to dramatically decrease the amount of POS at high vacuum levels. The utility of the model is that we can make fair comparisons that are clinically relevant. For instance, one interesting finding in doing this work is that POS levels can vary dramatically from eye to eye, such that parameters that are safe in one eye could be dangerous in another, showing that we need to vary our overall parameters to be safe from patient to patient. So, in general, you can decrease POS by elevating the bottle, decreasing the bore of the tip, decreasing the flow of the instrument and/or decreasing vacuum. It also turns out that the POS protectors such as the ABS tip for the Alcon systems and Cruise Control may, but not always, help in controlling POS.

In conclusion, it is important to understand the machine as well as the parameters used to optimize both efficiency and safety. From the work, as outlined, it is clear as to what can be done to optimize safety. Furthermore, very short ultrasound pulses at 4–6 ms with variable on–off times do improve efficiency with additional safety documented with regard to wound burn and corneal protection. Torsional ultrasound also improves efficiency with the virtual elimination of chatter and may protect against wound burn.

Take Home Pearls

ßDo not rely on the machine-indicated values as they may be inaccurate.

ßVery short bursts of ultrasound and a vertical chopping approach are very protective of

wound burn.

ßPost-occlusion surge can be minimized by raising the irrigation bottle, decreasing flow and

maximum vacuum, and moving to a smallerbore phaco needle.

ßFlow restrictors, such as Cruise Control, can dramatically tame post-occlusion surge where it

is severe, such as in Venturi vacuum systems.

ßEach eye can vary quite dramatically with regard to the amplitude of post-occlusion surge.

References

1.Adams W, Brinton J, Floyd M, et al (2006) Phacodynamics: an aspiration flow vs vacuum comparison. Am J Ophthalmol 142:320–322

2.Bradley, Olson RJ (2006) A survey about phacoemulsification incision thermal contraction incidence and causal relationships. Am J Ophthalmol 141:222–224

3.Britton JP, Adams W, Kumar R, et al (2006) Comparison of thermal features associated with 2 phacoemulsification machines. J Cataract Refract Surg 32:288–293

4.Fishkind W, Bakewell B, Donnenfeld ED, et al (2006) Comparative clinical trial of ultrasound phacoemulsification with and without the WhiteStar system. J Cataract Refract Surg 32:45–49

5.Floyd MS, Valentine JR, Olson RJ (2006) Fluidics and Heat Generation of Alcon Infiniti and Legacy, Bausch & Lomb Millennium, and Advanced Medical Optics Sovereign Phacoemulsification Systems. AJO 142:387–392 ([3] Table 1)

6.Floyd MS, Valentine JR, Olson RJ (2006) Fluidics and Heat Generation of Alcon Infiniti and Legacy, Bausch & Lomb Millennium, and Advanced Medical Optics Sovereign Phacoemulsification Systems. AM J Ophthalmology 142: 387–392 ([3] Table 4)

7.Floyd MS, Valentine JR, Olson RJ (2006) Fluidics and heat generation of Alcon Infiniti and Legacy, Bausch & Lomb Millennium and Advanced Medical Optics Sovereign phacoemulsification systems. Am J Ophthalmology 142: 387–392

8.Georgescu D, Payne M, Olson RJ (2007) Objective measurement of postocclusion surge during phacoemulsification in human eye bank eyes. Am J Ophthalmology 143:437–440.

9.Olson MD, Miller KM (2005) In-air thermal imaging comparison of Legacy AdvanTec, Millenium, and Sovereign WhiteStar phacoemulsification systems. J Cataract Refract Surg 31:1640–1647

10.Brinton JP, Adams W, Kumar R, Olson RJ. (2006) A comparison of Legacy and Sovereign phacoemulsification machine thermal ratios using different ultrasound power settings. JCRS 32: 288–293 [1] Figure 2

11.Bradley MJ, Olson RJ. (2006) Results from a wound burn survey. AJO 141: 222–224 [10] The Table

12.Olson RJ, Jin Y, Kefalopoulos G, et al (2004) Legacy AdvanTec and Sovereign WhiteStar: a wound temperature study. J Cataract Refract Surg 30:1109–1113

13.Payne M, Waite A, Olson RJ (2006) Thermal inertia associated with ultrapulse technology in phacoemulsification. J Cataract Refract Surg 32:1032–1034

14.Georgescu D, Payne M, Olson RJ. (2007) A typical comparative set-up for four phacoemulsificiation machines in the same eye-bank-eye. AJO 143:437–440 [12] The Figure

15.Soscia W, Howard JG, Olson RJ (2002) Microphacoemul-

sification with WhiteStar. A wound-temperature study. J Cataract Refract Surg 28:1044–1046

16.Wade M, Isom R, Georgescu D, et al (2007) Efficacy of Cruise Control in controlling postocclusion surge with Legacy and Millenium venturi phacoemulsification machines. J Cataract Refract Surg 33:1071–1075

17.Georgescu D, Kuo AF, Kinard KI, Olson RJ. (2008) A Fluidics Comparison of Alcon Infiniti, Bausch & Lomb Stellaris, and Advanced Medical Optics Signature Phacoemulsification Machines. AJO 145:1014–1017 [14] Figure 3

18.Georgescu D, Kuo AF, Kinard KI, Olson RJ. (2008) A Fluidics Comparison of Alcon Infiniti, Bausch & Lomb Stellaris, and Advanced Medical Optics Signature

Phacoemulsification Machines. AJO 145:1014–1017 [14]

Figure 1

19.Wade M, Isom R, Georgescu D, Olson RJ. (2007) The impact of Cruise Control on Millennium with the venturi pump is clearly evident. 33: 1071–1075 [13] Figure 3

20.Georgescu D, Kuo AF, Kinard KI, et al (2008) A fluidics comparison of Alcon Infiniti, Bausch & Lomb Stellaris, and Advanced Medical Optics Signature phacoemulsification machines. Am J Ophthalmology 145:1014–1017

21.Mackool RJ, Sirota MA (2005) Thermal comparison of the AdvanTec Legacy, Sovereign WhiteStar, and Millenium phacoemulsification systems. J Cataract Refract Surg 31:812–817

5.3 MICS with Different Platforms

5.3.1MICS with the Accurus Surgical System

Arturo Pèrez-Arteaga

Core Messages

ßWhile performing MICS with the Accurus machine, the fluidics are improved, because of

the advantages of fluidics control for posterior segment surgery in addition to those for anterior segment surgery.

ßThe use of internal forced infusion incorporated in the Accurus machine is a very efficient

tool, especially when using incision sizes of less than 1 mm.

ßThe internal forced infusion has the advantage of maintaining a constant positive intraocular

pressure, thereby avoiding the surge

ßThe key to using forced infusion is to obtain a fluid rate of 45 ml/min as a minimum, with the

irrigating chopper or cannula that the surgeon is accustomed to use. There is no single parameter for all devices. Settings must be individualized.

ßThe force of infusion can be preprogrammed and so the surgeon is able to switch between

two different forces with only the foot-pedal, avoiding the need for touching the panel or the remote control.