Purpose

One of the characteristic clinical findings of Graves’ Orbitopathy (GO) is upper eyelid retraction associated with lateral flare. The present study aimed to evaluate the dynamic behavior of eyelid flare during blinking and downward saccadic movements in patients with GO.

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Methods

This cross-sectional study included 20 eyelids with eyelid retraction secondary to GO. Eyelid contour kinematics were quantified using high-resolution video recordings during spontaneous blinking and vertical saccadic movements. Eyelid contours were analyzed using the Bézier function in ImageJ. For blinking analysis, three positions were selected: primary gaze (A), an intermediate phase in which the upper eyelid crossed the pupillary center (B), and the final phase of eyelid closure (C). For downward saccades, primary gaze (A) and maximal downgaze (C) were analyzed. A central midpupil lid distance (MPLD1) and a lateral measurement obtained 2.5 mm from the lateral canthus (L4MPD) were evaluated in each position.

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Results

Among the 20 eyelids analyzed, 12 demonstrated flare, defined by an L4MPD equal to or greater than 60% of central MPLD. During spontaneous blinking and vertical lid saccadic movements, the flare progressively disappeared as the eyelid descended. In the final phase of blinking and saccades, L4MPD values approximated MRD1 values, resulting in flattening of the eyelid contour and disappearance of the lateral flare phenomenon in all affected eyelids.

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Conclusion

The etiological mechanism of eyelid flare remains controversial. Proposed mechanisms include lateral extensions of Müller’s muscle, fibrosis of the intermuscular septum, increased lateral scleral show in proptotic eyes, and thickening of the lateral horn of the levator palpebrae superioris muscle. Since blinking and downward saccades involve relaxation of the levator palpebrae superioris muscle, the disappearance of flare during these movements suggests that eyelid flare is unlikely to represent a fixed restrictive phenomenon, depending instead on excessive lateral levator contraction.

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Additional Authors

First name	Last name	Base Hospital / Institution
Sarah	Soares Brassaloti	Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (FMRP-USP)
Juliana	Albano de Guimarães
Denny Marcos	Garcia
Antonio Augusto	Velasco e Cruz	Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (FMRP-USP)

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