Bell's phenomenon protects the tear film and ocular surface after frontalis suspension surgery for congenital ptosis

Purpose: To assess alterations in the tear film and ocular surface after frontalis suspension repair in patients with pediatric congenital ptosis with either intact or poor Bell's phenomenon. Methods: The study involved 15 patients (23 eyes) with poor Bell's phenomenon (group 1) and 21 patients (33 eyes) with intact Bell's phenomenon (group 2) who underwent frontal is suspension surgery using autogenous fascia lata. The control group comprised 15 age-matched subjects (30 eyes) (group 3). Corneal esthesiometry, tear film break-up time (BUT) measurement, Schirmer II tests, and vital staining were performed prospectively before surgery and 1, 3, and 6 months postoperatively. Results: Group 1 had a lower mean BUT at all post-operative follow-up time points compared to group 2. Group 1 had a greater mean fluorescein staining score (FSS) at 6 months postoperatively compared to group 2. The degree of lagophthalmos strongly correlated with BUT and FSS at 6 months postoperatively in group 1, but not in group 2. In group 1 mean lagophthalmos (5.2 mm) and amount of eyelid elevation (5.8 mm) were higher in abnormal FSS eyes (n = 17) than in normal FSS eyes (n = 6) (3.3 and 3.9 mm, respectively). Conclusion: Bell's phenomenon prevents tear film instability and ocular surface damage in eyes with lagophthalmos induced by frontalis suspension surgery. In patients with poor Bell's phenomenon, ptosis correction of more than 5.5 mm or lagophthalmos of more than 5.0 mm could increase the risk of exposure keratopathy, necessitating careful postoperative monitoring.