Vertical globe position changes following levator resection surgery

To highlight possible vertical globe position changes following levator muscle resection surgery for simple congenital ptosis.

A retrospective chart review was conducted on patients who developed overcorrection with alleged hypoglobus following unilateral levator resection. Margin reflex distance 1 (MRD1) and vertical palpebral fissure (VPF) were measured, and vertical globe displacement was determined by comparing globe positions between both eyes, using the Image-J 1.54k software.

Twenty-eight patients (12 males and 16 females) with a mean age of 9.07   ±   4.15 years were included. Eleven (39.3%) had prior ptosis surgery. The median preoperative MRD1 was 0 mm (range:  - 2 to 2), which increased to 7.7 mm (3.1-9.9), 5.75 mm (3.4-8.0), and 4.7 mm (3.0-6.3) at the 1st, 2nd, and 3rd follow-ups, respectively (p < 0.001). The median VPF was 5.7 mm (3.8-8.5) preoperatively, peaking at 12.2 mm (7.3-14.9) at 1 week before decreasing to 10.2 mm (8.1-12.9) and 9.5 mm (8.0-12.5) at subsequent visits (p < 0.001). The median inferior globe displacement was 2.5 mm (0.7-3.6) at 1 week, improving to 1.1 mm (0.0-2.4) and 0 mm (0.0-1.4) at later follow-ups (p < 0.001). Reverse Bell's phenomenon was observed in 42.9% of eyes; conjunctival fornix prolapse in 17.9%.

Maximal/supramaximal levator resection surgery could result in translational descent of the globe (hypoglobus) possibly due to injury of the conjoint fascial sheath. Alternatively, transient superior rectus muscle dysfunction could lead to a rotational movement of the globe (hypotropia).