PURPOSE:To characterize corneal nevocoarization (CoNV) in vivo.METHODS:Patients with CoNV were categorized into those with active disease defined by the presence of corneal infiltrates and/or edema and those with inactive disease, the latter divided into those with or without corneal red blood cell traffic (RBCT). CoNV were imaged using in vivo confocal microscopy (IVCM) and angiography. Leakage and uptake of dye from the extravascular to intravascular space were investigated using repeat angiography and digital subtraction analysis. Vessel parameters and the presence of RBCT were analyzed using custom-designed software.RESULTS:Thirteen patients with CoNV were included: 4 had active and 9 had inactive disease with CoNV present for 3.5 ± 1.7 months and 30.2 ± 30.7 months, respectively. Using a combination of digital subtraction analysis and IVCM, presumed lymphatic vessels were detected only in patients with active CoNV. These vessels were characterized by an indistinct vessel wall, carrying nucleated cells, and on IVCM, it had a mean diameter of 19.7 ± 6.1 μm (11-30 μm). The ratio of the diameter of presumed lymphatic vessels to that of neighboring vessels was 0.6 ± 0.1 (0.5-0.6). Of the patients with inactive disease, 4 had CoNV with RBCT (mean age CoNV, 17.3 ± 7.6 months) and 5 (mean age CoNV, 40.6 ± 35 months) had CoNV without evidence of RBCT on biomicroscopy, but evident on angiography and IVCM. These represent perfused vessels with no or intermittent RBCT.CONCLUSIONS:CoNV can be characterized in vivo using a combination of IVCM and angiography. The vascular features vary according to the age of the CoNV and disease activity. Further improvements in angiographic image alignment, however, are needed.