The ocular biometry characteristics of young patients with primary angle-closure glaucoma

Abstract

Background: Although primary angle-closure glaucoma (PACG) mainly occurs in elderly people, diagnosis of PACG in young patients is not uncommon. So far, there is no article specialized on the ocular anatomical characteristics in these patients.In this study, ocular anatomical characteristics in young PACG patients are analyzed. Methods: In this retrospective, comparative study, patients diagnosed with PACG and received ultrasound biomicroscopy (UBM) examination in our department were included. Patients were divided into two groups: a young group composed of patients ≤ 45 years and an old group composed of patients > 45 years. A-scan ultrasonography and ultrasound biomicroscopy (UBM) were used to measure ocular biometric parameters of patients in the two groups including axial length (AL), lens thickness (LT), central anterior chamber depth (ACD), anterior chamber width (ACW), angle opening distance 500 (AOD500), anterior chamber angle 500 (ACA500), iris thickness 1000 μm from the iris root (IT1000), iris thickness 500 μm from the iris root (IT500), trabecular-ciliary process angle (TCPA), trabecular-ciliary process distance (TCPD), scleral– ciliary process angle (SCPA), lens vault (LV), and pupil diameter (PD). Plateau iris (PI) and basal iris insertion were determined from UBM images, and the prevalence of PI and basal iris insertion were compared between the two groups. The incidence of postoperative malignant glaucoma (MG) was also determined in both groups and ocular anatomical predictors for the development of MG were evaluated in young PACG patients. Results: One hundred fifteen patients were included into young group and 480 patients were included into old group. The young group had shorter TCPD, shorter AL, narrower TCPA, narrower SCPA thinner Lens compared to the old group. There were no significant differences in ACD, AOD 500, ACA500, LV, IT500, IT1000, PD or ACW between the two groups. The prevalence of PI was 22.6% in old group and 66.1% in young group (P < 0.001). More young PACG patients displayed basal iris insertion compared to old PACG patients (P < 0.001). 87 patients in the young group and 201 patients in the old group underwent trabeculectomy in our study. Among these patients, 21 young patients and 11 old patients developed MG after trabeculectomy (P < 0.001). Conclusions: Shorter AL, more anteriorly positioned ciliary body, higher prevalence of PI may be responsible for the etiology of young PACG patients. Our results suggest that shorter AL, shorter TCPD and narrower TCPA may be predictors for development of MG in young PACG patients after trabeculectomy.