굴절교정레이저각막절제술과 레이저각막절삭성형술에서 신경성장인자의 농도와 의미

Nerve Growth Factor Concentration and Implications in Photorefractive Keratectomy Versus Laser in Situ Keratomileusis

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). Methods: A prospective, non-randomized comparative clinical trial. 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, corneal sensation, tear film break-up time (BUT) and Schirmer values were measured before and 1 day, 1 week, 1 month, 3 months, and 6 months after the surgery. Results: The postoperative mean tear NGF/total tear protein ratio (NGF/tP) increased in both PRK and LASIK patients compared to their preoperative levels (p<0.0001). At 1 week and 1 month postoperatively, the NGF/tP ratio was higher in PRK than in LASIK subjects (p<0.0001). Up to 6 months postoperatively, the mean corneal sensation after LASIK in the ablated zone was lower than the preoperative sensation (p<0.0001), whereas this was not the case in PRK subjects. Mean BUT and Schirmer values were significantly lower in LASIK-treated eyes compared to PRK-treated eyes up to 6 months postoperatively (p<0.0001). The early postoperative tear NGF/tP ratio correlated with the postoperative 6 month corneal sensation, BUT and Schirmer values. Conclusions: The difference in postoperative corneal sensation and ocular surface dryness between PRK- and LASIK-treated eyes was related to the difference in the early postoperative levels of NGF/tP, which implies NGF might influence corneal nerve regeneration after these two surgeries.