RESUMEN
PURPOSE: To study the features of upper eyelid in healthy individual and different types of congenital ptosis in the Indian population using ultrasound biomicroscopy (UBM). METHODS: This was a prospective observational study at a tertiary care center. Eyelid structure of healthy individuals with no eyelid abnormalities (n = 19); simple congenital ptosis (n = 33) cases; Marcus Gunn jaw-winking ptosis (MGJWP, n = 7) cases, and blepharophimosis-ptosis-epicanthus inversus syndrome (BPES, n = 20) cases were studied on a vertical UBM scan using 50-MHz probe. Lid-thickness, tarsal-thickness, orbicularis oculi and levator-Muller-orbital septum-conjunctival (LMSC) complex were measured in primary gaze. Comparison was made between four groups and results were statistically analyzed using ANOVA test. In normal individuals, LMSC measurements were repeated in down-gaze imaging. RESULTS: Skin with subcutaneous tissue, LMSC complex and pre-aponeurotic fat-pad appeared echodense while orbicularis oculi and tarsus appeared echolucent. In primary gaze, mean thickness (± standard deviation) of the eyelid, tarsus, orbicularis oculi and LMSC, respectively, were: 1.612 ± 0.205, 0.907 ± 0.098, 0.336 ± 0.083, and 0.785 ± 0.135 mm in normal individual. LMSC showed 46.64% increase in thickness on down-gaze. The mean eyelid thickness and LMSC were thicker in MGJWP and BPES as compared to normal. In different types of congenital ptosis cases, various patterns of UBM imaging were observed. CONCLUSION: UBM allows noninvasive imaging of eyelid structures with good anatomical correspondence in normal eyelids and study the structural alterations of eyelids in different types of congenital ptosis. UBM can be used to highlight the anatomical difference in normal eyelids that may help modify the surgery for better cosmetic outcomes. Furthermore, it has the potential to be used in preoperative evaluation and operative planning in certain types of acquired ptosis, which needs to be evaluated.