Intraocular lens power calculation and optimized constants for highly myopic eyes

Abstract

Results indicate that the SRK II formula cannot be recommended for IOL power calculation in highly myopic patients. With optimized constants, the SRK/T, Haigis, Hoffer Q, and Holladay 1 formulas produced small deviation of postoperative refraction from target refraction.

Outcomes of cataract operations in extreme high axial myopia

“…Currently, there was no consensus regarding the most accurate standard formulas in negative-power IOL. Hagis formula, Hoffer Q formula or SRK/T have all been suggested as the most accurate formula in different studies, while some did not show significant differences between the formulas [5,22,23]. Apart from the widespread approach of targeting at a more myopic refraction, several solutions have been suggested to address this problem.…”

“…Apart from the widespread approach of targeting at a more myopic refraction, several solutions have been suggested to address this problem. These included the use of specific IOL constants for eyes with long axial length [5,23], axial length adjustments [24], and new generations of IOL formulas including the Barrett Universal II [25], Holladay 2, and Olsen formula [26]. Abulafia et al compared these options in eyes with axial length ≥ 26 mm and reported that all formulas and methods can achieve a high level of predictive ability with IOL power ≥ 6.0 D [27].…”

“…Keratometry was measured with partial coherence interferometry or autokeratometer (KR-8100P, Topcon, Japan). Intraocular lens power was determined by the SRK/T formula in all cases [5]. User Group for Laser Interference Biometry (ULIB) constants were used, with different sets of A constants for positive-and negativepower IOL.…”

Comparison of IOL power calculation formulae for pediatric eyes

“…[4][5][6][7][8]10,11 Optimizing or personalizing the lens constant has been recommended by authors of several formulae to improve their accuracy and predictability. [13][14][15][16] Personalizing the lens constant can be used to make global adjustments for a variety of practice-specific variables (eg, surgical technique, variations in AL and K measurements, and so on). In fact, failure to personalize lens constants has been shown to give suboptimal refractive outcomes following cataract surgery in adult eyes.…”

Refraktive Vorhersagbarkeit und Stabilität von 3-teiligen vs. 1-teiligen Intraokularlinsen bei hoher Achsenmyopie

“…Die SRK-T-Formel ist eine etablierte Methode zur Biometrie bei Patienten mit hoher Achsenmyopie und hinsichtlich refraktiver Ergebnisse der Haigis-oder Holladay-1-Formel ähnlich [11,15,18,20]. Haigis [4] hat aber kürzlich die Bedeutung unterschiedlicher A-Konstanten für Positiv-Dioptrien-und Negativ-Dioptrien-IOLs hervorgehoben.…”