Intravital microscopy of leukocyte-endothelial dynamics using the Heidelberg confocal laser microscope in scleritis and allergic conjunctivitis

Purpose: To examine leukocyte-endothelial cell rolling and arrest in human ocular vessels overlying sites of inflammation in various ocular inflammatory diseases in comparison to normal controls using the Heidelberg confocal laser microscope, which provides images with greater clarity and resolution than the tandem scanning microscope that uses white light. Methods: Healthy controls (n=8) and patients with active anterior scleritis (n=7) or allergic eye disease (n=4) were scanned using the Heidelberg confocal laser microscope (HRT II) with the Rostock cornea module attachment for a minimum of 5 min at a depth of 45-120 μm from the conjunctival epithelial surface. Results: There was a marked increase in the number of rolling leukocytes in scleritis patients (534+/-119 cells per mm²/min) versus controls (6+/ -6 cells per mm²/min; p=0.0002) or allergic patients (59+/-44 cells per mm²/min; p=0.009). No statistically significant increase was seen in allergic patients compared to controls (p=0.059). A similar pattern was seen in the number of arrested leukocytes in patients with scleritis (56+/-23 cells per mm²) in comparison to either those with allergic eye disease or controls (each=0 cells per mm²; p=0.02). Conclusions: Patients with scleritis have a significantly increased number of rolling and arrested leukocytes in superficial ocular vessels in comparison to patients with mild allergic conjunctivitis and controls. The image quality with this microscope is superior to prior studies with a scanning microscope.