Evaluation of Toric Intraocular Lens(IOL) Combined with Capsular Tension Ring(CTR) in Patients with Cataract Combined with High Myopia

The objective of this study is to evaluate the postoperative visual quality and IOL stability in patients with cataracts and high myopia who have undergone surgery using astigmatism-correcting IOLs in conjunction with tension rings.It is a non-randomised retroprospective cohort study. Patients with high axial myopia (AL ≥ 26 mm) who underwent cataract phacoemulsification combined with toric IOL(Acrysof SN6ATY IQ toric IOL, Alcon, Alcon Laboratories, Fort Worth, Texas, USA) implantation from October 2020 to September 2023 at the Shanghai Tenth People's Hospital are selected. According to the usage of CTR, all patients will be divided into CTR group and control group, with a minimum follow-up of 3 months.Each patient underwent a comprehensive preoperative examination and ophthalmological examinations at the outpatient clinic 1 day, 1 week, 1 month, and 3 months postoperatively.Statistical analysis will be conducted using SPSS 26.0 statistical software.

Preoperative examination:Each patient underwent a comprehensive preoperative examination, which included evaluation of uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), corneal endothelial cells (CECs), axial length, corneal curvature, and corneal topography using subjective optometry, slit-lamp microscopy, funduscopic examination, intraocular pressure measurements, B-scan ultrasound of the eye, and corneal topography(Pentacam HR, OCULUS Optikgerate, Wetzlar, Germany), as well as other relevant parameters. Visual acuity was measured using a standard logarithmic visual acuity chart. Biometry of the operative eye was performed by a specialized technician using an IOL Master (IOLMaster 700, Carl Zeiss Meditec, Jena, Germany), and the Barret's formulaⅡ was applied to calculate the equivalent spherical equivalent (SE) of the toric IOL. The information was inputted into an online calculator (www.acrysoftoriccalculator.com) provided by Alcon to determine the necessary IOL refraction and axial position.

Surgery:The patients received tobramycin dexamethasone eye drops four times one day before surgery. Prior to surgery, the IOL axial position, the diameter size of continuous curvilinear capsulorhexis (CCC), and the incision position were measured and marked using the Image Guided System(VERION Reference Unit, Alcon GPS-WaveLight GmbH, Rheinstrasse, Germany). The pupil was dilated with compound tropicamide drops to a diameter of at least 8mm. The surgery was performed by an experienced surgeon following a standardized procedure. The surgical procedure was as follows: Proparacaine hydrochloride eye drops (ALCAINE, S.A.Alcon-Couvreur N.V., Belgium) were used to provide surface anaesthesia. The conjunctival sac was rinsed with 1% povidone-iodine. Afterwards, a 2.2-mm corneal incision and a 15° stab knife auxiliary incision were made under the guidance of digital navigation system. Inserting the viscoelastic into the anterior chamber and applying a continuous circular capsulorhexis method, a complete hydro dissection was performed. The lens nucleus was removed using ultrasonic emulsification, follow by aspirating the excess cortex and polishing the capsule. After propping up the capsular bag with viscoelastic, the intraocular lens (IOL) was implanted through the main incision (the CTR would be implanted before the IOL implantation). After suctioning off the viscoelastic, the IOL was adjusted to the predetermined axis under navigation guidance. Finally, the incision was hydrated. Tobramycin dexamethasone eye drops were used for 2 weeks postoperatively in all cases.

Postoperative management:All patients underwent ophthalmological examinations at the outpatient clinic 1 day, 1 week, 1 month, and 3 months postoperatively. The examinations included uncorrected distance visual acuity, intraocular pressure examination, subjective optometry, slit lamp microscopy, and SS-OCT (CASIA2, Tomey Corporation, Nagoya, Japan). The surgeon, using the same slit lamp microscope and a narrow band of light, measured the IOL axial position after the patients' pupils were fully dilated with compound tropicamide eye drops. The rotation degree was calculated as the absolute difference between the axial positions of the check and target.

Eligibility Criteria:
Inclusion Criteria:

* Cataract ultrasonic emulsification aspiration with one-stage implantation of astigmatic IOL at the Shanghai Tenth People's Hospital from October 2020 to September 2023;
* Ocular axial length ≥26.00mm;
* Completion of outpatient follow up for more than 3 months.

Exclusion Criteria:

* irregular corneal astigmatism, iris abnormalities, and pupil distortion;
* history of previous corneal or intraocular surgery;
* previous ocular diseases such as uveitis, retinopathy, macular degeneration, glaucoma, and keratoconus;
* postoperative posterior capsule rupture, and suspensory ligament dissociation of greater than 1 quadrant;
* corneal endothelial cell counts of less than 2000 cells/mm2.