Table 4.

Comparison with similar studies conducted previously

Study	Inferences	Other relevant details of previous study	Comparison of present study
Demill et al. evaluated the use of ASCRS calculator in eyes with prior RK. Formulas evaluated were the Humphrey Atlas method, average central power method, and the average ASCRS power. In our study, we have not compared the average central power method	ASCRS Average best predicts the IOL power	They recommended adding +1.00 to +1.50 D to the final power to achieve emmetropic outcomes	We have chosen -1.00 and−2.00 D as target refraction in the RK calculator in corneas with eight RK incisions and 16 incisions, respectively, to achieve emmetropia.[1] Barrett True-K had the highest percentage of eyes within±0.5 D and the least MedAE, equal to that of ASCRS Maximum power compared to others[1]
Packer et al., in 2004, evaluated the efficacy of corneal topography in determining central corneal refractive power in IOL power calculations in eyes status post-incisional and thermal keratoplasties	They had 80% of outcomes within ±0.5 D with the average central power[20]		Eyes post-thermal keratoplasty were not included in this study
Awwad et al. evaluated the efficacy of ACCP in IOL power prediction in status post-RK eyes	ACCP in 3-mm zone resulted in 87.5% of eyes being within ±0.5 D IOL prediction error	They used the same formula as the ASCRS calculator using measurements from the Topographic Modeling System (Tomey Corporation, Aichi, Japan)[21]	ACCP was not compared in the present study. Both Barrett True-K and ASCRS Average power had 56% of eyes within±0.50 D, but only Barrett True-K showed 100% of eyes within±1.50 D

ACCP=Average central corneal power, ASCRS=American Society of Cataract and Refractive Surgery, IOL=Intraocular lens, RK=Radial keratotomy