The purpose of this study is to compare the accuracy of capsulotomy assisted by intraocular caliper and Verion navigation system in phacoemulsification surgery and postoperative visual quality of patients.
Continuous curvilinear capsulorhexis (CCC) is an important and technically challenging procedure in cataract surgery. However, most surgeons perform CCC by experience or referring to the pupil size, which is highly subjective and the accuracy of capsulorhexis is unsatisfactory. The investigators developed a new modified intraocular caliper with standard calibration on the rinse needle, which can measure and locate the position of capsulorhexis. The surgeon can gently use the blunt needle in the front of the intraocular caliper to further make corresponding markers on the lens anterior capsule, and then carry out capsulotomy according to the marks. We found intraocular caliper-assisted capsulotomy can obviously improve the accuracy of capsulorhexis. The purpose of this study is to compare the accuracy and postoperative visual quality of intraocular caliper-assisted capsulotomy with those of digital image projection device VERION navigation system.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
DOUBLE
Enrollment
156
Intraocular caliper is a modified intraocular caliper with standard calibration on the rinse needle.
Verion Image Guided System (Alcon Laboratories, Inc.) is a digital image guidance system consisting of a diagnostic reference unit and a surgery pilot for intraoperative surgical assistance. The device can be used to align toric intraocular lens during surgery as well as support manual creation of a capsulorhexis with a predefined target diameter.
Zhongshan Ophthalmic Center，Sun Yat-Sen University
Guangzhou, China
Deviation of horizontal and vertical diameter of capsulorhexis from the target diameter (5.3 mm)
Images of the edges of IOL and capsulorhexis are taken at the end of the operation. Image J image analysis software is used to measure the horizontal diameter and vertical diameter of capsulorhexis with the diameter of IOL optical surface (6 mm) as the reference by two independently professional graders at the meantime, and further calculate the deviation of horizontal and vertical diameter of capsulorhexis from the target diameter (5.3 mm) .
Time frame: During the surgery
Uncorrected and corrected visual acuity
Visual acuity is evaluated with ETDRS visual acuity chart.
Time frame: One month after surgery
Ideal ratio of capsulorhexis
Ideal capsulorhexis is defined as a centered and round capsulorhexis, which can cover the edge of IOL optical surface continuously for 360 degrees with a diameter between 5.0 to 5.5 mm.
Time frame: During the surgery
Grades of capsulorhexis-IOL overlap
The capsulorhexis-IOL overlap of each patient is graded as 360-degree continuous overlap, 270\~360-degree overlap, 180\~270-degree overlap, 90\~180-degree overlap, and \< 90-degree overlap.
Time frame: During the surgery
Distance between pupil center and capsulorhexis center
Measured by Image J image analysis software.
Time frame: During the surgery
Horizontal and vertical diameter of capsulorhexis
Measured by Image J image analysis software.
Time frame: During the surgery
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Intraocular lens tilt
Measured by anterior segment OCT (CASIA2).
Time frame: One month after surgery
Intraocular lens decentration
Measured by anterior segment OCT (CASIA2).
Time frame: One month after surgery
Intraocular aberrations
Measured by OPD-SCAN III.
Time frame: One month after surgery
Deviation of horizontal and vertical diameter of capsulorhexis from the target diameter (5.3 mm)
Time frame: One month after surgery