González-Pérez J, Sánchez-García A, Parafita M A
Ocular Surface and Contact Lens Research Laboratory, Faculty of Optics and Optometry, Universidade de Santiago de Compostela, Spain.
Ocular Surface and Contact Lens Research Laboratory, Faculty of Optics and Optometry, Universidade de Santiago de Compostela, Spain.
J Optom. 2023 Oct 28;17(2):100485. doi: 10.1016/j.optom.2023.100485.
To study topographic epithelial and total corneal thickness changes in myopic subjects undergoing successful orthokeratology treatment in connection with the objective assessment of contact lens decentration.
A prospective-observational and non-randomized study in 32 Caucasian myopic eyes undergoing Ortho-k for 3 months. Total, epithelial, and stromal thicknesses were studied before and after Ortho-k treatment, using optical coherence tomography with anterior segment application software. Central, paracentral, and mid-peripheral values are taken along 8 semi-meridians.
The central average total corneal thickness was 4.72 ± 1.04 μm thinner after Ortho-K. The paracentral corneal thickness showed no significant changes (p = 0.137), while the mid-peripheral corneal thickness was increased by 3.25 ± 1.6 μm associating this increase exclusively to the epithelial plot (p<0.001). When lens centration was assessed, a lens fitting decentration less than 1.0 mm was found for the whole sample, predominantly horizontal-temporal (87.5%) and vertical-inferior (50%) decentring. Corneal topographical analysis revealed a horizontal and vertical epithelial thickness asymmetric change profile with paracentral temporal thinnest values, and mid-peripheral nasal thickest values.
The present study found a central corneal thinning induced by Ortho-k lenses in subjects with moderate myopia, only associated with a change in epithelial thickness, as well as mid-peripheral thickening, that seems to be mainly epithelial in origin. The authors also found a tendency of contact lens decentration toward temporal and inferior areas conditioning an asymmetric epithelial redistribution pattern.
研究成功接受角膜塑形术治疗的近视患者的角膜上皮厚度和总角膜厚度变化，并对隐形眼镜偏心情况进行客观评估。
对32只接受3个月角膜塑形术的白种人近视眼睛进行前瞻性观察和非随机研究。在角膜塑形术治疗前后，使用带有前段应用软件的光学相干断层扫描技术研究总角膜厚度、上皮厚度和基质厚度。沿着8条半子午线获取中央、旁中央和中周边的值。
角膜塑形术后，中央平均总角膜厚度变薄了4.72±1.04μm。旁中央角膜厚度无显著变化（p=0.137），而中周边角膜厚度增加了3.25±1.6μm，且这种增加仅与上皮层有关（p<0.001）。在评估镜片中心定位时，整个样本的镜片配适偏心小于1.0mm，主要为水平颞侧偏心（87.5%）和垂直下方偏心（50%）。角膜地形图分析显示，旁中央颞侧上皮厚度值最薄，中周边鼻侧上皮厚度值最厚，呈现出水平和垂直上皮厚度不对称变化的特征。
本研究发现，角膜塑形术镜片可导致中度近视患者中央角膜变薄，且仅与上皮厚度变化有关，同时还伴有中周边增厚，增厚似乎主要源于上皮层。作者还发现隐形眼镜有向颞侧和下方偏心的趋势，这导致了上皮分布模式的不对称。
