Abstract
Purpose :
Eyelid blinking serves to protect against drying through continuous tear distribution. Facial paralysis can lead to paralytic lagophthalmos, resulting in exposure of the ocular surface that can lead to corneal dryness, infection and ulceration. There are few studies of eyelid blinking dynamics. We are studying subjects with facial paralysis to better understand and treat it.
Methods :
We studied five adult subjects with facial paralysis but without adnexal, ocular or other, neurologic pathology that may affect blinking. One minute of spontaneous, bilateral blinking was recorded at 240 frames per second in upright and supine positions. Eyelid closure velocity, amplitude, and closure percentage (relative to the palpebral fissure) were calculated in horizontal (x) and vertical (y) axes for each eye using the Tracker® Video Analysis and Modeling Tool program.
Results :
Average age amongst patients was 57.2 years, with an average duration of facial paralysis of 56.2 months (SD 53.88 months). Compared to non-paralyzed eyes, paralyzed eyes moved vertically with 62.7mm/s slower velocity and 4.28mm less amplitude in upright and 50.27mm/s slower velocity and 3.97mm less amplitude in supine position. In the horizontal plane, the eyes moved with 34.57mm/s slower velocity and 2.40mm less amplitude in upright and 20.72mm/s slower velocity and 1.90mm less amplitude in supine position. Mean percent closure for paralyzed eyes was 44% less in upright and 45% less in supine position compared to non-paralyzed eyes.
Conclusions :
Facial paralysis led to decreases in all vertical and horizontal measurements, except percent closure, by greater than 50% relative to non-paralyzed eyes, in both upright and supine positions. The decrease in percent closure was almost the same in both positions, suggesting that gravity did not have as much of an effect on the closure percentage as paralysis did. Furthermore, paralyzed eyes often displayed a horizontal wobbling motion during closure rather than the medial movement seen in normal eyes, which could have implications in tear film spread and tear drainage. Future studies should include analysis of larger numbers of subjects as well as subjects with surgical interventions for paralytic lagophthalmos to better understand approaches to reanimating the eyelid.
This is a 2021 ARVO Annual Meeting abstract.