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K. Wang, G. Xu, X. Zhou, L. Wang, J. Lv; Transient Decrease of the Macular and Retinal Nerve Fiber Layer Thickness After LASIK Evaluated With Fourier Domain Optical Coherence Tomography. Invest. Ophthalmol. Vis. Sci. 2008;49(13):4213.
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© ARVO (1962-2015); The Authors (2016-present)
To determine in detail, with the use of recently developed Fourier/spectral Domain Optical Coherence Tomography (FD-OCT), whether the transient increase of intraocular pressure during Laser in situ keratomileusis (LASIK) suction can cause detectable changes in the macular and retinal nerve fiber layer (RNFL) thickness.
Both eyes in each of 20 sequential patients were included in this study. A FD-OCT system were used to acquire macular map and circular scans around the optic nerve head within 1 week prior to, 1 day and 1 week after LASIK. Those examinations were repeated 3 times in each visit and mean data were used to analyze. Macular map diameters were respectively 1mm(fovea), 3mm(parafovea) and 5mm(perifovea) centered in fovea. The full retina, inner retina, and outer retina thickness and volume were observed respectively in the fovea, parafovea and perifovea areas. Retinal nerve fiber layer thickness analysed included the following parameters: overall RNFL, superior hemisphere average, inferior hemishphere average, temporal average(further divded into IT and ST area), superior average(further divded into TS and NS area), nasal average(further divded into SN and IN area) , and inferior average(further divded into NI and TI area). Data from 3 visits were compared using the random-effects linear models (Stata/SE 8.0 statistic software). A P value less than 0.05 was considered significant.
The mean age of patients included in this study was 26±6.7 years. Mean preoperative spherical equivalent refrective error was -7.5±1.6 diopters (D). Mean time of microkeratome suction was 13±3 seconds. Intraocular pressure was normal at all pre- and postoperative examinations. The mean full retinal and inner retinal thickness in macular fovea, parafovea and perifovea area obtained by FD-OCT at 1 day postoperatively were thinner than that of preoperative datas. The nasal average retinal nerve fiber layer thickness postoperatively obtained by FD-OCT was significantly decreased than that of preoperative .
LASIK performed on myopic patients does have a significant effect on macular and retinal nerve fiber layer thickness determined by FD-OCT. Thanks to the high scanning speed and increase in resolution, the recent developed Fourior/spectral domain detection technology improved our visualization on retinal pathology relative to standard clinical practices. Further studies are required to further identify and reveal the risk of possible macular and retinal nerve fiber layer damage by elevated IOP during LASIK.
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