People with a high degree of farsightedness along with astigmatism have less predictable results.

对远视兼散光的人手术后结果的预期较少。

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Photorefractive keratectomy (PRK). PRK is sometimes used if you have a low to moderate degree of nearsightedness or farsightedness, or if you have nearsightedness with astigmatism.

屈光性角膜切除术(PRK)：当你有低于中等度数的近视或者远视，或者近视加散光，有时会选择prk。

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Since off-axis wander results in images which have astigmatism when the prism is placed in a converging beam, Glan types have slightly better imaging qualities than Nicla types.

因为当棱镜置于会聚光束中时，离轴漂移造成有像散的像，格兰型棱镜的成像质量比尼·科尔型略好。

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