Nerve growth factor concentration and implications in photorefractive keratectomy vs laser in situ keratomileusis

Keun Lee Hyung, Sub Lee Kyung, Chang Kim Hyeon, Ho Lee Sung, Kweon Kim Eung

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91 Citations (Scopus)


PURPOSE: To determine whether tear nerve growth factor (NGF) concentration correlates with corneal sensation and ocular surface dryness after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK). DESIGN: Prospective, nonrandomized comparative clinical trial. METHODS: Seventy eyes of 35 patients and 76 eyes of 38 patients underwent PRK and LASIK procedures to correct myopia and myopic astigmatism, respectively. Total tear protein level, tear NGF concentration, tear film breakup time (BUT) and Schirmer values were measured before and 1 day, 1 week, 1 month, 3 months, and 6 months after surgery. RESULTS: The postoperative mean tear NGF/total tear protein (NGF/tP) ratio increased in both PRK and LASIK patients compared with preoperative levels (P < .0001). At 1 week and 1 month postoperatively, the NGF/tP ratio was higher in PRK than in LASIK subjects (P < .0001). Before 6 months postoperatively, the mean corneal sensation after LASIK in the ablated zone was lower than the preoperative sensation (P < .0001), but this was not the case in PRK subjects. Mean BUT and Schirmer values were significantly lower in LASIK-treated eyes compared with PRK-treated eyes up to 6 months postoperatively (P < .0001). The early postoperative tear NGF/tP ratio correlated with the postoperative 6-month value of corneal sensation, BUT, and Schirmer values. CONCLUSIONS: The difference in the postoperative corneal sensation and ocular surface dryness between PRK-treated and LASIK-treated eyes might be related to the difference in the early postoperative levels of NGF, which is a potent nerve growth stimulator.

Original languageEnglish
Pages (from-to)965-971.e1
JournalAmerican Journal of Ophthalmology
Issue number6
Publication statusPublished - 2005 Jun

Bibliographical note

Funding Information:
This work was supported by a grant from the Korea Health 21 R&D project, Ministry of Health and Welfare, Republic of Korea (02-PJ1-PG1-CH02-0003).

All Science Journal Classification (ASJC) codes

  • Ophthalmology


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