Comparing the symmetry of upper eyelid following unilateral ptosis correction

Margin Reflex Distance 1(MRD 1) only describes the central height of upper eyelid and relies on the examiner's experience and disregards eyelid contour abnormalities. Therefore MRD 1 may not be sufficient for an acceptable result to evaluate the outcomes of ptosis surgery. The primary purpose of this study was to assess outcomes of unilateral ptosis correction based on parameters including degree of symmetry, MRD 1, peak height of the upper lid, temporal and nasal ocular surface area, and temporal/nasal area ratio with an objective, quantitative, and repeatable method.

This study was designed as a retrospective non-randomized case-control study. Medical records of the patients with unilateral ptosis between October 2015 and December 2020 were reviewed. Patients with unilateral ptosis who underwent surgical correction and levator function of 5 mm or greater were included in the study. Two groups were defined; ptotic eye was case group and contralateral eye was control group. Data analysis was performed Image J and Matlab softwares.

Thirty-four patients were included in the study. Mean age of patients was 58.8 ± 12.7 years (range 15-75 years). Mean follow-up time was 19.5 ± 7.3 months (range 8-40 months). Four patients were diagnosed with congenital ptosis and 30 patients aponeurotic ptosis. Mean preoperative degree of symmetry for overall eyelid contour was 36.6 ± 27.5% (range 1-92%). Mean postoperative degree of symmetry for overall eyelid contour was 72.4 ± 16.5% (range 55-92%). Temporal/Nasal (T/N) area ratios for contralateral normal eye was 1.19 pre-postoperative, and it was 1.11 preoperatively, 1.15 postoperatively for operated ptotic eye.

This study primarily demonstrated a quantitative, objective, and repeatable method to investigate the degree of symmetry after eyelid surgeries. Secondly, this study suggested that T/N ratio may not be a reliable parameter to evaluate the eyelid symmetry.