Cumulative sum analysis score and phacoemulsification competency learning curve

AIM： To use the cumulative sum analysis score（CUSUM） to construct objectively the learning curve of phacoemulsification competency.METHODS： Three second-year residents and an experienced consultant were monitored for a series of 70 phacoemulsification cases each and had their series analysed by CUSUM regarding posterior capsule rupture（PCR） and best-corrected visual acuity. The acceptable rate for PCR was 〈5%（lower limit h） and the unacceptable rate was 〉10%（upper limit h）. The acceptable rate for bestcorrected visual acuity worse than 20/40 was 〈10%（lower limit h） and the unacceptable rate was 〉20%（upper limit h）. The area between lower limit h and upper limit h is called the decision interval. RESULTS： There was no statistically significant difference in the mean age, sex or cataract grades between groups. The first trainee achieved PCR CUSUM competency at his 22 nd case. His best-corrected visual acuity CUSUM was in the decision interval from his third case and stayed there until the end, never reaching competency. The second trainee achieved PCR CUSUM competency at his 39^ th case. He could reach best-corrected visual acuity CUSUM competency at his 22 ^nd case. The third trainee achieved PCR CUSUM competency at his 41 st case. He reached bestcorrected visual acuity CUSUM competency at his 14 ^th case.CONCLUSION： The learning curve of competency in phacoemulsification is constructed by CUSUM and in average took 38 cases for each trainee to achieve it.

Prospective study of Centurion~？ versus Infiniti~？ phacoemulsification systems： surgical and visual outcomes

AIM： To evaluate surgical outcomes（SOs） and visual outcomes（VOs） in cataract surgery comparing the Centurion？ phacoemulsification system（CPS） with the Infiniti？ phacoemulsification system（IPS）.METHODS： Prospective, consecutive study in a singlesite private practice. Totally 412 patients undergoing cataract surgery with either the CPS using the 30-degree balanced？ tip（n=207） or the IPS using the 30-degree Kelman？ tip（n=205）. Intraoperative and postoperative outcomes were documented prospectively up to one month follow-up. Nuclear sclerosis（NS） grade, cumulated dissipated energy（CDE）, preoperative corrected distance visual acuity（CDVA）, and CDVA at one month were recorded. RESULTS： CDE was 13.50% less in the whole CPS compared with the whole IPS subcohort. In eyes with NS grade III or greater, CDE was 28.87% less with CPS（n=70） compared with IPS（n=44）（P=0.010）. Surgical complications were not statistically different between the two subcohorts（P=0.083）, but in the one case of vitreous loss using the CPS, CDVA of 6/4 was achieved at one month. The mean CDVAs（VOs） at one month for NS grade III and above cataracts were-0.17 log MAR（6/4.5） in the CPS and-0.15 log MAR（6/4.5） in the IPS subcohort respectively（P=0.033）.CONCLUSION： CDE is 28.87% less, and VOs are significantly improved, in denser cataracts in the CPS compared with the IPS. The authors recommend the CPS for cases with denser nuclei.

Seismic hazard analysis for central-western Argentina

In this study, we present a PSHA（Probabilistic Seismic Hazard Analysis） for the city of San Juan, which is located in the central-western region of Argentina（30°S-35.5°S; 66.5°W-71°W）. In addition to crustal earthquakes provided by catalogues, recent paleoseismological and neotectonic investigations have permitted to consider events which occurred during the last 400 years.Four seismogenic sources that could cause damages to the studied site corresponding to Precordillera,Western Sierras Pampeanas, Basement of the Cuyana Basin and Cordillera Principal were identified.Based on the evaluation of the contribution of these sources,maximum moment magnitudes above 7.5（Mw） are expected.High values of SA（spectral acceleration）（0.2 and 1 s periods） and PGA（peak ground acceleration） were found in the city of San Juan, which suggests that it is located in a zone of high seismic hazard.Finally, the obtained SA spectra were compared with the seismic-resistant construction standards of Argentina INPRES-CIRSOC 103 [1]. Results suggest that for the city of San Juan and for a return period of475 years, it covers the seismic requirements of the structures.