Accuracy Of Ten Intraocular Lens Power Calculation Formulas In Long Eyes In Tertiary Eye Care Center, Riyadh, Saudi Arabia

To compare the accuracy of 10 Intraocular Lens (IOL) power calculation formulas in predicting refractive status in long eyes undergoing cataract surgeries and factors affecting the accuracy.

The research was conducted at a Teriary Eye Center , King Khaled Eye Specialist Hospital, Riyadh Saudi Arabia.

The ASCRS IOL Calculation Formula Analyzer was used for data entry.

This retrospective cohort study included patients with eyes of >26mm axial length (AL) and operated for phacoemulsification cataract surgery with IOL implantation between 2015 and 2021 at a tertiary eye hospital in Saudi Arabia. The ASCRS IOL Calculation Formula Analyzer was used to compare the formulas. For each formula, SEQ error within ± 0.25, ± 0.50 , ±1.00 were recorded . AL was graded as <29mm, 29 to 31mm, and > 31mm. SEQ error within ±1.0D was considered acceptable to correlate to the demographic and preoperative ocular parameters.  Formulas used were ( SRKT , WKSRKT, Holladay, Haigis, HillRBF, EVO, Kane, Barret , HofferQST, PearlDGS )

In 105 participants, the accuracy of ±1.00 was SKR/T 76.2%, WK-SRKT 84.8%, Holladay 63.8%, Haigis 85.7%, Hill- RBF 88.6%, EVO 86.7%, Kane 85.7%, Barrett universal ii 87.6%, Hoffer QST 75.2% and Pearl DGS 77.1%. EVO, Kane, and Barrett universal ii and Hill-RBF formulas had ± 0.50D error in more than 50% of long eyes. The accuracy significantly declined in eyes of higher grades of AL when SKR/T, Holladay, Haigis, and Hoffer QST formulas were used. EVO and Kane scored better at SEQ error of ±0.25 when the analysis was done on Acysof IOL . Four Types of IOL was used in the study Acrysof, Sensar, Alcon multipiece and Tecnis. Demographic, systemic, and ocular comorbidities did not significantly affect the accuracy of all formulas. 

In long eyes, Kane, EVO,  Barrett universal ii and Hill- RBF seem to provide better accuracy in predicting SEQ compared to other formulas.