Blood rheology and retinopathy in premature infants with very low birth weight

Impaired retinal blood flow may be involved in the development of retinopathy of prematurity (ROP). We investigated hemorheological parameters in 44 premature infants (birth weight 610 to 2010 g, gestational age 25 to 34 weeks) at a postnatal age of 6 weeks. 25 infants showed no evidence of ROP and 7 developed ROP stage I (group' A: no-or-mild ROP, n = 32). Five infants developed ROP stage II and 7 ROP stage III (group B: moderate to severe ROP, n = 12). Plasma viscosity increased with increasing ROP severity and was significantly higher in group B than in group A (1.19 ± 0.06 vs. 1.00 ± 0.02 mPas; p = 0.0005, mean ± SEM). Plasma IgM was higher in group B patients (0.58 ± 0.08 vs. 0.47 ± 0.03 gil; p = 0.016) and RBC aggregation index was slightly increased in group B when compared to group A (6.33 ± 1.17 vs. 5.40 ± 0.49; P = 0.055). These data suggest that elevated plasma viscosity and RBC aggregation may be involved in the development of ROP.