Increased accommodation following adaptation to image blur in myopes

Prolonged exposure to blurred images produces perceptual adaptatio

Axial Elongation in Myopic Children and its Association With Myopia Progression in the Correction of Myopia Evaluation Trial.

OBJECTIVES: Describe axial elongation using 14-year longitudinal data in a large, ethnically diverse group of myopic children, estimate age and axial length (AL) at stabilization, and evaluate associations between the progression and stabilization of AL and myopia. METHODS: Axial length was measured by A-scan ultrasonography annually. Axial length data were fit with individual polynomial functions and curve-based parameters (AL at stabilization and age at stabilization when annual rate of axial elongation ≤0.06 mm) were estimated. For myopia progression, noncycloplegic spherical equivalent refractions were fit with Gompertz functions. RESULTS: Four hundred thirty-one participants, with AL and myopia data fit successfully, were classified into four cohorts: Younger (n=30); Older (n=334); AL Stabilized at Baseline (n=19); and AL Not Stabilized (n=48). At AL stabilization, for participants in the Younger and Older Cohorts, mean (SD) age and AL were 16.3 (2.4) years and 25.2 (0.9) mm, respectively. No associations were found between age at AL stabilization and ethnicity, sex, or number of myopic parents. At stabilization, sex and number of myopic parents (both P<0.003), but not ethnicity, were significantly associated with AL. Axial length and myopia progression curves were highly correlated overall (all r>0.77, P<0.0001). However, unlike AL, the amount of myopia did not differ significantly between males and females. CONCLUSIONS: In most of the participants, AL increased rapidly at younger ages and then slowed and stabilized. The close association between growth and stabilization of AL and myopia is consistent with the suggestion that axial elongation is the primary ocular component in myopia progression and stabilization

Longitudinal changes in corneal curvature and its relationship to axial length in the Correction of Myopia Evaluation Trial (COMET) cohort

Purpose: To describe longitudinal changes in corneal curvature (CC) and axial length (AL) over 14 years, and to explore the relationship between AL and CC, and the axial length/corneal radius (AL/CR) ratio. Methods: In total 469, 6 to <12-year-old, children were enrolled in COMET. Measurements of refractive error, CC (D), CR (mm), and ocular component dimensions including AL were gathered annually. Linear mixed models were used to evaluate longitudinal changes adjusting for covariates (gender, ethnicity, lens type, baseline age and baseline refraction). The Pearson correlation coefficient between AL and CC was computed at each visit. Results: There was a slight but significant (p < 0.0001) flattening in CC over 14 years. At all visits females had significantly steeper CC than males (overall difference = 0.53 D, p < 0.0001). Caucasians had the steepest CC, and Hispanics the flattest (p = 0.001). The correlation between AL and CC was −0.70 (p < 0.0001) at baseline (mean age = 9.3 years) and decreased to −0.53 (p < 0.0001) at the 14-year visit (mean age = 24.1 years). The average AL/CR ratio was 3.15 at baseline and increased to 3.31 at the 14-year visit. The correlation between the magnitude of myopia and AL/CR ratio was significantly higher (p < 0.0001) at each visit than the correlation between myopia and AL alone. Conclusions: Differences in average corneal curvature by age, gender, and ethnicity observed in early childhood remain consistent as myopia progresses and stabilizes. This study also demonstrates increases in the AL/CR ratio as myopia progresses and then stabilizes, supporting observations from previous cross-sectional data

Optic Nerve Tilt, Crescent, Ovality, and Torsion in a Multi-Ethnic Cohort of Young Adults With and Without MyopiaONH Characteristics With and Without Myopia

PurposeThe purpose of this article is to evaluate optic nerve head (ONH) characteristics in an ethnically diverse cohort of young U.S. adults.MethodsIn this study, 409 myopes and 206 nonmyopes (median age 22 years) completed measures including biometry and spectral domain optical coherence tomography from enface (ovality and torsion) and cross-sectional (tilt and crescent width) scans. Associated factors were evaluated using multivariable models.ResultsIn myopic versus nonmyopic right eyes, median tilt (6.0° vs. 2.4°; P &lt; 0.0001) and frequency of crescents (49% vs. 10%; P &lt; 0.0001) were higher in myopes. Right eyes with crescents had higher median tilts (8.8° [myopic], 9.0° [nonmyopic]) than those without crescent (2.5° [myopic], 2.1° [nonmyopic]), irrespective of refractive group (both P &lt; 0.0001). Torsion was similar between groups, with a slight difference in ovality (0.89 vs. 0.91; P &lt; 0.03). Data in the left eyes were similar, and modeling was done only for the right myopic eyes. Multivariable models showed that an increased tilt was associated with ethnicity (P &lt; 0.001), the presence of crescent (P &lt; 0.001), and smaller ONH diameter (P &lt; 0.0031), with interactions between ethnicity and crescent (P = 0.002). Specifically, ONH tilt was significantly higher in Asian eyes without crescent (P &lt; 0.0001 for all comparisons), and crescent width was associated with increased tilt in non-Asian eyes (P &lt; 0.02). Crescent width was associated with ethnicity (greatest in Asians) and disc tilt. Interactions were observed between tilt and ethnicity, whereby tilt had a greater effect on crescent width in non-Asian eyes, and crescent width was associated with increased tilt in non-Asian eyes.ConclusionsThe data clarify the influence of ethnicity and myopia on ONH characteristics in young adults and may inform future studies of biomechanical properties or of retinal pathology of the myopic eye