Zonular function: a new hypothesis with clinical implications.

A new hypothesis about zonular function is presented that has implications in regard to the cause and treatment of ocular hypertension and open-angle glaucoma. This hypothesis is based on the concept that the lens is under constant tension. The anterior and posterior zonules serve a different function than do the equatorial zonules. The anterior and posterior zonules are passive in terms of structural support of the lens; the equatorial zonules are the active components during accommodation.