Function of levator palpebrae superioris in dry eye disease

Purpose To evaluate the effect of levator palpebrae superioris in patients with dry eye disease. Methods 168 eyes of 84 patients (group 1 = fair levator function <= 9 mm, 78 eyes; group 2 = good levator function > 9 mm, 90 eyes) were retrospectively enrolled. Levator function test, Ocular Surface Disease Index Questionnaire (OSDI), Schirmer I test, noninvasive tear break up time (NItBUT), corneal staining score, meibography, meibum quality and expressibility scores, tear meniscus height, and partial blinking rate (PBR) were examined. Results There was no statistically significant differences between group 1 (0.45 +/- 0.76) and 2 (0.58 +/- 0.76) according to OSDI and corneal stain (P > 0.05). PBR and NItBUT in group 2 (9.29 +/- 4.01 and 4.76 +/- 2.39, respectively) were significantly worse than those in group 1 (5.88 +/- 3.99 and 5.78 +/- 2.94, respectively) (P < 0.05). There was a significantly positive correlation between levator function and partial blinking rate (R = 0.4114, P = 0.0002). Meibum expressibility and lipid thickness in group 2 (0.48 +/- 0.70 and 1.39 +/- 0.45, respectively) were significantly better than those in group 1 (1.29 +/- 0.65 and 1.12 +/- 0.33, respectively) (P < 0.05) (Fig. 3). There was a significantly negative correlation between levator function and meibum expressibility grade (R = -0.3869, P = 0.0006) (Fig. 5). Conclusion The eyes with good levator function showed shorter tear break-up time due to a higher partial blinking rate, but showed better lipid thickness due to better meibum expressibility compared with the eyes with fair levator function. Evaporative dry eye disease in the eyes with good levator function can be compensated for by a better meibum expressibility.