To Örebro University

Purpose: The majority of all preterm birth are moderate-to-late preterm (MLP) birth, defined as birth at 32–36 weeks of gestation. These individuals have an elevated morbidity risk compared with full-term individuals; however, little is known of the ocular development. The purpose of the present study was to evaluate ocular dimensions in relation to growth and metabolic factors in MLP adolescents.

Methods: In this prospective cohort study, 50 MLP adolescents participated (26 girls; mean gestational age 35.0 weeks; mean age 16.5 years). When recruited at birth, the exclusion criteria were chromosomal abnormalities, severe malformations, syndromes, or being born to mothers with chronic diseases. A control group consisted of 50 adolescents born full-term (30 girls; 40.3 weeks; 16.7 years). Total axial length (TAL), palpebral fissure length (PFL), and intercanthal distance (ICD) were measured. The TAL was evaluated using optical biometry (IOL Master). The PFL and ICD were measured using a ruler. Head circumference, length, weight, body mass index, and serum levels of insulin-like growth factor I and insulin-like growth factor binding protein 3 were evaluated. Serum levels of the metabolic factors leptin and adiponectin were measured. The MLP and control group were compared regarding all variables using Mann Whitney U-test. Ocular dimensions were analyzed to find any possible association with growth and metabolic factors using Spearman rank correlation.

Results: The MLP group had shorter TAL and PFL, and wider ICD compared with controls, shown in Table 1. There was no significant difference regarding growth, leptin, or adiponectin. Within the MLP group, TAL correlated with length (right eye (RE) r=0.46, p<0.001; left eye (LE) r=0.48, p<0.001), head circumference (RE r=0.46, p<0.001; LE r=0.44, p=0.001), and weight (RE r=0.53, p<0.001; LE r=0.51, p<0.001). The PFL correlated with length (RE r=0.53, p<0.001; LE r=0.58, p<0.001), and leptin (RE r=-0.43, p=0.004; LE r=-0.46, p=0.002). No other significant correlation was found.

Conclusions: In the present study, being born MLP were shown to impact ocular growth including TAL, PFL, and ICD. Furthermore, these variables were found to be associated with leptin levels and general growth.