Cataracts are the leading cause of blindness worldwide, and phacoemulsification combined with intraocular lens implantation has become the most mainstream surgical approach. With advancements in surgical techniques and equipment, this procedure has evolved from a simple vision-restoring surgery into the era of refractive surgery. Patients now have higher expectations for postoperative visual quality, particularly the recovery of early vision, which directly impacts their satisfaction. Intraoperative surgical details have a direct influence on postoperative visual acuity. Thanks to intraoperative optical coherence tomography (iOCT) technology, surgeons have gradually recognized that factors such as surgical incisions and intraoperative anterior chamber collapse can affect the survival of corneal endothelial cells after surgery, which is directly related to early postoperative vision and patient satisfaction. Swept-source intraoperative OCT (SS-iOCT) has further improved imaging range and clarity, helping us discover that the depth of intraoperative ultrasound energy use (such as cumulative dissipated energy) correlates with postoperative corneal endothelial cell loss. This suggests that compared to performing phacoemulsification at the capsular opening plane or in the anterior chamber, intracapsular phacoemulsification may reduce postoperative corneal endothelial cell loss, potentially leading to better early postoperative vision, which is crucial for patient satisfaction. However, evidence is still lacking. Therefore, this study aims to compare the effects of intracapsular versus extracapsular phacoemulsification on early postoperative vision, as well as long-term visual acuity, corneal endothelial cells, corneal changes, and the incidence of intraoperative and postoperative complications.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
128
During phacoemulsification, real-time imaging of the anterior segment was performed using SS-iOCT (Tupai, China), but the surgeon was not able to view the images. The surgeon was instructed to proceed with phacoemulsification as per routine, using phaco energy (i.e., level 3). All other surgical steps were identical to conventional surgery.
During phacoemulsification, real-time imaging of the anterior segment was performed using SS-iOCT (Tupai, China). The surgeon was required to confirm under SS-iOCT guidance that the phaco tip was located within the capsular bag (as judged by two observers not involved in the surgery) before applying phaco energy (i.e., level 3). All other surgical steps were identical to conventional surgery.
Zhongshan Ophthalmic Center, Sun Yat-sen University
Guangzhou, Guangdong, China
The best-corrected distance visual acuity at 1 day postoperatively.
It was evaluated using the ETDRS visual acuity chart by a masked optometrist, with the examination procedure following the standard ETDRS visual acuity testing protocol, and the unit of measurement was logMAR.
Time frame: 1 day postoperatively
Coefficient of variation of corneal endothelial cell size
Time frame: Post-operative day 1, week 1, month 1, month 3, month 6
The percentage loss of central corneal endothelial cell density compared to the preoperative baseline at post-operative day 1 and post-operative
Time frame: 1 day and 1 month postoperatively
Percentage of hexagonal cells
Time frame: Post-operative day 1, week 1, month 1, month 3, month 6
Central corneal thickness
Time frame: Post-operative day 1, week 1, month 1, month 3, month 6
Corneal endothelial cell density
Time frame: Post-operative day 1, week 1, month 1, month 3, month 6
The best-corrected distance visual acuity at other time frame
Time frame: Post-operative week 1, month 1, month 3, month 6
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