ลักษณะความหนาของแผ่นกระจกตาที่ถูกแยกชั้น ในการผ่าตัดแก้ไขภาวะสายตาสั้นด้วยเลเซอร์

ผู้แต่ง

  • Boonphen Jongsareejit, M.D. กลุ่มงานจักษุวิทยา โรงพยาบาลนครปฐม

บทคัดย่อ

          Purpose : To evaluate the thickness of corneal flaps created with the same blade in bilateral simultaneous LASIK by the Carrizo/Barraquer microkeratome and identify factors that may influence flap thickness.

          Methods : During Jan 1, to June 30, 2002. 116 eyes of 58 patients who had bilateral simultaneous laser in situ keratomileusis with the C & B microkeratome were prospectively evaluated. Preoperatively the manifest refraction, keratometry, and central corneal thickness were measured. The microkeratome automated type with the suction ring designed to create 130 micron thick and variable ring number depend on keratometry. One blade was used in each case. The central corneal thickness was measured with ultrasonic pachymetry (Tomey, SP2000).  After the flap was lifted, the stromal bed thickness was measured by the same procedure. Flap thickness was calculated by subtracting the central stromal bed thickness from the central corneal thickness.

          Results : The mean preoperative manifest refraction spherical equivalent was -5.48 D ± 2.53 SD RE, -5.17D ± 2.88 SD LE. The corneal keratometry was 43.92D ± 1.40 SD RE, 43.82 D ± 1.48 SD LE. The central corneal thickness was 540.83 µm ± 34.40 SD RE, 540.16 µm ± 34.98 SD LE. The first corneal flap thickness was 159.21 µm ± 24.95. The second corneal flap thickness was 143.52 µm ± 29.06. There was no correlation between corneal flap thickness and the degree of myopia or the corneal refractive power. The key findings was a linear relationship between flap thickness and the central corneal thickness. The first corneal flap thickness was thicker than the second flap thickness by scientific significant (P < 0.001).

          Conclusions : The finding of this study is that corneal flap thickness did not appear to be influenced, by the degree of myopia or the corneal refractive power ; however, there was a linear relationship between flap thickness and the central corneal thickness. Interestingly, we found a statistically significant mean difference ; the first corneal flap thickness thicker than the second flap thickness. This results suggested note-worthy especially for high myopia. This difference will be beneficial for surgeon to decide operated second flap on the eye that need more dose of laser treatment. On the other hand, thin flap allow for more stromal potentially available for deeper ablations.

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เผยแพร่แล้ว

2018-08-06