Investigation of correlation between corneal thickness and intraocular pressure in New Zealand Albino Rabbits

Abstract

The aim of this study was to determine intraocular pressure (IOP) and central corneal thickness (CCT) measurements in healthy rabbits to establish clinical reference values and to investigate the possible relationship between these measurements. The study included 40 eyes of 20 New Zealand albino rabbits, aged 1.5-2 years. All the eyes were healthy with no abnormalities, corneal disease, or evidence of glaucoma. An ultrasonographic pachymeter was used to measure CCT and TonoVet® was used to measure IOP. Correlations between IOP and CCT measurements were examined. The mean CCT was 388.2 ± 38.22 µm in the right eye and 391.8± 59.18 µm in the left eye. IOP was measured as 16 ± 3.76 mmHg in the right eye and 16 ± 2.73 mmHg in the left eye. No correlation was determined between the IOP and CCT, and this indicated that the TonoVet® readings of CCT and IOP did not cause a deviation that could be determined. There is a need for further studies of different animals to investigate the effect of corneal thickness on the IOP measurements made with TonoVet®.

Determination of intraocular pressure and Schirmer tear test and the comparison between the applanation tonometer (Tono‐Pen AVIA®) and the rebound tonometer (TonoVet Plus®) in mini lionhead rabbits

“…The average IOP obtained for Mini Lionhead rabbits was 11.5 mmHg with the Tono‐Pen Avia® and 17.7 mmHg with the TonoVet Plus®. The value observed with the rebound tonometer was similar to that found in healthy New Zealand rabbits (approximately 16 mmHg) with the TonoVet® tonometer 36 . However, the IOP values in Mini Lionhead were lower than those observed in Dutch Belted rabbits with rebound (21.90 ± 2.00 mmHg) and applanation (21.60 ± 2.00 mmHg) tonometers 34 .…”

“…In this case, factors such as the thickness and biomechanical properties of the cornea may be involved, as described before in several species 25,40 . However, the thickness of the central cornea effect on the IOP values measured with the TonoVet® (rebound) was not observed in rabbits, 36 indicating that further studies related to the effect of corneal thickness on IOP values measured with the different models of tonometers are required.…”