A moderate decrease in intraocular pressure was demonstrated during both the second part of pregnancy and the first two months after delivery. Dynamic tonometry performed in 55 pregnant women revealed increased corneal indentation pulse (CIP) amplitudes in the first part of pregnancy. From the 20th week on, however, a steady decrease occurred until the CIP amplitudes at term measured about one third of the normal nonpregnant value. The CIP amplitudes were still below the normal average half a year after delivery.
Also, the form of the CIP amplitudes changed in pregnancy, as revealed by marked decreases in the relative crest time. This change of the pulse curve form was observed during the entire pregnancy and was so characteristic that dynamic tonometry might be introduced as a diagnostic test for pregnancy.
Hørven I, Gjønnaess H. Corneal Indentation Pulse and Intraocular Pressure in Pregnancy. Arch Ophthalmol. 1974;91(2):92-98. doi:10.1001/archopht.1974.03900060098002