[Study on the evaluation of pterygium activity with in vivo confocal microscopy]

Objective: To observe the characteristics of pterygium with in vivo confocal microscopy (IVCM) and understand pterygium activity with the density of inflammatory cells, formation of new blood vessels, and the number of activated keratocytes within the stroma. Methods: A prospective case-controlled study. Thirty-six pterygia from 28 patients were analyzed in this study. A pterygium activity score was obtained by summing four scores of ocular discomfort, pterygium hyperemia, keratitis, and the presence of Fuchs patches. Among them, the low activity of pterygium (PAS score less than 3 points) appeared in 12 eyes and high activity of pterygium (PAS score ≥ 4 points) in 24 eyes. All Patients underwent pterygium IVCM quantitative analysis by observing the boundaries between the pterygium and the adjacent cornea, the density of goblet cells and dendritiform inflammatory cells and Fuchs patches. The correlation of pterygium activity between IVCM and PAS with slit lamp was analyzed with Spearman correlation analysis. Results: The presence of inflammatory cells, numerous blood vessels, and irregular boundary between the cornea and the pterygium with infiltration of hyper-reflective cells in the adjacent corneal epithelium were signs observed with IVCM associated with pterygium activity. With IVCM technique, epithelial cells, goblet cells, and dendritiform inflammatory cells of various sizes were observed within the pterygium epithelium.The active (PAS ≥4) pterygium showed irregular boundaries between the pterygium and the adjacent cornea (score, 0.84±0.51) comparing with inactive subjects (score 0.23±0.12, t=2.68, P=0.009). Fuchs patches were observed as islets of hyper-reflective polygonal cells in front of the pterygium head with blurred boundary. The score (0.75±0.25) in active group showed significant changes as compared with normal subjects (0.23±0.12, t=3.79, P=0.001). The score of dendritiform inflammatory cells, activated keratocytes, and goblet cells in active group were 2.75±0.76, 1.92±0.68, and 2.08±0.42, which were significantly higher than those in inactive group (1.25±0.55, 0.50±0.25, 1.15±0.32, P=0.035, 0.030, <0.01). There was significant positive correlation between IVCM activity and traditional slit lamp PAS. Conclusion: Quantitative analysis of dendritiform inflammatory cells, vascular proliferation and activated keratocytes of pterygium by IVCM may be a reliable evaluation method to evaluate the activity of pterygium.(Chin J Ophthalmol, 2016, 52: 755-763).