Assessment of posterior capsule penetrability by Pentacam Scheimpflug system / 中华实验眼科杂志

ABSTRACT

Background Posterior capsule opacification (PCO) is a common complication following cataract surgery.Establishing an objective morphological evaluation method of PCO is of important clinical significance for the prevention of PCO,but there are many problems in previous evaluating methods,and pentacam picture appears to be a useful method of assessing PCO.Recognizing the characters of different types of posterior capsule disorder and optimizing the evaluation details in tentacam picture are helpful for us to prevent and treat PCO.Objective This study was to investigate the characters of posterior capsule disorders with Pentacam tomograms.Methods Eightyfour eyes of 82 patients were included in Zhongshan Ophthalmic Center from January to October in 2011.Slit-lamp photography and retroilluminated photography were captured after full mydriasis,and then the Pentacam imaging was performed by using 50-scan acquisition protocol,and high-resolution Pentacam tomograms were reconstructed and analyzed by Image J software.The features of the posterior capsule disorders in Pentacam tomogram were assessed,and the mean pixel-intensity at the central 4-mm diameter and 3-mm diameter was calculated and compared.The percentage of eyes being interfered by the anterior capsule in the two analyed areas was calculated.This study was approved by Zhongshan Ophthalmic Center,and uritten informed consent was obtained from each patient prior to any examination.Results The posterior capsular membranes were completely clear under the blue background in 30 eyes without posterior capsulaopathy on the Pentacam images.In 54 eyes of 52 patients with PCO,different intensities of gray patches were exhibited on the blue background in the elschnig-pearl-type PCO,and white-color nontransparence patches were seen in the fibrosis-type PCO.The mean pixel-intensity value (inter-quartile range) was 37.07 U and 38.65 U at the central 4-mm area and 3-mm area respectively,without significant difference between them (P=0.606).Capsular block syndrome was found in 3 eyes of 3 patients,showing even gray appearance on the Pentacam images and mean pixel-intensity of 12.40,15.68 and 36.77 U at the central 3-mm area.The gray strip-like appearance on the blue background was seen in 1 eye with capsular shrinkage,and the mean pixel-intensity was 48.34 U at the central 3-mm area.The examination outcomes of 14.81％ (8/54) eyes were disturbed by the anterior capsule in the central 4-mm analysis mode,but the outcomes were unaffected in central 3-mm analysis mode.Conclusions Different types of posterior capsule disorders appear particular scenery in Pentacam tomograms.There is no difference of mean pixel-intensity between the central 4-mm analysis mode and the central 3-mm analysis mode.A central 3-mm analysis mode is more available to justify the penetrability of the posterior capsule.