Introduction: Many reports have suggested that upper eyelid position and brow height can be interdependent; however, the relation is not universally observed. This study aims to understand the prevalence of this phenomenon and examine the utility of phenylephrine testing in predicting brow height change after surgery.
Methods: Ptotic eyelids undergoing Muller's muscle conjunctiva resection surgery in which phenylephrine testing was performed were included. The distance from both the center of the pupil to the upper eyelid and the lower brow margin were measured in the midpupillary line. Measurements were performed based on photographs taken on presentation, after phenylephrine testing and at postsurgical follow-up. Change in eyelid margin and brow position between each of these conditions was assessed. Associations between changes in eyelid margin and brow position were analyzed, and a receiver operating characteristic curve for brow change after phenylephrine instillation as a predictor of postoperative brow change was fit.
Results: In the sample of 125 eyes, there was a significant change in mean marginal reflex distance one both with application of phenylephrine and after surgery (p < 0.05). There was no significant change in brow height with instillation of phenylephrine (p > 0.05). There was a significant change in brow height with surgery (1 mm; p < 0.05). Change in marginal reflex distance one with surgery or with phenylephrine was not significantly correlated with change in brow height after surgery (Pearson's r = 0.06; p > 0.05). Brow height change with phenylephrine was significantly correlated with brow height change after surgery (p < 0.05). Clinically relevant brow height change was defined as mean change minus one standard deviation, for a total decrease of 3.8 mm. By this criterion, 13.6% patients (n = 17) demonstrated clinically relevant brow height change. These patients had a greater preoperative brow height (p < 0.05) and a greater response to phenylephrine (p < 0.05). Based on receiver operating characteristic analysis, a threshold change of 3.5 mm in brow height with phenylephrine had a sensitivity of 0.94, and specificity of 0.10 for postoperative brow height change.
Conclusions: Approximately 15% of the population studied tends to have a significant change in brow position with ptosis surgery. Patients who do not demonstrate a reduction in brow height of at least 3.5 mm after phenylephrine instillation preoperatively are unlikely to have clinically relevant brow height reduction after surgery.