Zebrafish eye metrics graphed with respect to time. A. Eye axial length measured by SD-OCT increases during the lifetime of the growing fish. lrp2 zebrafish eyes are larger than wild-type at all timepoints measured. B. Lens diameter increases as the fish grows. lrp2 zebrafish lenses are larger than wild-type at 1 month, but are not significantly larger at 3 months or 1 year. C. Retinal radius increases consistently as the fish age, and lrp2 retinal radii are greater than wild-type at all timepoints measured. Error bars show SD.

SD-OCT used to measure the relationship between zebrafish retinal radius and lens radius, or relative refractive error. A. Wild-type zebrafish retinal radius shows a very good linear relationship with lens radius, and the best-fit line can be used to calculate the ratio coefficient which predicts correct retinal radius for each eye from the measured lens radius. lrp2 retinal radius: lens radius ratios have poorer linear relationships and have a higher ratio coefficient predicting that each lrp2 eye will have a longer required focal distance than wild-type. B. Relative refractive error compares the difference between calculated retinal radius based on lens radius measurements and observed retinal radius (center of lens to back of RPE). Relative refractive errors are made from a general equation, and individual wild-type sample groups are shown at each timepoint to demonstrate the variability seen when using this equation (grey bar shows lowest and highest average values). lrp2 zebrafish are more myopic than wild-types and consistently become more myopic as they age. Error bars show SD. C. Example of laser-assisted ray-tracing through a dissected lens to calculate focal length. Shown are individual images (i, iii), or composites (ii, iv) to indicate the light-ray intersection point either without line tracing (i, ii), and with lines tracing (iii, iv) to aid visualization.

Dark-rearing zebrafish leads to myopia induction. Sibling zebrafish were raised in either light or dark conditions and relative refractive errors measured at various timepoints. Dark-reared zebrafish showed relative refractive errors at each timepoint, which were significantly lower than light-reared controls. Error bars show SEM.