Sensory innervation to the cornea from the trigeminal ganglion is important for perceiving stimuli, maintaining hydration, and avoiding injury. Corneal nerve dysfunction forms the pathophysiologic basis of ocular diseases, causing considerable morbidity such as neurotrophic keratitis and dry eye disease.1,2 Ophthalmic surgical procedures, including corneal transplant, radial keratotomy, photorefractive keratectomy, and laser-assisted in situ keratomileusis (LASIK), cause corneal nerve disruption and dysfunction.3 Corneal nerve imaging (e.g., optical coherence tomography and confocal laser scanning) has provided insight into the process of corneal reinnervation. Clinical studies have shown that corneal nerves regenerate over several years after surgical transection; however, the nerve density never returns to presurgery values. For example, subbasal nerve density decreased by 82% in 5 days after LASIK.4 A gradual increase in density was observed at 2 weeks after surgery; however, even 2 years after LASIK, nerve density was only 64% of preoperative values.4 Similarly, subbasal nerve density is not restored to normal even 40 years after penetrating keratoplasty.5 Median subbasal nerve density in clear grafts is also significantly lower than that in normal corneas.6 Although these studies have described the phenomenological process associated with corneal reinnervation, the associated molecular events remain largely unknown. As a result, despite the clinical need to promote corneal nerve regeneration in neurotrophic corneas, few specific therapeutic interventions are available.7 One reason for insufficient progress in this area is the limited availability of methodologies to investigate the effect of interventions on corneal nerve regeneration. Fortunately, the relatively recent introduction of neurofluorescent thy1-YFP mice has made sequential in vivo investigations of corneal nerves feasible.8 Here, we performed serial in vivo imaging in thy1-YFP mice to analyze changes in nerve fiber density (NFD) and the pattern of regenerated nerves after lamellar transection surgery. NFD was defined as the total length of fibers within the area of the contour in which nerves were traced.9 This study provides baseline data for future investigations of interventions to improve nerve regeneration.