Haque Sameena, Fonn Desmond, Simpson Trefford, Jones Lyndon
Centre for Contact Lens Research, School of Optometry, University of Waterloo, Waterloo, Ontario, Canada.
Optom Vis Sci. 2007 Apr;84(4):343-8. doi: 10.1097/OPX.0b013e318042af1d.
To assess the corneal swelling response to two myopic correction corneal refractive therapy (CRT) lenses of varying Dk/t values, worn for a single night. Change in thickness of the total cornea, stroma, and epithelium was measured across the horizontal meridian using optical coherence tomography (OCT).
In this double-masked, randomized study, twenty subjects wore a CRT design lens in each eye, manufactured from Menicon Z (MenZ; Dk/t = 91) and Equalens II (EqII; Dk/t = 47) materials. Baseline corneal thickness was measured centrally and at four points either side of the central cornea using OCT, the night before sleeping at the Centre for Contact Lens Research. The next morning, lenses were removed, and thickness measurements were repeated 1, 3, 6, and 12 h after removal.
On lens removal, the MenZ eye had central and paracentral corneal swelling (mean +/- SD) of 4.1 +/- 2.0% and 5.6 +/- 2.4%, and the EqII eye had 5.8 +/- 2.6% and 7.0 +/- 2.6%. These values were significantly different from baseline (ReANOVA; p < 0.001) and were different between lens materials (p < 0.001). The central epithelium thinned by 10.0 +/- 4.5% in the MenZ eye and by 10.2 +/- 8.5% in the EqII eye, with the mid-peripheral epithelium thickening by 13.4 +/- 7.9% in the MenZ eye and 18.3 +/- 9.8% in the EqII eye (all changes different from baseline p < 0.001). These epithelial values were not statistically different between materials (p > 0.05). Stromal swelling values on lens removal were 5.7 +/- 2.2% centrally and 5.5 +/- 3.0% mid-peripherally (MenZ) and 7.7 +/- 3.1% centrally and 6.6 +/- 2.9% mid-peripherally (EqII) (all p < 0.001 from baseline). Central stromal swelling was different between eyes at lens removal (p < 0.001). Stromal thickness in both eyes returned to baseline values within 3 h.
The higher-Dk/t MenZ material caused significantly less overnight corneal and stromal swelling than the Eqll material, which reinforces the need to prescribe lenses with high Dk/t for overnight wear. Neither central epithelial thinning nor paracentral thickening are significantly affected by Dk/t.
评估佩戴一晚后，两种不同Dk/t值的近视矫正角膜屈光治疗（CRT）镜片对角膜肿胀的反应。使用光学相干断层扫描（OCT）测量水平子午线上全角膜、基质和上皮厚度的变化。
在这项双盲随机研究中，20名受试者每只眼睛佩戴由美尼康Z（MenZ；Dk/t = 91）和Equalens II（EqII；Dk/t = 47）材料制成的CRT设计镜片。在接触镜研究中心睡觉前一晚，使用OCT测量角膜中央以及中央角膜两侧四个点的基线角膜厚度。第二天早上，取下镜片，并在取下后1、3、6和12小时重复测量厚度。
取下镜片时，佩戴MenZ镜片的眼睛中央和旁中央角膜肿胀（均值±标准差）分别为4.1±2.0%和5.6±2.4%，佩戴EqII镜片的眼睛分别为5.8±2.6%和7.0±2.6%。这些值与基线有显著差异（重复测量方差分析；p < 0.001），且镜片材料之间也有差异（p < 0.001）。MenZ镜片组眼睛中央上皮变薄10.0±4.5%，EqII镜片组眼睛中央上皮变薄10.2±8.5%，MenZ镜片组眼睛中周边上皮增厚13.4±7.9%，EqII镜片组眼睛中周边上皮增厚18.3±9.8%（所有变化与基线相比p < 0.001）。这些上皮变化在材料之间无统计学差异（p > 0.05）。取下镜片时基质肿胀值在中央为5.7±2.2%，中周边为5.5±3.0%（MenZ），中央为7.7±3.1%，中周边为6.6±2.9%（EqII）（所有与基线相比p < 0.001）。取下镜片时两眼中央基质肿胀不同（p < 0.001）。两眼基质厚度在3小时内恢复到基线值。
与EqII材料相比，Dk/t值更高的MenZ材料导致过夜角膜和基质肿胀明显更少，这进一步证明了需要开具高Dk/t值的镜片用于过夜佩戴。Dk/t对中央上皮变薄和旁中央增厚均无显著影响。
