Concordance of diurnal intraocular pressure between fellow eyes in primary open-angle glaucoma

Evaluation and treatment of glaucoma 24hours a day. Where are we and where are we going?

Current management of glaucoma generally involves medical, laser, or surgical treatment in order to achieve an intraocular pressure (IOP) control which is commensurate with either stability or delayed progression of the disease. Although the follow-up of glaucoma patients is usually carried out with sporadic and isolated intraocular pressure measurements, the literature already indicates that this might not the best option to manage glaucoma patients. This article reviews the importance of 24hours intraocular pressure monitoring based on studies and publications that exist in this regard to date. A critical review on the methodology of these publications has been conducted. The need is stressed for further studies on the intraocular pressure patterns in different types of glaucoma, as well as the pattern with different therapies used in glaucoma aimed at optimising the management of the disease.

Concordance of 24-h intraocular pressure curve in patients with untreated unilateral primary open-angle glaucoma

The present study aimed to assess the concordance of 24-h intraocular pressure (IOP) curves between glaucomatous and contralateral eyes for patients with untreated unilateral primary open-angle glaucoma (POAG). A total of 32 patients with unilateral POAG and 32 age-matched normal subjects were enrolled. The IOP measurements were performed every 2 h over a 24-h period. The concordance of the 24-h IOP curves was assessed via the correlation coefficient (r), intraclass correlation coefficient (ICC) and repeated-measures analysis of variance (ANOVA). No significant difference was identified between all IOPs, as well as the mean, peak and trough IOP or IOP fluctuations of the paired eyes in the two groups. The strength of association of all IOPs was moderate in the glaucoma group (r, 0.752-0.867) and the normal controls (r, 0.625-0.873). IOP readings at each time-point indicated a high agreement in the glaucoma group (ICC, 0.857-0.929) and the normal controls (ICC, 0.768-0.932). Repeated-measures ANOVA indicated that the 24-h IOP curves of the paired eyes had parallel profiles in the two study groups (P=0.837 and P=0.897, respectively). The glaucoma patients had significantly higher proportions of all IOPs displaying absolute differences of ≥2 and ≥3 mmHg (46.09 vs. 35.68%, P<0.001; 29.69 vs. 12.50%, P<0.001, respectively). In conclusion, the 24-h IOP curves of the paired eyes had parallel profiles in unilateral glaucoma patients and normal subjects. However, unilateral glaucoma patients had a significantly larger proportion of IOP differences of ≥2 and ≥3 mmHg.

Bilateral tear film alterations in patients with unilateral quiescent herpes simplex keratitis

PURPOSE

To evaluate bilateral tear function and corneal sensitivity in patients with unilateral quiescent herpes simplex keratitis (HSK) and determine the correlation between corneal sensitivity and tear secretion in both eyes.

METHODS

Thirty-five patients diagnosed with unilateral quiescent HSK and 35 heathy controls were included in this study. Bilateral tear osmolarity, Schirmer's test, the tear break-up time (TBUT) and corneal sensitivity were measured in all participants.

RESULTS

In the HSK group, both eyes demonstrated a significant increase in tear osmolarity, and a decrease in Schirmer's test and the TBUT compared with healthy controls (All p < 0.001). The bilateral tear osmolarity and Schirmer's test were similar, but the TBUT (4.9 ± 2.1 versus 7.4 ± 2.0 second; p < 0.001) and corneal sensitivity (35.1 ± 1.9 versus 54.3 ± 0.8 mm; p < 0.001) were significantly lower in the affected eyes. The bilateral tear osmolarity, Schirmer's test and the TBUT were significantly correlated with corneal sensitivity of the affected eye (All p < 0.001). When corneal sensitivity of the unaffected eye was treated as a control variable, tear osmolarity (R = -0.626, p < 0.001), Schirmer's test (R = 0.739, p < 0.001) and the TBUT (R = 0.691, p < 0.001) of the unaffected eyes were still significantly correlated with the corneal sensitivity of the affected eyes.

CONCLUSIONS

Unilateral quiescent HSK causes bilateral tear impairment, which depends on the loss of corneal sensitivity in the affected eye. In the affected eye with severe corneal sensitivity loss, bilateral dry eye occurred.

24-h Efficacy of Glaucoma Treatment Options

Current management of glaucoma entails the medical, laser, or surgical reduction of intraocular pressure (IOP) to a predetermined level of target IOP, which is commensurate with either stability or delayed progression of visual loss. In the published literature, the hypothesis is often made that IOP control implies a single IOP measurement over time. Although the follow-up of glaucoma patients with single IOP measurements is quick and convenient, such measurements often do not adequately reflect the untreated IOP characteristics, or indeed the quality of treated IOP control during the 24-h cycle. Since glaucoma is a 24-h disease and the damaging effect of elevated IOP is continuous, it is logical that we should aim to understand the efficacy of all treatment options throughout the 24-h period. This article first reviews the concept and value of diurnal and 24-h IOP monitoring. It then critically evaluates selected available evidence on the 24-h efficacy of medical, laser and surgical therapy options. During the past decade several controlled trials have significantly enhanced our understanding on the 24-h efficacy of all glaucoma therapy options. Nevertheless, more long-term evidence is needed to better evaluate the 24-h efficacy of glaucoma therapy and the precise impact of IOP characteristics on glaucomatous progression and visual prognosis.

Contralateral intraocular pressure lowering effect of prostaglandin analogues

Background:

Though the use of prostaglandin analogues (PGA) for reduction of intraocular pressure (IOP) has shown a marked increase, studies evaluating the contralateral effects of PGA are limited.

Aims:

To evaluate if PGA treatment in one eye has an effect on the IOP of the untreated fellow eye.

Design:

Retrospective study.

Materials and Methods:

Thirty patients of open-angle glaucoma with no previous antiglaucoma treatment underwent 24-hour diurnal IOP phasing. They subsequently were started on a uniocular trial with PGA, and had office diurnal IOP measurements 6 weeks later. Twenty-four hour diurnal consisted of 8 IOP readings over 24 hours and office diurnal consisted of 4 IOP readings between 8 AM and 6 PM at 3 hourly intervals.

Statistical Analysis:

IOPs of the fellow eye during the office diurnal were compared with IOPs at similar time points during the 24-hour diurnal using paired t-tests.

Results:

Mean (± standard deviation) IOP in the treated eye reduced (P < 0.001) from 17.17 ± 3.2 mm Hg at baseline to 13.7 ± 2.4 mm Hg at 6 weeks, while that in the untreated eye reduced from 16.4 ± 3.1 mm Hg to 14.8 ± 2.7 mm Hg (P = 0.01). The decrease in IOP in the untreated fellow eye was statistically significant at 8 AM (2.7 mm Hg, P = 0.003) and 11 AM (2.3 mm Hg, P = 0.01) but not so at 2 PM (1.2 mm Hg, P = 0.10) and 5 PM (0.9 mm Hg, P = 0.19). The amount of IOP reduction in the untreated eye was significantly associated with the magnitude of IOP reduction in the treated eye (β = 0.69, P = 0.008).

Conclusion:

Uniocular PGA treatment tends to reduce the IOP of the untreated fellow eye.

Efficacy of a contact lens sensor for monitoring 24-h intraocular pressure related patterns

Purpose

To study performance of a contact lens sensor (CLS) for 24-hour monitoring of IOP-related short-term patterns and compare with IOP obtained by pneumatonometry.

Methods

Prospective clinical trial. Thirty-one healthy volunteers and 2 glaucoma patients were housed for 24 hours in a sleep laboratory. One randomly selected eye was fitted with a CLS (Triggerfish, Sensimed, Switzerland), which measures changes in ocular circumference. In the contralateral eye, IOP measurements were taken using a pneumatonometer every two hours with subjects in the habitual body positions. Heart rate (HR) was measured 3 times during the night for periods of 6 minutes separated by 2 hours. Performance of CLS was defined in two ways: 1) recording the known pattern of IOP increase going from awake (sitting position) to sleep (recumbent), defined as the wake/sleep (W/S) slope and 2) accuracy of the ocular pulse frequency (OPF) concurrent to that of the HR interval. Strength of association between overall CLS and pneumatonometer curves was assessed using coefficients of determination (R²).

Results

The W/S slope was statistically significantly positive in both eyes of each subject (CLS, 57.0 ± 40.5 mVeq/h, p<0.001 and 1.6 ± 0.9 mmHg/h, p<0.05 in the contralateral eye). In all, 87 CLS plots concurrent to the HR interval were evaluated. Graders agreed on evaluability for OPF in 83.9% of CLS plots. Accuracy of the CLS to detect the OPF was 86.5%. Coefficient of correlation between CLS and pneumatonometer for the mean 24-h curve was R² = 0.914.

Conclusions

CLS measurements compare well to the pneumatonometer and may be of practical use for detection of sleep-induced IOP changes. The CLS also is able to detect ocular pulsations with good accuracy in a majority of eyes.

Trial Registration

ClinicalTrials.gov NCT01390779

Intraocular pressure fluctuation and glaucoma progression: what do we know?

While mean intraocular pressure (IOP) has long been known to correlate with glaucomatous damage, the role of IOP fluctuation is less clearly defined. There is extensive evidence in the literature for and against the value of short-term and long-term IOP fluctuation in the evaluation and prognosis of patients with glaucoma. We present here the arguments made by both sides, as well as a discussion of the pitfalls of prior research and potential directions for future studies. Until a reliable method is developed that allows for constant IOP monitoring, many variables will continue to hinder us from drawing adequate conclusions regarding the significance of IOP variation.

Effects of several anti-glaucoma medications on the circadian intraocular pressure fluctuations in patients with primary open-angle glaucoma

PURPOSE

The purpose of the present study was to elucidate the effects of several anti-glaucoma medications on the circadian intraocular pressure (IOP) fluctuations in patients with primary open-angle glaucoma (POAG).

PATIENTS AND METHODS

POAG patients (n=61; 61 eyes) with or without glaucoma medications were included. IOP measurement at 14 time points (12, 15, 18, 21, 0, 6, 9, 12, 15, 18, 21, 0, 6, and 9 o'clock) was performed over a period of 48 h. IOP changes occurring in the first 24 h and the subsequent 24 h were evaluated by several therapeutic factors.

RESULTS

A nocturnal acrophase pattern was observed in all the eyes with POAG. The shape of the first 24 h IOP curve was similar to that of the following 24 h IOP curves. However, there were fewer overall IOP levels in the second 24 h time period. Circadian IOP fluctuation patterns exhibited in each eye on the 1st and 2nd days were single acrophase patterns: diurnal acrophase (1st day, 54.0%; 2nd day, 60.7%) and nocturnal acrophase (1st day, 36.1%; 2nd day, 31.1%), and no single acrophase patterns: flat (1st day, 6.6%; 2nd day, 4.9%) and double acrophase (1st day, 3.3%; 2nd day, 3.3%). Among the different medication groups, a nocturnal acrophase circadian pattern was observed in the patient groups being treated by combinations of prostaglandin analog (PG) and β blocker or PG, β blocker and carbonic anhydrase inhibitor (CAI). However, this was not apparent in patient groups with or without single anti-glaucoma medications or a combination of PG and CAI.

CONCLUSIONS

The present study of IOP monitoring patients with POAG over a period of 48 h indicated that their changes in circadian patterns of IOP were affected by types of anti-glaucoma medications.

Bilateral nerve alterations in a unilateral experimental neurotrophic keratopathy model: a lateral conjunctival approach for trigeminal axotomy

To study bilateral nerve changes in a newly developed novel mouse model for neurotrophic keratopathy by approaching the trigeminal nerve from the lateral fornix. Surgical axotomy of the ciliary nerve of the trigeminal nerve was performed in adult BALB/c mice at the posterior sclera. Axotomized, contralateral, and sham-treated corneas were excised on post-operative days 1, 3, 5, 7 and 14 and immunofluorescence histochemistry was performed with anti-β-tubulin antibody to evaluate corneal nerve density. Blink reflex was evaluated using a nylon thread. The survival rate was 100% with minimal bleeding during axotomy and a surgical time of 8±0.5 minutes. The blink reflex was diminished at day 1 after axotomy, but remained intact in the contralateral eyes in all mice. The central and peripheral subbasal nerves were not detectable in the axotomized cornea at day 1 (p<0.001), compared to normal eyes (101.3±14.8 and 69.7±12.0 mm/mm² centrally and peripherally). Interestingly, the subbasal nerve density in the contralateral non-surgical eyes also decreased significantly to 62.4±2.8 mm/mm² in the center from day 1 (p<0.001), but did not change in the periphery (77.3±11.7 mm/mm², P = 0.819). Our novel trigeminal axotomy mouse model is highly effective, less invasive, rapid, and has a high survival rate, demonstrating immediate loss of subbasal nerves in axotomized eyes and decreased subbasal nerves in contralateral eyes after unilateral axotomy. This model will allow investigating the effects of corneal nerve damage and serves as a new model for neurotrophic keratopathy.

The value of intraocular pressure asymmetry in diagnosing glaucoma

PURPOSE

To investigate the amount of intraocular pressure (IOP) asymmetry in a large group of ethnically diverse patients with and without glaucoma, and to delineate the risk for glaucoma which increasing amounts of IOP asymmetry confer upon the patient.

PATIENTS AND METHODS

Collaborative retrospective study of 326 glaucoma patients and 326 controls. Former Wills Eye Institute fellows collected single pre-treatment measurements of IOP on patients diagnosed as having definite glaucoma based on characteristic optic nerve damage and confirmatory visual field damage. Patients with a normal eye examination who had normal-appearing optic discs and no apparent glaucoma, or who had a normal eye examination in association with refractive error or cataract, were used as controls.

RESULTS

Intraocular pressure asymmetry is a significant risk factor for having glaucoma (odds ratio, 2.14; 95% confidence interval, 1.86-2.47; P<0.001). Absence of IOP asymmetry between the fellow eyes is associated with a 1% probability of having glaucoma. A difference of 3 mm Hg is associated with a 6% probability of having glaucoma, and a difference of >6 mm Hg with a 57% probability of having glaucoma. The association between IOP asymmetry and glaucoma status is significant for subjects with both elevated IOP (P=0.014) and statistically normal IOP (maximum IOP ≤ 21 mm Hg; P<0.001).

CONCLUSIONS

Inter-eye asymmetry of IOP is a common finding in patients with glaucoma. There is a direct relationship between the amount of IOP asymmetry between the fellow eyes and the likelihood of having glaucoma.

Is the observed lowering of intraocular pressure due to treatment?

Objective:

Use Bayes' theorem to estimate the intraocular pressure (IOP) lowering effect of medical treatment initiated for glaucoma and determine if IOP comparisons to the baseline IOP of the same eye is clinically useful.

Materials and Methods:

The probability that treatment with prostaglandin is responsible for an observed 20% decrease in IOP with prostaglandin treatment was calculated using Bayes' theorem using the following available information: the probability of a 20% decrease in IOP given treatment with prostaglandin, the probability of a treatment effect using prostaglandin and the overall probability of a 20% decrease in IOP. The calculations were repeated to account for a possible 2 mmHg overestimation of effect caused by measurement error in performing applanation tonometry.

Results:

The probability that treatment is responsible for an observed 20% decrease in IOP following initiation of treatment with a prostaglandin was 99%. After adjusting for measurement error this probability was 98%. Obtaining two IOP measurements marginally increased the probability.

Conclusion:

Following initiation of treatment with prostaglandin, Bayes' theorem allows us to infer that treatment effect is the most likely explanation for an observed 20% decrease in IOP from the baseline; this inference remains even after adjusting for known measurement error. The high probability of a treatment effect is due to the high prior odds of treatment effect and the high likelihood ratio for prostaglandin producing such an effect. If data is available, similar calculations can be used for other percentage decreases, other medications and for the monocular trial.

Asymmetry of 24-hour intraocular pressure reduction by topical ocular hypotensive medications in fellow eyes

PURPOSE

A core assumption for the 1-eye therapeutic trial of ocular hypotensive medications is the symmetrical reduction of intraocular pressure (IOP) in paired eyes. This assumption was evaluated for 24-hour IOP reduction in patients who underwent monotherapy or adjunctive therapy.

DESIGN

Database study.

PARTICIPANTS

Patients 41 to 79 years of age with primary open-angle glaucoma or ocular hypertension.

METHODS

Twenty-four-hour IOP data from the paired eyes of patients undergoing bilateral monotherapy (n = 66) of latanoprost, travoprost, timolol, or brimonidine or bilateral adjunctive therapy (n = 52) with brinzolamide or timolol added to latanoprost monotherapy were analyzed retrospectively. Measurements of IOP were obtained every 2 hours in a sleep laboratory before and after at least 4-week drug treatments. Strengths of association for single-pair IOP reductions and average IOP reductions in the paired eyes during the office-hour, diurnal, nocturnal, and 24-hour periods and in different body positions were analyzed.

MAIN OUTCOME MEASURES

Variance for the difference, percentage distribution of large absolute difference, and coefficient of determination (r(2)) in the paired IOP reductions.

RESULTS

The standard deviations for the differences in single-pair IOP reductions from the means were larger than 2.5 mmHg for all periods and body positions under monotherapy and adjunctive therapy. Absolute differences in single-pair IOP reductions of the cutoff thresholds of 3 and 2 mmHg or more occurred in more than 20% and 36% cases, respectively. Corresponding coefficients of determination were 0.240 to 0.374 with monotherapy and 0.215 to 0.381 with adjunctive therapy. When the average differences in the paired IOP reductions were analyzed for a specific period and posture, the standard deviations for the differences in the paired IOP reductions and the percentage distributions of large absolute differences were reduced, and most coefficients of determination were improved.

CONCLUSIONS

There is only a weak association between the right- and left-eye responses to IOP-lowering monotherapy or adjunctive therapy during a 24-hour period when single-pair IOP data are considered. Considering the averages of multiple paired IOP responses can improve the strength of the association.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Asymmetry of diurnal intraocular pressure fluctuation between right and left eyes

PURPOSE

To evaluate diurnal curves of intraocular pressure (IOP) in the right and left eyes of non-glaucomatous patients.

METHODS

We measured IOP during waking hours and in habitual positions in 102 non-glaucomatous patients every 2 hr between 09.00 hr and 23.00 hr using a Goldman applanation tonometer. Individual factors and biometries were measured and associated with diurnal IOP variations.

RESULTS

There was no significant difference in IOP variation between the right and left eyes over eight time-points (repeated measure anova, P = 0.995). The mean coefficient of IOP in the right and left eyes at the eight time-points ranged from 0.806 to 0.887. Forty-one (40.2%), 15 (14.7%) and five (4.9%) patients showed at least one asymmetrical IOP variation over seven time intervals at the cut-off value ≥ 2, ≥ 3 and > 3 mmHg, respectively. Mean incidence of asymmetrical IOP variation was 10.9 ± 1.6% at ≥ 2 mmHg, 2.9 ± 0.8% at ≥ 3 mmHg and 0.8 ± 0.4% at > 3 mmHg. Age, differences in anterior chamber depth, lens thickness and axial length showed several significant associations with the incidence of asymmetrical IOP variation.

CONCLUSION

Diurnal variation of IOP showed asymmetry between right and left eyes in patients without glaucoma. Ageing and differences in local ocular factors between bilateral eyes may affect the incidence of asymmetrical IOP variation.

The utility of the monocular trial: data from the ocular hypertension treatment study

OBJECTIVE

To determine whether adjusting the intraocular pressure (IOP) change of the trial eye for the IOP change of the fellow eye (i.e., monocular trial) is a better assessment of medication response than testing each eye independently.

DESIGN

Analysis of data from a prospective, randomized, clinical trial.

PARTICIPANTS

Two hundred six participants with ocular hypertension randomized to the observation group and later started on a topical prostaglandin analog (PGA).

METHODS

Participants were started on a topical PGA in 1 eye and returned in approximately 1 month to determine medication response. The IOP response of the trial eye was determined by the IOP change between baseline and 1 month in the trial eye alone (unadjusted method) and by adjusting for the IOP change in the fellow eye between the same visits (adjusted method). Our "gold standard" for medication response was the IOP change in the trial eye between up to 3 pre- and 3 posttreatment visits on the same medication. Pearson correlation was used to compare the gold standard with the unadjusted and adjusted methods. In addition, symmetry of IOP response between trial and fellow eyes to the same medication was determined by correlating the trial eye IOP change between up to 3 pre- and 3 posttreatment visits to the fellow eye IOP change between the same visits.

MAIN OUTCOME MEASURES

Correlations of IOP change of the trial eye using the gold standard to the IOP change of the trial eye using the unadjusted and adjusted methods.

RESULTS

The correlations of IOP change using the gold standard to the IOP change using the unadjusted and adjusted methods were r = 0.40 and r = 0.41, respectively. The correlation of IOP change of both eyes between the same pre- and posttreatment visits was r = 0.81.

CONCLUSIONS

The monocular trial (i.e., adjusted method) appears equivalent to testing each eye independently (i.e., unadjusted method); however, neither method is adequate to determine medication response to topical PGAs. Both eyes have a similar IOP response to the same PGA. Further studies to understand IOP fluctuation are necessary to improve current methods of assessing medication response.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

The monocular trial controversy: a critical review

PURPOSE OF REVIEW

The utility of the monocular trial to determine the response to topical ocular hypotensive medications has been recently debated. This review provides a critical evaluation of recent studies and discusses factors that affect the accurate determination of medication response.

RECENT FINDINGS

Recent concerns about the validity of the monocular trial arise from studies reporting a low-to-moderate correlation of intraocular pressure (IOP) response between the first and second eyes to the same topical ocular hypotensive medication. Few studies, however, have addressed the classic monocular trial that adjusts IOP in the trial eye based on IOP change in the fellow eye. Conflicting results from prior studies are due to differences in study question, study design, and method of analysis. Factors such as variability of IOP, diurnal variation, and regression to the mean further complicate the understanding of whether monocular trials or binocular simultaneous trials (i.e. testing each eye separately) are better for determining medication effect.

SUMMARY

The issue of whether or not to use the monocular trial remains controversial. A more clear understanding of factors such as nontherapeutic variability of IOP within the same eye and between eyes may elucidate the answer to this question. Further studies of monocular and binocular trials are needed to clarify which method better estimates medication response.

Variability of intraocular pressure measurements in observation participants in the ocular hypertension treatment study

PURPOSE

To describe variability of intraocular pressure (IOP) measurements within the same eye and between right and left eyes over a 60-month period in participants in the Ocular Hypertension Treatment Study.

DESIGN

Analysis of data from a prospective, randomized clinical trial.

PARTICIPANTS

Eight hundred ten participants randomized to the observation group.

METHODS

Intraocular pressure measurements were obtained at the baseline visit and every 6 months thereafter. Pearson correlation coefficients were calculated for IOP measurements in the same eye between visits and for IOP measurements between right and left eyes of participants at each visit. Differences in IOP measurements between visits are reported in percent change (>15%, >20%, and >30%) and in millimeters of mercury (<3 mmHg, 3-5 mmHg, and >5 mmHg). The effects of regression to the mean, consistency in time of day, and sequence of IOP measurement of right and left eyes were examined.

MAIN OUTCOME MEASURES

Correlation of IOP measurements between consecutive 6-month visits.

RESULTS

The correlation of IOP measurements within the same eye between consecutive visits was r = 0.62, whereas the correlation of IOP measurements between right and left eyes at the same visit was r = 0.72. Thirteen percent of eyes had >20% change in IOP between consecutive visits. Sixty-six percent of eyes had a change in IOP within 3 mmHg, and 10% of eyes had a change in IOP >5 mmHg between visits. Eyes with a higher baseline IOP had a lower IOP at 6 months. There was a stronger correlation of IOP measured within 2 hours of the time of day between visits (r = 0.56) than >2 hours apart (r = 0.39). IOP of the right eye, which was measured first, was 0.3+/-2.8 mmHg higher than the left eye.

CONCLUSIONS

The variability of IOP measurements in the same eye between consecutive visits is moderate and is greater than the variability of IOP measurements between right and left eyes at the same visit. Factors affecting the variability of IOP measurement include regression to the mean, time of day, and measurement order. Knowledge of variability in IOP and its measurements may help clinicians establish a more accurate baseline IOP, target IOP, and assessment of medication effect.

Efficacy and tolerability of a large scale change in regimen from latanoprost to travoprost in glaucoma patients at the Manhattan Veterans Administration Hospital

Objective

This retrospective study was designed to investigate the efficacy and tolerability of travoprost 0.004% substituted for latanoprost 0.005% in glaucoma patients at the Manhattan Veterans Administration Hospital.

Research design and methods

We conducted a chart review of patients with stable intraocular pressure (IOP) undergoing a formulary change in regimen from latanoprost 0.005% to travoprost 0.004%. Diagnoses included primary open angle glaucoma, ocular hypertension, pigment dispersion glaucoma, and pseudoexfoliation glaucoma.

Main outcome measures

The primary outcome measures were IOP change between baseline and 6 months and patient-reported adverse events throughout the study.

Results

In the single therapy group (N = 60 eyes), the mean baseline IOP on latanoprost was 15.8 mmHg; after 6 months on travoprost, it was 14.9 mmHg (p < 0.1). In the concomitant therapy group (N = 126 eyes), the mean baseline IOP was 16.7 mmHg; after 6 months on travoprost, it was 15.9 mmHg (p < 0.01). A reduction of IOP ≥ 3 mmHg occurred in 28 eyes of 21 patients at 6 months. An increase of IOP ≥ 3 mmHg occurred in 5 eyes of 4 patients at 6 months. One patient was switched back to latanoprost due to irritation at 3 months. No other patient-reported adverse events, including increased hyperemia, were observed throughout the follow-up period.

Conclusions

A change in therapeutic regimen from latanoprost 0.005% to travoprost 0.004% maintained IOP control in stable patients, and in some produced a further reduction in IOP. A change in therapy from latanoprost to travoprost was effective and well-tolerated for the glaucoma patients in this study.