Effect of latanoprost on diurnal variations of intraocular pressure in normal-tension glaucoma

OBJECTIVES: To study the effect of instillation of latanoprost on the diurnal variation in the intraocular pressure(IOP), blood pressure, and pulse rate in patients with normal-tension glaucoma(NTG). SUBJECTS AND METHODS: The diurnal variation in the IOP was determined in 23 eyes in 23 NTG patients after a washout period of 4 weeks or longer. The diurnal variation in IOP was then remeasured after latanoprost monotherapy of 8 weeks or longer. The IOP was measured by the Goldmann applanation tonometer at 10:00, 13:00, 16:00, 19:00, 22:00, 01:00, 03:00, 07:00, and 10:00 before and after treatment, and the IOP at each time point, mean diurnal IOP, maximum IOP, minimum IOP, and range of variation in IOP were compared before and after treatment. The blood pressure and pulse rate before and after treatment were also measured and compared. RESULTS: The IOP decreased significantly at all time points. The treatment caused significant decreases in the mean diurnal IOP, maximum IOP, minimum IOP, and range of variation in IOP. There were no differences in the blood pressure and pulse rate before and after treatment. CONCLUSIONS: Latanoprost significantly decreases the IOP throughout the day in NTG patients, and has no effects on the blood pressure and pulse rate. It is therefore useful in the treatment of NTG.     

Long term effect of latanoprost on intraocular pressure in normal tension glaucoma

AIM: To determine the long term effect of latanoprost on the intraocular pressure (IOP) of patients with normal tension glaucoma (NTG). METHODS: Newly diagnosed patients with NTG were recruited into the study and had their baseline IOPs measured hourly between 8 am and 5 pm using a handheld electronic Tonopen. Patients with fixation threatening field defects were placed immediately into the treatment group while those with non-fixation threatening field defects were randomised into either the treatment group or the control group (no treatment). Treatment consisted of once daily topical latanoprost 0.005%. After a minimum period of 6 months, the patients underwent a second period of IOP phasing. RESULTS: 76 newly diagnosed patients with NTG were recruited-26 had fixation threatening disease, 25 were randomised to treatment, and 25 randomised to the control group. The average duration of treatment was 11 months. The average and maximum diurnal IOP for the patients randomised to treatment were statistically significantly lower than for the control patients at follow up (p<0.05). The treated group as a whole demonstrated a 17% decrease in the average diurnal IOP and a 19% decrease in the maximum diurnal IOP when compared to baseline IOP. 41% of those treated achieved a decrease of at least 20%, but only 10% of patients achieved a decrease of at least 30%. CONCLUSION: Latanoprost had a sustained hypotensive effect in eyes with NTG and 41% of treated patients achieved a reasonable response. However, in the majority of eyes with NTG, latanoprost monotherapy may be insufficient in producing a desirable 30% reduction in IOP.     

Circadian changes of intraocular pressure and ocular perfusion pressure after timolol or latanoprost in Caucasians with normal-tension glaucoma

Purpose To evaluate the circadian effects on intraocular pressure (IOP) and ocular perfusion pressure (OPP) of 0.5% timolol or 0.005% latanoprost in Caucasian patients affected by normal-tension glaucoma (NTG). Patients and methods In this crossover trial, 30 consecutive NTG subjects underwent three 24-hour assessments of IOP, blood pressure (BP), heart rate (HR), and OPP [calculated according to the formula OPP = (1/3 systolic BP + 2/3 diastolic BP) x 2/3 – IOP]: at baseline, and after 1-month treatment with timolol or latanoprost. These parameters were recorded at 4 a.m., 8 a.m., noon, 4 p.m., 8 p.m., and midnight. Results Both timolol and latanoprost reduced IOP (p < 0.001), with a difference in favour of latanoprost of 1.3 mmHg (95% CI 0.9, 1.6; p < 0.001). After timolol, BP and HR decreased with respect to baseline (p < 0.001). Latanoprost increased mean OPP (3.6 mmHg, 95% CI 2.9, 4.3; p < 0.001), whereas timolol did not improve it. Conclusions Latanoprost induces an IOP reduction greater than timolol, also achieving a better circadian flattening of the IOP curve. Only latanoprost significantly increased mean 24-hour OPP. The management of Caucasian NTG patients should be critically realized, considering the 24-hour influence of each IOP-lowering drug on the ocular blood perfusion.     

Effect of latanoprost on intraocular pressure in steroid-induced glaucoma

PURPOSE: To study the effect of monotherapy with latanoprost 0.005% on intraocular pressure (IOP) in a prospective nonrandomized clinical trial of patients newly diagnosed with steroid-induced secondary open-angle glaucoma. PATIENTS AND METHODS: Eight patients (16 eyes) with newly diagnosed steroid-associated secondary open-angle glaucoma were prescribed latanoprost 0.005% once a day in each eye. The initial IOP before treatment served as an internal control for each eye. Intraocular pressure was remeasured after 1 month of monotherapy with latanoprost. Investigators (WJS) were blinded to initial IOP at the time of remeasurement. After discontinuation of steroids, IOP was rechecked. If IOP was stable, latanoprost was discontinued. Intraocular pressure was rechecked 2 to 4 weeks later to confirm an association with steroid use. RESULTS: Intraocular pressure was significantly decreased after treatment with latanoprost (18.3 +/- 2.8 mm Hg) compared with initial IOP (25.3 +/- 9.1 mm Hg). This change represented a 28% decrease in IOP compared with baseline levels. Average IOP after discontinuation of steroids and latanoprost (17.3 +/- 1.4 mm Hg) did not differ from IOP measured during treatment with latanoprost, but it was significantly less than the initial IOP before treatment. No adverse effects were noted. CONCLUSIONS: Monotherapy with latanoprost is safe and effective in patients with steroid-induced glaucoma. Advantages include lack of systemic side effects and convenient once-daily dosing.     

Effect of hospitalization on intraocular pressure in patients with high tension and normal tension glaucoma

PURPOSE: To determine the effect of hospitalization on intraocular pressure (IOP) in glaucoma patients. DESIGN: Prospective case series. METHODS: IOP was measured on three consecutive days in 26 high-tension (HTG) and 13 normal-tension (NTGwm) glaucoma patients under IOP-lowering treatment, and in 28 normal-tension glaucoma patients without IOP-lowering treatment (NTGnm), and change was compared by analysis of variance. RESULTS: IOP decreased significantly, but comparably, in the three groups and between right and left eyes, although, the relative change to IOP on day 1 was significantly less pronounced in the group without treatment on day 2 and 3 compared with the treated groups. CONCLUSIONS: Glaucoma patients showed a significant decrease in IOP during hospitalization. Although this decrease was more pronounced among the treated patients, it was also present in nontreated patients. Consequently, other factors than improved compliance during hospitalization must play a role in this phenomenon.     

Changes in intraocular pressure and ocular perfusion pressure after latanoprost 0.005% or brimonidine tartrate 0.2% in normal-tension glaucoma patients

OBJECTIVE: To evaluate and compare the effects of latanoprost 0.005% once daily and brimonidine tartrate 0.2% twice daily in patients with normal-tension glaucoma (NTG). DESIGN: A randomized, open-label, crossover study. PARTICIPANTS: Twenty-eight NTG patients with progressive visual field defects/optic disc excavation, new disc hemorrhage, or field defects that threatened fixation. INTERVENTION: Patients were randomly allocated to one of two groups. Patients in group 1 were treated with latanoprost, lubricant, and brimonidine for 4 weeks each, whereas patients in group 2 were treated with brimonidine, lubricant, and latanoprost for 4 weeks each. MAIN OUTCOME MEASURES: Intraocular pressure (IOP), pulse rate, and blood pressure were measured at 8 am, 12 noon, and 4 pm after each 4-week treatment. Ocular perfusion pressure (OPP) was calculated. RESULTS: Latanoprost and brimonidine reduced the average IOP by 3.6 +/- 1.9 mmHg (P < 0.001) and 2.5 +/- 1.3 mmHg (P < 0.001), respectively, with a significant difference between the two regimens (P = 0.009). Both drugs significantly reduced IOP at each time point. Latanoprost decreased IOP significantly more than did brimonidine at 8 am (11.7 +/- 2.2 mmHg vs. 13.7 +/- 2.1 mmHg, P = 0.004) and 4 pm (11.4 +/- 2.1 mmHg vs. 13.2 +/- 2.9 mmHg, P = 0.004), but IOP was equal between the two agents at 12 noon (11.5 +/- 2.6 mmHg vs. 11.5 +/- 2.3 mmHg, P = 0.967). IOP was maintained at 12 mmHg or lower in 18 (66.7%) of 27 patients after treatment with latanoprost and in 9 (33.3%) of 27 patients after treatment with brimonidine. Latanoprost monotherapy reduced IOP by 30% in 8 patients (29.6%), but brimonidine monotherapy did not reduce IOP by that much in any of the patients. OPP increased after latanoprost treatment (P < 0.001) but did not increase after brimonidine treatment (P = 0.355). There was no significant change in pulse rate or blood pressure. CONCLUSIONS: Both latanoprost and brimonidine reduce IOP in NTG patients. Brimonidine has a peak IOP-lowering effect equal to that of latanoprost but produces a higher mean diurnal IOP than does latanoprost because of its shorter effect. Latanoprost might favorably alter optic disc blood perfusion by increasing OPP.     

Rabbit diurnal ocular tension variations.

Ocular tension recorded by pneumatonography was estimated at 4-hour intervals during six consecutive 24-hour periods in 8 New Zealand rabbits. The animals had been acclimatized for more than 8 weeks to artificial light from 08.00 to 20.00 h and dark for the other 12 h. Inter- and intrarabbit consistency was enough to allow the generalization that the lowest pressure occurred at noon (mean -0.8 mm Hg from baseline average), while the highest pressures (mean + 1.2 mm Hg above baseline average) occurred at 16.00 and 20.00 h. Only three other studies have measured rabbit ocular tensions throughout 24 h, but for shorter periods: one observed a light-induced rise as in the present study, but the other two studies found a rise during darkness.     

Prolonged retinal arteriovenous passage time is correlated to ocular perfusion pressure in normal tension glaucoma

BACKGROUND: The pathogenesis of normal tension glaucoma (NTG) might be related to impaired autoregulation of ocular blood flow. The purpose of the study is to evaluate retinal haemodynamics by fluorescein angiography and to correlate arteriovenous passage times (AVP) with ocular perfusion pressure in patients with NTG and controls. METHODS: Thirty-five patients with NTG without any topical treatment (mean age 53 +/- 11 years) and 35 age-matched controls (mean age 53 +/- 11 years) were included in this study. Retinal AVP was assessed by video fluorescein angiography using a scanning laser ophthalmoscope (Rodenstock, Germany). Dye dilution curves of temporal superior and inferior arterioles and venules were evaluated by digital image analysis. AVP was correlated to mean arterial blood pressure and ocular perfusion pressure. RESULTS: The AVP was significantly prolonged in patients with NTG compared to controls (1.82 +/- 0.57 versus 1.42 +/- 0.46, p = 0.002). Patients with NTG and controls showed no significant differences in intraocular pressure, mean arterial pressure and mean and diastolic ocular perfusion pressure. The AVP was significantly correlated to mean arterial pressure and mean and diastolic ocular perfusion pressure in patients with NTG (r = -0.54; p = 0.0006, r = -0.51; p = 0.002, r = -0.49, p = 0.002), but not in controls (r = -0.21; p = 0.23, r = -0.19; p = 0.27, r = 0.02, p = 0.93). CONCLUSIONS: Patients with NTG exhibit prolonged retinal AVP compared to controls. A significant correlation of retinal haemodynamics to mean arterial blood pressure and ocular perfusion pressure might reflect impaired autoregulation in NTG.     

Comparative analysis of the effects of dorzolamide and latanoprost on ocular hemodynamics in normal tension glaucoma patients

PURPOSE: To compare the effects of latanoprost (Xalatan) and dorzolamide (Trusopt) on ocular hemodynamics in normal-tension glaucoma patients. METHODS: A randomized, single-masked, parallel design study was conducted. After a 4-week washout period, 20 normal tension glaucoma patients, recruited from a single university-based ophthalmology clinic, received either latanoprost once daily or dorzolamide 3 times daily for 4 weeks. The subjects were examined at baseline and post-treatment. Outcome measures included heart rate (HR), blood pressure (BP), logMar visual acuity (VA), contrast sensitivity (CS), intraocular pressure (IOP), color Doppler imaging (CDI), and fluorescein angiography with the Rodenstock scanning laser ophthalmoscope (SLO). CDI measurements of the retrobulbar vessels included peak systolic velocity, end diastolic velocity, and the calculated resistance index. Arterio-venous passage time (AVP) in the superior and inferior temporal retina was calculated from the SLO angiograms. RESULTS: Neither dorzolamide nor latanoprost had any statistically significantly effect on HR or BP. Both drugs significantly lowered IOP without altering calculated ocular perfusion pressure (p<0.05). There was no statistically significant difference in any CDI measurement. Dorzolamide significantly decreased AVP time in the superior retina (p=0.011), while latanoprost did not (p=0.62). CONCLUSIONS: Dorzolamide, unlike latanoprost, significantly reduced AVP times in the superior temporal retina in normal tension glaucoma (NTG) patients.     

Effect of latanoprost 0.005% and brimonidine tartrate 0.2% on pulsatile ocular blood flow in normal tension glaucoma

AIM: To determine the effect of brimonidine tartrate 0.2% and latanoprost 0.005% on pulsatile ocular blood flow (POBF) in patients with normal tension glaucoma (NTG). METHOD: NTG patients with progressive optic neuropathy, new disc haemorrhage, or field defects that threatened fixation were enrolled into a randomised, investigator masked, crossover study. Group I patients received 4 weeks each of latanoprost, lubricant, and brimonidine, while group II patients received 4 weeks each of brimonidine, lubricant, and latanoprost. Diurnal POBF was measured at baseline and after each 4 week treatment. RESULTS: 25 patients completed the study and had reliable POBF measurement at each visit. There was no significant diurnal change in baseline POBF (p = 0.768). Latanoprost increased POBF by 213 (SD 257) micro l/min (22.8%, p <0.001) while brimonidine increased it by 97 (183) micro l/min (10.4%, p = 0.014). POBF increased at 8 am (p = 0.004), 12 noon (p = 0.002), and 4 pm (p <0.001) with latanoprost, while it increased only at 8 am (p = 0.016) with brimonidine. After adjusting for the factor of IOP, neither latanoprost nor brimonidine increased POBF significantly. CONCLUSIONS: Latanoprost increases the mean POBF that is related to its IOP lowering effect. The increase in POBF noted after brimonidine is within the range of long term variation and may not be attributable to the drug effect.     

Impact of intraocular pressure fluctuations on progression of normal tension glaucoma

AIM: To investigate short- and long-term intraocular pressure (IOP) fluctuations and further ocular and demographic parameters as predictors for normal tension glaucoma (NTG) progression. METHODS: This retrospective, longitudinal cohort study included 137 eyes of 75 patients with NTG, defined by glaucomatous optic disc or visual field defect with normal IOP (<21 mm Hg), independently from therapy regimen. IOP fluctuation, mean, and maximum were inspected with a mean follow-up of 38mo [standard deviation (SD) 18mo]. Inclusion criteria were the performance of minimum two 48-hour profiles including perimetry, Heidelberg retina tomograph (HRT) imaging, and optic disc photographs. The impact of IOP parameters, myopia, sex, cup-to-disc-ratio, and visual field results on progression of NTG were analyzed using Cox regression models. A sub-group analysis with results from optical coherence tomography (OCT) was performed. RESULTS: IOP fluctuations, average, and maximum were not risk factors for progression in NTG patients, although maximum IOP at the initial IOP profile was higher in eyes with progression than in eyes without progression (P=0.054). The 46/137 (33.5%) eyes progressed over the follow-up period. Overall progression (at least three progression confirmations) occurred in 28/137 eyes (20.4%). Most progressions were detected by perimetry (36/46). Long-term IOP mean over all pressure profiles was 12.8 mm Hg (SD 1.3 mm Hg); IOP fluctuation was 1.4 mm Hg (SD 0.8 mm Hg). The progression-free five-year rate was 58.2% (SD 6.5%). CONCLUSION: Short- and long-term IOP fluctuations do not result in progression of NTG. As functional changes are most likely to happen, NTG should be monitored with visual field testing more often than with other devices.     

Effect of nocturnal blood pressure reduction on circadian fluctuation of mean ocular perfusion pressure: a risk factor for normal tension glaucoma

PURPOSE: To study blood pressure (BP), intraocular pressure (IOP), and mean ocular perfusion pressure (MOPP) in patients with untreated normal tension glaucoma (NTG), and to investigate the relationship between circadian MOPP fluctuation and visual field status at initial presentation. METHODS: IOP and BP were evaluated in hospital over 24 hours in 132 patients with NTG, with measurements taken every 2 hours between 12 PM and 10 AM the following day, except for the period between 12 and 6 AM, during which measurements were taken every 3 hours. MOPP was calculated from the 24-hour IOP and BP data. Patients were classified into three groups-nondippers, dippers, and overdippers-corresponding to the degree of reduction in their nocturnal mean arterial pressure (MAP) compared with their diurnal MAP. IOP and systemic and ocular hemodynamic parameters were compared among the groups. The correlations between circadian MOPP fluctuation and visual field scores (mean deviation [MD] and corrected pattern standard deviation [CPSD]) at initial presentation were analyzed. RESULTS: Forty-one (31.1%) of the patients with NTGs were classified into the nondipper group, 36 (27.2%) into the dipper group, and 55 (41.7%) into the overdipper group. Marked circadian MOPP fluctuation was noted in the overdipper group (P < 0.05). Circadian MOPP fluctuation showed positive associations with visual field indices at initial diagnosis of NTG (P < 0.05, R2 = 0.056 with MD, R2 = 0.038 with CPSD). CONCLUSIONS: Marked circadian MOPP fluctuation was associated with nocturnal BP reduction. Circadian MOPP fluctuation may be a risk factor for the development of NTG.     

Comparison of the effects of latanoprost and timolol gel-forming solution on diurnal variation of intraocular pressure in normal-tension glaucoma

OBJECTIVE: To compare the effects of latanoprost (Lat) and timolol gel-forming solution (Tg) on the diurnal variation of intraocular pressure (IOP) in normal-tension glaucoma (NTG). SUBJECTS AND METHODS: A total of 47 NTG patients (47 eyes) were randomly assigned to receive Lat alone (25 eyes) or Tg alone (22 eyes). IOP was measured at fixed time points during 24 hours before and after treatment with each drug. In addition, blood pressure and pulse rate were measured before and after treatment. RESULTS: Lat reduced IOP significantly at all time points of measurement. Tg reduced IOP significantly at all time points of measurement except at 22:00 and 03:00. Percent reductions in the IOP at 03:00 and in the mean diurnal IOP were significantly greater in the Lat group than in the Tg group. In the Lat group there was no change in diastolic pressure or pulse rate after treatment, but in the Tg group these parameters decreased significantly. CONCLUSIONS: Comparison of diurnal variation of IOP before and after treatment shows that Lat is more effective than Tg in lowering IOP. In addition, Lat does not affect blood pressure or pulse rate.     

Diurnal fluctuation and concordance of intraocular pressure in glaucoma suspects and normal tension glaucoma patients

PURPOSE: The study objective was to determine the concordance of intraocular pressure (IOP) in glaucoma suspects (GS) and normal tension glaucoma (NTG) patients. METHODS: This was a retrospective review of diurnal curves of untreated GS and NTG patients. No subject had IOP greater than 21 mm Hg. We defined GS patients as having suspicious optic nerves with normal visual fields, and NTG patients as having glaucomatous optic nerves with associated visual field loss. Goldmann applanation tonometry was performed at 10:00, 13:00, 16:00, 19:00, 22:00, and 07:00. Linear association of OD and OS IOP was estimated using Pearson correlation coefficient (r). The diurnal period was divided into 7 time intervals of 3, 6, 9, 12, 15, 18, and 21 hours, and the absolute difference in change in IOP between fellow eyes and probability that it was within 3 mm Hg were calculated. RESULTS: The study included 68 GS and 95 NTG subjects. The diurnal curves of the OD and OS showed a parallel course in both groups. The average correlations (r) of OD and OS IOP over the 6 time points were 0.78 and 0.81 for GS and NTG, respectively. The mean absolute difference in IOP change between OD and OS over the 6 time intervals ranged between 1.4 and 1.9 mm Hg for GS, and 1.3 and 1.5 mm Hg for NTG subjects. The probability that this difference was within 3 mm Hg ranged between 87% and 94% for GS, and 86% and 93% for NTG subjects. CONCLUSIONS: The diurnal variation in IOP between the 2 eyes in GS and NTG is largely concordant in approximately 90% of the time.