Validity of noninvasive meibography systems: noncontact meibography equipped with a slit-lamp and a mobile pen-shaped meibograph.

Meibomian glands (MGs) secrete lipids (meibum) into the tear film and prevent excessive evaporation. MG dysfunction (MGD) is a major cause of evaporative dry eye. Recent studies have demonstrated that evaporative dry eye resulting from MGD is far more common than aqueous-deficient dry eye is. Meibography is the only technique that can be used to observe the structure of MGs in silhouette, by illuminating the eyelids from the skin side, and can detect the morphological abnormalities in MGs. However, conventional meibography uses a transilluminating light probe directly applied onto the eyelid and thus is invasive. To assess this problem, we developed 2 noninvasive meibography systems (a slit-lamp type and mobile type). In this review, various clinical applications of noninvasive meibography systems are demonstrated. Changes in MGs were examined in contact lens wearers or in patients with allergic conjunctivitis, MGD, aqueous-deficient dry eye, or long-term antiglaucoma eye drop use. The use of a noninvasive meibography system could detect morphological changes such as dropout, shortening, dilation, and distortion of MGs in patients. The ability to detect detailed changes of MGs using noninvasive meibography enhances the power to diagnose MGD and correctly decide the most effective treatment for patients with MGD.