Purpose
Frontalis action is widely accepted as contributing to lid position and levator palpebrae superioris function. We sought to evaluate the extent of frontalis contribution to lid position and levator function in both healthy volunteers and patients presenting with ptosis.
Methods
IRB approval was obtained for this prospective study. Data was collected with sequential recruitment of patients presenting to a large subspecialty practice. Data points collected include: ocular dominance, presence of brow ptosis, levator function with and without brow fixation, and margin-reflex distance of the upper lid (MRD1) in resting position with and without brow fixation as well as with maximal brow elevation. Demographic data such as age, gender and race were also collected.
Results
A total of 41 eyes were measured. Average MRD1 of healthy volunteers with brow fixation was 3.8 mm (SD = 0.5), without brow fixation was 4.4 mm (SD = 0.7), and with maximal brow elevation was 7.4 mm (SD = 1.3). In ptosis patients, average MRD1 with brow fixation was 1.7 mm (SD = 1.2), without brow fixation was 2.2 mm (SD = 1.2), and with maximal brow elevation was 5.6 mm (SD = 1.75). Differences between maximal brow elevation and fixed brow MRD1 was statistically significant in healthy and ptosis groups (p < 0.001 and p < 0.001 respectively). Differences with and without brow fixation were also significant in healthy and ptosis groups (p = 0.03 and p < 0.001 respectively). Average levator function in healthy patients was 15 mm (SD = 2.34) with brow fixation, and 16.2 mm (SD = 1.7) without. In ptosis patients, average levator function with brow fixation was 14.6 mm (SD = 1.1) and without brow fixation was 16.5 mm (SD = 1.5). Differences in levator function with and without brow fixation were also statistically significant in healthy and ptosis groups (p = 0.001 and p < 0.001 respectively).
Conclusions
Although widely accepted, no study has evaluated the extent of frontalis contribution to both lid position and levator function. Our study demonstrates that unintentional and maximal frontalis action contributes significantly to both measurements in healthy volunteers and ptosis patients.