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PubMed1993

Tonometry in the general practice setting (I): Tono-Pen compared to Goldman applanation tonometry.

Intraocular pressure was measured in 132 consecutive patients over the age of 20 in a general practice with two general practitioners (GP). Tono-Pen tonometry was compared to Goldmann applantation tonometry in a masked, randomized design. Also, agreement between Tono-Pen measurements by the GPs and the ophthalmologist was estimated. Both mean difference between Tono-Pen and Goldmann applantation measurements and mean differences between Tono-Pen readings made by GPs and ophthalmologist were less than 1 mmHg. Ninety-five percent limits of agreement between the two methods were approximately -4.5 mmHg and 5.5 mmHg, and between observers approximately -4 mmHg and 5 mmHg. The Tono-Pen was agreeable both to patients and physicians. The GPs made as accurate measurements as the ophthalmologist. The wide limits of agreement are clinically much more important than the small differences between means. Random variation was much greater than systematic variation. Wide limits of agreement will apply to all known methods of clinical tonometry.

Adult↗
PubMed2006

Comparison of rebound tonometry with Goldmann applanation tonometry and correlation with central corneal thickness.

BACKGROUND/AIMS: Rebound tonometry (RT) is performed without anaesthesia with a hand held device. The primary aim was to compare RT with Goldmann applanation tonometry (GAT) and to correlate with central corneal thickness (CCT). The secondary aim was to prove tolerability and practicability of RT under "study conditions" and "routine practice conditions." METHODS: In group 1 (52 eyes/28 patients), all measurements were taken by the same physician, in the same room and order: non-contact optical pachymetry, RT, slit lamp inspection, GAT. Patients were questioned about discomfort or pain. In group 2 (49 eyes/27 patients), tonometry was performed by three other physicians during routine examinations. RESULTS: RT was well tolerated and safe. Intraocular pressure (IOP) ranged between 6 mm Hg and 48 mm Hg. No different trends were found between the groups. RT tended to give slightly higher readings: n = 101, mean difference 1.0 (SD 2.17) mm Hg; 84.1% of RT readings within plus or minus 3 mm Hg of GAT; 95% confidence interval in the Bland-Altman analysis -3.2 mm Hg to +5.2 mm Hg. Both RT and GAT showed a weak positive correlation with CCT (r2 0.028 and 0.025, respectively). CONCLUSIONS: RT can be considered a reliable alternative for clinical screening and in cases where positioning of the head at the slit lamp is impossible or topical preparations are to be avoided.

Adult↗
PubMed2003

The evaluation of tonometry and self-tonometry with Ocuton tonometers.

BACKGROUND: The purpose of the present study was to evaluate the clinical applicability of the Ocuton-A and Ocuton-S applanation tonometers, and to compare their use and accuracy parameters to those of Goldmann applanation tonometry (GAT). MATERIAL/METHODS: In the first study, intraocular pressure (IOP) was measured with an Ocuton-A tonometer, followed by another measurement using GAT in 15 subjects (30 eyes). Ocuton-tonometry was performed on three occasions separated by three-minute intervals. In Study 2 the impact of increased patient familiarity on measurement accuracy using the self-tonometer was investigated in 5 subjects (10 eyes) by comparing two consecutive series of five Ocuton-S measurements. In Study 3 nine trained volunteers measured their own IOP with an Ocuton-S self-tonometer after GAT and Ocuton-A measurements by an experienced investigator. RESULTS: Study 1 showed that the measured IOP value was significantly higher using the Ocuton-A tonometer, compared to values obtained using GAT. In Study 2 we found that increased practice in self-tonometry did not alter measurement accuracy. In Study 3 the difference between IOP readings obtained with the Ocuton-S and Ocuton-A instruments was not significant. CONCLUSIONS: The portable Ocuton-A tonometer may become a useful instrument for IOP measurement by professional workers outside the clinic. Qualified patients are able to use the Ocuton-S self-tonometer reliably even after limited training, and its measurement accuracy is acceptable for IOP monitoring. Both the Ocuton A and S devices consistently overestimate the IOP by approximately 2 mm Hg compared to the corresponding Goldmann readings.

Aged↗
PubMed2004

Accuracy of dynamic contour tonometry compared with applanation tonometry in human cadaver eyes of different hydration states.

BACKGROUND: In an experimental laboratory investigation we compared intraocular pressure (IOP) measurements obtained by dynamic contour tonometry (DCT), Goldmann applanation tonometry (GAT), and pneumatonometry (PTG) with intracameral manometry on human cadaver corneas of different hydration conditions. METHODS: Ten freshly enucleated eyes were de-epithelialized. Two tubes were placed in the anterior chamber in opposite directions and connected to a transducer and to a bottle system filled with balanced salt solution. The pressure in the eye was then adjusted between 5 mmHg and 58 mmHg by electronically altering the height of the bottle. Central corneal thickness (CCT) was registered and IOP measurements were obtained with DCT, GAT, and PTG at each manometric pressure reading. Immediately after the trial the same corneas were artificially dehydrated and the same measurement regimen was repeated. RESULTS: In the pressure range defined by the bottle height 10-50 cm, IOP values measured by DCT were 0.50 mmHg (95% CI=0.40-0.60) and 0.36 mmHg (95% CI=0.25-0.47) higher than manometric readings before and after dehydration, respectively. GAT showed consistently lower values than manometry, the difference being -3.48 mmHg (95% CI=-3.91 to -3.05) and -3.14 mmHg (95% CI=-3.39 to -2.89), respectively. Similar results were obtained with PGT, namely differences of -4.75 mmHg (95% CI=-5.21 to -4.29) and -3.98 mmHg (95% CI=-4.48 to -3.48) for the hydrated and the dehydrated corneal condition, respectively. Only DCT showed no significant change in accuracy between hydrated and dehydrated corneas. CONCLUSIONS: In this in vitro study DCT values for IOP were significantly closer to the manometric reference pressure than those obtained using GAT and PTG, independent of the state of corneal hydration.

Aged↗
PubMed1999

Self-tonometry with the Ocuton S versus Goldmann tonometry.

BACKGROUND: The purpose of the study was to evaluate the acceptance and reproducibility of a new self-tonometer (Ocuton S) and to compare it with the Goldmann applanation tonometer. METHODS: The Ocuton S was studied in 20 healthy volunteers and 100 patients. After detailed explanation to each individual and a number of test measurements, we studied the reproducibility and accuracy of the Ocuton S in 20 healthy volunteers with and without topical anaesthesia. Acceptance was graded by means of visual analogue scales. Each volunteer had to measure his/her own IOP in three consecutive measurements. The data were compared with Goldmann tonometry at random times. One hundred patients were introduced to the Ocuton S. Either three consecutive self-measurements of IOP were performed and then compared with three consecutive measurements by Goldmann tonometry, or vice versa. This was done randomly. RESULTS: Forty-one of 100 patients were unable to perform three consecutive measurements with the Ocuton S after at least 15 min introduction time to the device (non-success). Fifty-nine of 100 patients were able to measure their IOP with the Ocuton S. The mean pressure value with the Ocuton S was 23.2+/-8.2 mmHg, compared with Goldmann 18. 4+/-5.7 mmHg. The difference of 5+/-5.7 mmHg was statistically significant (paired t-test p<0.01). The visual analogue scale scores of healthy volunteers (100 mm = maximal comfort, 0 mm = not acceptable), was 72+/-31 in anaesthetised eyes and 39+/-41 mm without anaesthesia. CONCLUSION: The Ocuton S seems to be an acceptable means for the majority of patients of measuring their IOP at home. Refinement of the accuracy of the device seems necessary.

Adult↗
PubMed2006

Comparison of dynamic contour tonometry and goldmann applanation tonometry in glaucoma patients and healthy subjects.

PURPOSE: To investigate the agreement in the measurement of intraocular pressure (IOP) obtained by dynamic contour tonometry PASCAL (DCT-PASCAL) and Goldmann applanation tonometry (GAT) in glaucoma eyes and healthy eyes with different central corneal thickness (CCT). DESIGN: Prospective cross-sectional study. METHODS: In a randomized order, three consecutive IOP measurements were performed on 197 eyes of 107 subjects by one examiner using both DCT-PASCAL and GAT on all eyes. Furthermore, ultrasonic pachymetry was performed. The Spearman correlation coefficient (r) was determined to compare IOP readings between DCT-PASCAL and GAT. Regression-based Bland and Altman analysis was used to evaluate agreement between the instruments. RESULTS: Mean IOP values obtained by both instruments were significantly correlated in healthy and glaucoma eyes (all healthy eyes [n = 66]: r = 0.8, P < .001, all glaucoma eyes [n = 131]: r = 0.96, P < .001). Neither GAT nor DCT-PASCAL showed a significant correlation with CCT (GAT: all eyes: r = 0.009, P = .9, DCT-PASCAL: all eyes: r = -0.05, P = .5). Bland and Altman analysis revealed the existence of proportional bias. Thus, 95% limits of agreement between the instruments varied with the actual IOP measurement. CONCLUSIONS: DCT-PASCAL and GAT revealed a strong correlation in IOP measurements between glaucoma and healthy eyes. However, the analysis of agreement indicated some discrepancies between the instruments. Measurements with both GAT and DCT-PASCAL were not correlated with central corneal thickness.

Adult↗
PubMed2005

Comparison of dynamic contour tonometry with goldman applanation tonometry over a wide range of central corneal thickness.

PURPOSE: To compare dynamic contour tonometry with Goldmann applanation tonometry in structurally normal corneas over a wide range of central corneal thickness (CCT). PATIENTS AND METHODS: Twenty-five patients each with normal CCT (group A), thin corneas (group B), and thick corneas (group C) had IOP measured with the Goldmann (GAT) and dynamic contour tonometer (DCT). RESULTS: In group A (mean CCT = 552 +/- 16 microm) the mean GAT was 15.9 +/- 3.1 mm Hg and mean DCT was 16 +/- 3.3 mm Hg (P = 0.91). In group B (mean CCT = 491 +/- 19 microm) the mean GAT was 13.2 +/- 3.5 mm Hg and the mean DCT was 15.9 +/- 3.5 mm Hg (P = 0.009). For group C (mean CCT = 615 +/- 22 microm), the mean GAT was 17.4 +/- 3.8 mm Hg and the mean DCT was 17.4 +/- 3.5 mm Hg (P = 0.95). The 95% agreement limits for DCT were -3.1 mm Hg to 2.9 mm Hg. The mean GAT-DCT difference was -2.6 mm Hg in thin corneas and -0.06 mm Hg in thick corneas. Below 520 microm reduction of 10 microm in CCT appears to result in a significant underestimation of the GAT IOP by 0.7 mm Hg (P < .001) and above 580 microm a non-significant overestimation of 0.2 mm Hg per 10 microm increase in CCT (P = 0.27). CONCLUSION: Dynamic contour tonometer agrees well on average with GAT but the agreement limits are wide. In structurally normal thin corneas DCT may give a more accurate assessment of the true IOP but it does not appear to have any benefit over GAT in thick corneas.

Adult↗
PubMed2007

Clinical evaluation of applanation resonance tonometry: a comparison with Goldmann applanation tonometry.

PURPOSE: The purpose of this study was to calibrate and evaluate the precision of the new applanation resonance tonometry (ART) in a clinical study designed in accordance with the International Standard Organization's requirements. METHODS: This was a prospective, randomized, single-center study, where healthy volunteers and patients participated. A total of 153 eyes were divided into 3 groups with respect to their intraocular pressure (IOP) at screening: <16 mm Hg, 16 to 23 mm Hg, and >23 mm Hg. IOP was measured with Goldmann applanation tonometry (GAT) as reference method and by ART in both a biomicroscope (ARTBiom) and a handheld (ARTHand) setup with a 10-minutes pause between methods. The mean of 6 readings was regarded as one measurement value. RESULTS: Mean age of the subjects was 59 years (range 20 to 87 y). GAT showed a mean IOP of 20.0 mm Hg (range 8.5 to 43.5 mm Hg, n=153). The precision was 2.07 mm Hg for ARTBiom and 2.50 mm Hg for ARTHand, with a significant dependency for age as compared with GAT. Measurement order produced a decreasing IOP with a mean of 2.3 mm Hg between the first and last method. CONCLUSIONS: The precision obtained in both ARTBiom and ARTHand was within the limits set by the International Standard Organization standards for tonometers. The standardized procedure and the stability of the biomicroscope setup resulted in a slightly better precision as compared with the handheld setup. Despite a 10-minutes pause between measurements, the order was a significant factor, possibly because the patients were more apprehensive at the first measurement.

Adult↗
PubMed1990

Airpuff tonometry versus applanation tonometry.

In order to study the reliability of airpuff tonometry, 230 eyes of 115 patients had their IOP measured with 2 airpuff tonometers, NCT and Pulsair, and one applanation tonometer, Perkins handheld Goldmann Type, between Dec 87 and March 89. Each patient had three readings per eye with each airpuff instrument and two readings per eye with the Perkins instrument. Mean age for the group was 68 +/- 11 (SD), range 36-87 years. The mean values were for Perkins: 21.21 +/- 6.27 R.E., 21.28 +/- 5.67 L.E.; for NCT: 21.11 +/- 6.95 R.E., 21.27 +/- 5.41 L.E.; for Pulsair: 23.05 +/- 6.00 R.E., 23.76 +/- 5.39 L.E. The ranges were for Perkins: 9-45 R.E., 9-38 L.E.; for NCT: 8-59 R.E., 11-38 L.E.; for Pulsair: 9-52 R.E., 11-38 L.E. For the Pulsair a value of 18 was found to be a cut-off point below which there were no false negatives, and for the NCT this value was found to be 17. A linear relation between airpuff and applanation tonometry was found, but also a large spread, both for false positives and false negatives.

Adult↗
PubMed2006

Comparison of Proview phosphene tonometry with Goldmann applanation tonometry.

BACKGROUND: To compare intraocular pressures obtained using a handheld pressure phosphene tonometer (PPT) (Proview, Bausch & Lomb Pharmaceuticals, Inc., Tampa, Fla.) with Goldmann applanation tonometry. METHODS: Comparative case series of 30 randomly selected patients. RESULTS: The readings obtained with the pressure phosphene tonometer display a higher mean and a larger standard deviation than those obtained with the Goldmann applanation tonometer (GAT). Differences between PPT and GAT readings tended to decrease as a function of increased Goldmann levels. The relation of Proview and Goldmann readings (r = 0.32) and the scatterplot were not consistent with the hypothesis that the 2 methods are equivalent. INTERPRETATION: Our results indicate that the pressure phosphene-type handheld tonometry method, which does not appear to provide an accurate and consistent measure of intraocular pressure, is substantially less reliable than the Goldmann method.

Adult↗
PubMed2006

[Goldmann applanation tonometry and dynamic contour tonometry. Comparison of intraocular pressure measurements in the course of product certification according to EN ISO 8612:2001].

BACKGROUND: The aim of the study was to compare intraocular pressure (IOP) measurements between Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT) during product certification according to the international requirements for ophthalmic instruments (tonometers, ISO 8612:2001). METHODS: The study included 160 eyes of 80 subjects. IOP measurements were performed four times consecutively on each instrument in randomized order. The difference of mean IOP measurements between GAT and DCT was analyzed. Furthermore, Bland and Altman analysis was performed to assess agreement between the instruments. RESULTS: The mean difference between DCT and GAT IOP measurements was 0.30+/-2.18 mmHg. At low to normal IOP values of 7-16 mmHg and higher IOP values of > or =23 mmHg, the difference between DCT IOP measurements and GAT IOP measurements increased in the opposite direction (1.44+/-1.59 mmHg and -1.47+/-2.57 mmHg). The Bland and Altman analysis revealed a fixed bias of -0.4+/-2.0 mmHg. CONCLUSIONS: The test tonometer DCT exceeds the requirements for the international standard for tonometers ISO 8612:2001. The results are valid for a central corneal thickness of 540+/-40 microm.

Calibration↗
PubMed2005

Dynamic contour tonometry versus Goldmann applanation tonometry: a comparative study.

BACKGROUND: Various sources of error, including central corneal thickness (CCT) and structural corneal rigidity, have been proposed for Goldmann applanation tonometry (GAT). The Pascal dynamic contour tonometer (DCT) is a novel device designed for intraocular pressure (IOP) measurements assumed to be largely independent of CCT and corneal curvature. We compared DCT with GAT in eyes with normal corneas of various thickness. METHODS: We prospectively measured IOP using DCT and GAT in random order in 100 eyes of 100 subjects (M:F=46:54; mean age 42+/-19, range 23-88 years). RESULTS: Mean DCT values were about 1 mm Hg higher than GAT readings (16+/-3 vs 15+/-3 mmHg, p=0.001). Bland-Altman analysis of individual pairs of DCT and GAT measurements revealed a bias of -1.0 mmHg [95% confidence interval (CI): +/-1.2]. Neither GAT nor DCT showed a significant correlation with CCT (533+/-48, range 399-641 microm). CONCLUSIONS: In eyes with normal corneas, DCT allows suitable and reliable IOP measurements which are in good concordance with GAT. Comparison of DCT with intracameral manometry is desirable in the future.

Adult↗
PubMed2006

Dynamic contour tonometry (DCT) versus Goldmann applanation tonometry (GAT) - a comparison of agreement and reproducibility.

BACKGROUND: The PASCAL dynamic contour tonometer (DCT) is a novel device designed for intraocular pressure (IOP) measurements. It is assumed to be largely independent of corneal properties. In a previous study we compared DCT with Goldmann applanation tonometry (GAT) in 100 right eyes with normal corneas. The aim of the present study is to evaluate whether differences DCT-GAT >or= 2.0 mmHg found in the previous study are reproducible and also present in the fellow eye. METHODS: Twenty-three of the 100 patients (M:F = 8:15, mean age: 36 +/- 11 SD, range 22-53 years) with a previous difference DCT-GAT >or= 2.0 mmHg were included in the present study. The minimum interval between the initial and the current examination was 3 weeks. The IOP-values of the fellow eyes in this subgroup were assessed in parallel. RESULTS: The difference DCT-GAT was 2.44 +/- 0.4 SEM mmHg in the subgroup of the 23 right eyes and 2.03 +/- 0.5 SEM mmHg for the fellow eyes, compared to 0.94 +/- 0.5 SEM mmHg in the initial sample of 100 eyes. CONCLUSIONS: In cases with higher difference between DCT-GAT, the difference is reproducible and even present in the fellow eye. We, therefore, assume that the differences are not caused by chance, but by differing biomechanical corneal properties.

Adult↗
PubMed2004

Comparison of dynamic contour tonometry with goldmann applanation tonometry.

PURPOSE: The dynamic contour tonometer (DCT; Pascal tonometer) is a novel tonometer designed to measure intraocular pressure (IOP) independent of corneal properties. The purpose of this study was a comparison of the DCT with the Goldmann applanation tonometer (GAT) with respect to mean of IOP readings, the influence of ocular structural factors on IOP readings, and both intra- and interobserver variability, in a large group of healthy subjects. METHODS: In a prospective study of 228 eyes, IOP measurements by GAT and DCT were compared, and the effects of central corneal thickness (CCT), corneal curvature, axial length, and anterior chamber depth were analyzed. To evaluate intra- and interobserver variability, IOP was measured in eight eyes by four observers. RESULTS: There was a high concordance between the IOP readings obtained by DCT and GAT. However, IOP readings were consistently higher with DCT than with GAT (median difference: +1.7 mm Hg, interquartile range [25th-75th percentile] = 0.8-2.7 mm Hg). In contrast to GAT, multivariable regression analysis showed no significant effect of corneal thickness, corneal curvature, astigmatism, anterior chamber depth, and axial length on DCT readings. For repeated measurements the intraobserver variability was 0.65 mm Hg for the DCT and 1.1 mm Hg for the GAT (P = 0.008). Interobserver variability was 0.44 mm Hg for the DCT and 1.28 mm Hg for the GAT (P = 0.017). CONCLUSIONS: IOP measurements by DCT are highly concordant with IOP readings obtained from GAT but do not vary in CCT and have a lower intra- and interobserver variability. DCT seems to be an appropriate method of tonometry for routine clinical use.

Astigmatism↗
PubMed1991

[Relevance of ocular pressure tonometry and classical tonometry with reference to prognosis in suspected glaucoma and ocular hypertension].

A total of 44 eyes of patients with suspected glaucoma or ocular hypertension were examined both by ocular pressure tonometry (OPT) according to Ulrich and by tonography according to Leydhecker. The visual fields of these eyes were prospectively followed up for 3 years to compare the prognostic value of the two methods. In 30 of the 44 eyes a worsening visual field loss was observed, while in 14 the visual fields showed no change. Much better correlation was noted between values obtained by OPT and changes in visual field than between values obtained by tonography and visual field loss. Conventional tonography yielded 39% of false-negative values, but only 11% were recorded with OPT. Therefore, according to results of these and further investigations, OPT appears to be a more helpful and reliable method for assessment and decisions on therapy in patients with suspected glaucoma or ocular hypertension.

Humans↗
PubMed2006

[Reproducibility of dynamic contour tonometry. Comparison with TonoPenXL and Goldmann applanation tonometry - a clinical study on 323 normal eyes].

BACKGROUND: The PASCAL Dynamic Contour Tonometer (DCT) is a new diagnostic approach for the digital measurement of intraocular pressure (IOP) in eyes with glaucoma. The aim of this study was to evaluate the reproducibility of DCT in normal eyes and to compare DCT with Goldmann applanation tonometry (GAT) and TonoPenXL. PATIENTS AND METHODS: A prospective cross-sectional study on 323 normal, consecutive eyes was performed. Eyes with an IOP of more than 23 mmHg (GAT) were excluded. Central corneal power (Zeiss Ophthalmometer) and central corneal thickness (ultrasound pachymetry: Tomey AL-1000) were taken. The IOP readings were obtained as follows: 3 x DCT [quality of measurement, IOP and ocular pulse amplitude (OPA) were taken], 1 x TonoPenXL, GAT, finally: once again DCT to evaluate the tonography effect. RESULTS: The quality of 3 following IOP (DCT) readings was good (quality Q1 = 43.4 %, Q2 = 32.5 %, Q3 = 22.7 %). The reproducibility of the IOP (DCT) measurements was excellent (first measurement IOP (DCT) = 18.1 +/- 3.4 mmHg, second measurement IOP (DCT) = 18.1 +/- 3.4 mmHg, third measurement IOP (DCT) = 17.8 +/- 3.4 mmHg, Cronbach's alpha = 0.976). First and second IOP (DCT) values showed a strong correlation (r = 0.93). A significant tonography effect was observed between first and third IOP (DCT) measurements (0.4 mmHg; p = 0.004). Mean OPA (DCT) was 3.0 mmHg during the first three measurements (Cronbach's alpha = 0.964). IOP (DCT) and OPA (DCT) reproducibility showed no laterality. IOP (DCT) (17.7 +/- 3.4 mmHg) was significantly higher than IOP (TonoPenXL) (16.0 +/- 3.2 mmHg, n = 275; p < 0.001) and higher than IOP (GAT) (14.5 +/- 3.1 mmHg, n = 275; p < 0.001). The effect of tonography between the third and last IOP (DCT) measurement was zero (p = 0.6). IOP (DCT) and IOP (GAT) values were only weak correlated with central corneal thickness. CONCLUSIONS: IOP and OPA values measured with the DCT are extraordinary reproducible in normal eyes. Frequently, DCT detects higher IOP values than those obtained with TonoPenXL and GAT. A reproducible measurement of IOP and OPA may open new diagnostic fields, e. g., in glaucoma detection or ocular vascular diseases.

Cross-Over Studies↗
PubMed2006

Comparison of intraocular pressure measured by Pascal dynamic contour tonometry and Goldmann applanation tonometry.

AIMS: To compare the intraocular pressure (IOP) measurements obtained using the Pascal dynamic contour tonometer (PDCT) with the standard Goldmann applanation tonometer (GAT) and to correlate these with central corneal thickness (CCT) in patients with normal corneas. METHODS: A prospective, masked, comparative case series of 116 eyes from patients attending a glaucoma clinic. IOP was measured with PDCT by one examiner and with GAT by a masked, independent examiner. A mean of six CCT readings was used for analysis. RESULTS: IOP measured by the two instruments correlated significantly (r=0.77; P<0.0001). IOP measured by GAT correlated strongly with CCT (r=0.37, P=0.0001) whereas the relationship between IOP measured by PDCT and CCT approached significance (r=0.17, P=0.073). The differences between GAT and PDCT measured IOP also correlated strongly with CCT (r=0.37, P<0.0001). The 95% limits of agreement between GAT and PDCT were +/-4.2 mmHg. Dividing the eyes into three groups on the basis of CCT, demonstrated those in the thickest tertile showed a poorer agreement between instruments and the GAT measured significantly higher IOP in this group (P=0.003) while the PDCT showed no significant differences with different CCTs (P=0.37). CONCLUSION: Demonstration of the relative independence of PDCT IOP measurements from CCT supports a potential clinical role for this instrument, particularly for subjects with CCT outside the normal range.

Adult↗