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Thang Luong PHAM, Jiucheng He, Azucena H Kakazu, Haydee E P Bazan; Left eye corneal nerves altered by corneal injury in the right eye. Invest. Ophthalmol. Vis. Sci. 2019;60(9):5081. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
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.
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.
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.
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.
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