he reviews and updates the technology associated with the fluidics and the deployment of ultrasonic power for new. Phacoemulsification has been the dominant mode of cataract extraction in the United States for at least the past 2 decades. As such, it has generated its own ge .
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To create a pressure gradient the bottle is placed at a height above the patient. News Room Media Inquiries. The bevel at the end of standard tips can range from degrees.
Tip selection is dependent on the lens removal technique and the hardness of the lens. As such, it has generated its own genre of monographs, initially emphasizing the conversion to phacoemulsification and later stressing the fashionable technique of the moment or the author’s favored methods, which were often outdated by the time of publication.
Total power is a combination of the frequency of the needle movement and stroke length. This text takes a much different approach. Evaluate appropriate steps to handle challenging cases involving zonular instability, dense cataracts, or soft cataracts.
The length of the needle movement. Combination tips try to take advantage of both the occlusion and cutting abilities.
Purchase access Subscribe to JN Learning for one year. Another source of fluid loss is through wound leakage. Lower frequencies are less efficient and higher frequencies create excess heat.
Course Objectives Upon successful completion of this activity, participants should be able to: Identify phacodynamics modulations for special situations, including aspiration, vacuum, bottle height and phaco power. Course Objectives Upon successful completion of this activity, participants should be able to:.
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Rigid noncompliant aspiration tubing will also decrease the amount of surge. This is phacoynamics Surge The higher the compliance the greater the surge amplitude during occlusion break. The jackhammer effect is the physical striking of the needle against the nucleus. The cavitation effect is created energy that is released when micro-bubbles implode. Low vacuum is helpful during sculpting of a hard or large nucleus, in which the high power intensity of the tip may be applied near the iris or anterior capsule.
The amount of ultrasound and or aspiration is controlled by the surgeon by pushing down the foot pedal. The fluid travels from the irrigation bottle through plastic tubing, into ;hacodynamics phaco needle and finally into phacodybamics anterior chamber of the eye. The ultrasound generating mechanism of the phaco handpiece causes the tip attached to it to vibrate rapidly back and forth.
Venting allows vacuum levels to be equilibrated to air or fluid into the aspiration line. The fluid that leaves the anterior chamber. Larger angles degrees are desirable for sculpting whereas smaller angles degrees are preferred for steps that need vacuum such as quadrant removal or chopping. Sponsored by the Cataract Clinical Committee, this webinar will cover phacodynamics, techniques, and OVDs for the rock hard cataract, including machine specifics and femto laser-assisted considerations.
Change from continuous to pulse. More phacodynamic tips may have compound angles. Selection of the appropriate one depends on the type of lens removal technique. If the balance of inflow and out flow is altered, the anterior chamber can be under or over-pressurized. Understanding the mechanical principles underlying this technology allows the surgeon to optimize machine settings and safely trouble shoot problems encountered during surgery.
Sharpness of the tip is directly proportional to the tip angle. Another mechanism to reduce surge is venting. To make a purchase of the nucleus the surgeon wants a short amount of energy then to drop back into apiration foot position 2 To chop it is easiest to use a burst mode of a burst width ohacodynamics ms then to have the vacuum on fixed so that it will build pgacodynamics. Identify basic parameter considerations in phacodynamics, including aspiration, vacuum, and phaco power.
Understanding phacodynamics. – PubMed – NCBI
Create a free personal account to download free article PDFs, sign up for alerts, customize your interests, and more. Copyright American Medical Association. Flow is dependent upon the vacuum level setting. Whenever the phaco power is set at percent the stroke length is the maximum permissible for that machine.
The longer the stroke phacodyjamics, the greater the physical impact on the nucleus, and the greater the generation of cavitation forces.
Stroke length is determined by foot pedal excursion in position 3 during linear control of phaco. This page was last modified on Phacodynamifs 19,at Create a free personal account to access your subscriptions, sign up for alerts, and more. The primary example of the flow pump is the peristaltic pump.
When the tip of the phaco needle is occluded, negative pressure will build in the tubing. Sign in to access your subscriptions Sign in to your personal account. This adjustment of using pulse will reduce the energy in the eye by the percentage of time designated as off.