Nerve Growth Factor Concentration and Implication in Photorefractive Keratectomy v Laer In itu Keratomileui

Purpoe To determine whether tear nerve growth factor (NGF) concentration correlate with corneal enation and ocular urface dryne after photorefractive keratectomy (PRK) and laer in itu keratomileui (LAIK). Deign Propective, nonrandomized comparative clinical trial. Method eventy eye of 35 patient and 76 eye of 38 patient underwent PRK and LAIK procedure to correct myopia and myopic atigmatim, repectively. Total tear protein level, tear NGF concentration, tear film breakup time (BUT) and chirmer value were meaured before and 1 day, 1 week, 1 month, 3 month, and 6 month after urgery. Reult The potoperative mean tear NGF/total tear protein (NGF/tP) ratio increaed in both PRK and LAIK patient compared with preoperative level (P< .0001). At 1 week and 1 month potoperatively, the NGF/tP ratio wa higher in PRK than in LAIK ubject (P< .0001). Before 6 month potoperatively, the mean corneal enation after LAIK in the ablated zone wa lower than the preoperative enation (P< .0001), but thi wa not the cae in PRK ubject. Mean BUT and chirmer value were ignificantly lower in LAIK-treated eye compared with PRK-treated eye up to 6 month potoperatively (P< .0001). The early potoperative tear NGF/tP ratio correlated with the potoperative 6-month value of corneal enation, BUT, and chirmer value. Concluion The difference in the potoperative corneal enation and ocular urface dryne between PRK-treated and LAIK-treated eye might be related to the difference in the early potoperative level of NGF, which i a potent nerve growth timulator.