To observe and measure the levator aponeurosis (LA) in patients with unilateral aponeurotic ptosis (AP) using high-frequency (22 MHz) B-mode ultrasound with a water balloon.

Thirty-two unilateral APs were recruited. Palpebral fissure height (PFH), levator function (LF), and marginal reflex distance 1 (MRD1) of the affected eyes and the normal control eyes were measured. Sagittal ultrasound images of the central upper eyelid of both eyes were captured, and ultrasound indicators such as the thickness of the LA, the distance from the upper border of the tarsal plate to the septoaponeurosis junction (TJD), the thickness of the tarsal plate (TTP), the height of the tarsal plate (HTP), and the distance from the insertion point of the LA to the lower border of the tarsal plate (ITD) were measured in the ultrasound images.

The PFH, LF, MRD1, and thickness of the LA were all significantly lower in the affected eyes compared to the normal control eyes. The TJD value in the affected eyes was significantly greater than that in the normal control eyes. In contrast, the other three measurement parameters—namely, TTP, HTP, and ITD—showed no significant intergroup differences.

High-frequency (22 MHz) B-mode ultrasound is a noninvasive and highly effective tool for visualizing and measuring the LA. In cases of unilateral AP, the LA exhibits reduced thickness compared to that of normal control eyes.