Morphologic and Biometric Characteristics of Preexisting Posterior Capsule Defects in Congenital Cataracts During the First Year of Life

Overview

Few descriptive studies have focused on the anatomical parameters in patients with preexisting PCDs. The characteristics of cataract morphology and anatomical parameters in these patients remained unclear, when compared with CC patients with intact posterior capsule. We conduct the current study to compare the cataract morphology and preoperative parameters, including central corneal thickness, axial length, anterior chamber depth, lens thickness, corneal diameter, keratometry，dialated pupil diameter and intraocular pressure, between CC patients with preexisting PCDs and those with intact posterior capsule, and to explore potential risk factors for preexisting PCDs.

This retrospective study reviewed infants (≤1 years old) with CC who were undergoing cataract extraction without IOL implantation at the Eye Hospital of Wenzhou Medical University, Hangzhou, China. CC patients with preexisting PCDs were placed in Study group, while CC patients with intact posterior capsule were included as controls. The preexisting PCD was diagnosed if signs of a sharply bordered defect or white dots on the posterior capsule and/or in the anterior vitreous were detected. The intraoperative diagnosis of preexisting PCD was confirmed when the signs were observed after uneventful aspiration of the lens cortex. Patients who were incooperative to complete the preoperative examinations were excluded. All CC patients were divided into two groups according to integrity of posterior capsule. Patients with a confirmed preexisting PCD were placed into the PCD group. Others with intact posterior capsule were in the control group. The preoperative data including sex, age at surgery, laterality of disease, and accompanying ocular anomalies were collected. For all the CC patients, the preoperative examinations were completed under sedation. Central corneal thickness was obtained by a handheld ultrasonic pachymeter (PachPen, Accutome, US). Axial length, anterior chamber depth, lens thickness and length of vitreous cavity were measured via an immersion A-scan (Axis nano, Quantel Medical, French). An experienced examiner repeated the measurement 10 times and the mean value was included. The keratometry values and intraocular pressure were gained by a handheld keratometer (HandyRef-K, NIDEK, Japan) and a handheld tonometer (Icare, Vantaa, Finland), respectively. Diameter of cornea and dilated pupil (dilated by tropicamide 0.5% and phenylephrine hydrochloride 0.5%) was measured just before surgery. All surgeries were performed by the same surgeon (Y.E.Z.) under general anesthesia. Bimanual irrigation/aspiration and 2-port 23G anterior vitrectomy were performed. Three ophthalmologists reviewed all surgical recordings. The integrity of posterior capsule was masked to them. Morphological characteristics of cataracts were documented before surgery. After removing opaque cortex and/or nucleus, the configuration of preexisting PCDs was described.