Predictive Factors Of Anterior Segment Enlargement After Cataract Surgery

The aim of this study was to compare the anterior segment parameters obtained by Anterior Segment Optical Coherence Tomography (AS-OCT) before and after cataract surgery, as well as to identify the preoperative factors related to a more enlargement of the anterior segment by developing a predictive model of it.

1. Vissum Grupo Miranza, Alicante, Spain; 2. Grupo de Investigación en Optometría (GIOptom), Universidad de Alicante, Alicante, Spain; 3. Division of Ophthalmology, Universidad Miguel Hernández, Alicante, Spain

This is a prospective and longitudinal study involving patients eligible to cataract surgery or clear lens exchange without ocular pathologies different to cataract. All patients underwent an AS-OCT measurement before and approximately one-month after the surgery using the Casia2 device (Tomey ®), as well as the standard ocular exam in both visits. The comparisons between the anterior segment parameters obtained in the preoperative and postoperative status were performed by Wilcoxon signed rank test considering a significance level of 0.05. The preoperative factors related to a more enlargement of the anterior segment were identified by Spearman correlations and calculating 2 predictive models by back-wise lineal regression.

The sample included 404 eyes of 404 subjects including only one eye per subject to avoid the selection bias. Iridocorneal angles and the rest of parameters presented a significative increase after the surgery (p<0.001), confirming a general enlargement of the anterior segment. The preoperative Lens Thickness (LT) and Lens Vault (LV) were the most involved factors in the anterior segment enlargement, presenting significant correlations with all anatomic variations (p<0,05). Particularly, the maximum correlations were observed with ACD variation (∆ACD): Rho LT-∆ACD= 0.604; Rho LV-∆ACD= 0.619. The model predicting ∆ACD included LT and LV, while the model predicting ∆Trabecular Iris Angle [TIA] at 750 µm included age, LT and TIA-750.

This study demonstrates an enlargement of the anterior segment after a cataract surgery, existing preoperative factors influencing a more notably enlargement. Particularly, presenting a thicker and elevated crystalline lens before the surgery was related to a more pronounced enlargement. Moreover, statistical models have been developed to predict the surgical change on anterior chamber depth and trabecular iris angle. It could be useful in the clinical practice of cataract surgeons to manage patients affected simultaneously by cataract and narrow chamber.