Abstract
Purpose :
Corneal nerves play a central role in maintaining homeostasis of the ocular surface and tissue transparency. Damage to corneal nerves leads to a decrease in tear production and blinking reflex, as well as impaired epithelial wound healing, which results in loss of transparency and vision. Previous studies using a corneal injury mouse model that damage the nerves as PRK or LASIK refractive surgeries have shown how the nerves regenerate as a function of time after injury. Herein, we investigate the effect of the right-eye surgery on left-eye corneal nerve density.
Methods :
Eight-week-old female CFW mice were used. The corneal epithelium and 1/3 of the anterior stroma from the right eye were removed from a 2mm diameter central area under anesthesia. At 1, 6, 12, and 24 hours, and at 1, 2, and 3 days after injury, the left uninjured eyes were enucleated and fixed for future corneal dissection and were immunostained with anti-PGP9.5, anti-substance P (SP), and anti-transient receptor potential cation channel subfamily M member 8 (TRPM8) antibodies. Corneal wholemount images were taken and analyzed to measure the nerve density. The corneal nerve density at all time points was compared to the corneas of uninjured mice.
Results :
Compared to corneas of uninjured mice, there was a decrease of total nerve density in the left uninjured corneas during the first 2 days after right-eye injury. The nerve density in the left cornea started to decrease at 1 hour with the lowest nerve density at 6 – 24 hours and then recovered by 2 days after right-eye injury. Most corneal nerve changes occured in the center area of the left non-surgical corneas. Moreover, our data showed that SP, not TRPM8-positive nerves decreased in the left uninjured cornea. However, TRPM8-positive nerves and terminals are still decreased 50% in the injured eye at 3 months after the corneal wound.
Conclusions :
Alterations of the density of corneal sensory nerves in the left uninjured eye after right-eye surgery raises questions about the nerve response of the cornea after unilateral surgical procedures. Careful care and evaluation of the left eye after right-eye injury should be taken into account to reduce complications before left-eye surgery.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.