Two-and-a-half percent phenylephrine eye drops were used in combination with 0.5% tropicamide for routine pupillary dilation in 10 low weight infants. Significant systolic blood pressure elevation was noted in eight of 10 infants. A matched control group dilated with cycloplegics alone did not show a significant rise in systolic blood pressure. The mean change in pupillary dilation in the study group was 3.9 mm compared with 3.1 mm in the control group. This difference is not statistically significant. We therefore recommend that cycloplegic agents alone be used for pupillary dilation in these high risk infants.