Short-term Intraocular Pressure Fluctuations Research Articles

Effects of cataract surgery on short-term intraocular pressure fluctuations in patients with primary angle-closure and primary angle-closure glaucoma

Introduction. Cataract surgery results in a reduction of intraocular pressure, but it has not been sufficiently investigated how it affects short-term intraocular pressure fluctuations. The aim of this study was to evaluate the effects of cataract surgery on short-term intraocular pressure fluctuations in patients with primary angle-closure, with or without glaucoma. Material and Methods. A prospective interventional clinical study included 31 patients (eyes) with primary angle-closure/primary angle-closure glaucoma (study group) and 31 patients (eyes) with cataract only (control group). All subjects underwent cataract surgery. Preoperatively, and at the first, third and sixth postoperative months, diurnal tension curves for the assessment of intraocular pressure was performed and the mean intraocular pressure and short-term intraocular pressure fluctuations were evaluated. Results. Postoperatively, the mean intraocular pressure and short-term intraocular pressure fluctuations were significantly reduced in both groups. In the study group, the highest mean intraocular pressure reduction was - 4.14 ? 2.50 mmHg, and in the control group it was - 2.44 ? 1.76 mmHg. The highest reduction of short-term fluctuations was - 1.61 ? 3.55 mmHg in the study group, and - 0.55 ? 1.72 mmHg in the control group. In both groups, a significant negative correlation was found between the preoperative and postoperative mean intraocular pressure and short-term intraocular pressure fluctuations. At the end of the research, the number of medications was reduced by 18.4% compared to the preoperative period. Conclusion. Cataract surgery in patients with primary angle-closure/primary angle-closure glaucoma results in a significant reduction of intraocular pressure, short-term intraocular pressure fluctuations, and a reduction in the number of medications.

Effect of antiglaucoma agents on short-term intraocular pressure fluctuations after intravitreal bevacizumab injections.

To evaluate the effect of prophylactic pressure-lowering medications on intraocular pressure (IOP) spikes after intravitreal injections (IVIs) METHODS: In this randomized double-blind clinical trial, 74 eyes that were candidates for intravitreal anti-vascular endothelial growth factor (VEGF) injection (IVI) (0.05mL, 1.25mg of bevacizumab) were enrolled and sorted randomly into five groups, group 1: topical timolol 0.5% (n = 16); group 2: topical brimonidin (n = 15); group 3: oral acetazolamide 250mg (n = 14); group 4: intravenous mannitol (1.5 gr/kg) (n = 16); group 5: no intraocular pressure-lowering medication (n = 13). Medications were administered 30-60min prior to injection. None of the patients had history of glaucoma. Intraocular pressure was measured before (baseline), 5min after (T5), 10min after (T10), 15min after (T15) and 30min after (T30) IVI using Goldmann Tonometer. There was a statistically significant, but relatively weak negative correlation between the amount of vitreous reflux post-IVI intraocular pressure elevation (Spearman's rho = -0.315, p = 0.006). There was no difference of the amount of vitreous reflux (P = 0.196) between study groups. The baseline mean IOP for Groups 1, 2, 3,4 and 5 were 11.19 ± 3.7, 10.07 ± 2.19, 11 ± 2.98, 10.13 ± 3.48 and12.54 ± 2.60mmHg, respectively. (P = 0.214) There was no difference of peak IOP spike between groups at T5: 37 ± 19.7, 34.80 ± 15.76, 33.43 ± 18.29, 33.56 ± 16.88, 34.92 ± 9.99mmHg (P = 0.977). There was also no difference of IOP at T10, T15 and T30 between study groups: P = 0.979, P = 0.994 and P = 0.692, respectively. Although it is advisable to prevent IOP spikes, our study showed that use of prophylactic pressure-lowering medications with every mechanism of action has no effect in IOP spikes following intravitreal bevacizumab injections in non-glaucomatous eyes. Trial registrationThe study was registered with clinicaltrails.gov (ID# NCT02140450). Trial registration date: 05.09.2014.

Correlation between retinal nerve fiber layer thickness and IOP variation in glaucoma suspects and patients with primary open-angle glaucoma.

To analyze the relationship between retinal nerve fiber layer thickness (RNFLT) and intraocular pressure (IOP) variation in glaucoma suspects (GS) and patients with primary open-angle glaucoma (POAG). Thirty-one GS and 34 POAG patients underwent ophthalmologic examination and 24-h IOP measurements. GS had IOPs ranging from 19 to 24 mmHg and/or suspicious appearance of the optic nerve. POAG patients had reproducible abnormal visual fields. We only included patients who presented with short-term IOP fluctuation >6 mm Hg (∆IOP). Only one eye per patient was included through a randomized process. Peripapillary RNFLT was assessed by spectral-domain optical coherence tomography. We correlated RNFLT with IOP parameters. Mean IOP was similar between GS and POAG groups (15.6 ± 3.47 vs 15.6 ± 2.83 mmHg, p = 0.90) as was IOP peak at 6 AM (21.7 ± 3.85 vs 21.3 ± 3.80 mmHg, p = 0.68). Statistically significant negative correlations were found in POAG group between IOP at 6 AM and RNFLT in global (rs = -0.543; p < 0.001), inferior (rs = -0.540; p < 0.001), superior (rs = -0.405; p = 0.009), and nasal quadrants (rs = -0.561; p < 0.001). Negative correlations were also found between ∆IOP and RNFLT in global (rs = -0.591; p < 0.001), and all other sectors (p < 0.05). In GS IOP at 6 AM correlated only with inferior quadrant (rs = -0.307; p = 0.047). IOP at 6 AM and ∆IOP had negative correlations with RNFLT quadrants in POAG. In GS this correlation occurred between IOP at 6 AM and inferior quadrant. These findings may indicate potential risk factors for glaucoma progression.

Role of Histamine H₃ Receptor Antagonists on Intraocular Pressure Reduction in Rabbit Models of Transient Ocular Hypertension and Glaucoma.

Intraocular pressure (IOP) has a tendency to fluctuate throughout the day, reaching its peak in the early morning in healthy subjects or glaucoma patients. Likewise, histamine tone also fluctuates over time, being lower at nighttime. Numerous studies have demonstrated a correlation between short-term IOP fluctuation and glaucoma progression; however, it has not yet been determined whether histamine plays a role in IOP fluctuations. The aim of this research was to establish the distribution of the histamine receptor proteins and respective mRNAs in the eye by western blot, immunohistochemistry and RT-PCR in New Zealand rabbits. Furthermore, we used a transient ocular hypertension (OHT) model induced by injection of 50 µL of 5% hypertonic saline into the vitreous and a stable OHT model (100 µL 0.1% carbomer in the anterior chamber) to address the potential IOP-lowering ability of H3 receptor (H3R) antagonists (ciproxifan, DL76 and GSK189254). IOPs were performed with a Tono-Pen at baseline and 60, 120 and 240 min post treatment after transient OHT induction and, every day for 12 days in the stable OHT model. All histamine receptor subtypes were localized in the rabbit retina and ciliary body/trabecular meshwork. All the treatments lowered IOP in a dose-dependent fashion between 0.3% and 1%. More specifically, the effects were maximal with ciproxifan at 60 min post-dose (IOP60 change = −18.84 ± 4.85 mmHg, at 1%), remained stable until 120 min (IOP120 change = −16.38 ± 3.8 mmHg, at 1%) and decayed thereafter to reach baseline values at 240 min. These effects were highly specific and dependent on histamine release as pre-treatment with imetit (H3R agonist, 1%) or pyrilamine (H1R antagonist, 1%) largely blocked ciproxifan-mediated effects. Color Doppler ultrasound examination was performed to evaluate changes in ophtalmic artery resistivity index (RI) before and after repeated dosing with DL 76, GSK189254, ciproxifan and timolol. Chronic treatments with H3R antagonists and timolol improved the vascular performance of ophthalmic arteries and reduced retinal ganglion cell death. Oxidative stress was also reduced and measured 8-Hydroxy-2′-deoxyguanosine (8OHdG) expression, and by dihidroethydium (DHE) staining. These results demonstrated that the histamine system participates in IOP regulation and that H3R antagonists could represent a future promising therapy for glaucoma. Further studies should be focused on the long-term IOP circadian fluctuations.

Intraocular pressure fluctuation and the risk of glaucomatous damage deterioration: a Meta-analysis.

To systematically review whether the increased fluctuation of intraocular pressure (IOP) is a risk factor for open angle glaucoma (OAG) progression. Scientific studies relevant to IOP fluctuation and glaucoma progression were retrieved from MEDLINE, EMBASE and CENTRAL databases, and were listed as references in this paper. The hazard ratio (HR) was calculated by using fixed or random-effects models according to the heterogeneity of included studies. Individual data for 2211 eyes of 2637 OAG patients in fourteen prospective studies were included in this Meta-analysis. All studies were longitudinal clinical studies with follow-up period ranging from 3 to 8.5y. The combined HR was 1.23 (95%CI 1.04-1.46, P=0.02) for the association between IOP fluctuation and glaucoma onset or progression with the evidence of heterogeneity (P<0.1). Subgroup analyses with different types of IOP fluctuation were also evaluated. Results indicated that the summary HR was 0.98 (95%CI 0.78-1.24) in short-term IOP fluctuation group, which showed no statistical significance with heterogeneity, whereas, the combined HR was 1.43 (95%CI 1.13-1.82, P=0.003) in long-term IOP fluctuation group without homogeneity. Sensitivity analysis further showed that the pooled HR was 1.10 (95%CI 1.03-1.18, P=0.004) for long-term IOP fluctuation and visual function progression with homogeneity among studies (P=0.3). Long-term IOP fluctuation can be a risk factor for glaucoma progression based on the presented evidence. Thus, controlling the swing of IOP is crucial for glaucoma or glaucoma suspecting patients.

Investigation of intraocular pressure fluctuation as a risk factor of glaucoma progression.

PurposeSince the role of short- and long-term intraocular pressure (IOP) fluctuation as a predictor of glaucoma progression is still controversial, the purpose of this study was to investigate the role of IOP fluctuation in a non-selected patient cohort.Materials and methodsTwo-hundred and forty eyes of 120 glaucoma patients (51% female) with a mean age of 64.5 years were included. Inclusion criteria were at least a visual field (VF) and a 48-hour diurnal phasing of IOP including nocturnal measurement. Glaucoma progression was defined as – if available – confirmed progression of reproducible VF defects in at least three VF examinations or increase of cup area on optic nerve imaging (Heidelberg Retina Tomograph [HRT]) with at least two images after baseline. If results were stable or less than previously mentioned VF or HRT examinations were available, it was classified as “no progression”.ResultsGlaucoma progression was seen in seven of 240 eyes in the VF analysis and ten of 240 eyes on HRT. Of all 240 eyes, 92 and 41 eyes fulfilled the criteria to be included for progression evaluation on VF and HRT analysis, respectively. Mean time to progression ± standard error was 3.6±0.2 years on VF and 4.5±0.3 years on HRT. Univariate and multivariate Cox regression analyses revealed short-term IOP fluctuation (P<0.0001) and maximum IOP (P<0.001) as risk factors for glaucoma progression on VF. There was no significant influence of demographic characteristics, ocular or general health on glaucoma progression.ConclusionShort-term IOP fluctuation was associated with the progression of glaucoma in this non-selected cohort of glaucoma patients receiving phasing of IOP.

24-hour IOP fluctuation: myth or reality?

Existing literature is divided on the importance of short-term intraocular pressure fluctuation as an independent factor of glaucoma development and progression. In this paper we present evidences for and against the value of 24-hour intraocular pressure fluctuation in the evaluation and prognosis of patients with glaucoma. Potential directions for future studies and the role of new instruments for continuous intraocular pressure monitoring will be presented.

Correlation between short-term and long-term intraocular pressure fluctuation in glaucoma patients.

PurposeWe investigated correlations between short-term and long-term intraocular pressure (IOP) fluctuations.MethodsWe examined 50 eyes of glaucoma patients who were followed for >2 years. We measured short-term IOP fluctuation using a Triggerfish® contact lens sensor (CLS). The short-term IOP fluctuation (mVeq) was defined as the difference between the maximum value and the minimum value measured during the 24-hour course with CLS. The long-term IOP fluctuation was defined by four parameters: 1) the mean IOP (mmHg) determined during follow-up; 2) the IOP difference, which was defined as the difference between the maximum IOP and the minimum IOP; 3) the standard deviation of IOP; and 4) the peak IOP, which was defined as the maximum IOP. Correlations between these parameters and the short-term IOP fluctuation were examined.ResultsThe mean follow-up period was 5.4 years. The average IOP was 15.0±4.0 mmHg. The range of short-term IOP fluctuation identified with CLS was significantly correlated with all the four long-term IOP fluctuation parameters.ConclusionShort-term IOP fluctuations were found to be associated with long-term IOP fluctuations. Examination of 24-hour IOP fluctuations with the CLS might be useful for predicting the long-term IOP fluctuation.

The Value of Water Drinking Test as a Clue for Short Term Intraocular Pressure Fluctuation

Purpose: To assess the relations between the intraocular peaks detected during water drinking test (WDT) and modified diurnal tension curve (mDTC) in glaucomatous and non-glaucomatous eyes. Likewise to assess reliability of WDT as a reliable substitute. Patients and methods: Forty eyes from forty participants (21 males and 19 females) were recruited in this prospective cross-sectional study; twenty participants with known Primary Open Angle Glaucoma and the other twenty participants with non- glaucomatous healthy eyes which served as control. Four IOP measurements were taken at 8:00 am, 12:00 pm, 4:00 pm and 8:00 pm which represented the mDTC, while WDT was represented by a single measurement of IOP before ingestion of one liter of water over five minutes, followed by three IOP measurements after ingestion of this amount of water at thirty minute intervals. The data collected were statistically evaluated using the statistical package for social science (SPSS) program for presence of a correlation between the two methods. Results: The IOP peaks and fluctuations detected during the WDT were strongly correlated to peaks and fluctuations observed during the mDTC. 90% of participants had a peak IOP at 8:00 am, while 7.5% had a peak IOP at 12:00 pm, 2.5% at 4:00 pm and none of the participants had IOP peak at 8:00 pm during the mDTC. In the WDT, 87.5% of the participants had a peak IOP after 30 minutes of ingesting one liter of water, while 12.5% had a peak IOP after 60 minutes. None of the participants had IOP peak after 90 minutes of ingesting one liter of water. IOP fluctuation in mDTC ranged from: 1-4.5 mmHg in 95% of normal participants, 7-11 mmHg in 83.3% of glaucoma suspects, 1.5-5 mmHg in SST subgroup and 4-11 mmHg in the glaucoma on medication subgroup. There were relatively similar results in the WDT fluctuation, whereas 38 cases out of 40 (95%) showed a difference of ± 2 mmHg or less between the two methods. Conclusion: Intraocular pressure peaks and fluctuations detected during the water drinking test could be used in clinical practice to estimate the peaks and fluctuations observed during the modified diurnal tension curve.

Efficacy of Timolol 0.1% Gel and a Prostaglandin Analog in an Unfixed Combination Compared to the Corresponding Fixed Combinations

To investigate the intraocular pressure (IOP) reduction with prostaglandin analogs (PGAs)-timolol fixed combinations versus the unfixed combination of the same PGAs and timolol 0.1% in gel-forming carbomer. Patients with primary open-angle glaucoma (POAG) receiving for at least 4 weeks the fixed combinations of PGA-timolol, administered once a day in the evening (0.005% latanoprost with 0.5% timolol, 0.004% travoprost with 0.5% timolol, 0.03% bimatoprost with 0.5% timolol) were switched to an unfixed combination of the same PGA (once a day in the evening) with timolol 0.1% in gel-forming carbomer (once a day in the morning) for at least 4 weeks. The primary endpoint was to compare efficacy of fixed vs unfixed combinations in lowering IOP. The effects of both regimens on short-term IOP fluctuations were also assessed. A total of 32 patients (64 eyes) fulfilled inclusion criteria: 17 patients received latanoprost-timolol fixed combination, 9 travoprost-timolol fixed combination, 6 bimatoprost-timolol fixed combination. For all considered time periods each unfixed combination induced an IOP reduction significantly higher than the corresponding fixed combination (paired t test: p<0.05 in all measurements). The diurnal IOP reduction was significantly higher during the unfixed combinations (p<0.001). Unfixed combinations significantly decreased IOP diurnal fluctuations and increased the percentage of patients with daily IOP fluctuation ≤2 mm Hg. In this pilot study, PGA and timolol seems to be more effective in POAG treatment when administered as unfixed combinations, reducing both IOP and daily fluctuations. The once a day timolol 0.1% gel-forming carbomer may be a valuable option in PGA-timolol unfixed combination regimen.