Made available in DSpace on 2016-07-18T17:53:15Z (GMT). No. of bitstreams: 1 Claudia Lizandra Ricci.pdf: 291013 bytes, checksum: b9dccb042e091da74b7d28825ae3639d (MD5) Previous issue date: 2015-03-17 / The objective of this study was to measurement of the intraocular pressure (IOP) with Kowa HA-2 tonometer in cats analyzing the calibration, the accuracy and the validation of ambulatory clinical use. For calibration the post-mortem study was accomplished in 10 healthy eyes of 5 cats comparing the ocular manometry with the values of the IOP checked with the tonometer. For evaluation of the accuracy an in vivo study was accomplished in 20 healthy eyes of 10 anesthetized cats being compared the ocular manometry with the IOP obtained with the tonometer. For validation of the ambulatory clinical study of the IOP measurement was accomplished in 78 eyes of 39 healthy cats, in 7 eyes with clinical signs of glaucoma and in 20 eyes with clinical signs of uveitis. The correlation coefficient (r²) between the manometer and the tonometer was 0.993 and the equation of lineal regression was y=0.0915x+0.0878 in postmortem study. In the in vivo study the medium values of IOP in the manometry were 15.6±1.1 mmHg and in the tonometry were 15.5±1.2 mmHg, there was no statistics significant difference between the manometry and the tonometry. In the ambulatory clinical study with healthy cats the medium values of IOP with the tonometer were 15.0±1.5 mmHg, in the eyes with clinical signs of glaucoma were 38,4±8,1 mmHg and in the eyes with clinical signs of uveitis were of 10,4±2,0 mmHg. Therefore, there was a satisfactory correlation and accuracy between the IOP values obtained by direct ocular manometry and the tonometer in question. In the ambulatory clinical study the IOP values obtained with the tonometer were compatible for animals with healthy eyes and with clinical signs of glaucoma and uveitis. So, we can conclude that the Kowa HA-2 tonometer can be used in the routine ophthalmic examination, as it is a practical method for IOP measurement in cats. / O objetivo deste estudo foi mensurar a pressão intraocular (PIO) com o uso do tonômetro Kowa HA-2 em gatos, analisando a calibração, a acurácia e a validação do seu uso clínico ambulatorial. Para calibração foi realizado o estudo post-mortem em 10 olhos sadios de 5 gatos comparando a manometria ocular com os valores da PIO aferida com o tonômetro. Para avaliação de sua acurácia foi realizado um estudo in vivo em 20 olhos sadios de 10 gatos anestesiados comparando-se a manometria ocular com a PIO obtida com o tonômetro. Para validação do seu uso clínico ambulatorial foi realizado um estudo da mensuração da PIO em 78 olhos sadios de 39 gatos, em 7 olhos com sinais clínicos de glaucoma e em 20 olhos com sinais clínicos de uveíte. O coeficiente de correlação (r²) entre o manômetro e o tonômetro Kowa HA-2 foi de 0,993 e a equação de regressão linear foi y=0,0915x+0,0878 no estudo postmortem. No estudo in vivo, os valores médios de PIO na manometria foram de 15,6±1,1 mmHg e na tonometria foram de 15,5±1,2 mmHg não havendo diferença estatística significativa entre a manometria e a tonometria. No estudo ambulatorial com os gatos sadios, os valores médios de PIO com o tonômetro Kowa HA-2 foram 15,0±1,5 mmHg, nos olhos com sinais clínicos de glaucoma foram 38,4±8,1 mmHg e nos olhos com sinais clínicos de uveíte foram 10,4±2,0 mmHg. Houve, portanto, correlação e acurácia satisfatória entre os valores de PIO com a manometria e o tonômetro em questão. No estudo ambulatorial os valores de PIO obtidos com o tonômetro foram compatíveis para animais com olhos sadios e com sinais clínicos de glaucoma e uveíte. Desta maneira, podemos concluir que o tonômetro Kowa HA-2 pode ser empregado no exame oftálmico de rotina, pois trata-se de um método prático na aferição da PIO em gatos.

Background: Compare Goldmann applanation tonometer (GAT) prism and correcting applanation tonometry surface (CATS) prism to intracameral intraocular pressure (IOP), in vivo and in vitro. Methods: Pressure transducer intracameral IOP was measured on fifty-eight (58) eyes undergoing cataract surgery and the IOP was modulated manometrically to 10, 20, and 40 mmHg. Simultaneously, IOP was measured using a Perkins tonometer with a standard GAT prism and a CATS prism at each of the intracameral pressures. Statistical comparison was made between true intracameral pressures and the two prism measurements. Differences between the two prism measurements were correlated to central corneal thickness (CCT) and corneal resistance factor (CRF). Human cadaver eyes were used to assess measurement repeatability. Results: The CATS tonometer prism measured closer to true intracameral IOP than the GAT prism by 1.7+/-2.7 mmHg across all pressures and corneal properties. The difference in CATS and GAT measurements was greater in thin CCT corneas (2.7+/-1.9 mmHg) and low resistance (CRF) corneas (2.8+/-2.1 mmHg). The difference in prisms was negligible at high CCT and CRF values. No difference was seen in measurement repeatability between the two prisms. Conclusion: A CATS prism in Goldmann tonometer armatures significantly improve the accuracy of IOP measurement compared to true intracameral pressure across a physiologic range of IOP values. The CATS prism is significantly more accurate compared to the GAT prism in thin and less rigid corneas. The in vivo intracameral study validates mathematical models and clinical findings in IOP measurement between the GAT and CATS prisms.

Background: Goldmann applanation tonometry (GAT) error relative to intracameral intraocular pressure (IOP) has not been examined comparatively in both human cadaver eyes and in live human eyes. Futhermore, correlations to biomechanical corneal properties and positional changes have not been examined directly to intracameral IOP and GAT IOP. Methods: Intracameral IOP was measured via pressure transducer on fifty-eight (58) eyes undergoing cataract surgery and the IOP was modulated manometrically on each patient alternately to 10, 20, and 40 mmHg. IOP was measured using a Perkins tonometer in the supine position on 58 eyes and upright on a subset of 8 eyes. Twenty one (21) fresh human cadaver globes were Intracamerally IOP adjusted and measured via pressure transducer. Intracameral IOP ranged between 5 and 60 mmHg. IOP was measured in the upright position with a Goldmann Applanation Tonometer (GAT) and supine position with a Perkins tonometer. Central corneal thickness (CCT) was also measured. Results: The Goldmann-type tonometer error measured on live human eyes was 5.2 +/- 1.6 mmHg lower than intracameral IOP in the upright position and 7.9 +/- 2.3 mmHg lower in the supine position (p <.05). CCT also indicated a sloped correlation to error (correlation coeff. = 0.18). Cadaver eye IOP measurements were 3.1+/-2. 5 mmHg lower than intracameral IOP in the upright position and 5.4+/- 3.1 mmHg in the supine position (p <.05). Conclusion: Goldmann IOP measures significantly lower than true intracameral IOP by approximately 3 mmHg in vitro and 5 mmHg in vivo. The Goldmann IOP error is increased an additional 2.8 mmHg lower in the supine position. CCT appears to significantly affect the error by up to 4 mmHg over the sample size.