Variation of intraocular pressure comparing rebound (TONOVET Plus®) and applanation (TONO-PEN VET®) tonometry in New Zealand rabbits treated with Amlodipine®

Rabbits have played an important role in ophthalmological research processes, however in the environment there has been a deficiency of sensitive equipment in measurement of intraocular pressure for this species. To compare intraocular pressure (IOP) measured with rebound (TONOVET Plus®) and applanation (TONO-PEN VET®) tonometry in healthy New Zealand rabbits treated with Amlodipine. Twelve healthy male New Zealand white rabbits, 5 months old; two groups with 6 individuals were used in this study. The experimental group was given Amlodipine® at a dose of 5 mg/kg, once a day for a month. Blood pressure and intraocular pressure were measurement before treatment and 6 h after treatment in a period of one month. A trend is noted where the group of animals treated with amlodipine® presents lower values than the control group, both in systolic and diastolic pressure. The systolic pressure of the control group showed an average of 116.5 ± 7.9 mmHg and 117.4 ± 8.9 mmHg and the treatment group showed an average of 113.6 ± 7.9 mmHg and 111.8 ± 10.0 mmHg (pretreatment and posttreatment respectively). Tonometry: the values obtained using the TONOVET Plus® (19 ± 3 mmHg) are on average higher than the values obtained using the TONO-PEN VET® (17 ± 3 mmHg). It was possible to demonstrate the relationship between systemic blood pressure and intraocular pressure in New Zealand white rabbits. Rebound tonometry showed less variability in results than applanation tonometry. This study confirmed that both tonometers are reliable for measuring IOP in rabbits.