Comparison of anterior segment in nanophthalmic eyes with secondary chronic angle closure glaucoma and eyes with chronic primary angle closure glaucoma: an ultrasound biomicroscopy study

Abstract

Purpose : Anterior segment of nanophthalmos with secondary chronic angle closure glaucoma (NSCACG) is similar to chronic primary angle-closure glaucoma (CPACG). This retrospective, cross-sectional study was to detect the difference of anterior segment between the NSCACG and CPACG using ultrasound biomicroscope (UBM) and found which one are more prone to malignant glaucoma under the surgery.

Methods : Thirty-two consecutive patients (52 eyes) with NSCACG were recruited. Thirty-six patients (59 eyes) with CPACG were also randomly recruited in the same period. The ultrasound biomicroscopic parameters of the anterior segment structure were measured for anterior chamber depth (ACD), pupil diameter (PD), lens vault (LV), spur-spur distance (SSD), ciliary process-ciliary process distance (CCD), angle opening distance₅₀₀ (AOD₅₀₀), trabecular-iris angle (TIA), trabecular-ciliary processes distance (TCPD), ciliary body max thickness (CBMT), iris convexity (IC), peripheral iris thickness (PIT), iris-zonule distance (IZD) and trabecular ciliary process angle (TCPA). Biometric measurements including lens thickness (LT) and axial length (AL) were also reviewed simultaneously. The comparisons of the above parameters between the NSCACG group and CPACG group were performed by using the independent t-test and Mann-Whitney U test according to the distribution of the data.

Results : The mean age was 45.86 ± 11.43 years (mean ± standard deviation) and 58.40 ± 12.51 years in NSCACG group and CPACG group, respectively. The AL, ACD, SSD, CCD, TCPD, PIT, IZD and TCPA in eyes with NSCACG were smaller than eyes with CPACG (P<0.05). The LT/AL, LV and IC were larger in the eyes with NSCACG than those with CPACG (P<0.05). There were no significant differences in LT, PD, AOD500, TIA and CBMT between these two groups (P＞0.05).

Conclusions : Compared with CPACG, the anterior segment in the eyes with NSCACG is narrower and the ciliary ring is smaller with more anteriorly rotated ciliary bodies while LT/AL is larger and LV is greater, which might infer that the eyes with NSCACG are more likely to occur malignant glaucoma due to the influence of the surgery.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.