Long Anterior Zonules
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Long Anterior Zonules
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Long anterior zonules (LAZ) is a condition where the zonular fibers extend more centrally on the anterior lens capsule than usual. LAZ is characterized by the presence of zonular fibers that extend more than 1.5-2mm anterior to the equator, and is thought to be remnants of the tunica vasculosa lentis. In some cases of LAZ, persistent pupillary membranes can also be present.
LAZ has been associated with shallowing of the anterior chamber and a thicker crystalline lens with higher risk of angle closure and angle closure glaucoma. Patients with LAZ may also develop K-spindles and heavily pigmented trabecular meshwork, leading to increased intraocular pressure. One variety of LAZ has been linked to age over 50 years, female sex, hyperopia, shorter axial length, and persistent pupillary membrane iris strands. A genetic association has also been identified in some patients with LAZ who have a serine to arginine substitution in the C1QTNF5 gene, causing late-onset retinal degeneration. During cataract surgery, patients with LAZ may be at an increased risk of capsular tears, particularly if there is zonular cutting during the capsulorhexis procedure.
In conclusion, long anterior zonules is a condition characterized by zonular fibers that extend more centrally on the anterior lens capsule than usual. It has been associated with a higher risk of glaucoma (both pigmentary and angle closure). LAZ may lead to development of K-spindles and heavily pigmented trabecular meshwork. Ophthalmologists should carefully examine and monitor patients with LAZ, especially for signs of glaucoma and retinal degeneration, and take additional precautions during cataract surgery to prevent complications.
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References:
1. Vogt A. Lehrbuch und Atlas der Spaltlampenmikroskopie. 2nd ed. Berlin: Springer: 1931:2:367-83.
2. Moroi SE, Lark KK, Sieving PA, Nouri-Mahdavi K, Schlötzer-Schrehardt U, Katz GJ, Ritch R. Long anterior zonules and pigment dispersion. Am J Ophthalmol. 2003 Dec;136(6):1176-8.
