In Vivo Confocal Microscopic Study of Hard Contact Lens-Induced Lipid Keratopathy Secondary to Corneal Neovascularization in a Rabbit Hypercholesterolemic Model.

ABSTRACT

OBJECTIVES: In vivo confocal microscopy was used to observe the morphological presentations and anatomical correlations between corneal neovascularization (NV) and intracorneal lipid deposition in a rabbit model of contact lens (CL)-induced lipid keratopathy secondary to corneal NV. METHODS: Rabbits were divided into 3 groups (1) 8-week normal diet, (2) 8-week high-cholesterol diet, and (3) 4-week normal diet followed by 4-week high-cholesterol diet. Corneal NV was induced by closed-eye CL. The formation and maturation of corneal NV were shown by immunohistochemical staining against CD31 and high-molecular-weight melanoma-associated antigen. In vivo confocal microscopy identified corneal NV and lipid deposition. Acquired images for each eye were arranged and mapped into subconfluent montages. RESULTS: In group 1, corneal NV sprouting formed from the peripheral to the central cornea by the end of week 4. Pericytes around vessels were shown after 2 weeks of CL wear. In group 2, lipid deposition started from the peripheral cornea and progressively covered the whole cornea. In group 3, lipid deposition was found first in the central cornea after 2 weeks of high-cholesterol diet and progressed to cover the peripheral cornea. In vivo confocal microscopy demonstrated four different patterns of intracorneal lipid deposition spindle shapes arranged randomly or in parallel, amorphous shapes, multiangular shapes, and mixed types. Intracorneal lipid deposition was distributed from basal corneal epithelium to deep stroma. CONCLUSIONS: Intracorneal lipids tend to accumulate around newly formed corneal NV but can extend to the area covered with mature NV. In vivo confocal microscopy can demonstrate various shapes and depths of intracorneal lipid deposition.