Effect of topical Phenylephrine on the upper eyelid crease position.

Purpose: To investigate the effect of Phenylephrine test on the upper eyelid crease position. Material and Methods: This study follows a prospective and analytical design and included patients with unilateral acquired involutional ptosis recruited between January 2015 and January 2018. In the Phenylephrine test, 1 drop of Phenylephrine 10% was instilled on the inferior fornix of the ptotic eye and the eyelid crease position was evaluated 10 min after. Results: A total of 60 patients were included in the final sample. The mean Margin‐to‐reflex distance 1 (MRD1) of the ptotic eye was 2.1 ± 1.0 and 3.8 ± 0.6 mm before and 10 min after the instillation of Phenylephrine, respectively. The difference between the means was statistically significant (p < 0.001). Ninety‐five per cent of the eyes had a positive Phenylephrine test result. Of this, 100% showed a decrease in the height of eyelid crease after the drop. There was a statistically significant decrease in the height of eyelid crease from 10.3 ± 2.5 to 7.8 ± 2.0 mm (p < 0.001). Conclusion: Phenylephrine test not only affects the eyelid position but also the eyelid crease height. We show a significative decrease in eyelid crease height to a symmetrical level with the contralateral lid in all patients that had a positive Phenylephrine test result. This effect is probably due to a posterior lamella shortening secondary to Müller's muscle contraction and suggests that the eyelid crease is not only determined by the projections of levator aponeurosis, but also by the entire force vector of the upper eyelid retractors. [ABSTRACT FROM AUTHOR]