In vivo confocal microscopy in blepharitis

BACKGROUND: Dysfunction of the meibomian glands with inflammation and obstruction has been suggested to be an important factor in the pathogenesis of chronic blepharitis. Few objective tests are, however, available to examine the meibomian glands directly. PATIENTS AND METHODS: Nineteen patients with anterior blepharitis, meibomitis, meibomian gland dysfunction or severe keratoconjunctivitis sicca associated with blepharitis as well as 10 patients with normal lid margins were examined with the HRTII/RCM in vivo confocal microscope. Scans of the tear film, the tarsal conjunctiva, the hair follicles and the meibomian glands were analysed by a masked observer. RESULTS: Patients with normal lid margins exhibited a minimal round cell infiltrate in the tarsal conjunctival epithelium and largely normal ducts of the meibomian glands lined with a multilayered epithelium as well as normal gland acini. In patients with anterior blepharitis, blepharitis associated with autoimmune peripheral ulcerative keratitis and blepharitis in the context of severe dry eye, confocal microscopy disclosed normal meibomian glands. In 12 patients with blepharitis/meibomitis or meibomian gland dysfunction, profound pathology was visible with dilatation and obstruction of the meibomian gland ducts. In 15 of 19 patients with blepharitis/meibomitis, but not in meibomian gland dysfunction, an intense inflammation was observed in the tarsal conjunctival epithelium and stroma. In one patient, demodex folliculorum was evident in vivo. In patients with normal lid margins as well as in patients with blepharitis, hair follicles appeared within normal limits. CONCLUSIONS: In vivo confocal microscopy allowed the examination of the tear film, the tarsal conjunctiva, the lid margin including the lash follicles and the meibomian glands. In patients with meibomian gland disease pathological changes could be visualised and documented objectively. The presence of an inflammatory infiltrate permitted us to differentiate between meibomitis and meibomian gland dysfunction. Changes of the lash follicles do not seem to play an important role in blepharitis. Thus, in vivo confocal microscopy represents an objective technique in the classification and follow-up of patients with blepharitis.