Purpose: To compare the accuracy of biometry using conventional A-scan ultras onography and partial coherence interferometry, and to improve the accuracy of b iometry by sequential audit of postoperative refractive er...Purpose: To compare the accuracy of biometry using conventional A-scan ultras onography and partial coherence interferometry, and to improve the accuracy of b iometry by sequential audit of postoperative refractive error. Methods: The stud y was performed in three phases. In phase 1, 20 consecutive patients undergoing routine phacoemulsification underwent biometry using bothA-scan ultrasonography and the Zeiss IOLMaster (ZIOLM).Asingle experienced optometrist refracted all p atients 2 weeks after surgery. The errors between expected and achieved refracti on were calculated and compared between the two methods. In phases 2 and 3, a fu rther 22 and 20 patients, respectively, were recruited and only the ZIOLM was us ed for biometry. The manufacturer’s suggested A-constant was refined and the e rror between expected and achieved refraction was calculated. Results: In phase 1, the median unexpected error for the ZIOLM was +0.63 (interquartile range +0 .368 to +1.015) and for A-scan biometry was 0.24 (interqu artile range-1.335 to +0.802). In phase 1 65%of patients’- postoperative refractions were found to be within 1.0 D of emmetropia using th e ZIOLM (55%using A-scan biometry). Refinements to the A-constant improved th is to 95%by phase 3. Conclusion: An error was identified in IOL power estimatio n with the ZIOLM, when using the manufacturer’s recommended A-constant (recomm ended and previously optimized ultrasound A-constant 118.0; ZIOLMoptimized A-c onstant 118.6). Serial modifications to the A-constant were successful in reduc ing the unexpected error towellwithin the tolerance limits of published internat ional standards.展开更多
Background: The aim of this work was to investigate the accuracy of prediction of three different biometric methods for the calculation of posterior chamber intraocular lenses. Methods: In 59 consecutive patients who ...Background: The aim of this work was to investigate the accuracy of prediction of three different biometric methods for the calculation of posterior chamber intraocular lenses. Methods: In 59 consecutive patients who underwent extracapsular cataract- extraction with posterior chamber intraocular lens implantation, we compared the refractive results at the first day (D1) and 6 weeks (W6) after surgery with the calculated refraction of three biometric methods: the Carl Zeiss “ IOL- Master 99” (IOLM), the Biovision “ Echograph Class 1- Type B” (BIOV) and the Allergan Humphrey “ Ultrasonic Biometer Mod. 820” (AHUB). For statistical calculation box- plots, the Wilcoxon signed- rank test and linear regression analysis were used. Results: In all patients the mean of the postoperative refraction was - 0.07 D (SD: 1.41) at day 1 and 0.12 D (SD: 1.18) at week 6. Compared to the postoperative refraction at week 6, the calculated refractive values were higher in all three measuring devices: IOLM: + 0.28 D (SD: 0.67), BIOV: + 0.60 D (SD: 0.88), AHUB:+ 0.26 D (SD: 0.92). There were no statistically significant differences between IOLM and BIOV, or respectively, AHUB and BIOV (P < 0.000 1), but a significant difference was found between IOLM and AHUB, (P=0.906). To adjust for systematic differences of the agreement, one can calculate the postoperative refraction at week 6 (REF6) from IOLM by using the linear regression formula: REF6=1.1 × .IOLM+ 0.3. Conclusion: A comparison between the three biometric methods and the refractive results at day 1 and week 6 after cataract surgery with implantation of a posterior chamber intraocular lens showed that the calculated mean values obtained from the three biometric methods are higher than the real postoperative refraction. Calculations using the Zeiss IOL- Master and the Allergan Humphrey Ultrasonic Biometer are closer to the patient’ s postoperative refraction than calculations using the Biovision Echograph.展开更多
Dear Editor,We present a case of combined application of CIRCLE software(Carl Zeiss Meditec AG,Germany)and topography-guided laser-assisted in situ keratomileusis(Topo-LASIK)for small-incision lenticule extraction(SMI...Dear Editor,We present a case of combined application of CIRCLE software(Carl Zeiss Meditec AG,Germany)and topography-guided laser-assisted in situ keratomileusis(Topo-LASIK)for small-incision lenticule extraction(SMILE)enhancement.SMILE is a safe,minimally invasive corneal laser surgery using a femtosecond laser to create an extractable stromal lenticule.展开更多
文摘Purpose: To compare the accuracy of biometry using conventional A-scan ultras onography and partial coherence interferometry, and to improve the accuracy of b iometry by sequential audit of postoperative refractive error. Methods: The stud y was performed in three phases. In phase 1, 20 consecutive patients undergoing routine phacoemulsification underwent biometry using bothA-scan ultrasonography and the Zeiss IOLMaster (ZIOLM).Asingle experienced optometrist refracted all p atients 2 weeks after surgery. The errors between expected and achieved refracti on were calculated and compared between the two methods. In phases 2 and 3, a fu rther 22 and 20 patients, respectively, were recruited and only the ZIOLM was us ed for biometry. The manufacturer’s suggested A-constant was refined and the e rror between expected and achieved refraction was calculated. Results: In phase 1, the median unexpected error for the ZIOLM was +0.63 (interquartile range +0 .368 to +1.015) and for A-scan biometry was 0.24 (interqu artile range-1.335 to +0.802). In phase 1 65%of patients’- postoperative refractions were found to be within 1.0 D of emmetropia using th e ZIOLM (55%using A-scan biometry). Refinements to the A-constant improved th is to 95%by phase 3. Conclusion: An error was identified in IOL power estimatio n with the ZIOLM, when using the manufacturer’s recommended A-constant (recomm ended and previously optimized ultrasound A-constant 118.0; ZIOLMoptimized A-c onstant 118.6). Serial modifications to the A-constant were successful in reduc ing the unexpected error towellwithin the tolerance limits of published internat ional standards.
文摘Background: The aim of this work was to investigate the accuracy of prediction of three different biometric methods for the calculation of posterior chamber intraocular lenses. Methods: In 59 consecutive patients who underwent extracapsular cataract- extraction with posterior chamber intraocular lens implantation, we compared the refractive results at the first day (D1) and 6 weeks (W6) after surgery with the calculated refraction of three biometric methods: the Carl Zeiss “ IOL- Master 99” (IOLM), the Biovision “ Echograph Class 1- Type B” (BIOV) and the Allergan Humphrey “ Ultrasonic Biometer Mod. 820” (AHUB). For statistical calculation box- plots, the Wilcoxon signed- rank test and linear regression analysis were used. Results: In all patients the mean of the postoperative refraction was - 0.07 D (SD: 1.41) at day 1 and 0.12 D (SD: 1.18) at week 6. Compared to the postoperative refraction at week 6, the calculated refractive values were higher in all three measuring devices: IOLM: + 0.28 D (SD: 0.67), BIOV: + 0.60 D (SD: 0.88), AHUB:+ 0.26 D (SD: 0.92). There were no statistically significant differences between IOLM and BIOV, or respectively, AHUB and BIOV (P < 0.000 1), but a significant difference was found between IOLM and AHUB, (P=0.906). To adjust for systematic differences of the agreement, one can calculate the postoperative refraction at week 6 (REF6) from IOLM by using the linear regression formula: REF6=1.1 × .IOLM+ 0.3. Conclusion: A comparison between the three biometric methods and the refractive results at day 1 and week 6 after cataract surgery with implantation of a posterior chamber intraocular lens showed that the calculated mean values obtained from the three biometric methods are higher than the real postoperative refraction. Calculations using the Zeiss IOL- Master and the Allergan Humphrey Ultrasonic Biometer are closer to the patient’ s postoperative refraction than calculations using the Biovision Echograph.
基金Supported by the Shanghai Rising-Star Program(No.21QA1401500)Shanghai Natural Science Foundation(No.23ZR1409200).
文摘Dear Editor,We present a case of combined application of CIRCLE software(Carl Zeiss Meditec AG,Germany)and topography-guided laser-assisted in situ keratomileusis(Topo-LASIK)for small-incision lenticule extraction(SMILE)enhancement.SMILE is a safe,minimally invasive corneal laser surgery using a femtosecond laser to create an extractable stromal lenticule.
