Shima Fukuoka,1–3 Reiko Arita,2–4 Rika Shirakawa,2,3 Naoyuki Morishige2,5 1Department of Ophthalmology, Omiya Hamada Eye Clinic, 2Lid and Meibomian Gland Working Group (LIME), Saitama-shi, Saitama, 3Department of Ophthalmology, University of Tokyo School of Medicine, Bunkyo-ku, Tokyo, 4Department of Ophthalmology, Itoh Clinic, Saitama-shi, Saitama, 5Department of Ophthalmology, Oshima Eye Hospital, Fukuoka-shi, Fukuoka, Japan Purpose: To examine the changes in meibomian gland morphology and ocular higher-order aberrations (HOAs) in eyes with chalazion and its excision. Methods: Seven male patients with previous history of chalazion excision and seven control male subjects were enrolled. Changes in meibomian gland morphology (meiboscores, gland dropout, and shortening) were evaluated by using meibography equipped in a wavefront analyzer KR-1W and in a slit-lamp device BG-4M. Ocular HOAs were measured sequentially with KR-1W. The tear film breakup time (BUT) was measured. Results: Both KR-1W and BG-4M visualized meibomian gland as clear similar images. The tear film BUT (mean ± SD, 5.6±3.0 vs 9.4±2.3 seconds, P=0.025), the total meiboscore (median [interquartile range], 2 (2-3) vs 0 (0-1), P=0.007) as well as the meibomian gland dropout rate (86% vs 14%, P=0.008) and shortening rate (100% vs 29%, P=0.031) differed significantly between the patient and control groups. The first total ocular HOAs (0.142±0.063 vs 0.130±0.015, P=0.80) were similar in both groups, whereas the stability index of the total HOAs over time (0.0041±0.0048 vs -0.0012±0.0020, P=0.030) differed significantly between the patient and control groups. Conclusions: Chalazion and its excision were associated with dropout and shortening rate of meibomian glands. The morphological changes of meibomian glands in chalazion may be associated to instability of the tear film, which was suggested by the tear film BUT and the stability of ocular HOAs. Keywords: meibomian gland, meibography, wavefront analyzer, higher-order aberrations, chalazion excision