Backgroud: Although Primary angle-closure glaucoma (PACG) mainly occurs in elderly people, diagnosis of PACG in young patients is not uncommon . However, there is no article specialized on the ocular anatomical characteristics in these patients.
Methods: In this retrospective, comparative study, patients diagnosed with PACG and recieved ultrasound biomicroscopy (UBM) examination in our department were included. Patients were divided into two groups: a young group comprised of patients aged ≤45 years of age and an old group comprised of patients>45 years of age. 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 angle closure 500 (ACA500), iris thickness 1000 mm from the iris root (IT1000), iris thickness 500 mm 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 base iris insertion were determined from UBM images, and the prevalence of PI and base 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 malignant glaucoma were evaluated in young PACG patients.
Results: 115 patients were included into young group and 144 patients were included into old group. The eyes of patients in the young group had shorter TCPD, shorter AL, narrower TCPA and narrower SCPA compared to the eyes of patients in the old group. There were no significant differences in ACD, LT, AL, LV, AOD 500, ACA500, IT500, IT1000, PD or ACW between the two groups. The prevalence of PI was 25.0% in older patients and 66.1% in younger patients (P < 0.001). Significantly more young patients had base iris insertion compared to old patients (P < 0.001). 87 patients in young group and 79 patients in old group underwent trabeculectomy in our department. Among these patients, 21 young patients and 4 old patients developed MG after trabeculectomy (P < 0.001).
Conclusions: AL was shorter, the ciliary body was positioned more anteriorly, prevalence of PI was higher, and incidence of postoperative MG was higher in younger PACG patients compared to older PACG patients. Our results suggest that shorter AL, shorter TCPD and narrower TCPA may be predictors for development of malignant glaucoma in young PACG patients after trabeculectomy.