Bogan S J, Maloney R K, Drews C D, Waring G O
Department of Ophthalmology, Emory University School of Medicine, Atlanta, GA 30322.
Arch Ophthalmol. 1991 Jun;109(6):834-41. doi: 10.1001/archopht.1991.01080060098034.
We used computer-assisted videokeratography to compare the topographies of 32 corneas from 23 subjects after radial keratotomy with those of 47 normal corneas from 47 subjects controlled for age and preoperative keratometric and refractive power. Three ophthalmologists independently classified color-coded videokeratographs based on the color-coded pattern of dioptric power distribution and the cross-sectional shape. Corneas that had radial keratotomy exhibited a polygonal pattern not seen in normal eyes; this occurred in 59% of corneas. All normal corneas demonstrated a cross-sectional shape configuration that was steeper centrally than peripherally; 79% of corneas after radial keratotomy had a shape that was flatter centrally than peripherally. After radial keratotomy, the dioptric power increased from the center to the periphery (radius of approximately 4.6 mm) by 2.8 +/- 2.2 diopters (mean +/- SD), with a sharp inflection zone ("paracentral knee") 2.7 mm from the center; normal corneas showed a smooth decrease in power from the center to the periphery of 1.9 +/- 0.5 diopters.
我们使用计算机辅助角膜地形图仪，比较了23名接受放射状角膜切开术的受试者的32只角膜与47名年龄、术前角膜曲率和屈光力相匹配的正常受试者的47只角膜的地形图。三名眼科医生根据屈光度分布的颜色编码模式和横截面形状，对彩色编码的角膜地形图进行了独立分类。接受放射状角膜切开术的角膜呈现出正常眼睛中未见的多边形模式；59%的角膜出现这种情况。所有正常角膜的横截面形状均为中央比周边陡峭；79%接受放射状角膜切开术的角膜形状为中央比周边平坦。放射状角膜切开术后，屈光度从中心到周边（半径约4.6毫米）增加2.8±2.2屈光度（平均值±标准差），在距中心2.7毫米处有一个明显的转折区（“旁中心拐点”）；正常角膜的屈光度从中心到周边呈平滑下降，为1.9±0.5屈光度。
