Normal Intraocular Pressure of Neonates Measured with Tono-pen

ABSTRACT

PURPOSE: It is difficult to estimate definite intraocular pressure of neonates. We intended to evaluate neonatal normal intraocular pressure using Tono-pen, and compared mean intraocular pressures between groups divided by sex, birth weight, and gestational age. METHOD: We measured the intraocular pressure with Tono-pen in 504 eyes of 252 newborn, who admitted in our hospital from June 2000 to January 2001 at their the second day of life. One observer measured the intraocular pressure with Tono-pen five to ten times after proparacain HCL 0.5% instillation on regular time. Only 5% of Tono-pen's coefficient of variance was considered valuable. Neonates suspected having congenital glaucoma or retinopathy were excluded. Conclusively, 462 eyes of 231 newborns were included. Mean gestational age was 38 weeks and 6 days. Mean birth weight was 3.23 kg. We achieved average intraocular pressures of neonates having gestational age between 38 weeks and 42 weeks, and birth weight between 3.0 kg and 3.5 kg. We achieved also average intraocular pressure of neonates divided by sex, gestational age, and birth weight, compared them with average intraocular pressure of normal neonates by 3-way ANOVA. RESULT: Average of intraocular pressure of normal neonates was 13.61+/-2.02 mmHg. Intraocular pressure of normal neonates is not statistically significant in the classification by sex, gestational age, and birth weight.(p-value>0.05) CONCLUSION: These value will aid the ophthalmologists in the diagnosis and screening of congenital glaucoma.