Evidence for Posterior Zonular Fiber Attachment on the Anterior Hyaloid Membrane

Abstract

Contrary to the classic description, the majority of posterior zonular fibers are not attached directly to the posterior lens capsule, but are anchored to the anterior hyaloid membrane on their path from the ciliary body to the posterior capsule. This finding is in good agreement with several previous observations and models that suggest support of the posterior lens surface during accommodation.

Scanning electron and optical microscopic studies of the system of porcine zonular fibres

“…2,5 As shown in Figure 1 it is obvious that the zonular network only connected at the equatorial stripe of the lens. We can see in Figure 1/D that the zonular fi bres spread at the equatorial line of the lens but their structure is clearly distinguishable from the lens capsule.…”

“…Many papers have been dealt with the analysis of zonules usually with electron microscope. [2][3][4][5][6] For the investigation of the mechanical behaviour of zonular fi bres in macroscopic level fi rst of all we need the geometry of the network system. There are only very few data about the size of the zonular bundles.…”

Computer-animated model of accommodation and presbyopia

“…4 The crossing zonular fibers include 2 zonular pathways: anterior vitreous zonular fibers from the ciliary valley to Weiger ligament and PIZ-LE zonular fibers from the posterior insertion zone to the lens equator. The anterior vitreous zonular fibers have been identified by several teams of researchers over the past decade, [5][6][7][8] and the PIZ-LE zonular fibers were identified by . 10 The geometry and movement of the model help to identify the function of the crossing zonular fibers in supporting and shaping the lens.…”

“…Until recently, there has been a gap in our knowledge of the zonular apparatus. In 2006, Bernal et al 5 described the "evidence for a posterior zonular fiber attachment on the hyaloid membrane." This structure likely represents the hyalocapsular zonule previously described by Albrecht and Eisner in 1982, 14 and we now refer to these fibers as the anterior vitreous zonule.…”

“…4 As many investigators have noted, the architecture of the zonular fibers determines the way the forces of ciliary-body contraction are distributed in shaping the lens during accommodation and disaccommodation. The recent studies by Bernal et al, 5 Nankivil et al, 6 Croft et al, 7 and L€ utjen-Drecoll et al 8 include new understanding of the zonular anatomy, and this has been incorporated into the first version of the computer-animated model. In 2013, in landmark studies, a team of Americans and Europeans described an additional zonular fiber and documented movements of the zonular fibers, anterior hyaloid, choroid, and sclera with endoscopy and video UBM.…”