Electronic tonometry in the newborn.

Mackay-Marg electronic tonometry was performed without any kind of drugs in 604 eyes of newborn babies (up to 4 days of age). The first 100 cases were eliminated from the sample due to the significantly higher intraocular pressures obtained, attributed to small number of tonometries in each eye. The decision is fully discussed. The remaining cases (504 eyes) gave a mean of 12.41 mm Hg and a standard deviation of 2.58. The most important finding was the extreme and continuous variations found in newborn intraocular pressure; some hypotheses are discussed in this regard. The concept of 'basal intraocular pressure' is introduced to use the lowest intraocular pressure as a more homogenous comparative level than the ones previously used. Standardized anesthetic procedure is recommended for baby tonometry. While the possibilities of the Mackay-Marg electronic tonometer are recognized, the Goldmann tonometer (manual model) is found to be more reliable for clinical decisons in babies.