The Epidemiology and Clinical Features of Blepharoptosis in Taiwanese Population

Blepharoptosis describes a condition of low-lying upper eyelid that may affect individuals of all ages under various etiologies. It may be of congenital or acquired form by the timing of onset or be divided into myogenic, neurogenic, aponeurotic, or mechanical types according to the mechanism. Our goal was to report the characteristics of age-specific blepharoptosis and to analyze the association between levator function (LF) and ptosis severity of each ptosis subtype.

The retrospective, single-center, cross-sectional study consisted of patients diagnosed with blepharoptosis in the plastic surgery practice at a medical center between September 2009 and May 2017. We reported patients' age at presentation, sex, laterality of ptosis, etiology, classification, and evaluation of ptosis including levator function and ptosis severity.

During a nine-year span of study, a total of 1975 eyelids of 1164 Taiwanese patients aged between 2 and 88 years were enrolled in the research (mean = 57.73 ± 13.41 years). The female-to-male ratio was 2.72 (95% confidence interval [CI]: p < 0.0001). Acquired blepharoptosis and bilateral blepharoptosis were more frequently observed (55.85%, p < 0.0001 and 69.67%, p < 0.0001, respectively). In age-specific relative incidence of blepharoptosis, myogenic ptosis was the majority in patients younger than 40 years. Early onset of aponeurotic ptosis was observed in young contact lenses wearers. Aponeurotic blepharoptosis was the predominant type of ptosis in the senior population older than 40 years (p < 0.0001). Among the subtypes, mechanical ptosis had the most preserved LF (p < 0.0001). LF and MRD1 had statistically positive correlations in all subtypes of blepharoptosis, in which neurogenic ptosis demonstrated the severest levator dysfunction for each millimeter in MRD1 reduction.

Of the 1164 Taiwanese patients, blepharoptosis had a higher propensity for female gender and the age between the second to fourth decades. Bilateral involvement of blepharoptosis with acquired type was frequently diagnosed. Myogenic ptosis had a preponderance in age younger than 40 years, while aponeurotic ptosis usually affects senile population. Many mild degree myogenic ptosis was simultaneously recognized in young-aged adults seeking aesthetic double eyelid surgery. Early onset of acquired aponeurotic ptosis was also observed in contact lens wearers given the trend of decorative contact lens use. Levator dysfunction was implicated in the pathology of not only myogenic ptosis but aponeurotic, mechanical, and neurogenic ptosis. Moreover, levator function of neurogenic ptosis was most severely impacted in each MRD₁ reduction among all subtypes of blepharoptosis.

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