An Analysis of Wound Burns in the United States and Canada Randall J Olson, MD Clara Chan, MD Michael Bradley, MD Tyler Sorenson, MS4 Funded by an unrestricted grant from Abbott Medical Optics (Randall Olson is a consultant to this company) From the John A Moran Eye Center at the University of Utah (Olson and Sorenson), The University of Toronto (Chan) and the University of Rochester (Bradley)

Bradley AJO 2006;141:222 A wound burn survey of the Western US. 76581 surgeries with a wound burn incidence of about 1 per 1000. Approach from 1.3/1000(D & C) to 0.26/1000 (Vertical chop; p=0.003) Machine from 1.2/1000 (Legacy) to 0.56/1000 (Sovereign; p=0.014) Power from 1.76/1000 (continuous) to 0.26/1000 (hyperpulse; p<0.0001) Multivariate analysis: Power followed by approach in importance.

Other wound burn in vitro work JCRS 2006;32:1222 (OVD) OVD + ultrasound = exothermic reaction Most exothermic Viscoat (up to 6.3 x BSS) and Healon 5 (up to 5.2 x BSS; p<0.0001 for both). AJO (in press) on transversal ultrasound Ozil 37% heat output of continuous (p<0.0001) Ellips 42% heat output of OZil (aspiration blocked; p<0.0001) Longitudinal friction additive

2009 Wound burn survey in the US and canada Web-site based survey launched Summer 2009. Included machine, power modulation, approach, OVD, and incision size. Both general use and specific use with wound burns recorded. Worked through state and provincial societies. All Ophthalmologists queried at least 3 times and 3 times more for any missing data. multivariate analysis still being refined.

Wound burn & machines used Machine Used # of Wound Burns # of Surgeries Wound Burns per 1000 Surgeries Legacy 96 154,562 0.62 Infiniti 187 455,507 0.41 Millennium 30 93,686 0.32 Sovereign 40 153,790 0.26 Signature 7 32,609 0.21 Stellaris 3 22,992 0.13 Legacy > than the rest (p<0.0001); Infiniti > than the rest minus Legacy (p=0.0009)

Wound burn & power modulation # Wound Burns # Surgeries Wound Burn per 1000 Surgeries Continuous 81 104,737 0.77 OZil + Long. 120 223,937 0.54 Burst 21 60,769 0.35 Pulse 32 104,761 0.31 OZil (alone) 60 215,314 0.28 Hyperpulse 45 199,959 0.23 Ellips +/- Long. 13,961 0.00 Continuous vs Burst, Pulse and Hyperpulse (P<0.0001); OZil vs OZil + Longitudinal ultrasound (P<0.0001); Ellips vs OZil +/- Longitudinal (P=0.017)

Wound burn & surgical approach Divide & Conquer + Carousel vs all other approaches; P < 0.0001. Stop and Chop vs all other chopping approaches + phaco flip; P < 0.0001. Surgical Approach # Wound Burns # Surgeries Wound Burns per 1000 Surgeries Carousel 9 12,026 0.75 Divide & Conq. 267 421,763 0.63 Stop & Chop 74 167,897 0.44 Vertical Chop 32 138,173 0.23 Phaco Flip 8 46,115 0.17 Horizont. Chop 15 118,234 0.13 Pre-Chop 2 38,231 0.05

Wound burns / 1000 Surgeries Wound burn & OVD use Healon 5 vs all but Viscoat/DuoVisc; P < 0.0001. Viscoat/DuoVisc vs all but Healon 5; P < 0.0001. Heaon 5 vs Viscoat/DuoVisc; P < 0.0001 OVD Used # Wound Burns # Surgeries Wound burns / 1000 Surgeries Healon 5 38 14,275 2.7 Viscoat/DuoVisc 246 478,754 0.51 DisCoVisc 31 69,763 0.44 Provisc 25 57,008 Amvisc 14 36,941 0.38 Healon 15 60,931 0.25 Ocucoat 9 40,060 0.22 Amvisc Plus 76,523 0.20 Healon GV 7 54,026 0.13 Healon D/Vitrax 8,400 0.00

Wound burn & incision size No significant differences Incision Size # Wound Burns # Surgeries Wound Burns per 1000 Cases 2.8mm or more 124 284,115 0.44 2.41 to 2.79mm 169 446,687 0.38 2.11 to 2.4mm 49 128,184 1.5 to 2.1mm 19 50,982 0.37

Other findings The region with the lowest incidence of wound burn (Canada) had 51% of the wound burn rate of the highest incidence region (Northeastern US; P = 0.0001); however wound burn incidence was significantly lower with surgeons busier than the median (800 surgeries per year; P < 0.0001) and Canada had the highest percentage of busy surgeons of any region (74%). Still working on filling in some key missing data points, but the data is 99% complete. With complete data a multivariate analysis will be most valuable. For instance Infiniti incidence (0.41/1000cases) is surely impacted by OZil + longitudinal incidence of 0.54/1000 cases with 223,937 surgeries.

CONCLUSIONS Overall wound burn incidence 50% less than 2006 AJO study. In vitro work on OVDs and transversal does have support in this survey. Differences in machine wound burn incidence certainly impacted by proprietary power modulations (multivariate analysis will sort this out). Power modulation follows total heat production theory very closely. Approach varied substantially and generally follows 2006 AJO paper. Healon 5 followed by Viscoat increases wound burn risk. Incision size does not appear to be a factor.