Abstract
Purpose :
To study the ability of a simplified nomogram, that can be used as a mental calculation, to approximate IOL power in myopic eyes post LASIK.
Methods :
Nomogram predictions were calculated by adding a set number of diopters to the pre- operative SRK/T (5 for KM 25-30, 4 for KM 30.01-35, 2.5 for KM 35.01-40, 1.5 for KM 40.01-42.99, 1 for KM 43-45). Records of 64 eyes of 51 myopic patients who underwent cataract surgery after LASIK were reviewed. The percentage of eyes with post-operative spherical equivalent (SE) within 0.5 D and 1D of preoperative target was calculated. The proportion of predictions within 0.5 D and 1 D of Optiwave Refractive Analysis (ORA) and Barrett True K (BTK) IOL values were calculated.
Results :
Refractive outcomes showed 71.9% and 93.75% of eyes with post-operative SE within 0.5 D of target refraction respectively. The nomogram IOL prediction fell within 0.5 D of BTK value in 85.94% (n=55) of eyes and within 1 D in 93.75% (n=60) of eyes. The nomogram output fell within 0.5 D of ORA prediction in 68.75% (n=44) of eyes and within 1 D in 92.19% (n=59) of eyes. There were no significant differences between the nomogram and ORA IOL predictions (mean difference 0.07 D, p=0.86) or between the nomogram and BTK IOL predictions (mean difference 0.04 D, p=0.92).
Conclusions :
This nomogram approximates IOL power in myopic eyes post LASIK and can be used for mental calculation of IOL power.
This is a 2021 ARVO Annual Meeting abstract.