The Role of Vitreous Zonule Attachments to the Posterior Lens Equator in Primary Angle Closure Glaucoma

Shorter axial length was associated with the absence of the attachments between the posterior insertion zone of the vitreous zonules and the posterior lens equator. Primary angle closure disease eyes without vitreous zonules had a more anteriorly rotated ciliary body.

To assess the clinical significance of the attachments between the posterior insertion zone of the vitreous zonules and the posterior lens equator (PVZ INS-LE strands) and vitreous zonules (VZ) in primary angle closure disease (PACD).

This cross-sectional study consisted of 90 PACD and 30 cataract eyes from an eye clinic. PVZ INS-LE strands, VZ, and anterior segment parameters were assessed by ultrasound biomicroscopy (UBM). The presence of PVZ INS-LE strands and VZ was compared between groups. Baseline ocular characteristics and UBM parameters were compared among PACD eyes. Factors associated with the absence of PVZ INS-LE strands and VZ were identified.

Forty percent of control eyes and 71.1% of PACD showed PVZ INS-LE strands absent. PACD 22.2% and no control eyes showed VZ absent. PVZ INS-LE strands absent group had shorter axial length ( P =0.018), larger ciliary-ciliary angle ( P =0.010), and smaller trabecular-ciliary process distance at 750 μm ( P =0.022). Shorter axial length was independently associated with absence of PVZ INS-LE strands (OR=2.230; 95% CI: 1.027-4.838; P =0.043). VZ absent group had larger ciliary-ciliary angle ( P <0.001), smaller trabecular-ciliary angle ( P =0.040), shorter iris-ciliary process distance at 750 μm ( P =0.092), and shorter trabecular-ciliary process distance at 750 μm ( P =0.026).

PVZ INS-LE strands were less likely to be seen in APACD and their fellow eyes. All types of PACD eyes had less presence of VZ. PACD eyes without VZ appeared to have more anterior rotation of the ciliary body. Shorter AL was independently associated with the absence of PVZ INS-LE strands.