Evaluation of a rebound tonometer for measuring intraocular pressure in dogs and horses.

The research article discusses a study examining the accuracy of a rebound tonometer in measuring intraocular pressure (IOP) in dogs and horses, compared with measurements taken using applanation tonometry and direct manometry.

Research Methodology

• The study was conducted on 100 dogs and 35 horses with clinically normal eyes.
• In addition, 10 enucleated (surgically removed) eyes from 5 dogs, and 6 enucleated eyes from 3 horses were used in the experiment.
• In the enucleated eyes, IOP was sequentially increased from 5 to 80 mm Hg using direct manometry, and subsequent measurements were taken with the rebound tonometer.
• In the dogs and horses, the tonometry results from the rebound tonometer were compared with those of applanation tonometry.

Research Findings

• The results showed a high correlation (r² = 0.99) between the pressures obtained by direct manometry and those obtained by the rebound tonometer in the enucleated eyes of both dogs and horses.
• The average IOPs obtained with the rebound tonometer were 10.8 ± 3.1 mm Hg (range, 5 to 17 mm Hg) for the dogs and 22.1 ± 5.9 mm Hg (range, 10 to 34 mm Hg) for the horses.
• IOPs measured with the applanation tonometer averaged 12.9 ± 2.7 mm Hg (range, 8 to 18 mm Hg) for dogs and 21.0 ± 5.9 mm Hg (range, 9 to 33 mm Hg) for horses.
• The rebound tonometer measurements were, on average, 2 mm Hg lower in the dogs and 1 mm Hg higher in the horses than the measurements obtained via applanation tonometer.

Conclusions

• The research concludes that the rebound tonometer is an accurate tool for estimating IOP in clinically normal dogs and horses.
• Although slight differences were identified when compared to applanation tonometry, there was a high degree of correlation between pressures obtained by direct manometry and those by the rebound tonometer, suggesting its validity as a reliable tool in measuring IOP.