To Örebro University

Purpose: Previous studies have mostly focused on ophthalmological complications associated with being born extremely preterm despite that moderate-to-late preterm (MLP) account for 85% of all preterm births. The aim was to examine fundus morphology and visual function in adolescents born MLP, in comparison with controls born full-term.

Methods: A prospective population-based cohort study of 247 MLP individuals (110 girls, gestational age 32-36 weeks) with no syndromes or history of retinopathy of prematurity participated in a neonatal study in 2002-2004. Later on, they have been included in ophthalmological follow-up studies at age 8 (n=50) and 12 (n=22). In the present study, 50 adolescents (26 girls; mean age 16.5 years) were examined regarding best corrected visual acuity (BCVA), refraction, and ocular morphology, measured by optical coherence tomography (Topcon, Japan). A group of 50 adolescents (30 girls, mean age 16.7 years) born full-term served as controls. Participants with refraction outside +/-6 diopters were excluded. T-test was used for statistical analysis.

Results: The MLP-group (n=48) showed a thinner macular retinal nerve fibre layer (RNFL) inner mean in right eye (RE) (26.4±1.5 vs 27.1±1.7 μm; p=0.029) and in left eye (LE) (26.3±1.5 vs 27.0±1.5 μm; p=0.022) compared with controls. A thinner macular RNFL outer mean was found both in RE (40.2±4.4 vs 42.6±4.2 μm; p=0.011) and LE (40.3±4.0 vs 42.1±4.3 μm; p=0.034) (Fig.1A-B). A thicker central macular retinal thickness (MRT) (249.3±20.9 vs 239.9±16.4 μm; p=0.016) and a thinner total peripapillary (pp)RNFL (104.8±8.8 vs 109.1±8.3 μm; p=0.027) were found in RE. The BCVA in best eye was lower in the MLP-group (n=50) compared with controls (-0.09±0.08 vs -0.12±0.09 logMAR; p=0.022). At age 8, MLP births showed a thinner total macular volume and a thicker foveal minimum, central MRT, and central macular RNFL in RE. At age 12, a thicker foveal minimum and thinner outer macular RNFL were found in LE.

Conclusions: MLP-birth may be associated with ophthalmological macular and ppRNFL changes as well as lower BCVA in adolescence. Similar morphology findings have been shown at younger ages, thus the fundus results persist into young adulthood.