IMPORTANCE Slowing myopia progression could decrease the risk of sight-threatening complications.OBJECTIVE To determine whether soft multifocal contact lenses slow myopia progression in children, and whether high add power (+2.50 D) slows myopia progression more than medium (+1.50 D) add power lenses. DESIGN, SETTING, AND PARTICIPANTSA double-masked randomized clinical trial that took place at 2 optometry schools located in Columbus, Ohio, and Houston, Texas. A total of 294 consecutive eligible children aged 7 to 11 years with −0.75 D to −5.00 D of spherical component myopia and less than 1.00 D astigmatism were enrolled between
Purpose To determine the repeatability of eye length measurements made centrally and off-axis using a low-coherence interferometer. Methods Eye length was measured (left eye) in twenty-nine adults with a Haag-Streit Lenstar LS 900. Five measurements were made centrally, 10° temporally, and 10° nasally on the retina by the same examiner at two separate visits. Inter-visit repeatability was assessed by plotting the difference versus the mean of each pair of measurements (bias) and calculating the 95% limits of agreement (LoA). Within-session repeatability was determined by calculating the within-subject standard deviation (Sw) of five consecutive measurements at a visit. Due to variability noted 10° nasally, the Sw was also determined on a subset of 10 subjects using five measurements at one visit 30° nasally and 30° temporally. Results The mean ± SD age, spherical equivalent refractive error, and central axial length (at visit 1) were 24.0 ± 1.4 years, −3.46 ± 2.69 D, and 24.91 ± 1.10 mm, respectively. There was no significant bias for central, 10° nasal, or 10° temporal measurements between visits (all p > 0.09). The 95% LoA were: ±0.05 mm central, ±0.12 mm 10° nasal, and ±0.05 mm 10° temporal. The Sw (visit 1) were: 0.025 mm central, 0.045 mm 10° nasal, and 0.028 mm 10° temporal. The Sw in the subset of subjects with 30° measurements were 0.023 mm (30° nasal) and 0.030 mm (30° temporal). Conclusions Lenstar central and off-axis eye length measurements are very repeatable, though repeatability was not as good 10° nasally on the retina as indicated by the larger 95% LoA between visits and larger Sw. The Sw for measurements centrally and 30° off-axis were similar, suggesting the reduced repeatability 10° nasally is anatomical in nature. Despite greater variability 10° nasally, Lenstar off-axis repeatability is still superior to the repeatability of on-axis ultrasonography.
Children achieved BCVA with +2.50 D add MFCLs that was not different than with spectacles. Children typically required an over-refraction of -0.50 to -0.75 D to achieve BCVA. With a careful over-refraction, these +2.50 D add MFCLs provide good distance acuity, making them viable candidates for myopia control.
Purpose Spectral domain optical coherence tomography (SD-OCT) imaging permits in vivo visualization of the choroid with micron-level resolution over wide areas and is of interest for studies of ocular growth and myopia control. We evaluated the speed, repeatability and accuracy of a new a new image segmentation method to quantify choroid thickness compared to manual segmentation. Methods Two macular volumetric scans (25×30°) were taken from 30 eyes of 30 young adult subjects in two sessions, one hour apart. A single rater manually delineated choroid thickness as the distance between Bruch’s membrane and sclera across three B-scans (foveal, inferior and superior-most scan locations). Manual segmentation was compared to an automated method based on graph theory, dynamic programming, and wavelet-based texture analysis. Segmentation performance comparisons included processing speed, choroid thickness measurements across the foveal horizontal midline, and measurement repeatability (95% limits of agreement (LoA)). Results Subjects were healthy young adults (n=30; 24±2y; mean±SD; 63% female) with spherical equivalent refractive error of: −3.46±2.69 D (range: +2.62 to −8.50 D). Manual segmentation took 200 times longer than automated segmentation (780 vs 4 seconds). Mean choroid thickness at the foveal center was 263±24 μm (manual) and 259±23 μm (automated), and this difference was not significant (P = .10). Regional segmentation errors across the foveal horizontal midline (±15°) were ≤9 μm (median) except for nasal-most regions closest to the nasal peripapillary margin—15° (19μm) and 12° (16 μm) from the foveal center. Repeatability of choroidal thickness measurements had similar repeatability between segmentation methods (manual LoA: ±15 μm; automated LoA: ±14 μm). Conclusions Automated segmentation of SD-OCT data by graph theory and dynamic programming is a fast, accurate, and reliable method to delineate the choroid. This approach will facilitate longitudinal studies evaluating changes in choroid thickness in response to novel optical corrections and in ocular disease.
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