Latanoprost or brimonidine as treatment for elevated intraocular pressure: multicenter trial in the United States

PURPOSE: To compare the efficacy and tolerability of latanoprost or brimonidine in patients with elevated intraocular pressure (IOP). MATERIALS AND METHODS: This prospective, randomized, masked-evaluator, parallel-group, multicenter study in the United States included patients with primary open angle glaucoma or ocular hypertension. Patients received latanoprost 0.005% once daily (8:00 AM; n = 152) or brimonidine tartrate 0.2% twice daily (8:00 AM and 8:00 PM; n = 151). Patients underwent evaluation at screening, baseline (randomization), and after 0.5, 3, and 6 months of treatment. IOP was measured at 8:00 AM, 10:00 AM, noon, and 4:00 PM at baseline and the months 3 and 6 visits, and at 8:00 AM only at week 2. The main outcome measure was the difference in diurnal IOP change from baseline to month 6 between treatment groups. Adverse events were recorded at each visit. RESULTS: Baseline mean diurnal IOP levels were similar between groups. At month 6, the adjusted mean (+/- SEM) diurnal IOP reduction was 5.7 +/- 0.3 mm Hg in the latanoprost group and 3.1 +/- 0.3 mm Hg in patients receiving brimonidine (P < 0.001). The mean difference in diurnal IOP reduction was 2.5 +/- 0.3 mm Hg (95% CI: 1.9, 3.2; P < 0.001). Five times more patients receiving brimonidine than latanoprost were withdrawn from the study due to adverse events. CONCLUSION: Latanoprost instilled once daily is more effective and better tolerated than brimonidine administered twice daily for the treatment of patients with glaucoma or ocular hypertension. During therapy, the range of daily fluctuation of IOP is less for latanoprost compared with brimonidine.     

Association of central corneal thickness and 24-hour intraocular pressure fluctuation

PURPOSE: To evaluate the association between office-hour central corneal thickness (CCT) and 24-hour intraocular pressure (IOP) fluctuation in patients with glaucoma. DESIGN: Observational case-control study. METHODS: Measurements of IOP were obtained every 2 hours during a 24-hour period from 52 untreated glaucoma patients and 29 age-matched normal control subjects housed in a sleep laboratory. Habitual IOP measurements were obtained using a pneumatonometer in the sitting positions during the diurnal/wake period (7 AM to 11 PM) and in the supine position during the nocturnal/sleep period (11 PM to 7 AM). CCT was measured in all subjects using ultrasound pachymetry once during office hours. The association between IOP fluctuation (peak IOP-trough IOP) during the 24-hour period and the office-hour CCT was assessed in both glaucoma patients and healthy age-matched controls using Spearman rank order correlation. RESULTS: There was no statistically significant correlation between IOP fluctuation and CCT in glaucomatous (P=0.405) and normal subjects (P=0.456). CONCLUSIONS: Twenty-four-hour IOP fluctuations were not correlated with single CCT measurements taken during office hours in glaucoma patients.     

Relationship between corneal thickness and measured intraocular pressure in a general ophthalmology clinic

OBJECTIVE: To assess whether central corneal thickness (CCT) is a confounding factor in the classification of patients attending for glaucoma assessment in a district general hospital. DESIGN: Cross-sectional study by a single observer. PARTICIPANTS: Patients attending a general ophthalmic clinic: 235 clinically normal eyes, 52 eyes with normal-tension glaucoma (NTG), 335 eyes with primary open-angle glaucoma (POAG), 12 eyes with pseudoexfoliative glaucoma (PXE), 42 eyes with chronic angle closure glaucoma (CACG), and 232 glaucoma suspect (GS) eyes. INTERVENTION: Central corneal thickness was measured using ultrasonic pachymetry. MAIN OUTCOME MEASURE: Correlation of CCT and diagnosis. RESULTS: Mean CCT was 553.9 microm (95% confidence intervals [CI] for the mean, 549.0-558.8 microm) in the clinically normal eyes, 550.1 microm (95% CI, 546.6-553.7 microm) in the POAG eyes, 514.0 microm (95% CI, 504.8-523.3 microm) in the NTG eyes, 530.7 microm (95% CI, 511.2-550.1 microm) in the PXE eyes, 559.9 microm (95% CI, 546.8-573.0 microm) in the CACG eyes, and 579.5 microm (95% CI, 574.8-584.1 microm) in the GS eyes. The differences of mean CCT between the groups were highly significant (P< 0.001 analysis of variance). Eighty-five percent of eyes with NTG and only 36% of eyes with POAG had a mean CCT of 540 microm or less. Thirteen percent of eyes with POAG and 42% of GS eyes had a mean CCT greater than 585 microm. CONCLUSIONS: The CCT measurement is desirable in patients attending for glaucoma assessment in a district general hospital to avoid misclassification resulting from the relationship between CCT and tonometric pressure. Central corneal thickness alone is not an accurate predictor for the clinical diagnosis in this group of eyes. However, many eyes diagnosed as having NTG have thin corneas, which would tend to lower the tonometrically recorded intraocular pressure (IOP), so the finding of a less-than-normal thickness cornea introduces some doubt as to the diagnosis of NTG. For the GS eyes, most eyes had thick corneas, which would tend to increase the tonometrically recorded IOP. Thus, GS eyes with modest elevation of IOP and a thick cornea may be at low risk of progressing to POAG. Thus, many patients with "high IOPs" and a thick CCT do not necessarily have high IOPs and may not need to be followed as GS eyes.     

Diurnal variation of intraocular pressure in low tension glaucoma

Around-the clock intraocular pressure (IOP) measurement were performed in 104 eyes of 52 low tension glaucoma (LTG) cases. Subjects were all hospitalized and IOP measurements were done every 2 hours from 6:00 AM to 12:00 PM and every 3 hours from 12:00 PM to 6:00 AM. All LTG patients met the following criteria, (1) glaucomatous optic nerve head change and corresponding visual field defect, (2) normal open angle, (3) IOP less than or equal to 21mmHg at any time of IOP measurement, (4) no obvious neurological or rhinological disorders that could affect the optic nerve, (5) no history of hemodynamic crisis or cardiovascular disorders except mild hypertension. Peak IOPs were most frequently observed at 10:00 AM, but about 55% of all observed peaks were in the time period from 6:00 PM to 8:00 AM. Most troughs were observed from 2:00 PM to 10:00 PM. The mean IOP, the diurnal variation and the difference between both eyes in the same person averaged 14.1, 4.9, and 0.6mmHg, respectively. Assuming that the period of rhythm is 24 hours, the results of IOP measurements fitted a cosine curve using the least square method. In 44% of all eyes, significant correlation coefficient (r greater than or equal to 0.6, p less than 0.05) between the measured and the predicted IOPs was noted, and an equation, IOP = 14.3 + 1.7cos 2 pi (t/24-0.4 radian), was obtained. Comparing the present results with former ones, we concluded that the IOP changes in LTG patients were similar to those in normal individuals.     

Diurnal variation of ocular hysteresis in normal subjects: relevance in clinical context

BACKGROUND: This study was conducted to assess the diurnal variation in ocular hysteresis, as measured by the Ocular Response Analyser to establish a relationship between diurnal hysteresis variation and diurnal intraocular pressure (IOP) variation. METHODS: Forty-two normal eyes of 21 colleagues and staff in a teaching hospital in Birmingham, UK, were recruited. The IOP and hysteresis were measured by the Ocular Response Analyser. The central corneal thickness (CCT) was measured using a hand-held ultrasonic pachymeter in the mid-pupillary axis. RESULTS: The mean ocular hysteresis at 8 am was 12.7 +/- 2.3 mmHg, at 11 am was 12.2 +/- 2.0 mmHg, at 2 PM was 12.7 +/- 2.1 mmHg and at 5 PM was 12.7 +/- 1.7 mmHg; the difference between the values at any time of measurement was not statistically significant (P > 0.9, repeated measures). IOP as measured by non-contact tonometry was 18.4 +/- 2.8 mmHg, 17.9 +/- 3.3 mmHg, 16.9 +/- 3.1 mmHg and 16.8 +/- 3.2 mmHg, respectively, for the same time period; the difference between the values in the morning and afternoon was statistically significant (P < 0.0001, repeated measures). The CCT was 548.8 +/- 29.5 microm, 547.0 +/- 31.4 microm, 548.2 +/- 29.6 microm and 548.6 +/- 29.4 microm, respectively; the difference between the values was not statistically significant at any time points. Multiple regression analysis showed the relationship between IOP and hysteresis was not statistically significant (P = 0.9). CONCLUSION: The ocular hysteresis reading was almost constant throughout the day, whereas the IOP readings showed highest values in the morning with a reducing trend being lowest in the afternoon. The CCT values were almost stable throughout the day. IOP appears to vary independently of a variation in hysteresis or CCT.     

Effects of central corneal thickness and corneal curvature on the intraocular pressure measurement by Goldmann applanation tonometer and ocular blood flow pneumatonometer

PURPOSE: To assess the effects of central corneal thickness (CCT) and corneal curvature (CC) on the measurements of intraocular pressure (IOP) using Goldmann applanation tonometer (GAT) and the ocular blood flow pneumatonometer (OBFT). METHODS: 104 patients were recruited from a glaucoma clinic. The CCT was measured using ultrasound pachymetry and the mean radius of CC using a keratometer. The IOP of each eye was measured using both GAT and the OBFT in a random order. Right eyes only were analysed for statistical purposes. RESULTS: The mean (+/-SD) IOP by GAT and OBFT was 18.2 mmHg (+/-4.4) and 18.2 mmHg (+/-4.0), respectively, with no statistically significant difference. IOP measurement with both instruments varied with CCT and CC. GAT showed an IOP increase of 0.40 mmHg per 10 microm increase of CCT and OBFT showed an increase of 0.38 mmHg in IOP per 10 microm increase of CCT. Multiple regression analysis showed that the effect of CCT was statistically significant (P<0.001) on IOP recorded by both the GAT and OBFT but CC did not have a statistically significant effect on IOP recordings performed by either technique. CONCLUSION: IOP measurements by GAT and OBFT are positively correlated with CCT with both tonometers being similarly affected. There was no significant correlation between CC and IOP measured by either tonometer.     

Corneal thickness and visual field damage in glaucoma patients

PURPOSE: To verify whether there was a significant correlation between central corneal thickness (CCT) and visual field damage in patients with primary open angle glaucoma (POAG). METHODS: A total of 99 eyes with POAG were consecutively recruited. Patients were classified as glaucomatous based on visual field and optic nerve head damage. All underwent applanation tonometry, Humphrey perimetry, and measurement of CCT with ultrasonic pachymetry. Based on CCT value, the sample was split at the mode in two groups (group 1<535 microm, n=49; group 2>or=535 microm, n=50). RESULTS: Entire cohort: mean CCT 554 microm+/-45.03; mean deviation (MD) -6.68 dB+/-7.32; pattern standard deviation (PSD) 5.33+/-3.75; intraocular pressure (IOP) 17.91+/-4.16 mmHg with treatment. Group 1: CCT was 504.8 microm+/-30.8; MD -9.01 dB+/-8.72; PSD 6.38+/-3.99; IOP 18.02 mmHg+/-4.66. Group 2: mean CCT 574.6 microm+/-35.03; MD -4.39 dB+/-4.70; PSD 4.25+/-3.19; IOP 17.79 mmHg+/-3.57. A significant difference was found between the two groups for both MD and PSD. Linear regression analysis showed a significant correlation between CCT and PSD (P<0.001). CONCLUSIONS: Our data show that patients with a thinner cornea had a worse MD and PSD. As a thinner CCT causes an underestimation of the true IOP, there may be a delay in the diagnosis of POAG or an inadequate estimate of the clinical course despite apparently desirable IOP applanation readings.     

A double-masked, randomized clinical trial comparing latanoprost with unoprostone in patients with open-angle glaucoma or ocular hypertension

PURPOSE: To compare the intraocular pressure (IOP) reducing effect and safety of latanoprost 0.005% once daily with unoprostone 0.12% twice daily in patients with primary open-angle glaucoma (POAG) or ocular hypertension (OH). DESIGN: An 8-week, double-masked, randomized, parallel-group, single-center clinical trial. PARTICIPANTS: A total of 108 patients with POAG or OH were enrolled. INTERVENTIONS: After completing a wash-out of ocular hypotensive medications, patients were randomized to receive either latanoprost once daily in the evening plus placebo once daily in the morning, or unoprostone twice daily (morning and evening). MAIN OUTCOME MEASURES: IOP was measured at 10:00 AM and at 5:00 PM at baseline and at week 8, and before 12:00 noon at week 2. Ocular and systemic safety assessments were performed. RESULTS: From an overall baseline of 24.1 mmHg, latanoprost reduced IOP by 6.7 mmHg (28%) and unoprostone reduced IOP by 3.3 mmHg (14%). The difference between the groups of 3.4 mmHg was significant (P: < 0.001, analysis of covariance; 95% confidence interval [CI]: -4.7 to -2.1) in favor of latanoprost. A >/=30% reduction in mean IOP from baseline was achieved by 44% of latanoprost-treated patients compared with 8% of unoprostone-treated patients. The incidence of adverse events was low and comparable between the groups. CONCLUSIONS: Latanoprost administered once daily was significantly more effective in reducing IOP compared with unoprostone administered twice daily in patients with POAG and OH.     

Comparison of Pentacam Scheimpflug camera with ultrasound pachymetry and noncontact specular microscopy in measuring central corneal thickness

PURPOSE: Although central corneal thickness (CCT) can be measured by several methods, interchangeability of different modalities has not been fully investigated. CCT is known to correlate with intraocular pressure (IOP). The aim of this study was to evaluate the agreement of Pentacam Scheimpflug system with noncontact specular microscopy (NCSM) and ultrasound (US) pachymetry in measuring CCT and the relation between IOP taken with Goldmann applanation tonometer (GAT) and the CCT measured with these three methods. METHODS: The right eyes of 135 enrolled persons without antiglaucoma drug use (100 females and 35 males), who comprised 32 patients with primary open-angle glaucoma, 14 with ocular hypertension, 45 with primary angle-closure glaucoma, and 44 controls, were studied. Intermethod comparison of CCT was made by the 95% limits of agreement analysis according to Bland and Altman. Linear regression analysis was used to assess the relationship between IOP and CCT taken with each modality. RESULTS: The mean CCT (+/-SD) taken with Scheimpflug, US, and NCSM was 559.49 +/- 38.44 microm, 553.01 +/- 39.33 microm, and 552.04 +/- 42.95 microm, respectively. The average values of CCT taken with the three instruments were not significantly different (one-factor ANOVA; p = 0.26), although the marginal mean difference between Scheimpflug and US or NCSM was statistically significant (paired t test; p = 0.0009 and 0.005, respectively). The 95% limits of agreement were 6.47 +/- 43.21 microm between Scheimpflug and US, 7.45 +/- 58.86 microm between Scheimpflug and NCSM, and 0.98 +/- 51.69 microm between US and NCSM. There was a positive association between IOP and CCT measured with US or NCSM, whereas there was no correlation between IOP and CCT measured with Scheimpflug. CONCLUSIONS: Although CCT values measured with Scheimpflug, US, and NCSM are closely similar, clinicians should keep in mind that these methods are not simply interchangeable.     

Diurnal variation of intraocular pressure in normal-tension glaucoma

PURPOSE: Measurement of diurnal variation of intraocular pressure(IOP) is important for precise diagnosis of normal-tension glaucoma(NTG). We studied diurnal variation of IOP of NTG using a self-measuring tonometer. METHODS: A total of 159 patients(318 eyes) who were diagnosed as having NTG in Osaka Koseinenkin Hospital between 1994 and 2002 measured their own diurnal variation of IOP at home every 3 hours (8 times a day) using a prototype self-measuring non-contact air-puff tonometer(Hometonometer). RESULTS: The maximum IOP, the minimum IOP, and the range of diurnal variation of IOP were 16.8 +/- 2.0 mmHg(mean +/- standard deviation), 12.8 +/- 1.7 mmHg, and 4.0 +/- 1.3 mmHg, respectively. Maximum IOP occurred most frequently at noon(24.3%), 9:00 am(21.4%), and 6:00 am(17.4%). In 69.2% of eyes, maximum IOP was found during outpatient clinic hours(9:00 am to 6:00 pm). Minimum IOP occurred most frequently at midnight(34.1%), 3:00 am(22.8%), and 9:00 pm(17.8%). CONCLUSIONS: Approximately 30% of NTG patients have maximum IOP outside of outpatient clinic hours, and therefore measuring IOP in the early morning is important for determining the precise diurnal variation of their IOP. We hope that a safe self-measuring tonometer with which patients can measure their own IOP will be come commercially available soon, so that we can provide them with more individualized glaucoma treatment using the appropriate combination of medicines.     

Comparison of intraocular pressure lowering effect of once daily morning vs evening dosing of latanoprost/timolol maleate combination

PURPOSE: To compare intraocular pressure (IOP) reduction profiles of latanoprost-timolol maleate fixed combination (LTFC) administered in the morning or evening in primary open angle glaucoma (POAG). METHODS: A prospective, randomized study including 60 eyes of 30 patients with POAG was carried out. Patients were randomized to treatment with LTFC at 8 PM (Group 1) or at 8 AM (Group 2). After therapy of 4 weeks, IOP was measured at 2 AM, 6 AM,10 AM, 2 PM, 6 PM, and 10 PM and compared with baseline values and latanoprost therapy alone. RESULTS: Mean diurnal baseline IOPs and IOPs after treatment with latanoprost and LTFC were 23.6+/-2.6, 16.7+/-2.3, and 15.5+/-2.2 mmHg in Group 1 and 23.1+/-2.6, 16.9+/-2.4, and 15.7+/-2.4 mmHg in Group 2. LTFC lowered IOP more than latanoprost at all time points in both groups (p<0.001) (except 6 AM in Group 2). The mean IOP range after LTFC therapy was lower than the baseline in Group 1 whereas it was not different in Group 2. IOP at 10 AM was significantly higher than the other time points at baseline measurements in both groups (p<0.01) but after treatment there was no difference (p>0.05). According to IOP reduction from baseline, there was a statistically significant difference between groups in favor of Group 1 at 6 AM, 10 AM, and mean diurnal measurement (p<0.01). CONCLUSIONS: Both morning and evening dosing of LTFC were effective in lowering diurnal IOP in patients with POAG. However, evening dosing of LTFC seemed to be more effective in controlling IOP especially in the morning and avoiding the fluctuations with lower range of IOP.     

Diagnosis and treatment outcome of mycotic keratitis at a tertiary eye care center in eastern india

Background

A noninferiority trial was conducted to evaluate the efficacy of a single evening dose of fixed-combination latanoprost 50 μg/mL and timolol 0.5 mg/mL (Xalacom^®; LTFC), in Chinese patients with primary open-angle glaucoma (POAG) or ocular hypertension (OH) who were insufficiently controlled on β-blocker monotherapy or β-blocker-based dual therapy.

Methods

This 8-week, randomized, open-label, parallel-group, noninferiority study compared once-daily evening dosing of LTFC with the unfixed combination of latanoprost, one drop in the evening, and timolol, one drop in the morning (LTuFC). The primary efficacy endpoint was the mean change from baseline to week 8 in diurnal intraocular pressure (IOP; mean of 8 AM, 10 AM, 2 PM, 4 PM IOPs). LTFC was considered noninferior to LTuFC if the upper limit of the 95% confidence interval (CI) of the difference was < 1.5 mmHg (analysis of covariance).

Results

Baseline characteristics were similar for LTFC (N = 125; POAG, 70%; mean IOP, 25.8 mmHg) and LTuFC (N = 125; POAG, 69%; mean IOP, 26.0 mmHg). Mean diurnal IOP changes from baseline to week 8 were -8.6 mmHg with LTFC and -8.9 mmHg with LTuFC (between-treatment difference: 0.3 mmHg; 95%-CI, -0.3 to 1.0). Both treatments were well tolerated.

Conclusions

A single evening dose of LTFC was at least as effective as the unfixed combination of latanoprost in the PM and timolol in the AM in reducing IOP in Chinese subjects with POAG or OH whose IOP was insufficiently reduced with β-blocker monotherapy or β-blocker-based dual therapy. LTFC is an effective and well tolerated once-daily treatment for POAG and OH.

Trial registration

Clinicaltrials.gov registration: NCT00219596     

Repeatability and reproducibility of the BVI ultrasonic Pachymeter

PURPOSE: To evaluate the interobserver and intraobserver reliability of a commercially available, portable, ultrasonic pachymeter. METHODS: For the interobserver variability study, 42 healthy subjects underwent repeated ultrasonic pachymetry under topical anaesthesia performed by two observers. For the intraobserver study, another 30 further healthy subjects underwent repeated pachymetry by one of the observers. Agreement was analysed by means of Bland-Altman plots and by determination of the intraclass correlation coefficient. RESULTS: For the interobserver variability study, the mean measurement difference between observers was 0.7 microm (95% CI -0.8-2.2 microm) and the intraclass correlation coefficient was 0.9958 (95% CI 0.9922-0.9977). The Bland-Altman plot showed narrow limits of agreement with respect to central corneal thickness (CCT). For the intraobserver variability study, the mean difference between the repeated measurements was 0.9 microm (95% CI -3.1-1.3 microm). The intraclass correlation coefficient was 0.9934 (95% CI 0.9863-0.9969). A Bland-Altman plot again showed narrow limits of agreement with respect to CCT. The mean CCT for 72 subjects was 538 microm (95% CI 528-545 microm). CONCLUSIONS: Measurements of CCT using the BVI Pocket Pachymeter were repeatable and had excellent interobserver reliability. Measurement variation amounted to less than 0.2% assuming a mean CCT of 538 microm.     

Twenty-four-hour diurnal curve comparison of commercially available latanoprost 0.005% versus the timolol and dorzolamide fixed combination

PURPOSE: To evaluate the efficacy and safety of commercially available latanoprost 0.005% given every evening versus timolol 0.5% and dorzolamide 2% fixed combination (TDFC) given twice daily to white Greeks with primary open-angle glaucoma and ocular hypertensive patients. DESIGN: A single-masked, two-center, crossover comparison with two 6-week treatment periods occurring after at least a 3-week medicine-free period. Diurnal curve intraocular pressures were taken at 2:00 AM, 6:00 AM, 10:00 AM, 2:00 PM, 6:00 PM, and 10:00 PM. PARTICIPANTS: Thirty-four subjects with primary open-angle glaucoma or ocular hypertension were enrolled. INTERVENTIONS: Latanoprost 0.005% given every evening and TDFC twice daily. MAIN OUTCOME MEASURES: The primary efficacy variable was diurnal intraocular pressure. RESULTS: Thirty-three patients completed the study. On the last day of treatment, the mean diurnal intraocular pressure for latanoprost was 15.9 +/- 2.3 mmHg and for TDFC was 15.3 +/- 2.0 mmHg (P = 0.05). Individual time points for intraocular pressure were not statistically different between groups except at the 10:00 PM time point, when the mean for TDFC was 14.6 +/- 2.7 mmHg and for latanoprost was 16.6 +/- 3.1 mmHg (P < 0.006). Eighteen patients overall preferred latanoprost versus 2 patients for the fixed combination, generally because of the greater convenience of once daily dosing. Adverse events were not significantly different between groups except that a bitter taste was found more frequently with TDFC (n = 9) than with latanoprost (n = 0; P = 0.009). Despite screening to exclude intolerance to beta-blockers, a single patient had to discontinue the TDFC because of new-onset asthma. CONCLUSIONS: This study indicates that the 24-hour diurnal intraocular pressure is lowered more, by a small but statistically significant amount, with TDFC compared with latanoprost in primary open-angle glaucoma and ocular hypertensive patients.     

Effect of different dose schedules of 0.15% unoprostone isopropyl on intraocular pressure and pupil size in the glaucomatous beagle.

The changes in intraocular pressure (IOP) and pupil size (PS) after instillations of 0.15% unoprostone isopropyl (Rescula, Novartis Ophthalmics, Duluth, GA) were investigated in the spontaneous glaucoma Beagle model. From the first-day baseline IOP of 27.3+/-3.2 mmHg placebo eye and 32.8+/-5.1 mmHg control eye, the mean+/-standard error of the mean (SEM) diurnal changes after 0.15% unoprostone, at 8 AM once-daily for the next 4 days, were 15.5+/-1.3 mmHg, 14.7+/-1.9 mmHg, 16.1+/-1.1 mmHg, and 17.0+/-1.5 mmHg, respectively, and were significantly different from the control eye. After 0.15% unoprostone was instilled at 8 PM, the mean+/-SEM baseline changes from the baseline IOP (insert drug eye 9 AM) in the drug eyes were 5.9+/-2.5 mmHg, 5.2+/-4.1 mmHg, 9.7+/-2.5 mmHg, and 3.6+/-3.6 mmHg, respectively. When 0.15% unoprostone was instilled twice-daily, the mean+/-SEM baseline IOP (insert drug eye 9 AM) changes were 13.6+/-0.7 mmHg, 13.9+/-1.4 mmHg, 11.3+/-1.0 mmHg, and 9.3+/-1.4 mmHg, respectively, and were significantly different from the control eyes. Miosis occurred within 2 hours and lasted several hours. Unoprostone isopropyl instilled once-daily (AM or PM), as well as twice-daily, produces significant decreases in IOP and PS in the glaucomatous Beagle.     

Comparison of central corneal thickness measurements by specular microscopy,ultrasound pachymetry,and ultrasound biomicroscopy

PURPOSE: To compare the reproducibility and mean values of central corneal thickness (CCT) obtained by specular microscopy, ultrasound pachymetry, and ultrasound biomicroscopy (UBM). SETTING: Department of Ophthalmology, University of Toronto, Toronto, Ontario, Canada. METHODS: Thirty-one healthy volunteers were recruited for a sample size of 62 eyes. All subjects had pachymetric measurements by specular microscopy, ultrasound pachymetry, and UBM. Three separate measurements meeting criteria for centrality and perpendicularity were recorded for each eye. RESULTS: The mean CCT by specular microscopy was 572 microm (95% confidence interval (CI), 566-578 microm), which was significantly greater than 550 microm (95% CI, 545-556 microm) (P<.001) and 555 microm (95% CI, 550-560 microm) (P<.001) by ultrasound pachymetry and UBM, respectively. The mean standard deviation (SD) of repeated measurements by specular microscopy was 7.82 microm, which was significantly greater than the mean SDs of 4.14 microm (P<.001) and 3.90 microm (P<.001) by ultrasound pachymetry and UBM, respectively. There was no statistically significant difference between the mean SDs by ultrasound pachymetry and UBM (P=.156). CONCLUSIONS: Although the CCT measurements by specular microscopy were significantly less reproducible than those by ultrasound pachymetry and UBM, the error levels were clinically acceptable. Both ultrasound pachymetry and UBM produced similar CCT measurements, which were significantly less than those generated by specular microscopy. One should be aware of the advantages and limitations of each machine and of possible differences in the CCT measurements by optical and ultrasound pachymetry.     

中央角膜厚度对24h眼压波动的影响

目的:探讨中央角膜厚度(central corneal thickness,CCT)对24h眼压波动的影响。方法:使用Goldmann眼压计测量39例78眼未治疗的青光眼患者和44例88眼年龄匹配的正常对照眼的24h眼压波动(5am,7am,10am,2pm,6pm,10pm),并用超声测厚仪测量CCT。结果:青光眼组和对照组的平均眼压分别为21.33±2.91和16.19±2.33mmHg(t=12.615,P=0.000);峰值分别为24.67±2.72和18.55±2.45mmHg(t=12.613,P=0.000);波动值分别为6.63±3.26和4.72±1.60mmHg(t=4.709,P=0.000);CCT分别为544.44±32.11和537.16±27.66μm(t=1.569,P=0.119)。CCT与青光眼组的眼压波动值无显著相关性(r=0.140,P=0.222);CCT与对照组的眼压波动值亦无显著相关性(r=0.050,P=0.642)。以CCT<545μm为薄角膜组,CCT≥545μm为厚角膜组进行对比分析,青光眼组和对照组的平均眼压、峰值、波动值的差异无显著性(P>0.05)。结论:CCT与24h眼压波动无显著相关性。     

Central corneal thickness measurement in clinical practice

OBJECTIVE: To determine if a single measurement of central corneal thickness (CCT) is an adequate sample to aid in glaucoma risk assessment in clinical practice. METHODS: Central corneal thickness was measured by ultrasound pachymetry (mean of 15 measurements for each eye) on two separate occasions at least one month apart (range, 33 to 610 days). Eyes with a history of prior incisional surgery or corneal pathology were excluded. RESULTS: Ninety-eight eyes of 98 patients (43 male, 55 female) were enrolled. Mean age was 61.2 +/- 15.5 years. Mean inter-test period was 276 +/- 124 days. No significant difference in mean CCT was observed between the two visits (549 +/- 41 microm versus 548 +/- 42 microm, P = 0.4, two-tailed, paired t test). Measured CCT values differed by more than 20 microm in 20 eyes (20.4%), whereas CCT difference of at least 40 microm was seen in 5 eyes (5.1%). There was no correlation between the measured or absolute difference in CCT and IOP (r = -0.016, P > 0.43), inter-test time period (r = 0.072, P > 0.23), and glaucoma diagnosis. CONCLUSION: Central corneal thickness measurements in this study differed by at least 20 microm in 20% of eyes. This has important implications for risk assessment, management, and follow-up of patients with glaucoma and related disorders. Factors affecting CCT measurement, such as examiner error or true alterations in corneal thickness, require continued investigation.     

Comparison of daytime efficacy and safety of dorzolamide/timolol maleate fixed combination versus latanoprost

PURPOSE: To compare the 12-hour efficacy and safety of dorzolamide/timolol fixed combination (DTFC) dosed twice daily versus latanoprost dosed every evening following a timolol run-in in primary open-angle glaucoma patients. METHODS: Following a 6-week timolol run-in patients were randomized to either DTFC or latanoprost for 6 weeks and then changed to the opposite treatment for 6 weeks. At the end of the run-in, and the end of each treatment period, the intraocular pressure (IOP) was measured every 2 hours between 8:00 AM and 8:00 PM. RESULTS: Thirty-one patients completed at least one time point in both treatment periods. Both treatments reduced the IOP for the diurnal curve, and at each time point, from the timolol run-in baseline (p<0.0001). The 12-hour IOP on timolol was 22.1+/-2.8 mmHg, whereas on DTFC it was 18.1+/-2.8 and latanoprost 18.3+/-3.1 mmHg (p=0.4). Further, there was no statistical difference in IOP between treatments at any time point (p< or =0.1). There was no statistical difference for any individual adverse event between treatments (p>0.05). CONCLUSIONS: This study suggests that following a timolol run-in both DTFC and latanoprost provide comparable daytime efficacy and safety.     

Relationship between travoprost and central corneal thickness in ocular hypertension and open-angle glaucoma

PURPOSE: To evaluate whether treatment with travoprost, an F2a prostaglandin analog, affects central corneal thickness (CCT) and whether intraocular pressure (IOP) response to the medication is related to baseline CCT. METHODS: This was a prospective, interventional, nonrandomized, nonconsecutive, clinical trial. In this multicenter study, 379 total patients, 220 with newly or previously diagnosed open-angle glaucoma (OAG), 141 with ocular hypertension (OHT), and 18 unspecified, were recruited from 15 Canadian sites. IOP and CCT assessments were performed at baseline and 6 weeks after treatment with travoprost. Patients on IOP-lowering therapy at the time of enrollment were washed out for 4 weeks before baseline examinations. IOP was measured with Goldmann tonometers and CCT with Accutome IV pachymeters. Statistical analysis was performed with S-PLUS software. RESULTS: Posttherapy mean IOP decreased by 6.31 mm Hg or 24.4% (P < 0.001), and regression analysis indicated relatively greater IOP reduction in patients with higher pretherapy IOP (slope = 0.64; 95% CI, 0.54-0.76). Mean CCT decreased by 6.9 microm (P < 0.001). IOP reduction was not related to CCT reduction (slope = 0.253; 95% CI, -0.232 to 0.739; P = 0.305). Percent IOP decrease was not related to baseline CCT (slope = -0.02; 95% CI, -0.06 to 00.02; P = 0.33) in the total study sample. When OHT and OAG groups were considered separately, the OAG patients had less percent IOP decrease with thicker baseline CCT (slope = -0.067; 95% CI, -0.13 to -0.004; P = 0.037). CONCLUSIONS: Treatment with travoprost decreased IOP significantly and was associated with CCT thinning, which had little or no effect on actual IOP decrease. In the OAG group, IOP decrease was found to be statistically smaller in patients with thicker corneas.