Comparison of Four Lens Power Formulas for Sutureless Scleral-Fixated Carlevale Lens

Area of Science:

• Ophthalmology
• Refractive Surgery
• Intraocular Lens Technology

Background:

• Sutureless scleral fixation (SSF) is a technique for implanting intraocular lenses (IOLs).
• Accurate IOL power calculation is crucial for achieving desired refractive outcomes after cataract surgery.
• Predicting refractive outcomes for newer IOL fixation methods, like SSF, requires evaluating existing calculation formulas.

Purpose of the Study:

• To evaluate the predictability of four common intraocular lens (IOL) power calculation formulas for sutureless scleral fixation (SSF) of the Carlevale IOL.
• To compare the accuracy of SRK/T, Barrett II, Hoffer Q, and Holladay 1 formulas in predicting postoperative refractive error in this specific IOL fixation scenario.

Main Methods:

• A prospective, single-center, interventional case series.
• Inclusion of 69 eyes undergoing SSF of the Carlevale IOL.
• Comparison of refractive prediction errors (PE) using SRK/T, Barrett II, Hoffer Q, and Holladay 1 formulas, analyzing mean PE, median absolute error (MedAE), mean absolute error (MAE), and percentage of eyes within ±0.50 and ±1.00 D.

Main Results:

• The SRK/T, Hoffer Q, and Holladay 1 formulas showed prediction errors closer to zero.
• The Barrett II formula demonstrated a statistically significant systematic myopic error.
• No significant differences were found in MedAE, MAE, or the percentage of eyes within ±0.50/±1.00 D between the formulas.

Conclusions:

• The SRK/T, Hoffer Q, and Holladay 1 formulas are suitable for predicting refractive outcomes with the Carlevale IOL using SSF.
• The Barrett II formula is less accurate for this specific application and is not recommended.
• These findings aid surgeons in selecting appropriate IOL power calculation formulas for SSF procedures.