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Femto-phaco vs. conventional phaco: is there a measurable quality difference in medical outcome?

Session Details

Session Title: Cataract I

Session Date/Time: Friday 15/02/2013 | 10:30-12:30

Paper Time: 10:48

Venue: Hall 2

First Author: : J.Förster GERMANY

Co Author(s): :    T. Herbst   D. Uthoff           

Abstract Details


The aim of the study is to find out if possible differences in quality of medical treatments between femto phaco patients and conventional phaco patients are measurable with the help of a quality measurement system, called “Quality Index Bellevue” (QiB). The basis for examinations provides the “Quality Network Bellevue” (QNB). Within the QNB, the Eye Hospital Bellevue is actually connected to 44 established ophthalmologists. With the help of special software, pre- and postoperative findings are transferred between the participants and collected in a common data base, which includes more than 44.000 patient cases and more than 1.5 million medical findings.


Base for examinations is “Quality Index Bellevue System” (QiB), which transfers each medical finding into a quality index and bases upon the German school grading system. QiB system is built up of three subarea QiBs, which includes measurable and subjectively ascertained findings as well as different aspects of patient satisfaction.


Our choice of statistical methods depends on the level of measurement: For examinations on aggregate levels, we will use ANOVA test as well as ordinary t-test. For comparisons of single finding QiBs, we will come back to a Mann-Whitney-Test and Kruskal-Wallis tests respectively because of ordinal scale levels. Further possible examinations will be realized by appropriate statistical methods.


In preparation of analyses, we anticipated to find significant quality differences concerning IOL centration because of a more precisely capsulorhexis of Femto phaco procedure. Furthermore, we anticipated effective phaco time to be significant lower for femto phaco compared to conventional cataract procedure. As a consequence, “QiB anterior chamber” should be better for femto phaco procedure. Further possible advantages are anticipated in a relative improved cornea finding (QiB cornea) because of less endothelial cell loss. Patient satisfaction (QiB patient satisfaction) and BCVA / BUCVA (QiB BCVA / QiB BUCVA) may be significant better as well. First results give support for our hypotheses: We found significant differences in effective phaco time, endothelial cell loss (QiB cornea) and IOL centration (QiB IOL). Our first results reject the hypotheses of significant differences concerning patient satisfaction, BCVA, BUCVA and anterior chamber (QiB anterior chamber).


The femto phaco laser technology seems to be a momentously step in cataract surgery. The present study wants to explore the comparative advantages of this technic with the help of “Quality Index Bellevue” (QiB). This instrument of quality measurements rates the quality of medical output with the help of postoperative findings, which are transformed into school grades and which are weighted individually according to their influence on total quality. On the Basis of “Quality Network Bellevue” (QNB), objective judgments of postoperative findings as well as a sufficient large data base are guaranteed. The analysis of the resulting data set has been done according to applicable statistical methods. Because of disparities in level of measurement, different methods have been used. Our first results show significant quality differences in three peri- and postoperative findings (phaco time, endothelial cell loss, IOL centration). We did not find significant discrepancies in patient satisfaction, BCVA, BUCVA and anterior chamber. Since data ascertainment is still in process, further possible findings will be identified in the context of following statistical analyses.

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