The relationship between intraocular pressure and glaucoma: An evolving concept

Diurnal variation in intraocular pressure (IOP) is well recognized, yet important decisions in glaucoma management are frequently made after 1 or 2 IOP measurements. Twenty-four-hour monitoring of IOP may identify IOP variation and spikes. This study determined the value of 24-hour IOP monitoring in routine clinical practice. Data were acquired retrospectively from case notes of 29 glaucoma patients sequentially admitted for 24-hour IOP monitoring while taking their established antiglaucoma therapy. While there was no difference between the mean clinic (office) and mean 24-hour IOP measurements, the peak IOP during 24-hour monitoring was on average 4.9 mm Hg higher than the peak clinic IOP (P<0.0001). In 4 (13.8%) patients, the peak IOP over 24 hours was at least 12 mm Hg higher than the clinic peak. Peak IOP values occurred outside normal office hours in 51.7% of patients. Twenty-four-hour IOP monitoring resulted in a change of clinical management in 23 (79.3%) patients, including 13 (44.8%) who were offered trabeculectomy. Twenty-four-hour monitoring of IOP frequently led to a change of glaucoma management by identifying IOP fluctuations and spikes. High IOP and wide diurnal IOP variation are considered major risk factors for glaucoma progression, and standard clinic follow-up evaluations failed to identify these phenomena.

ABSTRACTPurpose: To investigate diurnal intraocular pressure (IOP) fluctuation in eyes with angle-closure.Materials and methods: Seventy-seven eyes of 77 newly diagnosed patients with angle closure [33 subjects with primary angle-closure suspects (PACS), 23 subjects with primary angle-closure (PAC), and 21 subjects with primary angle-closure glau-coma (PACG)] were enrolled after laser peripheral iridotomy for this prospective, cross-sectional study.Goldmann applanation tonometry (GAT) was performed at 08:00, 12:00, 16:00, 20:00, and 04:00 hours. Mean diurnal IOP, peak IOP, trough IOP, and IOP fluctuation (peak-trough) were compared between groups.Results: The mean age of the enrolled subjects was 56.8 ± 5.4 years, with 30 males and 47 females. Intraocular pressure fluctuation was significantly higher in the PACG (7.4 ± 2.8 mm Hg) and PAC (5.5 ± 2.3 mm Hg) groups compared with PACS subjects (4.4 ± 1.5 mm Hg). The highest IOP was recorded at 04:00 hours in all but two patients. Two PACS, 10 PAC and 8 PACG patients, with normal office hour IOP had IOP peaks > 21 mm Hg at night. Twenty-five percent patients (20/77) had abnormal IOP despite good office hour readings.Conclusion: Primary angle-closure glaucoma and PAC eyes showed diurnal IOP fluctuations greater than 5 mm Hg in most subjects, with peak IOP recorded at 04:00 hours. Peak IOP was higher than office hour IOP recordings in subjects with angle-closure. A diurnal variation curve is recommended in these subjects, especially in cases with controlled IOP during office hours.How to cite this article: Bhartiya S, Ichhpujani P. Diurnal Intraocular Pressure Fluctuation in Eyes with Angle-closure. J Curr Glaucoma Pract 2015;9(1):20-23.

PurposeGrowth Differentiation Factor 15 (GDF15) was previously identified as a molecular marker of retinal ganglion cell stress in rodent models of glaucoma and was elevated in the aqueous humor (AH) of patients with primary open-angle glaucoma as a possible risk factor for glaucoma progression. The purpose of this study was to determine whether changes in the AH GDF15 levels were associated with intraocular pressure (IOP) changes in eyes undergoing glaucoma surgery.Methods Here, we performed a prospective, longitudinal pilot study in nine patients to determine whether changes in AH GDF15 levels from surgery to post-surgery follow-up were associated with IOP fluctuation. An initial AH sample was taken from the peripheral corneal paracentesis during planned glaucoma surgery, and a second sample was taken during an outpatient follow-up visit, approximately six months later.ResultsThere was a statistically significant correlation between GDF15 fold change and IOP standard deviation (r = 0.87, P = 0.003), IOP range (r = 0.87, P = 0.003), and maximum IOP (r = 0.86, P = 0.003). There was no correlation between the GDF15 fold change and baseline IOP (r = 0.50, P = 0.17), final IOP (r = 0.038, P = 0.92), or mean IOP (r = 0.40, P = 0.28).ConclusionOur findings in this pilot study suggest that longitudinal changes in AH GDF15 may be associated with IOP fluctuation during the postoperative period. Further studies are necessary to corroborate these findings in a larger patient population and to explore the possibility that AH GDF15 may be used not only to improve treatment algorithms but also as a surrogate endpoint in clinical trials.

To evaluate the correlation between age and intraocular pressure (IOP) measured every 3 h for 24 h in older normal-tension glaucoma (NTG) patients. Ninety consecutive patients suspected of having NTG on the basis of both visual field defect and disc appearance were hospitalized for measurement of nyctohemeral IOP every 3 h over a 24-h period with a Goldmann tonometer after a 4-week wash-out of any existing medication. Sixty-nine patients (76.7%) were diagnosed as having NTG. Sixty-nine eyes of 69 subjects were enrolled for this prospective, cross-sectional study. They were divided into two groups by age (cut-off between 59 and 60 years: group 1, under 60 years; group 2, over 60 years). The correlations between age and the mean, maximum and minimum IOP and IOP variation of the eight nyctohemeral IOP measurements nyctohemerally were evaluated for each group. The times of day at which the maximum and minimum IOPs were observed were recorded. Groups 1 and 2 consisted of 28 patients (age: 50.2+/-6.1 years) and 42 patients (age: 70.3+/-6.1 years) ( P<0.0001), respectively. Neither mean, maximum or minimum IOP nor the IOP variation was significantly different between the groups (all P values > or =0.115). The mean, maximum and minimum IOP in group 2 were all correlated with age ( n=41; r=-0.516, P=0.0004; r=-0.434, P=0.004; r=-0.522, P=0.0004, respectively), while none of those in group 1 was correlated with age (all P values > or =0.303). The IOPs of the elder NTG patients have a negative correlation with age while those of the younger ones have no relation to age.

The impact of intraocular pressure fluctuations on the progression of glaucoma and associated factors.

Background/aims:To determine the medium-term effect of travoprost on the daytime intraocular pressure (IOP) of patients with normal tension glaucoma (NTG)Methods:Newly diagnosed NTG patients underwent baseline, daytime, hourly IOP phasing. Patients...

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. 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). 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%). 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.

Intraocular pressure (IOP) reduction continues to be the mainstay of glaucoma treatment. IOP fluctuations increase the risk of progression. In patients with well controlled office hours IOPs, very few studies have compared the effectiveness of surgical versus medical management in controlling the peaks and fluctuations in IOP. This prospective case series compared the 24 hour IOP fluctuations and IOP profiles in 10 patients with well controlled open angle glaucoma (OAG), in whom one eye was managed medically and the other had undergone surgery. 24 hour phased IOP measurements (10 AM, 2 PM, 6 PM, 10 PM, 2 AM, 6 AM) were recorded by Goldmann Applanation Tonometry (GAT) and Tonopen. Mean and peak IOPs, IOP fluctuation and 24 hour curves were compared. The 24 hour mean GAT IOP was 15.78 ± 1.43 mmHg in the medical group and 12.85 ± 1.97 mmHg in the surgical group. The peak IOPs were 18.90 ± 1.10 mmHg and 15.10 ± 2.18 mmHg in the medical and surgical groups respectively. 24 hour fluctuation was 4.20 ± 1.47 mmHg in the surgical group compared to 6.20 ± 1.47 mmHg the medical group. Surgical group showed no peaks whereas an early morning peak was seen in the medical group. Mean nocturnal IOP (mean of 2 AM and 6 AM IOPs) in supine position was lower in the surgical group as compared to the medical group (Tonopen 11.65 ± 1.83 vs 14.96 ± 2.87 mmHg; GAT 13.05 ± 2.46 vs 16.35 ± 2.65 mmHg respectively). Thus,in this case series, we found that in OAG patients with well controlled IOPs, the surgical group showed lower 24 hour IOP fluctuation, as well as lower mean and peak IOPs. The early morning peak in IOP was seen only in the medical group.

Introduction Severely burned patients are at risk for high intraocular pressures (IOP) and permanent vision loss from orbital compartment syndrome (OCS). Identification of at-risk patients for timely intervention is critical. This study aims to identify OCS risk factors and determine IOP trends to guide optimum monitoring in burn patients. Methods Medical records of burn patients seen by the ophthalmology service between 2004 and 2019 were reviewed. Patients undergoing resuscitation were split into those with high IOPs (PHigh IOP; ≥ 26 mmHg) and those with normal IOPs (PControl; IOPs ≤ 25 mmHg). Additional analysis to determine the timing of IOP elevations was performed on 13 patients (6 from the resuscitation group and 7 with facial burns). Results 33 of the 430 patients reviewed met inclusion criteria. Twenty-six patients underwent resuscitation, 6 of whom had elevated IOPs. Analysis of the PHigh IOP (n = 6) and PControl (n = 20) groups showed that elevated IOPs were associated with larger total body surface area (TBSA) burned (p = 0.002), a higher likelihood of exceeding the IVY index (&amp;gt; 250 ml/kg) (p = 0.018), and higher Parkland Formula calculated volume (p &amp;lt; 0.001). Maximum IOP and actual fluid resuscitation volume were linearly related (p &amp;lt; 0.001). Analysis of all patients with elevated IOP showed increases of 0.5 to 7 mmHg/hour with a highest absolute rise of 31 mmHg over 12 hours. All elevations occurred within 24 hours post injury. 8 patients had OCS, 2 of whom were not resuscitated due to small TBSA burns.33 of the 430 patients reviewed met inclusion criteria. Twenty-six patients underwent resuscitation, 6 of whom had elevated IOPs. Analysis of the PHigh IOP (n = 6) and PControl (n = 20) groups showed that elevated IOPs were associated with larger total body surface area (TBSA) burned (p = 0.002), a higher likelihood of exceeding the IVY index (&amp;gt; 250 ml/kg) (p = 0.018), and higher Parkland Formula calculated volume (p &amp;lt; 0.001). Maximum IOP and actual fluid resuscitation volume were linearly related (p &amp;lt; 0.001). Analysis of all patients with elevated IOP showed increases of 0.5 to 7 mmHg/hour with a highest absolute rise of 31 mmHg over 12 hours. All elevations occurred within 24 hours post injury. 8 patients had OCS, 2 of whom were not resuscitated due to small TBSA burns. Conclusions While large TBSA burns, exceeding the Ivy Index, and Parkland Formula calculated volume are potential OCS risk factors in burn patients, 25% of the patients who developed OCS had facial burns and did not require resuscitation. Earlier involvement of ophthalmology and more frequent IOP checks in susceptible burn patients will help identify those most at risk for OCS and vision loss. Applicability of Research to Practice Both the characteristics and the timing of increased intraocular patients is critical to ensuring prompt involvement of the ophthalmology team and treatment of the eye to preserve vision.

The role of elevated intraocular pressure (IOP) in the progression of glaucoma optical neuropathy has emphasized repeatedly. The question about the role of elevated IOP as the underlying cause of glaucoma arose in the early 1960s. However, epidemiological studies have questioned the role of IOP as a diagnostic criterion for glaucoma, due to the relatively rare detection the disease among those with ocular hypertension and frequent detection of glaucoma with normal IOP. Multicenter studies determining the role of antihypertensive therapy in the treatment of glaucoma, have shown the importance of reducing IOP: decricing IOP at 1 mm Hg reduced the risk of developing glaucoma on 10-19%. In addition, it was found that the rate of glaucoma progression is very variable. It depends not only on the form of glaucoma, but also on other factors such as the stage of disease and therapy. Swedish study shown normal-tension glaucoma often progressed among the patients with more aggressive treatment such as argon laser trabeculoplasty or trabeculectomies. According to the study’s data, age is the most important risk factor for the progression of normal-tension glaucoma. Such questions as fluctuations in IOP, reduction of retrobulbar blood flow, antihypertensive treatment on the progression of glaucoma are still discussed. Despite the fact that the latter UKGTS multicenter study (2014) showed a decrease in the rate of progression of glaucoma in patients treated with latanoprost, a high percentage of non-treated patients didn’t have disease’s progression. In this regard, the role of IOP as main starting factor in glaucoma pathogenesis is still open.

Introduction: The aim of this study was to assess the effect of phacoemulsification and endo-cyclophotocoagulation (phaco-ECP) on intraocular pressure (IOP) fluctuation as assessed by the water drinking test (WDT) in primary open angle glaucoma (POAG). Methods: This was a prospective observational study carried out at a tertiary referral centre. POAG patients on topical antiglaucoma medications and planned for phaco-ECP were recruited. WDT was performed before surgery and 6 weeks postoperatively by drinking 10 mL/kg of water in 5 min followed by serial IOP by Goldmann applanation tonometry measurements at 15, 30, 45, and 60 min. Mean IOP, IOP fluctuation (difference between highest and lowest IOP), IOP reduction, and factors affecting IOP fluctuation were analysed. Results: Twenty eyes from 17 patients were included. Baseline IOP was similar before (14.7 ± 2.7 mm Hg) and after (14.8 ± 3.4 mm Hg, p = 0.90) surgery. There was no difference in mean IOP (17.6 ± 3.4 mm Hg vs. 19.3 ± 4.7 mm Hg pre- and postoperative, respectively, p = 0.26) or peak IOP (19.37 ± 3.74 mm Hg vs. 21.23 ± 5.29 mm Hg, p = 0.25), albeit a significant reduction in IOP-lowering medications (2.2 ± 1.15 vs. 0.35 ± 0.93, p < 0.001) postoperatively. IOP fluctuation was significantly greater (6.4 ± 3.2 mm Hg vs. 4.6 ± 2.1 mm Hg, p = 0.015) with more eyes having significant IOP fluctuation of ≥6 mm Hg (11 eyes [55%] vs. 4 eyes [20%], p < 0.001) postoperatively. Factors that were significantly associated with increased postoperative IOP fluctuations were higher preoperative IOP fluctuation (β = 0.69, 95% CI 0.379–1.582, p = 0.004) and more number of postoperative antiglaucoma medications (β = 0.627, 95% CI 0.614–3.322, p = 0.008). Conclusion: Reducing aqueous production with phaco-ECP does not eliminate IOP fluctuation in POAG patients. The increase in postoperative IOP fluctuation suggests increased outflow resistance after phaco-ECP.

Diurnal Intraocular Pressure Fluctuation and Associated Risk Factors in Eyes with Angle Closure

Assessment of the Quality of Glaucoma Referral Letters Based on a Survey of Glaucoma Specialists and a Glaucoma Guideline

To evaluate the reproducibility of intraocular pressure (IOP) peaks and fluctuations detected during the water-drinking test (WDT) in patients with exfoliation syndrome (XFS) and exfoliative glaucoma (XFG). This prospective study included 34 XFS and 30 XFG patients. Each patient was evaluated twice, with the two WDTs performed on a 30-day interval. We recorded IOP peak (highest IOP during the WDT) and IOP fluctuation (IOP peak minus IOP before the test). Bland-Altman analysis was applied to assess the agreement of IOP peaks and fluctuations between the two consecutive visits. We defined reproducible as within 4 mmHg for IOP peak and within 2 mmHg for IOP fluctuation. There were no significant differences in IOP values, IOP peaks and IOP fluctuations between the two visits for both XFS and XFG patients (p>0.05, for all). The coefficient of repeatability for IOP peak was 2.5mmHg and 3.5mmHg in XFS and XFG patients respectively and for IOP fluctuation, it was 2.1mmHg and 2.2mmHg. None of the XFS or XFG patients had an IOP peak difference higher than 4mmHg. Intraocular pressure (IOP) fluctuation differences above 2.0mmHg were found in 8.8% of XFS patients and 16.6% of XFG patients. Intraocular pressure (IOP) peak and IOP fluctuation have a reproducibility, both in XFS and in XFG.

Introduction This report explores the challenges faced in addressing early-stage primary open-angle glaucoma (POAG) in a 74-year-old male. Following a steroid-induced elevation in intraocular pressure (IOP) after endoscopic cyclophotocoagulation (ECP) in the right eye, the patient underwent minimally invasive canaloplasty and goniotomy using the OMNI® Surgical System (Sight Sciences) on his left eye. Case Description IOPs at diagnosis measured at 28 mmHg and 27 mmHg in the right and left eye, respectively, leading to the prescription of bilateral latanoprost. An adverse reaction to latanoprost resulted in eye swelling, hyperaemia, facial and jaw discomfort, and photophobia, prompting the cessation of the medication. In December 2022, bilateral selective laser trabeculoplasty (SLT) was performed, with minimal impact on IOP. Subsequently, in March 2023, right cataract surgery with ECP successfully reduced right eye IOP to 16 mmHg. Postoperatively, the use of dexamethasone 0.1% drops caused an intraocular steroid-response, increasing IOP (maximal IOP =25 mmHg), resolving upon medication completion. To mitigate prolonged steroid drop-associated complications, left eye phacoemulsification with OMNI canaloplasty and goniotomy was conducted in June 2023. Standard 4-week low-frequency steroid drops were administered postoperatively with no complications. Conclusions Pressure control was successfully achieved with IOP normalization to 15 mmHg bilaterally. Significant visual acuity improvements were noted post ECP (right eye=6/24 to 6/6) and OMNI (left eye=6/7.5 to 6/6). This case highlights the efficacy of OMNI combined with phacoemulsification in the safe reduction of IOP and sustained IOP control in POAG patients, alluding to its favourable safety profile.