Changes in anterior chamber volume after implantation of posterior chamber phakic intraocular lens in high myopia

BACKGROUND: The present study aimed to assess changes in, and the factors that influence, anterior chamber volume (ACV) after implantable contact lens (ICL) implantation in high myopia eyes using a Pentacam. METHODS: The study sampled 26 high myopia patients (45 eyes) who were treated with ICL implantation. These patients were followed for an average of 4.28 months postoperatively. ACV was measured with a Pentacam preoperatively and at 3 months postoperatively. The data were analyzed by paired samples Wilcoxon signed-rank test. Generalized estimating equation (GEE) model adjusting within-patient intereye correlations in addition to Pearson’s and Spearman’s correlation tests were performed to determine associations. RESULTS: The mean ACV was 198.33 ± 33.08 mm(3) before surgery and 118.65 ± 17.70 mm(3) after surgery. A significant decrease of 79.68 mm(3) (40.18%) (Z = 5.841, P < 0.001) was detected. Positive correlations were found between ACV changes and ICL central vault (r = 0.528, P < 0.001) and preoperative anterior chamber depth (ACD) (r = 0.665, P < 0.001). There were positive correlations between postoperative ACV and postoperative anterior chamber angle (ACA) at 3:00 o’clock (r = 0.448, P = 0.002) and at 9:00 o’clock (r = 0.405, P = 0.006). GEE regression model showed that postoperative ACV significantly positively correlated with preoperative ACV (P = 0.002), ACD (P = 0.002) and horizontal ACA (P = 0.005) and negatively correlated with ICL central vault (P < 0.001). CONCLUSION: Complementary to vault and ACD, ACV is a sensitive parameter with certain value of preoperative assessment and postoperative monitoring in ICL implantation.