Thermal comparison of the AdvanTec Legacy, Sovereign WhiteStar, and Millennium phacoemulsification systems
PURPOSE: To determine the operating temperature of ultrasonic tips used with the Alcon AdvanTec Legacy, AMO Sovereign WhiteStar, and Bausch & Lomb Millennium phacoemulsification systems. SETTING: Mackool Eye Institute, Astoria, New York, New York, USA. METHODS: Thermal imaging of ultrasonic tips (Legacy, WhiteStar, and Millennium) was performed in air and in human cadaver eyes using a duty cycle of 33% (WhiteStar) and 50% (Millennium and Legacy). In vitro temperatures were measured with the tip centered in the incision and intentionally decentered against the side of the incision. The stroke length of each instrument was also measured, and the operating frequency of the Legacy was evaluated with the addition of a tangential load. RESULTS: Open air and in vitro testing demonstrated that tip temperatures with the Legacy were consistently the lowest. Temperatures measured with the WhiteStar and Millennium systems were higher and generally similar to each other. At identical console power settings, the stroke length of the WhiteStar and Millennium tips was longer than that of the Legacy. The frequency of the Legacy handpiece did not change significantly (less than 200 Hz) under conditions of tangential tip loading. CONCLUSIONS: At identical console power settings and similar console duty cycles, the temperature elevation of ultrasonic tips was least for the Legacy and greater for the WhiteStar and Millennium under all conditions. The causes of these findings appear to be the longer stroke length of the WhiteStar and Millennium and the underestimation of the duty cycle with the WhiteStar
Health status of cable splicers with low-level exposure to lead: results of a clinical survey
The results of a cross-sectional clinical field survey of 90 telephone cable splicers are presented. Despite the rare occurrence of clinically overt lead poisoning among cable splicers, the observed prevalence of symptoms was 29% for lead-associated central nervous system symptoms and 21% for gastrointestinal symptoms. These two groups of symptoms were directly related to zinc protoporphyrin (ZPP) levels but no relationship was found between them and blood lead concentrations. Only 5% of the workers had significantly elevated blood lead levels (greater than 40 microgram/100ml). Because of the intermittent lead exposure encountered in this trade, individuals were identified with "normal" blood lead levels associated with "elevated" zinc protoporphyrin concentrations, indicating the difference in biological significance between exposure-(blood lead) and biological-response tests (ZPP). Suggestion is made that both types of diagnostic tests be utilized in the medical surveillance of lead-exposured workers.