Impact Of Tear Film Stability On The Accuracy Of Intraocular Lens Power Calculations

Accurate intraocular lens (IOL) power calculation is a critical component of achieving optimal visual outcomes in cataract surgery. The tear film plays a pivotal role in ensuring the reliability of preoperative measurements, particularly keratometry and optical biometry, which are essential for precise IOL power determination. This study examines the impact of tear film quality and stability on the accuracy of these measurements, highlighting the importance of addressing dry eye disease and other tear film abnormalities prior to surgery.

This study was conducted in a clinical setting at Department of Ophthalmology, Prof. K. Gibinski University Clinical Centre, Medical University of Silesia, Katowice, Poland with a sample of 60 cataract patients (120 eyes), evaluating the impact of tear film stability on IOL power calculations.

A total of 60 patients undergoing cataract surgery were enrolled (120 eyes) with presence of symptoms of dry eye syndrome. Preoperative measurements of corneal curvature and axial length were performed using optical biometry and keratometry (ZEISS IOL master 700). For the IOL calculation we used Barret Universal II formula. Tear film stability was assessed with non-invasive tear break-up time (NITBUT). The influence of tear film quality on IOL power calculations was evaluated by comparing the initial measurements taken in patients with dry eye symptoms and those obtained after 5 minutes of eye closure, allowing for tear film stabilization.

An improvement in tear film stability was observed following the 5-minute eye closure period. Initial measurements in patients with dry eye syndrome exhibited notable variability in corneal curvature, leading to inconsistencies in intraocular lens (IOL) power calculations. In contrast, measurements taken after tear film stabilization demonstrated greater reproducibility, resulting in more precise and repeatable IOL power predictions. The difference in IOL power calculation outcomes before and after stabilization was significant underscoring the critical role of tear film stability in optimizing the accuracy of IOL power determination.

Tear film stability significantly impacts the accuracy and reproducibility of IOL power calculations. Initial measurements in patients with dry eye syndrome can lead to variable results, while tear film stabilization through a brief period of eye closure improves measurement precision and repeatability. Enhancing tear film stability allows surgeons to minimize errors, avoid "refractive surprises," and improve patient satisfaction with postoperative outcomes. This is particularly important in the implantation of "premium" intraocular lenses, such as EDOF or multifocal lenses, where accurate power calculation is essential for optimal visual performance at multiple distances.