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A. Guerra, R. Velasco, O. Baca, A. Babayan, A. Jaen; Corneal Epithelial Behavior After PRK and LASEK Evaluated With Confocal Microscopy. Invest. Ophthalmol. Vis. Sci. 2007;48(13):5349.
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© ARVO (1962-2015); The Authors (2016-present)
To compare and observe the epithelial behavior in patients undergoing photo refractive keratectomy (PRK) and laser assisted subepitelial keratectomy (LASEK) using confocal microscopy
Prospective, longitudinal, comparative and experimental study. Patients undergoing PRK and LASEK on regular protocol were included. Patients were divided in two groups: group 1 patients in which PRK was performed, group 2 patients in which LASEK was done. Confocal microscopy (Confoscan 3, Nidek, Japan) and panoramic pictures in the slit lamp were taken at 1°, 4°, 5°, 12°, 18 and 25 postoperative days. Findings were compared between groups with clinical panoramic photographs in order to study the characteristics of epithelial growth . Also a corneal epithelial basal cell layer count was performed, in a constant area of 0.0192 mm2 (Software NAVIS 4.3.1 ®). The results were compared between groups and statistical analysis was done.
A total of 33 eyes were studied (17 patients) 21 eyes in group 1, and 12 eyes in group 2. A total of 58,800 confocal photographs were taken, only 900 pictures were selected for the study. A total of 576 clinical pictures were taken, 504 of group 1 and 72 of group 2, only 210 clinical photographs were used in this study. By day 4, pre-basal cells appeared in both groups, with a bilaminar layer in group 2. We noticed a complete replacement of the epithelial flap by pre-basal cells at day 5. By day 12 a bilaminar layer was seen in both groups, and a trilaminar appered by day 18. At day 25, in neither group, the epithelium had a normal appearance compared to the preoperative control. After day 5, group 2 showed hypertrophy and nucleated cells in basal epithelial layer compared with group 1. Preoperative cell density was 139.3 basal cells/0.0192 mm2 in group 1 and 156 basal cells/0.0192 mm2 in group 2. By day 25 the count was 135.4 basal cells/0.0192 mm2 and 144.3 basal cells/0.0192 mm2 in group 2. Cellular density had a statistical difference between both groups at day 5 (x=88.1 group 1, x=110.9 in group 2, P = 0.0008), 12 (x=113.7 group 1, x=128.3, P = 0.04) and 18 (group 1 x=122.5, x=144.4 group 2, P = 0.0001), and no statistical difference in the preoperative control (x=139.3 group 1, x=156.2 group 2 P = 0.06) and day 25 ( x=135.4 group 1, x=144.3 group 2 P = 0.3).
Corneal epithelium in PRK and LASEK at day 25 still has not returned to normal characteristics. Epithelial cell density in LASEK group is higher than in PRK group.
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