Abstract
Purpose: :
To analyze the host immune response and effects of anti-inflammatory treatment in MGD using laser in vivo confocal microscopy (IVCM).
Methods: :
IVCM (HRT3/RCM, Heidelberg Engineering) images of the palpebral conjunctiva and meibomian glands (MG) acquired from one eye of 5 healthy individuals, and both eyes of 11 patients with clinical diagnosis of MGD were analyzed. All participants had an ocular surface exam and symptom assessment using the Ocular Surface Disease Index (OSDI) questionnaire, followed by imaging, at initial and follow-up visits. Anti-inflammatory treatment was prescribed based on IVCM findings, and 6 patients had follow-up visits. Images were analyzed for inflammatory cell and acinar density of the conjunctiva and MGs. Fifteen parameters were evaluated and 3 images per parameter were analyzed. Student’s t-test and linear correlations were used for statistical analysis.
Results: :
Compared to normals, patients with MGD had significant conjunctival epithelial inflammation (576 ± 285 vs. 278 ± 203 cells/ mm2, p=0.03), thicker, more globular acinar epithelium (19 ± 3 vs. 15 ± 3µm, p=0.04), with possible trends towards higher intraglandular inflammation (55 ± 23 vs. 35 ± 26%, p=0.3), lower acinar density (76 ± 43 vs. 127 ± 48 acini/mm2, p=0.08) and greater corneal staining (grade 1 ± 0.7 vs. 0, p=0.07). After anti-inflammatory treatment, patients demonstrated markedly reduced epithelial, stromal and intraglandular inflammation (162 ± 191 vs. 576 ± 285 cells/ mm2 p=0.003; 17 ± 23 vs. 118 ± 139 cells/ mm2 p=0.04; 19 ± 12 vs. 55 ± 23% p=0.01 respectively), with improved TBUT (8 ± 1s vs. 5 ± 2s, p=0.01) and a possible trend towards improved corneal fluorescein staining (0.6 ± 0.5 vs. 1 ± 0.7; p=0.2). TBUT correlated negatively with epithelial and stromal inflammation (r=-0.3, -0.4, n=20), and corneal staining negatively with acinar density (r=-0.6, n=9). Interestingly, while clinical and imaging parameters improved on first follow-up, symptoms did not; OSDI displayed a trend for improvement only on subsequent follow-up (28 ± 22 vs. 40 ± 13, p=0.3).
Conclusions: :
IVCM demonstrates that MGD is associated with increased conjunctival and intraglandular inflammation. Anti-inflammatory therapy improves both clinical signs and imaging parameters, but is followed by a lag in symptomatic relief.
Keywords: cornea: tears/tear film/dry eye • inflammation • imaging/image analysis: clinical