Abstract ID: 26-375
Brow Elevation Increases Upper Eyelid Height Through Mechanical and Neuromuscular Mechanisms in Healthy Adults
Author: Tatsuya Sakamoto Base Hospital / Institution: Tsukazaki Hospital
Presentation Type: ePoster Presentation
Purpose
To quantify mechanical and neuromuscular contributions of brow elevation to upper eyelid height by comparing manual and voluntary elevation.
Methods
Prospective observational study of 56 healthy Asian adults (112 eyelids; mean age 32.9±8.4 years) without blepharoptosis, dermatochalasis, periocular surgery, or brow compensation at rest. Standardized calibrated frontal photographs were taken in relaxed primary gaze (Rest), investigator-applied manual brow elevation (Manual), and maximal voluntary brow elevation with natural lid opening (Voluntary). MRD-1, MRD-2, and pupil-to-brow distance (PTB) were measured with calibrated digital image analysis. Linear mixed-effects models with participant-level random intercepts accounted for inter-eye correlation.
Results
Compared with Rest, Voluntary increased MRD-1 by 2.71 mm (95% CI, 2.46–2.97; p<0.001) and Manual by 1.04 mm (95% CI, 0.78–1.30; p<0.001); Voluntary exceeded Manual by 1.68 mm. PTB increased similarly with Voluntary (6.69 mm; 95% CI, 5.78–7.60; p<0.001) and Manual (6.51 mm; 95% CI, 5.60–7.42; p<0.001), indicating comparable brow displacement. MRD-2 decreased with Voluntary (-0.37 mm; 95% CI, -0.52 to -0.22; p<0.001) but was unchanged with Manual (0.07 mm; 95% CI, -0.08 to 0.23; p=0.35).
Conclusion
Passive brow elevation increased MRD-1 by approximately 1 mm, supporting mechanical brow-lid coupling. Despite similar brow displacement, voluntary elevation produced a larger eyelid response, suggesting added neuromuscular co-activation. Brow position should be documented during assessment, and MRD-1 may need approximately 1-mm adjustment when brow recruitment is present.
Additional Authors
| First name | Last name | Base Hospital / Institution |
|---|---|---|
| Masashi | Mimura | Kea clinic,Department of Ophthalmology:Hyogo Medical University,Department of Ophthalmology:Ehime University |
| Tomoyuki | Maeda | Tsukazak Hospital |
| Mao | Tanabe | Tsukazak Hospital |
| Ayaka | Sakamoto | Tsukazak Hospital |
| Machiko | Karakawa | Tsukazak Hospital |
| Nanami | Kuroda | Tsukazak Hospital |
| Tsutomu | Yasukawa | Department of Ophthalmology, Graduate School of Medical Sciences, Nagoya City University |
| Hitoshi | Tabuchi | Tsukazak Hospital |