Prepapillary vascular loops – A new classification

Background: Prepapillary vascular loops are a type of congenital vascular anomaly seen on or around the optic disk. Patients with this condition are usually asymptomatic and are detected incidentally on routine fundus examinations. Differential diagnosis for this condition includes neovascularization of the disk and collaterals on the disk. Prepapillary capillary loops are not associated with any systemic condition. They are usually unilateral in presentation, but can rarely be bilateral. Purpose: To discuss the new proposed classification of prepapillary capillary loops. Synopsis: Prepapillary capillary loops are classified based on their location around the disk, loop characteristics such as elevation, shape, and covering, and presence of vitreoretinal traction. Highlights: The most common vascular loops are arterial in origin and rarely venous in origin. They can sometimes be associated with spontaneous and recurrent vitreous hemorrhage, branch retinal artery or vein occlusion, and subretinal hemorrhage. It is an important differential diagnosis in spontaneous vitreous hemorrhage. Treatment is symptomatic

Prepapillary Vascular Loops Associated with Retinal Diseases

PURPOSE: Prepapillary vascular loops are blood vessels that project from the optic disc into the vitreous cavity and then return to the disc to continue their natural cource. Ninety percent are arterial in origin and usually congenital anomaly. We report four cases of prepapillary vascular loops associated with retinal and choroidal disorders. METHODS: Prepapillary vascular channel which showed twisted or ringlike appearance without leakage on fluorescein angiogram constituted the diagnosis. However, there may be a sector delay in filling of the optic disc or retina supplied by the loop due to the increased distance that blood must travel through the loop. RESULTS: These cases are not associated with vision-threatening diseases. The associated retinal diseases are diabetic retinopathy in one case, retinitis pigmentosa in one case, contralateral posterior uveitis in two cases. They are arterial loops. In two eyes were observed multiple prepapillary vascular loops. The vessels may appear as simple hairpin loops, spiral, or corkscrew configuration. In our cases, the presence of a cilioretinal artery and retinal artery obstruction could not be determined; other complication associated with prepapillary vascular loops were not observed. CONCLUSIONS: We assume that prepapillary vascular loops may occur acquiredly associated with other ocular diseases.

SCANNING ELECTRON MICROSCOPE STUDIES OF THE MICROCIRCULATION IN THE NAIL BED OF THE TOE / 解剖学报

The vascular morphological character of the microcirculation in the nail bed of the toe have been studied with the scanning electron microscope. Three types of vascular network were identified: 1) The blood vessels at the proximal two fifth of the nail bed were parallelly arranged. 2) At the middle two fifths of the nail bed, the blood vessels interwoved with each other and formed the polygonal vascular networks. 3) At the distal one fifth of the nail bed there were only a few vascular loops running in a slanting position. These loops were connected with the vascular network from the papillary layer of the skin of the toe.