Histomorphometry of the Circular Peripapillary Arterial Ring of Zinn-Haller in Normal and Glaucomatous Eyes

Jost Jonas

Purpose: To examine location and size of the peripapillary arterial circle of Zinn-Haller (PACZH) in normal and glaucomatous human eyes.

Methods: The study included 29 human globes enucleated due to malignant choroidal melanoma (n=19) (control group) or due to secondary angle-closure glaucoma (n=10). Anterior-posterior histological sections were morphometrically evaluated.

Results: The PACZH was present in all eyes. The glaucoma group and the control group did not vary significantly in the distance from the PACZH to Bruch´s membrane (297±67 µm versus 270±67 µm;P=0.29), optic disc border (281±103 µm versus 391±170 µm;P=0.07), optic disc center (1059±191 µm versus 978±205 µm;P=0.30), and retrobulbar cerebrospinal fluid space (173±58 µm versus 172±81 µm;P=0.97), nor in the minimal PACZH diameter (39±18 µm versus 36±18 µm;P=0.74) and maximal PACZH diameter (78±37 µm versus 65±25 µm;P=0.36). The PACZH location, measured as distance from Bruch´s membrane, disc border, disc center and cerebrospinal fluid space, was not significantly associated with axial length (P=0.67,P=0.39,P=0.39, and P=0.58, respectively), horizontal globe diameter (P=0.55,P=0.17,P=0.56, and P=0.60, respectively), vertical globe diameter (P=0.60,P=0.22,P=0.86, and P=0.30, respectively). Both diameters were statistically independent of axial length (P=0.72 and P=0.58; respectively), horizontal globe diameter (P=0.60 and P=0.41, respectively) and vertical globe diameter (P=0.64 and P=0.52, respectively). All parameters were statistically independent of age (P>0.10) and gender (P>0.10).

Conclusions: The peripapillary arterial circle of Zinn-Haller was present in all human eyes examined and did not vary significantly in location and diameter between eyes with secondary angle-closure glaucoma and non-glaucomatous eyes, nor between myopic versus hyperopic eyes.