Cilioretinal arteries in large optic disks.

The cilioretinal arteries form a physiologic bypass between the ciliary and retinal circulation. The evaluation of photographs of 163 normal optic nerve heads revealed a significant (p less than 0.001) correlation between the number of cilioretinal arteries and the optic disk and cup size: the larger the disk and cup the more vessels. The vessels' prevalence in all optic disks was 27.0%. It increased from 0% in disks smaller than 2.00 mm2 to 50.0% in optic nerve heads larger than 4.1 mm2. No correlations existed between cilioretinal arteries and refraction, axial length, side, sex and age, according to the missing correlations between these parameters and optic disk and cup area. The presence of two or three cilioretinal arteries indicates a congenitally large optic disk and cup in normal eyes, and can be helpful in the differentiation of physiologic macrocups in macrodisks from glaucomatous cupping.