Arrested Corneal Flattening and Low Astigmatism as Stable Trends Over Decades in Danish Ex-preterms

Abstract

Background: Based on Danish cohort studies over half a century, to look for changes over time of corneal shape in childhood (curvature and astigmatism) in surviving Preterms (PT). Methods: In the most recent study 178 PT and 56 Full-Term (FT) children underwent cycloplegic Retinomax autokerato-refractometry at age 4-5 years. PT was subdivided according to the presence and severity of Retinopathy of Prematurity (ROP) Results: The PT children had either no ROP (n = 99), reversible ROP (n = 47) or laser treated ROP (n =32) and presented median refractive values of 1.5 D, 1.8 D and 1.1 D, respectively, versus 1.3 D in controls (P<0.05). The corresponding mean values for corneal Curvature Radius (CR) were 7.59±0.27 mm, 7.60±0.28 mm and 7.46±0.28 mm, compared with 7.79 ± 0.23 mm for FT (P<0.0001). As added analyses, CR was significantly correlated to birth weight (P<0.001) but not to gestational age (P=0.14). CR and astigmatism did not correlate with refraction. Corneal Astigmatism (CA) was of normal low order (cylinder mainly < 1 D) and with no difference between the two main groups. Within the PT group, treated ROP had a higher median cylinder and a top-value of -2.25 D. Conclusion: The stable anterior segment features over time contributed optically to occasional myopia of prematurity but did not explain it. Comparing with previous Danish PT investigations over 5 decades, a steeper cornea and low degree astigmatism remained hallmarks of PT, although with a slight impact suggested for the most advanced ROP.