# Effect of orbital fat decompression on eyelid contour according to midpupil lid distance in graves’ ophthalmopathy

## TL;DR

This study examines how orbital fat decompression affects eyelid shape in patients with Graves’ ophthalmopathy by measuring midpupil lid distances.

## Contribution

The study introduces a method to analyze eyelid contour changes using radial midpupil lid distance measurements after orbital fat decompression.

## Key findings

- Lower eyelid midpupil distances decreased significantly in nasal sectors after surgery.
- Upper eyelid contour remained largely unchanged postoperatively.
- Changes in eyelid contour were not correlated with the degree of proptosis reduction.

## Abstract

This study aimed to describe and compare eyelid contours before and after orbital fat decompression in patients with Graves’ ophthalmopathy (GO) by measuring their midpupil lid distances (MPLDs).

A retrospective comparative study of patients with GO who underwent orbital fat decompression was performed. Standard digital images of primary gaze were analyzed using a self-designed software. Radial MPLDs of the upper and lower eyelids were measured from 0° (nasal) to 180° (temporal) with 15° spacing. Pre- and postoperative MPLDs were compared and the relationship between MPLD changes and Hertel exophthalmometric value changes were analyzed. Eyelid contour symmetries were assessed using the nasal-to-temporal MPLD ratios.

A total of 31 eyes from 17 patients and 25 eyes from 17 normal participants (control) were included. The mean postoperative Hertel value change was 3.8 ± 1.1 mm. After orbital fat decompression, MPLDs in the lower eyelids decreased, more significantly on the nasal sectors (nasal 30°, 45°, 60°, 75°, and 90°, p = 0.030, 0.024, 0.036, 0.040, and 0.042, respectively). Conversely, MPLDs slightly increased in the upper eyelids but was not statistically significant. Changes in MPLDs did not correlate with the extent of proptosis reduction.

Orbital fat decompression effectively improves lower eyelid retraction in patients with GO, especially on the nasal sectors. This effect is independent from the amount of proptosis reduction. Upper eyelid contour remains unchanged after the surgery.