目的：评价运用Pentacam Scheimpflug成像测量晶状体核密度与torsinal超声乳化动力学参数(如：运用于老年核性白内障患者的超声能量水平、液体留存时间及液体量)间的关系。

方法：此研究为前瞻性双盲研究。瞳孔扩大后运用Pentacam Scheimpflug成像进行测量。白内障的等级由pentacam核密度测定法 \〖pentacam nucleus densitometry， PND； 又名Pentacam核分段(Pentacam nucleus staging， PNS)软件\〗自主分为1到5个等级。超声乳化术后，自动在Infiniti Ozil IP超声乳化系统监视器上计算并显示总超声(U/S)时间、累计耗散能、Torsional U/S时间以及估算液体的使用情况。组间差异运用单因素方差分析(ANOVA)进行评定，多组分析运用Tamhane测试法，PND测量的晶状体密度与torsinal超声乳化动力学参数间的关系运用Spearman相关分析进行评定。界定P<0.05时具有统计学意义。

结果：此项研究包括125例患者(125眼)，平均年龄为69.7±9.4岁(范围：48～88岁)，其中61例男性、64例女性。U/S总时间、torsional U/S时间、CDE及估算液体使用情况的范围分别为0.70～158.9s， 0.70～158.5s， 0.11～42.65和 21～98mL. PND组间数据有统计学差异。评估超声乳化动力学参数与PND数据间关系后得出PND数据与总超声时间(r=0.767； P<0.01)、torsional超声时间(r=0.767； P<0.01)、CDE(r=0.758； P<0.01)及液体使用量(r=0.602； P<0.01)均有显著相关性。

结论：白内障手术前运用PND评分法获得核密度的客观程度可为超声乳化术中的参数提供可靠的预见性。因此，对每一位患者进行每一单项超声乳化参数的评估，有助于降低超声乳化能量的使用量，减少内皮细胞丢失和类固醇的使用，加速视力的恢复。

AIM: To evaluate the relationship between the density values of the lens nucleus measured using Pentacam Scheimpflug imaging and torsional phacoemulsification dynamics such as the level of ultrasound energy, as well as the duration and amount of fluid used in patients with age-related nuclear cataract.

METHODS: This was a prospective observer-masked study. Pentacam Scheimpflug imaging was performed following pupil dilation. The cataracts were automatically graded from 1 to 5 using pentacam nucleus densitometry(PND), also known as Pentacam nucleus staging(PNS)software by the same observer. After phacoemulsification, total Ultrasound(U/S)time, Cumulative dissipated energy(CDE), Torsional U/S time, and Estimated fluid use were automatically calculated and displayed on the monitor of Infiniti OZiL IP phacoemulsification system. One-way analysis of variance(ANOVA)was used to assess differences between groups. The Tamhane test was used for multiple group analysis. Spearman correlation analysis was used to assess the relationship between lens density measured by PND and the dynamics of torsional phacoemulsification. P<0.05 was considered statistically significant.

RESULTS:In the present study, 125 eyes from 125 patients were evaluated. Mean age was 69.7±9.4y(range: 48-88y), and 61 men and 64 women were included. The highest and lowest values of U/S total time, torsional U/S time, CDE, and Estimated fluid use were 0.70 - 158.90s, 0.70-158.50s, 0.11-42.65, and 21-98 mL in groups, respectively. Significant differences were found among PND groups. When the relationship between phacoemulsification dynamics and PND values were evaluated, there were significant correlations between PND value and total ultrasound time(r=0.767; P<0.01), torsional ultrasound time(r=0.767; P<0.01), CDE(r=0.758; P<0.01), and amount of fluid used(r=0.602; P<0.01).

CONCLUSION:An objective degree of nucleus density obtained by PND scoring before cataract surgery may allow antecedent determination of intraoperative phacoemulsification parameters. Thus, individualized phacoemulsification parameters should be developed for each patient. This will lead to the use of a smaller amount of phacoemulsification energy, resulting in decreased in endothelial cell loss, quicker and better visual healing, and less steroid use.