Refractive Predictability of Third-Generation and Modern IOL Power Calculation Formulas in Yamane Intrascleral...

Area of Science:

• Ophthalmology
• Refractive Surgery
• Biomedical Engineering

Background:

• Yamane intrascleral fixation (YISF) is a technique used for IOL implantation in cases of aphakia or IOL subluxation.
• Accurate refractive prediction is crucial for successful visual outcomes after YISF.
• Evaluating the performance of different IOL power calculation formulas in this specific surgical context is essential.

Purpose of the Study:

• To compare the refractive predictability of third-generation and modern IOL power calculation formulas following YISF.
• To assess the impact of formula optimization on refractive outcomes in eyes undergoing YISF.

Main Methods:

• A retrospective analysis of 87 eyes undergoing YISF was conducted.
• Six IOL power calculation formulas were evaluated: third-generation (Hoffer Q, Holladay 1, SRK/T, T2) and modern (Barrett Universal II, EVO 2.0).
• Refractive predictability was assessed using mean error (ME), mean absolute error (MAE), median absolute error (MedAE), and proportions of eyes within ±0.50D and ±1.00D, before and after constant optimization.

Main Results:

• All formulas initially showed a hyperopic shift (ME +0.55D to +0.71D) with no significant differences in ME, MAE, or MedAE.
• SRK/T, BUII, and EVO 2.0 formulas had a higher proportion of eyes within ±0.50D pre-optimization.
• After constant optimization, all formulas demonstrated similar refractive performance, with no significant differences in MAE, MedAE, or refractive outcomes.

Conclusions:

• A consistent hyperopic shift was observed with all tested formulas after YISF.
• While some formulas showed initial advantages, all demonstrated comparable refractive predictability after constant optimization.
• Refractive outcomes after YISF are significantly influenced by intraoperative factors affecting the actual IOL position.