Twenty‐four‐hour measurement of IOP in rabbits using rebound tonometer

Abstract

To observe the Intraocular pressure (IOP) measurements over a 24-h period in New Zealand white rabbits. Thirty-four normal New Zealand white rabbits (68 eyes) were included in this study. The IOP values were determined with a rebound tonometer (RBT, Icare VET). Measurements were always obtained in the right eye first. The data showed that there was no significant difference in IOP between measurements, which indicated that the RBT showed good repeatability in this study (P = 0.920). There was no statistically significant difference between genders (P = 0.943). The IOP in right eyes was a little higher than left eyes (F = 45.96, P < 0.001). Comparison of the true IOP and RBT results over the entire pressure range (8-100 mmHg) revealed a statistically significant difference between them (P < 0.001). The mean difference between the RBT and true IOP (RBT-True IOP) was -22.65 ± 9.52 mmHg with 95% confidence interval (-27.1, -18.2 mmHg). In the light period (7 AM to 7 PM), the IOP was a little lower than during the dark period (8 PM to 6 AM); 9 AM and 2 PM were the lowest measurements (10 mmHg, 9.625 mmHg), and 10 AM (14.125 mmHg)was the highest measurement during the 24-h period. The IOP obtained by RBT underestimated the true IOP but the RBT had a good repeatability in IOP measurements. In the light period (7 AM to 7 PM), the IOP was a little lower than during the dark period (8 PM to 6 AM), which may be beneficial to the intervention therapy observation of glaucoma research in rabbits.