近視及散光病人施行準分子雷射輔助層狀角膜重塑術後之不同角膜弧度值變化

The Variance of Different Keratometric Readings after Laser Assisted in Situ Keratomileusis for Myopia and Astigmatism

胡朝乾(Chao-Chien Hu) ； 施玫如(Mei-Ru Shih) ； 盧雪玉(Hsuei-Yuh Lu)

《中華民國眼科醫學會雜誌》 38卷4期 (1999/12) Pp. 635-642

https://doi.org/10.30048/ACTASOS.199912.0009

摘要

Purpose: Owing to the variance of different keratometric readings can result in rather different IOL power calculations, we tried to discuss the differences between many different K. readings after LASIK surgery for moderate to high degree of myopia.
Methods: Twenty-nine eyes have been enrolled in this study. We recorded conventional keratometric readings by manual keratometry and average simulated keratometry (Avg. Sim. K) by corneal topography preoperatively. All the LASIK surgeries were performed with Schwind microkeratome and Schwind keratome-F excimer laser. We measured Avg.Sim.K and Eff. RP (Effective refractive power) at every follow-up visits postoperatively. Refraction-derived videokeratography at the spectacle and corneal plane were also calculated at the final visits. We analyzed these different K readings with statistics at last.
Results: We found there was no significant difference between manual K and Avg. Sim. K preoperatively (p＜0.05). The same result was also found between Avg. Sim. K and Eff. RP postoperatively (p＜0.05). However, rather differences between Avg. Sim. K and refraction-derived videokeratography at the spectacle and corneal plane were noted in our study. We also found a trend that as the achieved refractive changes at the spectacle and corneal plane increase, the differences between Avg. Sim. K and refraction-derived videokeratography at the spectacle plane and corneal plane will also increase. Both of the manual keratometry and average simulated keratometry (Avg.Sim.K) were used to measure anterior radius of cornea only, overestimation of corneal power by them could be expected after refractive surgery (LASIK or PRK) owing to negligence of posterior radius of cornea.
Conclusion: There was no differences between manaul K and Avg. Sim. K. preoperatively. Neither was there between Avg. Sim. K. and Eff.RP postoperatively in our study. However, we noted quite differences between Avg. Sim. K and refraction-derived videokeratography at the spectacle or corneal plane and found a moderate to strong correlation between these differences and achieved refractive changes at the spectacle or corneal plane.

並列摘要

Purpose: Owing to the variance of different keratometric readings can result in rather different IOL power calculations, we tried to discuss the differences between many different K. readings after LASIK surgery for moderate to high degree of myopia.
Methods: Twenty-nine eyes have been enrolled in this study. We recorded conventional keratometric readings by manual keratometry and average simulated keratometry (Avg. Sim. K) by corneal topography preoperatively. All the LASIK surgeries were performed with Schwind microkeratome and Schwind keratome-F excimer laser. We measured Avg.Sim.K and Eff. RP (Effective refractive power) at every follow-up visits postoperatively. Refraction-derived videokeratography at the spectacle and corneal plane were also calculated at the final visits. We analyzed these different K readings with statistics at last.
Results: We found there was no significant difference between manual K and Avg. Sim. K preoperatively (p＜0.05). The same result was also found between Avg. Sim. K and Eff. RP postoperatively (p＜0.05). However, rather differences between Avg. Sim. K and refraction-derived videokeratography at the spectacle and corneal plane were noted in our study. We also found a trend that as the achieved refractive changes at the spectacle and corneal plane increase, the differences between Avg. Sim. K and refraction-derived videokeratography at the spectacle plane and corneal plane will also increase. Both of the manual keratometry and average simulated keratometry (Avg.Sim.K) were used to measure anterior radius of cornea only, overestimation of corneal power by them could be expected after refractive surgery (LASIK or PRK) owing to negligence of posterior radius of cornea.
Conclusion: There was no differences between manaul K and Avg. Sim. K. preoperatively. Neither was there between Avg. Sim. K. and Eff.RP postoperatively in our study. However, we noted quite differences between Avg. Sim. K and refraction-derived videokeratography at the spectacle or corneal plane and found a moderate to strong correlation between these differences and achieved refractive changes at the spectacle or corneal plane.

並列關鍵字

Keratometric readings ； Laser Assisted In Situ Keratomileusis LASIK ； IOL power calculation