Evaluation of the efficacy and safety of phacoemulsification under the IOL protection: a randomized controlled clinical study

To observe the therapeutic effect of intraocular lens (IOL) protected phacoemulsification (PHACO) in patients with hard nucleus cataract.

A randomized controlled clinical study was conducted.A total of consecutive 120 patients (120 eyes) with hard nucleus cataract of Emery grade Ⅳ or Ⅴ were enrolled from January 2019 to May 2022.The patients were randomly divided into PHACO group receiving routine PHACO, IOL protected PHACO group receiving PHACO under IOL protection, and extracapsular cataract extraction (ECCE) group receiving ECCE, with 40 cases (40 eyes) in each group.Finally, 99 patients completed the follow-up, including 30 cases (30 eyes) in PHACO group, 35 cases (35 eyes) in IOL protected PHACO group, and 34 cases (34 eyes) in ECCE group.The total operation time, intraoperative PHACO time and cumulative energy release of each patient were recorded.The corneal endothelial cell density (ECD), coefficient of variation in endothelial cell area (CV), hexagonal endothelial cell ratio (6A), corneal astigmatism and the number of eyes with different grades of uncorrected visual acuity were measured and compared after 3-month follow-up.The intraoperative and postoperative complications were recorded.This study adhered to the Declaration of Helsinki and was approved by the Ethics Committee of Yanbian University Hospital (NO.2023002).Patients were informed of study content and purpose and signed a consent form before treatment.

There was no significant difference in ultrasonic energy and time between PHACO group and IOL protected PHACO group (P=0.691, 0.982).The total operation time was (38.81±2.73) and (36.45±3.45) minutes in PHACO group and IOL protected PHACO group, significantly shorter than (69.60±4.35) minutes in ECCE group (both at P<0.001).There was no significant difference in age, sex, lens nucleus hardness and other baseline data among the three groups before operation (all at P>0.05).Three months after operation, the number of patients with higher uncorrected visual acuity in PHACO group and IOL protected PHACO group was larger than that in ECCE group (P=0.006, 0.007).The ECD and 6A in IOL protected PHACO group were (2 155.57±177.88)/mm² and (41.31±5.18)%, respectively, which were significantly higher than (1 912.64±224.11)/mm² and (36.18±3.27)% in PHACO group, and the CV in IOL protected PHACO group was (50.34±5.90)%, which was lower than (55.67±3.30)% in PHACO group, showing statistically significant differences (P=0.007, 0.003, 0.005).At 1 week and 3 months after the operation, the corneal astigmatism was significantly lower in IOL-protected PHACO group than in ECCE group, but higher than in PHACO group, and the difference were statistically significant (all at P<0.05).

Compared with conventional PHACO, IOL-protected PHACO can effectively reduce the damage of corneal endothelium caused by ultrasonic energy, shorten the operation time and reduce postoperative inflammatory reaction compared with ECCE, and does not significantly increase postoperative corneal astigmatism.IOL-protected PHACO is an effective improved surgical method for patients with hard nucleus cataract.