Comparison between phacochop divideconquer and stop chop phacotechnique

Comparison between phaco-chop, divideconquer and stop & chop phaco-technique according to the cataract density Hae ri Yum, M. D. , Man Soo Kim, M. D. Eun Chul Kim, M. D. Department of Ophthalmology and Visual Science, The Catholic University of Korea No author has any financial or proprietary interest in any materials or methods mentioned

Introduction n Phacoemulsification was the technique that was performed in almost all cataract surgery. When phacoemulsification was first introduced, the nucleus was not divided and the phacoemulsification probe was used to sculpt and consume the nucleus. Compared with extracapsular cataract extraction, phacoemulsification in associated with additional potential risks of corneal endothelial cell damage.

Purpose n To compare the intraoperative and short-term postoperative outcomes of cataract surgery performed with 3 different types of the phacotechnique (phaco-chop, divide-conquer and stop & chop) under microcoaxial or conventional cataract surgery according to the cataract density.

Materials & Methods 90 cataract eyes with nuclear density from Grade 2 to 4 Cataract density (NO 2 , NO 3, NO 4) Phaco-Chop Divide-Conquer Stop & Chop

Materials & Methods n Intraoperative measurements v Effective phacoemulsification time (EPT) v Mean cumulative dissipated ultrasound energy (CDE) v Total balanced salt solution (BSS) use n Clinical measurements v v Preoperative, 1 -day postoperative, 1, 2 -month postoperative Best corrected visual acuity (BCVA) Central corneal thickness Endothelial cell count

Results <Baseline preoperative clinical data> Group 1 (Phaco-Chop) (n=30) Group 2 (Divide-Conquer) (n=30) NO 2 NO 3 Group 3 (Stop & Chop) (n=30) NO 2 NO 3 NO 4 NO 2 Mean age (y) 62. 1± 7. 0 69. 4± 6. 8 72. 6± 7. 3 61. 3± 8. 3 67. 3± 10. 2 70. 9± 7. 9 67. 7± 9. 2 69. 8± 9. 3 68. 2± 16. 0 Preoperative visual acuity (lod MAR) 0. 39± 0. 33 0. 27± 0. 05 0. 24± 0. 14 0. 28± 0. 14 0. 30± 0. 14 0. 22± 0. 11 0. 26± 0. 22 0. 34± 0. 16 0. 19± 0. 18 Preoperative corneal thickness (μm) 517± 18. 5 526± 11. 0 526± 9. 0 522± 15. 6 522± 12. 4 523± 12. 5 519± 11. 6 520± 15. 8 523± 12. 4 Preoperative endothelial cell count 2655± 333 2632± 315 2460± 336 2744± 405 2330± 543 2633± 303 2319± 278 2697± 304 2480± 367 No significant difference between groups NO 3 NO 4

Results <intra-op. /EPT, CDE, BSS use> EPT(sec) <0. 001 P value CDE(%) P value BSS use (ml) 0. 033 0. 009 *Tukey HSD and Duncan test 0. 003 *Tukey HSD and Duncan test 0. 017 P value 0. 048 *Tukey HSD and Duncan test The phaco-chop technique can provide more effective lens removal than divide-conquer and stop & chop phaco technique with lower phacoemulsification time and energy in the mature cataract. EPT: effective phacoemulsification time CDE: mean cumulative dissipated ultrasound energy BSS: balanced salt solution

Results Endothelial cell count loss rate (%) Nuclear opacity *Tukey HSD and Duncan test Although the mean endothelial cell loss was less in phaco-chop groups than those in divide-conquer and stop & chop groups , the difference between groups was not significant statistically.

Results CCT change (%) Nuclear opacity *Tukey HSD and Duncan test CCT: central corneal thickness (μm) Although the central corneal thickness increased after phacoemulsification , there was less change in phaco-chop than divide-conquer and stop & chop , the difference was not significant.

Results <BCVA (best corrected visual acuity)> Group 1 (Phaco-Chop) (n=30) Group 2 (Divide-Conquer) (n=30) NO 2 NO 3 NO 4 Pre op. 0. 39± 0. 33 0. 27± 0. 05 0. 24± 0. 14 1 day 0. 85± 0. 18 0. 75± 0. 16 1 month 0. 87± 0. 16 2 month 0. 91± 0. 10 NO 2 Group 3 (Stop & Chop) (n=30) NO 3 NO 4 NO 2 0. 28± 0. 14 0. 30± 0. 14 0. 23± 0. 11 0. 26± 0. 22 0. 34± 0. 16 0. 19± 0. 18 0. 75± 0. 16 0. 75± 0. 28 0. 77± 0. 19 0. 70± 0. 25 0. 71± 0. 29 0. 66± 0. 21 0. 63± 0. 17 0. 78± 0. 12 0. 77± 0. 14 0. 77± 0. 26 0. 78± 0. 18 0. 72± 0. 22 0. 81± 0. 18 0. 73± 0. 15 0. 78± 0. 18 0. 87± 0. 11 0. 85± 0. 09 0. 85± 0. 14 0. 87± 0. 08 0. 85± 0. 14 0. 87± 0. 12 0. 88± 0. 10 0. 86± 0. 12 No significant difference between groups NO 3 NO 4

Conclusion n The phaco-chop technique can provide more effective lens removal than divide-conquer with lower phacoemulsification time and energy in the mature cataract. n However, the phaco-chop, divide-conquer and stop & chop technique may be all effective for both of microcoaxial and conventional incision cataract surgery. n There is an advantage of phaco-chop over divide-conquer and stop & chop in both CCT and ECC change but this advantage is no significant difference statistically.