| Objective：To study and compare the effects of 2.2mm coaxial micro-incision phacoemulsification (C-MICS) with 2.75mm coaxial small-incisionphacoemulsification (C-SICS) on the postoperative visual quality, cornealendothelial density (CED) and intraoperative ultrasound energy level.Methods：A prospective, randomized and controlled clinical study wasconducted on 134 cataract patients of 167 eyes which were randomly dividedinto two groups: 2.2mm C-MICS group, made a clear corneal incision (CCI)at the highest refractive power meridian; 2.75mm C-SICS group, made a CCIat the highest refractive power meridian. Record and compare the generalpreoperative information of the two groups such as age, gender, cornealastigmatism distribution, nuclear hardness classification, intraocular pressureand pupil diameter. Uncorrected visual acuity (UCVA), best corrected visualacuity (BCVA), corneal astigmatism degree (CAD), corneal astigmatism axial(CAA), total high order aberration (t-HOA) of corneal 3 to 6 order aberration,spherical aberration (SA), coma, trefoil and high order astigmatism (HA)were measured in both groups at the time before the surgery, 1 week, 1 monthand 3 months after the surgery, and calculate the root mean square (RMS)value of the various types of aberration for statistical analysis. Measure theCED of two groups at the time before the surgery, 1 week, 1 month and 3months after the surgery. Record the phaco time (s) and average energy (%) inthe surgery, and calculate the effective phaco time (EPT). Compare andanalyze the above indicators of each time between the two groups, and analyze the correlation of EPT and nuclear hardness classification in bothgroups.Results：UCVA and BCVA in both groups was significantly improvedafter surgery, eye number of UCVA range greater than 0.7: 2.2mm group: 0eye (0%) preoperatively to 54 eyes (77.1%) 3 months postoperatively, P=0.00;2.75mm group: 0 eye (0%) preoperatively to 70 eyes (72.2%) 3 monthspostoperatively, P=0.00; eye number of BCVA range greater than 0.7: 2.2mmgroup: 2 eyes (2.86%) preoperatively to 68 eyes (97.1%) 3 monthspostoperatively, P=0.00; 2.75mm group: 0 eye (0%) preoperatively to 93 eyes(95.9%) 3 months postoperatively, P=0.00. UCVA of two groups began tostabilize 1 month postoperatively, while BCVA of two groups started tostabilize 1 week postoperatively. No significant difference was showed onUCVA and BCVA at each time between two groups (P＞0.05). PostoperativeCAD significantly decreased after surgery in both groups, CAD changes:2.2mm group: 0.73±0.43D preoperatively to 0.49±0.36D 3 monthspostoperatively, P=0.00; 2.75mm group: 0.87±0.57D preoperatively to0.53±0.38D 3 months postoperatively, P=0.00. CAD of 2.2mm group brieflyincreased 1 week postoperatively (P=0.01), followed by sustained reductions.No significant change was showed on CAD of 2.75mm group 1 weekpostoperatively (P=0.12), then continued decrease followed. CAD changes inamplitude between two groups showed no significant difference (P＞0.05).The CAA overall composition within two groups showed no significantdifference before and after surgery (P＞0.05), there was no significantdifference between two groups either (P＞0.05). Postoperative CED hadreduced in both groups, CED changes: 2.2mm group: 2510.88±268.81mm-2preoperatively to 2378.84±369.93mm-23 months postoperatively, P=0.01; 2.75mm group: 2524.62±251.69mm-2preoperatively to 2388.08±360.51mm-23 months postoperatively, P=0.00. Postoperative CED began to stabilize 1month postoperatively, CED at the time of 1month and 3 months after surgerywas of no significant difference in both groups (P＞0.05). CED changes inamplitude between two groups was of no significant difference (P＞0.05).Two groups of patients in EPT had no significant difference (P=0.07), EPTwas positively correlated with the nuclear hardness classification in bothgroups, the Spearman rank correlation coefficients were: 2.2mm group(rs=0.58, P=0.00); 2.75mm group: (rs=0.66, P=0.00). Postoperative t-HOAhad a significant reduction in both groups, t-HOA changes: 2.2mm group:2.02±0.93μm preoperatively to 1.50±0.23μm 3 months postoperatively,P=0.00; 2.75 mm group: 2.15±0.82μm preoperatively to 1.67±0.34μm 3months postoperatively, P=0.00. t-HOA had no significant change 1 weekpostoperatively in 2.2mm group (P=0.11), then began to decrease. 2.75mmgroup had a transient increase 1 week postoperatively (P=0.00), and fell to thepreoperative level 1 month postoperatively (P=0.13), then followed acontinue decrease. Changes in amplitude between two groups at each time thet-HOA was no significant difference (P＞0.05). Postoperative SA showedsignificant decrease in 2.2mm group, while no significant change in 2.75mmgroup, SA changes: 2.2mm group: 1.44±0.38μm preoperatively to1.22±0.17μm 3 months postoperatively, P=0.00; 2.75mm group:1.33±0.44μm preoperatively to 1.25±0.21μm 3 months postoperatively,P=0.09. SA was of no significant change 1 week postoperatively in 2.2mmgroup (P=0.98), then began to decline, while no significant difference on SAwas showed at any time in 2.75mm group compared with the time beforesurgery (P＞0.05). Postoperative coma value reduced to varying degrees in both groups, coma changes: 2.2mm group: 0.75±0.49μm preoperatively to0.40±0.20μm 3 months postoperatively, P=0.00; 2.75mm group:0.98±0.59μm preoperatively to 0.46±0.22μm 3 months postoperatively,P=0.00. No significant change took place in 2.2mm group 1 weekpostoperatively (P=0.24), then decreased gradually, while coma value in2.75mm group had a significant decrease 1 week postoperatively. Comachange in amplitude between two groups showed a significant difference 1month postoperatively compared with the time before surgery, 2.75mm grouphad a more greater decrease than 2.2mm group (P=0.01). Postoperative trefoildecreased in both groups, trefoil changes: 2.2mm group: 0.51±0.60μmpreoperatively to 0.33±0.17μm 3 months postoperatively, P=0.02; 2.75mmgroup: 0.56±0.44μm preoperatively to 0.36±0.16μm 3 months postoperatively,P=0.00. The trefoil value short-term increased in both groups 1 weekpostoperatively (P＜0.05), and 2.2mm group recovered to preoperative level(P=0.75), then continue to reduce, while trefoil value of 2.75mm group wasstill high 1 month postoperatively (P=0.01), then significantly reduced.Compared with the time before surgery, the trefoil value of 2.2mm groupdecreased greater than 2.75mm group 1 month postoperatively (P=0.04),while compared with the time 3 months postoperatively, 2.75mm groupreduced greater than 2.2mm group (P=0.00). Postoperative HA value waslower than the time before surgery in both groups, HA changes: 2.2mm group:0.37±0.38μm preoperatively to 0.18±0.08μm 3 months postoperatively,P=0.00; 2.75mm group: 0.49±0.53μm preoperatively to 0.37±0.22μm 3months postoperatively, P=0.03. HA value of 2.2mm group showed nosignificant change 1 week postoperatively (P=0.20), then gradually reduced,wile in 2.75mm group, the HA value did not change significantly (P＞0.05) until the time 3 months postoperatively when a significant decrease appeared(P=0.03). Compared with the time before surgery, the overall change of HAvalue in amplitude showed significant differences between two groups 3months postoperatively, the HA decreased rate in 2.2mm group wassignificantly greater than 2.75mm group (P=0.00).Conclusion：2.2mm coaxial micro-incision and 2.75mm coaxialsmall-incision phacoemulsification could effectively improve the uncorrectedvisual acuity and best corrected visual acuity, the BCVA became stable earlierthan UCVA in both groups. There was no significant difference in theamplitude of improvement in visual acuity between two groups. By makingCCI at the highest refractive power meridian, both 2.2mm C-MICS and2.75mm C-SICS could correct part of the preoperative corneal astigmatism,there was no significant difference in the change of CAD between two groups,changes of CAD in both groups at each time varied. Postoperative CAAcomposition within and between two groups showed no significant difference.CED reduced in both groups, but the magnitude of CED change was of nosignificant between two groups. EPT between two groups showed nosignificant difference, and the EPT was significantly correlated with nuclearhardness classification in both groups. By making CCI at the steepest cornealmeridian, both 2.2mm C-MICS and 2.75mm C-SICS could improve part ofthe anterior corneal surface HOA in varying degrees: Both groups couldimprove the 3 to 6 order t-HOA, coma and trefoil, but the overallimprovement amplitude was of no significant difference between two groups,the coma and trefoil changes varied at different time in both group. 2.2mmC-MICS could improve SA significantly, while 2.75mm C-SICS had no effecton SA, postoperative SA changes at different time varied in both groups. Both groups could improve the HA to some extent, but 2.2mm C-MICS was moresuperior at this aspect. |
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