Eye growth in term- and preterm-born eyes modeled from magnetic resonance images.

PURPOSE

We generated a model of eye growth and tested it against an eye known to develop abnormally, one with a history of retinopathy of prematurity (ROP).

METHODS

We reviewed extant magnetic resonance images (MRIs) from term and preterm-born patients for suitable images (n = 129). We binned subjects for analysis based upon postmenstrual age at birth (in weeks) and ROP history ("Term" ≥ 37, "Premature" ≤ 32 with no ROP, "ROP" ≤ 32 with ROP). We measured the axial positions and curvatures of the cornea, anterior and posterior lens, and inner retinal surface. We fit anterior chamber depth (ACD), posterior segment depth (PSD), axial length (AL), and corneal and lenticular curvatures with logistic growth curves that we then evaluated for significant differences. We also measured the length of rays from the centroid to the surface of the eye at 5° intervals, and described the length versus age relationship of each ray, L(ray)(x), using the same logistic growth curve. We determined the rate of ray elongation, E(ray)(x), from L(ray)dy/dx. Then, we estimated the scleral growth that accounted for E(ray)(x), G(x), at every age and position.

RESULTS

Relative to Term, development of ACD, PSD, AL, and corneal and lenticular curvatures was delayed in ROP eyes, but not Premature eyes. In Term infants, G(x) was fast and predominantly equatorial; in age-matched ROP eyes, maximal G(x) was offset by approximately 90°.

CONCLUSIONS

We produced a model of normal eye growth in term-born subjects. Relative to normal, the ROP eye is characterized by delayed, abnormal growth.