Refractive Accuracy of Barrett True-K vs Intraoperative Aberrometry for IOL Power Calculation in Post-Corneal Refractive Surgery Eyes.

PURPOSE: To compare the refractive predictability of intraoperative aberrometry (IA, ORA, Alcon) and Barrett True-K/Universal II formulas for intraocular lens (IOL) power calculations in post-corneal refractive surgery and normal eyes. METHODS: Retrospective study of normal and post-corneal refractive surgery eyes that underwent cataract surgery with IA at tertiary academic center. Preoperatively, IOL power calculations were performed using Barrett Universal II (normal eyes) or Barrett True-K (post-corneal refractive surgery eyes) formulas. Intraoperatively, aphakic IA measurements were used for IOL power calculations. Mean absolute refractive prediction error (MAE) and the percentage of eyes with prediction error within ±0.50, ±0.75 and ±1.00 D were calculated. Refractive predictability was also evaluated in short, normal, and long eyes. RESULTS: Two hundred and seventy-three eyes were included in the analysis. No statistically significant differences were observed between the MAE of preoperative formulas and IA for post-hyperopic laser vision correction (LVC), post-myopic LVC, post-radial keratotomy (RK) and normal eyes. For prediction error within ±0.5 D in post-corneal refractive surgery eyes, range of agreement between Barrett True-K and IA ranged from 28% (7/25) of the time in post-RK eyes to 49% (40/81) of the time in post-hyperopic LVC; the corresponding value for Barrett Universal II/IA was 62% (64/103) in normal eyes. When there was disagreement, IA outperformed Barrett True-K in post-hyperopic LVC eyes and Barrett formula outperformed IA in post-myopic LVC, post-RK, and normal eyes. CONCLUSION: IA appears to be comparable to Barrett formulas for IOL power calculations in post-corneal refractive surgery and normal eyes. In post-hyperopic LVC, IA yields better results compared to Barrett True-K formula; in real-life scenarios, IA reveals statistical advantage over the Barrett True-K no history formula for eyes post-hyperopic LVC.

Redefining vision assessment.

PURPOSE OF REVIEW: This review outlines ophthalmic diagnostic systems, which objectively evaluates the human visual system and its potential beyond that of Snellen acuity. RECENT FINDINGS: Advances in ophthalmic diagnostic systems have allowed for a deeper understanding of the optical principles of the human eye and have created the opportunity to evolve our current standards of vision assessment beyond Snellen acuity charts. Definitive comparative and validation trials will continue to be necessary in order for these advanced diagnostics to gain more widespread acceptance in the specialty, in addition to providing the guidance on the specific indications and utilities. SUMMARY: Advancements in wavefront analysis, light scatter measurements, and adaptive optics technologies can provide greater insight into an individual optical system's potential and irregularities. Modalities that test for anterior corneal surface and whole eye aberrations, light scatter and contrast sensitivity can be an excellent educational tool for our patients to help them better understand their visual dysfunction and can prove useful for medical or surgical decision-making.