QUANTITATIVE TOPOGRAPHIC CURVATURE MAPS OF THE POSTERIOR EYE UTILIZING OPTICAL COHERENCE TOMOGRAPHY.

PURPOSE: Deformations of the retina such as staphylomas in myopia or scleral flattening in high intracranial pressure can be challenging to quantify with en face imaging. We describe an optical coherence tomography-based method for the generation of quantitative posterior eye topography maps in normal and pathologic eyes. METHODS: Using "whole eye" optical coherence tomography, we corrected for subjects' optical distortions to generate spatially accurate posterior eye optical coherence tomography volumes and created local curvature (KM, mm-1) topography maps for each consented subject. We imaged nine subjects, three normal, two with myopic degeneration, and four with papilledema including one that was imaged longitudinally. RESULTS: Normal subjects mean temporal KM was 0.0923 mm-1, nasal KM was 0.0927 mm-1, and KM local variability was 0.0162 mm-1. In myopic degeneration, subjects KM local variability was higher at 0.0836 mm-1. In papilledema subjects nasal KM was flatter compared with temporal KM (0.0709 vs. 0.0885 mm-1). Mean intrasession KM repeatability for all subjects was 0.0036 mm-1. CONCLUSION: We have developed an optical coherence tomography based method for quantitative posterior eye topography that offers the ability to analyze local curvature with micron scale resolution and offers the potential to help clinicians and researchers characterize subtle, local retinal deformations earlier in patients and follow their development over time.

Intraoperative aberrometry vs modern preoperative formulas in predicting intraocular lens power.

PURPOSE: To compare the outcomes of an intraoperative aberrometer (ORA) to the Barrett Universal II (Barrett II) and Hill-RBF 2.0 (Hill-RBF) intraocular lens (IOL) power calculation formulas. SETTING: Duke University Eye Center, Durham, North Carolina, USA. DESIGN: Retrospective study. METHODS: Patients without history of refractive corneal surgery who had an uneventful cataract surgery from April 2016 to June 2018 were enrolled. Refractive prediction error was calculated with the Barrett II formula, the Hill-RBF formula, and the ORA intraoperative aberrometer (OIA) and was stratified by axial length, IOL type, and the percentage of eyes within a diopteric range of target refraction. RESULTS: Nine-hundred forty-nine eyes were included. The mean and median absolute predictive errors were 0.29 diopters (D) and 0.23 D (Barrett II), 0.31 D and 0.24 D (Hill-RBF), and 0.31 D and 0.25 D (intraoperative aberrometry), respectively (P > .05). Axial length stratification did not influence statistical difference in the IOL prediction methods. Barrett II outperformed the OIA toric multifocal (P = .011) group. Postoperative refraction was within 0.50 D of target in 84% (Barrett II), 83% (Hill-RBF), and 82% (OIA) of eyes (P > .05). CONCLUSIONS: Comparing the OIA to the Barrett II and Hill-RBF calculators, there was minimal clinical difference in the toric multifocal group. Regarding postoperative predicted spherical equivalent, for patients without a history of refractive surgery and good potential visual acuity, refractive outcome was not improved by utilizing the OIA.

Wide-field whole eye OCT system with demonstration of quantitative retinal curvature estimation.

Current conventional clinical OCT systems image either only the anterior or the posterior eye during a single acquisition. This localized imaging limits conventional OCT's use for characterizing global ocular morphometry and biometry, which requires knowledge of spatial relationships across the entire eye. We developed a "whole eye" optical coherence tomography system that simultaneously acquires volumes with a wide field-of-view for both the anterior chamber (14 x 14 mm) and retina (55°) using a single source and detector. This system was used to measure retinal curvature in a pilot population and compared against curvature of the same eyes measured with magnetic resonance imaging.