Orientador: Vital Paulino Costa / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-17T05:07:13Z (GMT). No. of bitstreams: 1 Lupinacci_AlvaroPedrosodeCarvalho_D.pdf: 8725508 bytes, checksum: 4f3d11456e7491230be37c721f4fe7a4 (MD5) Previous issue date: 2010 / Resumo: O presente estudo teve como objetivo medir a espessura corneana central (ECC) de indivíduos com catarata congênita e afacia cirúrgica após extração de catarata congênita. Indivíduos com catarata congênita ou afacia cirúrgica após cirurgia de catarata congênita foram recrutados prospectivamente e divididos em quatro grupos: catarata unilateral (n=14), catarata bilateral (n=18), afacia unilateral (n=32) e afacia bilateral (n=44). Um grupo controle foi selecionado a partir de indivíduos normais pareados por idade, gênero e etnia. Paquimetria ultrassônica foi realizada pelo mesmo observador com o aparelho Micropach 200P+ (Sonomed, Lake Success, Nova Iorque, EUA), após anestesia tópica com uma gota de oxibuprocaína 0,4%. Registrou-se a média de cinco medidas para cada olho. A ECC média do grupo controle (513,57±23,32µm) não foi significativamente diferente da média dos olhos contralaterais normais (526,36±38,52µm) (p=0,747) e dos olhos com catarata (527,00±36,03µm) (p=0,252) do grupo catarata unilateral. A ECC média de ambos os olhos do grupo catarata bilateral (olho direito: 547,69±34,17µm; olho esquerdo: 545,88±36,69µm) foi maior que a observada no grupo controle (olho direito: 516,06±18,66µm; olho esquerdo: 515,53±17,43µm) (p<0,01). A média da ECC dos olhos afácicos (597,25±44,14µm) no grupo afacia unilateral foi significativamente maior que as observadas nos olhos contralaterais saudáveis (523,47±21,42µm) e no grupo controle (511,81±18,81µm) (p<0,001). Ambos os olhos do grupo afacia bilateral apresentaram ECC média (olho direito: 615,75±61,03µm; olho esquerdo: 618,91±61,86µm) significativamente maior que no grupo controle (olho direito: 515,59±18,80µm; olho esquerdo: 515,86±18,51µm) (p<0,001). Observou-se ECC média significativamente maior nos olhos afácicos (uni e bilaterais) que nos olhos com catarata (uni e bilaterais) (p<0,001). Olhos afácicos após extração de catarata congênita apresentam córneas mais espessas que olhos fácicos normais. Olhos afácicos após cirurgia de catarata congênita também apresentam córneas mais espessas que olhos com catarata congênita, sugerindo que o aumento da espessura corneana central ocorra após a cirurgia / Abstract: This study aimed to measure the central corneal thickness (CCT) of patients with congenital cataract and surgical aphakia post congenital cataract extraction. Individuals with congenital cataract or aphakia after surgery for congenital cataract were recruited prospectively and divided into four groups: unilateral cataract (n=14), bilateral cataracts (n=18), unilateral aphakia (n=32) and bilateral aphakia (n=44). A control group was selected from healthy individuals matched for age, gender and ethnicity. Ultrasonic pachymetry was performed by the same observer with the Micropach 200P+ pachymeter (Sonomed, Lake Success, New York, USA) after topical anesthesia with a drop of oxybuprocaine 0.4%. The average of five measurements for each eye was recorded for the analysis. The mean CCT of the control group (513.57±23.32µm) was not significantly different from the contralateral normal eyes (526.36±38.52µm) (p=0.747) and eyes with cataract (527.00±36.03µm) (p=0.252) of the unilateral cataract group. The mean CCTs of both eyes in the bilateral cataract group (right eye: 547.69±34.17µm; left eye: 545.88 ± 36.69µm) were significantly thicker than the observed in the control group (right eye: 516.06±18.66µm; left eye: 515.53±17.43µm) (p<0.01). The mean CCT of aphakic eyes (597.25±44.14µm) in the unilateral aphakia group was significantly thicker than those observed in healthy contralateral eyes (523.47±21.42µm) and the control group (511.81±18.81µm) (p<0.001). Both eyes of the bilateral aphakia group had mean CCT (right eye: 615.75±61.03µm; left eye: 618.91±61.86µm) significantly thicker than the control group (right eye: 515.59±18.80µm; left eye: 515.86±18.51µm) (p<0.001). The mean CCT was significantly thicker in aphakic eyes (unilateral and bilateral) than in eyes with cataract (unilateral and bilateral) (p<0.001). Aphakic eyes after congenital cataract extraction have thicker corneas than normal phakic eyes and eyes with congenital cataract. This suggests that increased central corneal thickness occurs after congenital cataract extraction surgery / Doutorado / Oftalmologia / Doutor em Ciências Médicas

Hemodiluição normovolêmica aguda é um procedimento utilizado para diminuir a necessidade de transfusões sangüíneas em diversas cirurgias de grande porte. Poucos trabalhos avaliam as alterações hemodinâmicas e perfusão tecidual através de estudo ecocardiográfico e tonometria gástrica. Foram utilizados 23 porcos (peso 46.6 ± 6.0 kg) anestesiados com quetamina, fentanil e propofol e instrumentados para monitorização hemodinâmica convencional. Os animais foram randomizados em três grupos 30 minutos após estabilização da anestesia: Grupo I (Controle), Grupo II (amido hidroxietílico) e Grupo III (Ringer lactato). Os animais do grupo II e III foram submetidos ao protocolo de hemodiluição com hematócrito alvo de 15%. A retirada de sangue foi realizada em 30 minutos e a expansão plasmática feita simultaneamente com amido hidroxietílico ou Ringer lactato nas proporções de 1:1 ou 1:3 em relação ao sangue retirado. Os parâmetros hemodinâmicos e de oxigenação, pH gástrico, ecocardiografia transesofágica (fração de ejeção através do método Simpson) foram coletados antes da hemodiluição (T0), no fim do procedimento de hemodiluição (T1) e após uma e duas horas (T2, T3). Os dados foram submetidos a análise de variância para medidas repetidas, seguida pelo teste Tukey e teste T student. Resultados: Em relação aos parâmetros do grupo controle, não houve diferença significante durante todo o procedimento. No grupo II e grupo III, houve aumento no índice cardíaco após hemodiluição (T0=5,80±1,46; T1=10,64±1,69 L.min-1.m2 e T0=5,53±1,18, T1=7,91±1,40 L.min-1.m2 respectivamente), e diminuição do índice de resistência vascular sistêmica (T0=1753±336, T1=822±140 dina.s.cm-5.m-2 e T0=1673±566, T1=1026±190 dina.s.cm-5.m-2 respectivamente), ambos estatisticamente significante. A fração de ejeção apresentou aumento significativo após a hemodiluição no grupo II. O pH gástrico diminuiu significativamente no grupo III. O lactato arterial aumentou de forma significante no grupo III após a hemodiluição. A microscopia eletrônica do ventrículo esquerdo mostraram discreta destruição de miofilamentos no grupo II. Houve destruição importante nas miofibrilas no grupo III. Conclusão: Estes resultados sugerem que na hemodiluição moderada a grave, o amido hidroxietílico consegue preservar melhor a estabilidade hemodinâmica do que a solução de Ringer lactato. / Normovolemic acute hemodilution is a procedure utilized to decrease the needs of blood transfusion during a variety of surgical procedures. Nevertheless, there are few works that evaluate its pulmonary effects as well as hemodynamic changes by means of echocardiography and tonometric evaluation. Methods: 23 anesthetized pigs (weight 46.6 ± 6.0 kg) were instrumented for standard hemodynamic monitoring. In order to prevent possible effects of inhaled anesthetics on pulmonary mechanics, intravenous anesthesia was chosen and consisted of ketamine, fentanyl and propofol administered throughout the study. Thirty minutes after anesthesia stabilization animals were randomized in three groups: Group I (Control), Group II (hydroxyethyl starch) and Group III (Lactated Ringer’s). Animals of group II and III were submitted to acute normovolemic hemodilution to reach a pre-established hematocrit around 15%. Blood withdrawal was accomplished in thirty minutes and plasma expansion was performed simultaneously with hydroxyethyl starch or Lactated Ringer’s administered in a proportion of 1:1 or 3:1 in relation to the amount of bloods withdrawn. Hemodynamic, gastric pH, transesophageal echography (ejection fraction, by Simpon method) and oxygen transport were measured before blood withdrawal (T0), at the end of hemodilution (T1), one and two hours after the end of hemodilution (T2, T3). Data were submitted to analysis of Variance for repeated measures followed by the Tukey test and also to a student T test. Results: In regard to all parameters of Group I (Control), there were no significant difference during the whole procedure. In Group II and Group III, there was an increase in cardiac index after hemodilution (T0=5.80±1.46; T1=10.64±1.69 L.min-1.m2 and T0=5.53±1.18, T1=7.91±1.40 L.min-1.m2), and a decrease in systemic vascular resistance index (T0=1753±336, T1=822±140 dyne.s.cm-5.m-2 and T0=1673±566, T1=1026±190 dyne.s.cm-5.m-2), both statistically significant. Ejection Fraction increased significantly after hemodilution in group II. Gastric pH decreased significantly in Group III, and arterial lactate increased significantly after hemodilution in group III. Electron microscopy of left ventricular bipsies showed a slight destruction in filament and preserved myofibrillar ultrastructure in group II. There was important destruction in myofibrillar ultrastructure in group III. Conclusion: These results suggest that in severe hemodilution, hydroxyethyl starch preserves hemonodynamic stability better than Lactate Ringer’s.

It is widely known that Central Corneal Thickness (CCT) and Radius of Curvature (RoC) in uence the estimated IntraOcular Pressure (IOP) obtained from Goldmann Applanation Tonometry (GAT). However, not much is known about the in uence of corneal material properties, especially in a clinical setting. Several numerical studies have been conducted in an attempt to quantify the in uence of corneal material properties on the IOP. These studies agree that corneal material properties do in uence the estimated IOP, which contradict the initial premise on which GAT was designed, namely that material properties do not in uence the obtained GAT readings. Also, there is no consensus among these studies with respect to corneal material properties, thus a wide range of proposed properties exist. A possible explanation for this range of available corneal properties is the numerical modi elling assumptions used, which seem to be quite different. Different sets of experimental in ation test data were used to calibrate the constitutive models and different limbal boundary conditions were applied to simulate the experimental setup as well as in vivo conditions during GAT simulations. Therefore the purpose of this study is to determine whether these modelling assumptions in uence the obtained IOP and ultimately the overall conclusions. A Finite Element (FE) model of the human cornea is developed, implementing a constitutive model to represent the complex corneal structure and two limbal boundary conditions. This model is then calibrated using two different sets of experimental in ation test data. During calibration of the fibre reinforced elastic constitutive model it is found that independent of the assumptions made regarding the material coe cients, that the numerical in ation data compare well with the experimental data for all cases. Using this model a GAT simulation is conducted to estimate the IOP and the in uence of the modelling assumptions, cornea geometry and material properties are then investigated. The results indicate that the modelling assumptions, cornea geometry and material properties do infuence the estimated IOP. However, when assuming the cornea ground substance stiffness to be constant, it is found that the in uence on IOP due to material properties is not as significant. A correction equation is also proposed to account for the corneal geometric properties by calibrating the numerical model for a numerically normal cornea. This is done by utilising the various data sets which are obtained during the calibration of the constitutive model with the experimental inflation test data. It is concluded that using only inflation data to calibrate the constitutive model is not sufficient to uniquely describe the corneal material. This is evident as different material data sets are obtained, even though the experimental inflation data is matched well for a variety of considered cases. Each of these material data sets, in conjunction with geometric properties, yield different estimates for IOP during GAT simulations. This study therefore recommends the use of additional experimental data, such as strip extensometry, along with inflation test data to adequately calibrate a numerical model. It should also be noted that when modelling GAT care should be taken when considering the choice of limbal boundary condition, experimental data for calibration and assumptions made with regards to material coe cients, as these choices could potentially influence the outcomes and conclusions of a study. / Dissertation (MEng)--University of Pretoria, 2014. / gm2014 / Mechanical and Aeronautical Engineering / unrestricted

A tonometria é de extrema importância durante o exame oftálmico, pois auxilia no diagnóstico e no acompanhamento do glaucoma e de inflamações intraoculares. No entanto, os valores da pressão intraocular podem sofrer influência do momento do dia em que o exame é realizado. Objetivou-se avaliar a pressão intraocular (PIO) com tonômetro de rebote em equinos hígidos da raça Crioula em diferentes horários do dia. Foram avaliados ambos os olhos de 25 cavalos da raça Crioula, machos ou fêmeas, subdivididos em três categorias de diferentes idades designadas por GI: nove animais (3-5 anos de idade), GII: oito animais (6-8 anos de idade) e GIII: oito animais (9-16 anos de idade). Previamente à tonometria foram realizados teste lacrimal de Schirmer, biomicroscopia com lâmpada de fenda, prova da fluoresceína e oftalmoscopia indireta em todos os equinos. Num mesmo dia foram realizadas sete aferições da PIO (às 6, 9, 12, 15, 18, 21 e 24 horas). A avaliação estatística utilizou o teste T de Student quando haviam dois grupos de comparações, e o teste de análise de variância (ANOVA) para as variáveis PIO, horário de aferição (tempo) e categoria de idade. O valor médio da pressão intraocular obtido foi de 28,4±3,7 mmHg considerando todos os animais avaliados. Os valores médios da pressão intraocular para os equinos de GI, GII e GIII foram 29,2±3,5 mmHg, 28,4±4,3 mmHg e 27,7±3,2 mmHg, respectivamente. Não houve diferença estatisticamente significativa entre os olhos direito e esquerdo (p= 0,257), nem entre sexos (p= 0,284). Quando comparadas as idades, a PIO média foi significativamente maior nos indivíduos jovens (p= 0,012). Não houve diferença estatisticamente significativa entre os diferentes horários do dia (p= 0,560). Os valores da PIO aferidos com o tonômetro de rebote em equinos da raça Crioula sofreram influência da idade. Os valores da pressão intraocular média obtidos com tonômetro de rebote em equinos hígidos não variaram em diferentes horários ao longo do dia. / The tonometry is extremely important during ophthalmic examination, because assists in the diagnosis and follow-up of glaucoma and intraocular inflammation. However, intraocular pressure values may be influenced by the moment of the day it is measured. The objective was to evaluate the intraocular pressure (IOP) with Rebound Tonometer in healthy horses of the Crioula breed at different times of the day. Twenty five horses, male or female, were divided into three groups by age: Group I: nine horses (3-5 years old), Group II: eight horses (6-8 years old), and Group III: eight horses (9-16 years old). Ophthalmic examination was performed previously by Schirmer Tear Test, slit lamp biomicroscopy, fluorescein test and indirect ophthalmoscopy in all horses. Seven measurements of intraocular pressure were assessed on the same day (at 6, 9, 12, 15, 18, 21 and 24 hours).The Student’s T Test statistical analysis was used when there was two groups of comparisons, and the Analysis of Variance (ANOVA) was used for variables IOP, measurement time and age category. The average value of intraocular pressure was 28.4 ± 3.7 mmHg considering all the animals evaluated. The mean intraocular pressure for groups I, II and III were 29.2 ± 3.5 mmHg, 28.4 ± 4.3 mmHg and 27.7 ± 3.2 mmHg, respectively. There was no statistically significant difference between right and left eyes (p = 0.257), nor between genders (p = 0.284). When compared to the ages, the average IOP was significantly higher in young animals (p = 0.012). There was no statistically significant result between the different times of the day (p = 0.560). The IOP values measured with rebound tonometer in Crioula horses were influenced by age. The average intraocular pressure values obtained with rebound tonometer in healthy horses did not change with time of day.

The thesis investigates methods of examining corneal biomechanics using non-contact tonometry and introduces novel techniques to investigate corneal material properties in vivo. A comprehensive systems analysis of the CorvisST (CST) and Ocular Response Analyser (ORA) was performed. Pressure sensors were used to characterisation the airflow produced by the CST and the ORA. Distinct differences were observed between the central airflow pressures between the two devices: the CST pressure was higher and of shorter duration. Scheimpflug high-speed imaging via the CST allowed components of the corneal deformation to be investigated and the development of a 3D deformation matrix (time, depth and spatial resolution) through tracing of the anterior and posterior corneal surface. Measures of whole eye movement (WEM) with CST were found to be robust. WEM demonstrated an asymmetric profile and a correction method was developed to address the corneal deformation matrix for this asymmetry. Novel methods for characterisation of intrinsic material characteristics of the cornea were developed using numerical and graphical analytical procedures. Application of these parameters was tested on enucleated porcine eyes across a wide range of manometry internal ocular pressure (MIOP). The dynamic E-Modulus was found to be most affected by MIOP change. To investigate the in vivo distribution and heterogeneity of the corneal biomechanics, a novel set-up allowed the mapping of corneal biomechanics across the cornea using the CST (central, paracentral, peripheral) and ORA (central, peripheral). Biometric and demographic grouping of subjects allowed detection of discriminating factors between individuals. The results suggest that the in vivo cornea of healthy human adults can be characterised as a viscoelastic, damped system for longitudinal strain and a highly oscillating system for lateral strain. The cornea is approximately homogenous for measures of rigidity and dynamic E-Modulus but other corneal material characteristics (longitudinal and lateral strain, hysteresis, damping and compressibility) demonstrated regional differences. The experimental design employed allowed for strict control of biometric and biomechanical intersubject variables, based on gold-standard techniques as well as newly-developed methods, thereby creating a normative database for future use.

Master of Science / Department of Clinical Sciences / Amy J. Rankin / Objective – To measure blood aqueous-barrier breakdown following aqueocentesis using various needle sizes and to monitor the intraocular pressure (IOP) response. Animals – 24 healthy, adult dogs received treatment (24 treated eyes, 24 contralateral eyes); 3 dogs were untreated controls (6 control eyes). Procedures – Dogs receiving treatment were divided into 3 equal groups (25-, 27-, or 30- gauge needle aqueocentesis). In each dog the treated eye was determined randomly, the contralateral eye was untreated. Dogs that did not have aqueocentesis performed in either eye were used as controls. Aqueocentesis at the lateral limbus was performed under sedation and topical anesthesia. Anterior chamber fluorophotometry was performed before and after aqueocentesis on day 1. On days 2-5 sedation and fluorophotometry were repeated. Intraocular pressure was measured with a rebound tonometer at multiple time points. Results – Aqueocentesis resulted in blood-aqueous barrier breakdown in all treated eyes with barrier reestablishment present by day 5 detected by fluorophotometry. On day 2 the contralateral untreated eyes of all groups also showed statistically significant increased fluorescence (P < 0.05) following treatment of the opposite eye, but these values were not statistically significantly greater than untreated controls. In treated eyes there was no statistical difference in fluorescein concentration or IOP between 27- and 30-gauge needles. Use of the 25- gauge needle resulted in a statistically significant increase in anterior chamber fluorescence on days 3 and 5. It also caused a statistically significant increase in IOP 20 minutes following aqueocentesis as compared to the 27- and 30-gauge needles. Aside from this transient ocular hypertension, rapid resolution of ocular hypotony following aqueocentesis was observed in all treatment groups. Conclusions and Clinical Relevance – Aqueocentesis using a 25-gauge needle resulted in a greater degree of blood-aqueous barrier breakdown and a brief state of intraocular hypertension following paracentesis. Use of a 27- or 30-gauge needle is recommended for aqueous paracentesis. A consensual ocular reaction appeared to occur in dogs following unilateral traumatic blood-aqueous barrier breakdown and may be of clinical significance. Statistical significance was limited in this study due to high variability and large standard deviations.

Student Number :9900127Y - MSc (Eng) dissertation - Faculty of Engineering and the Built Environment / Arterial pulse wave analysis studies the wave shape of the blood pressure pulse. The pulse wave provides more information than the extreme systolic and dia- stolic pressures, measured with a cuff sphygmomanometer. The aim of the research is to investigate the design issues in a pulse wave analysis system, and to compare these to a commercially available system. The system was compared and validated by measuring the pulse wave at the radial artery (wrist) using the non-invasive technique of arterial tonometry. The design conformed to the IEC-601 safety standard to ensure patient safety. The data was compared against the data from the commercial system and analysis was performed in the time and frequency domain. The performance of the design suggests that, in some respects, the design was comparable to the commer- cial system, however, a number of performance characteristics fell short of the commercial system. Suggestions have been made to address these problems in further research.

A aferição da pressão intraocular (PIO) é essencial para o exame oftálmico. Objetivou-se estabelecer os valores da curva diária da PIO de porquinhos da índia de diferentes faixas etárias com tonômetro de rebote. A PIO foi aferida às 6, 12, 18 e 24 horas utilizando o tonômetro de rebote (Tonovet®). Os porquinhos da índia foram subdivididos em dois grupos com 10 animais no grupo I e 4 animais no grupo II, considerando as idades, designados por GI (animais entre 2 a 3 meses de idade) e GII (animais entre 2 a 3 anos de idade). Previamente, foram realizados teste da lágrima de Schirmer, prova da fluoresceína, biomicroscopia com lâmpada de fenda e oftalmoscopia indireta em todos animais. O valor médio da pressão intraocular foi de 12,0 ± 1,83 mmHg. Foram encontradas diferenças significativas entres as idades, sendo que os valores médios para o grupo I foram 11,63 ± 0,29 mmHg, e para o grupo II foram 12,82 ± 0,45mmHg (P= 0,0295). Não foram encontradas diferenças entre ambos os olhos (P= 0,7454). Não foram encontradas diferenças significativas nos valores da PIO relacionadas ao sexo (P= 0,1858). Os valores da PIO em porquinhos da índia tiveram alteração nas horas avaliadas. Com base nos resultados obtidos foi possível concluir que os valores da PIO em porquinhos da índia da sofrem alterações ao longo do dia. Os menores valores de pressão intraocular ocorreram às 18 horas. / The measuring of intraocular pressure (IOP) it is essential for the ophthalmic evaluation; the aim of this study was establish the values of the IOP diurnal curve of guinea pigs with different ages using the rebound tonometer (Tonovet®). The animals were divided according to the age in two groups, Group I (GI) constituted with 10 guinea pigs aged between 2 -3 moths, and Group II (GII), 4 animals with 2 -3 years of old. Previously the Schirmer tear test, fluorescein test, biomicroscopy with slit lamp, and direct optalmoscopy were performed on all animals. The men value of IOP was 12.0±0.34 mmHg. Statistical difference were found between ages (mean GI 11.64 ± 0.29 mmHg, and GII 12.83 ± 0.45mmHg), did not have statistical difference related with gender (P= 0.1858) or between eyes (P= 0.7454). In conclusion the guinea pigs had alteration of IOP true the day, the values of IOP are higher in the morning period, decrease true the day and at the night period haves an elevation again.

Background and aims: Unrecognized intestinal mucosal ischemia in severely ill patients may trigger development of multiple organ failure. Such ischemia can be evaluated by intraluminal tonometry reflecting mucosal PCO2 and intramucosal pH (pHi). The aims were to develop an apparatus for continuous saline tonometry (CST), to analyse circulatory control mechanisms during intestinal hypoperfusion and to evaluate the effect of dopexamine on intestinal circulation. Methods: A modified standard tonometry catheter was integrated in a closed system with circulating saline. By measuring saline PCO2 in a measurement unit pHi could be calculated. This novel system was tested in vitro and in vivo. In a porcine study, CST was evaluated against standard saline tonometry, tissue oxygenation (PO2 TISSUE), jejunal mucosal perfusion (laser doppler flowmetry; LDF) and mesenteric net lactate flux during graded reductions of superior mesenteric arterial pressure (PSMA). Local control mechanisms for maintenance of intestinal oxygenation were analysed. Effects of dopexamine on the intestinal vascular bed were explored. Mucosal lactate production was assessed by microdialysis. Results: CST measured accurate PCO2 values and changes in pHi during restricted intestinal circulation and at reperfusion. Local control mechanisms were insufficient at a PSMA of 30 mmHg, pHi was reduced to 7.10 and intestinal net lactate production was demonstrated. Absence of anaerobic intestinal metabolism was verified at PSMA ≥ 50 mmHg, pHi ≥ 7.22 and a PCO2 gap ≤ 15.8 mmHg. Dopexamine induced negative regional metabolic effects at the lowest PSMA, as expressed by decreased PO2 TISSUE and pHi, increased PCO2 gap and intestinal net lactate production. Conclusions: CST reflected changes in pHi, induced by intestinal hypoperfusion and at reperfusion. Levels of PSMA, pHi and PCO2 gap as indicators of aerobic conditions were defined. Dopexamine induced a decrease of PO2 TISSUE and pHi as well as an increase in lactate flux at the lowest PSMA level.

A aferição da pressão intraocular (PIO) é essencial para o exame oftálmico. Objetivou-se estabelecer os valores da curva diária da PIO de porquinhos da índia de diferentes faixas etárias com tonômetro de rebote. A PIO foi aferida às 6, 12, 18 e 24 horas utilizando o tonômetro de rebote (Tonovet®). Os porquinhos da índia foram subdivididos em dois grupos com 10 animais no grupo I e 4 animais no grupo II, considerando as idades, designados por GI (animais entre 2 a 3 meses de idade) e GII (animais entre 2 a 3 anos de idade). Previamente, foram realizados teste da lágrima de Schirmer, prova da fluoresceína, biomicroscopia com lâmpada de fenda e oftalmoscopia indireta em todos animais. O valor médio da pressão intraocular foi de 12,0 ± 1,83 mmHg. Foram encontradas diferenças significativas entres as idades, sendo que os valores médios para o grupo I foram 11,63 ± 0,29 mmHg, e para o grupo II foram 12,82 ± 0,45mmHg (P= 0,0295). Não foram encontradas diferenças entre ambos os olhos (P= 0,7454). Não foram encontradas diferenças significativas nos valores da PIO relacionadas ao sexo (P= 0,1858). Os valores da PIO em porquinhos da índia tiveram alteração nas horas avaliadas. Com base nos resultados obtidos foi possível concluir que os valores da PIO em porquinhos da índia da sofrem alterações ao longo do dia. Os menores valores de pressão intraocular ocorreram às 18 horas. / The measuring of intraocular pressure (IOP) it is essential for the ophthalmic evaluation; the aim of this study was establish the values of the IOP diurnal curve of guinea pigs with different ages using the rebound tonometer (Tonovet®). The animals were divided according to the age in two groups, Group I (GI) constituted with 10 guinea pigs aged between 2 -3 moths, and Group II (GII), 4 animals with 2 -3 years of old. Previously the Schirmer tear test, fluorescein test, biomicroscopy with slit lamp, and direct optalmoscopy were performed on all animals. The men value of IOP was 12.0±0.34 mmHg. Statistical difference were found between ages (mean GI 11.64 ± 0.29 mmHg, and GII 12.83 ± 0.45mmHg), did not have statistical difference related with gender (P= 0.1858) or between eyes (P= 0.7454). In conclusion the guinea pigs had alteration of IOP true the day, the values of IOP are higher in the morning period, decrease true the day and at the night period haves an elevation again.