Posterior zonules and lens extraction.

During experimental or surgical lens extraction, the posterior zonules are usually completely removed from the lens; however, many remain attached in a ring to the anterior hyaloid membrane (AHM). This phenomenon was studied in gross and scanning electron microscopic preparations. The posterior zonules were found to be multilayered, with both superficial and deep attachments to the lens. Circumferential zonular fibers were demonstrated increasingly with age. Attachment of the AHM was by a fibrillar perizonular meshwork and small infiltrating bundles. The posterior zonules separated from the lens by tearing into the superficial capsule, favoring preservation of their AHM attachments. This close zonular-AHM relationship is evidence for a coordinated vitreous-zonular action during accommodation. Postoperatively, zonular-AHM attachments may help to stabilize the AHM during movement of the globe.