Comparison of corneal flap thickness between primary eyes and fellow eyes using the Zyoptix XP microkeratome

Purpose To evaluate corneal flap thickness created in myopic laser in situ keratomileusis (LASIK) using the Zyoptix XP 120 microkeratome (Bausch & Lomb). Setting University-based eye clinic. Methods Corneal thickness was measured preoperatively and intraoperatively after flap creation in 62 consecutive patients (124 eyes) who had LASIK for the correction of myopia. Corneal flap thickness was calculated by subtracting stromal bed thickness from total corneal thickness. In each patient, both corneas (right followed by left) were cut by 1 the same Zyoptix XP 120 microkeratome blade at the same session. Results The mean actual flap thickness was 115.34 μm ± 16.34 (SD) in right eyes and 104.55 ± 14.34 μm in left eyes. The mean actual flap thickness in right eyes was not statistically significantly different from the 120 μm proposed by the manufacturer (P = .142); however, the mean actual flap thickness in left eyes was statistically significantly different from the 120 μm (P<.001). The mean flap thickness in the second eye was also statistically significantly thinner than in the first eye (P<.001). Conclusions The corneal flaps were thinner than expected when a Zyoptix XP 120 microkeratome was used in LASIK. Although the first cuts produced thinner flaps, this difference was not statistically significant. However, the second cuts produced significantly thinner flaps.

目的：评估使用Zyoptix XP 120微型角膜刀（博士伦公司）在近视激光原位角膜磨镶术（LASIK）中制作的角膜瓣厚度。 机构：大学附属眼科诊所。 方法：对62例连续的近视矫正LASIK患者（124只眼），在术前和制作角膜瓣后术中测量角膜厚度。角膜瓣厚度通过从角膜总厚度中减去基质床厚度来计算。在每位患者中，同一Zyoptix XP 120微型角膜刀刀片在同一次手术中切割双眼（先右眼后左眼）。 结果：右眼平均实际角膜瓣厚度为115.34μm±16.34（标准差），左眼为104.55±14.34μm。右眼平均实际角膜瓣厚度与制造商宣称的120μm相比，差异无统计学意义（P = 0.142）；然而，左眼平均实际角膜瓣厚度与120μm相比，差异有统计学意义（P<0.001）。第二只眼的平均角膜瓣厚度也比第一只眼显著更薄（P<0.001）。 结论：在LASIK手术中使用Zyoptix XP 120微型角膜刀时，角膜瓣比预期的更薄。尽管第一次切割产生的角膜瓣较薄，但这种差异无统计学意义。然而，第二次切割产生的角膜瓣明显更薄。