The 124 study subjects comprised 36 patients diagnosed with obstructive MGD at the University of Tokyo and Itoh Clinic and 88 normal volunteers (72 men and 52 women; mean±SD aged 38.1±14.4 years, range 20–80). The characteristics of the subjects are shown in table 1. The diagnosis of MGD was based on the presence of ocular symptoms, lid margin abnormalities (irregular lid margin, vascular engorgement, plugged meibomian gland orifices and antero- or postero- replacement of the mucocutaneous junction) and poor meibum expression even with hard digital pressure. The subjects included 80 eyelids of 42 subjects without meibomian gland loss on visual inspection of images (meiboscore=0), 104 eyelids of 57 patients with meibomian gland area loss of less than one-third of the total area (meiboscore=1), 26 eyelids of 11 patients with meibomian gland area loss between one-third and two-thirds of the total area (meiboscore=2) and 23 eyelids of 14 patients with meibomian gland area loss of more than two-thirds of the total area (meiboscore=3). Exclusion criteria included ocular allergies, contact lens wear, continuous eyedrop use, history of eye surgery and systemic or ocular diseases that might interfere with tear film production or function. Patients whose eyes exhibited excessive meibomian lipid secretion were also excluded. Images that were not sufficiently clear for automatic analysis were excluded. The exclusion criteria for the images included out of focus images and images that included something other than the eyelids and their surrounding tissues.