Refractive Accuracy of Intraocular Lens Power Calculation Formulas in Nonagenarians: A Retrospective Study

Area of Science:

• Ophthalmology
• Biomedical Engineering

Background:

• Cataract surgery is common in elderly populations.
• Accurate intraocular lens (IOL) power calculation is crucial for visual outcomes.
• Older adults (≥90 years) present unique challenges for refractive prediction.

Purpose of the Study:

• To compare the refractive predictive accuracy of three common IOL power calculation formulas: SRK/T, Barrett Universal II, and Haigis.
• To evaluate formula performance specifically in patients aged 90 years and older.

Main Methods:

• Retrospective observational study of 62 eyes from patients aged ≥90 years undergoing cataract surgery.
• Preoperative biometry using IOL Master 700.
• Comparison of predicted spherical equivalent with manifest refraction at 3 months postoperatively, analyzing Mean Absolute Error (MAE) and Root Mean Square Absolute Error (RMSAE).

Main Results:

• No statistically significant differences in MAE or RMSAE were found among the SRK/T, Barrett Universal II, and Haigis formulas (p > 0.12).
• The Barrett Universal II formula achieved the highest proportion of eyes within ±0.5 D of predicted refraction (64.5%).
• No specific biometric parameters were identified as significant predictors for achieving a refractive error within ±0.5 D.

Conclusions:

• The SRK/T, Barrett Universal II, and Haigis formulas demonstrate comparable refractive predictive accuracy in patients aged 90 years and older.
• In this elderly demographic, refractive outcomes may depend more on the precision of biometric data and the minimization of surgical risks than on the specific IOL power calculation formula used.