Intraocular Pressure Pattern Research Articles

Twenty-Four-Hour Intraocular Pressure Pattern In Glaucoma Suspects in an African Population.

Twenty-four-hour intraocular pressure measurement (Phasing) among glaucoma suspects showed higher intraocular pressure (IOP), greater fluctuation, and more varying peak times occurring mostly outside clinic hours, between 12 midnight and 8 am in 68.9% of them. To characterise 24-hour variation in IOP, in glaucoma suspects and normal individuals in an African population. A cross-sectional analytical study was carried out between March and October 2019 at the University of Ilorin Teaching Hospital. A total of 204 study participants, comprising 102 primary open angle glaucoma (POAG) suspects and 102 age and sex-matched controls with healthy eyes were recruited. Participants had a comprehensive ophthalmic examination. Measurements of IOP were taken every 2 hours during a 24-hour period using an iCare tonometer. The mean age was 43.64±14.02 SD and 43.02±13.55 SD ( P =1.000) for POAG suspects and controls, respectively. The mean peak IOP was significantly higher in POAG suspects (21.87± 4.65mmHg) compared with controls (17.17± 2.32mmHg) ( P <0.001). Whereas, the mean trough IOP reading was not significantly different between the 2 groups. In both groups of participants, the peak and trough IOP in the majority were recorded outside of clinic hours. The majority (68.9%) of POAG suspects had a peak IOP between midnight and 8 am, whereas the control group peaked mostly at 4 pm (16.7%) and 4 am (41.7%). Twenty-four-hour IOP variation was 6mmHg or less in 73.6% of control eyes, while in the POAG suspects, 83.3% of eyes had variation greater than 6mmHg. Compared with age and sex-matched healthy controls, glaucoma suspects of African descent showed significantly higher mean IOP and IOP variation, with most peak IOP detected outside of clinic hours.

Twenty-Four-Hour Intraocular Pressure in Chronic Primary Angle-Closure Disease.

Primary angle closure and primary angle closure glaucoma may exhibit normal intraocular pressure. Twenty-four-hour intraocular pressure fluctuation is highest in primary angle closure glaucoma. The degree of peripheral anterior synechiae was associated with a 24-hour intraocular pressure pattern in primary angle-closure disease without laser iridotomy. The purpose of this study was to study 24-hour intraocular pressure (IOP) patterns in eyes with chronic primary angle-closure disease and evaluate associations between peripheral anterior synechiae (PAS) and 24-hour IOP pattern. In this prospective cohort study, 59 eyes of 35 Asian patients with chronic primary angle-closure disease underwent complete ocular examinations at Ramathibodi Hospital, Mahidol University. Twenty-four-hour IOP records were obtained using Goldmann applanation tonometry at 2-hour intervals. Peak, mean, and trough 24-hour IOP values and 24-hour IOP fluctuation (difference between peak and trough values) were compared among groups. None of the participants received any treatment before complete data collection. Even univariable analysis demonstrated a significant difference in peak, mean, and trough IOP and 24-hour IOP fluctuation between the 3 groups; the magnitude of trough IOP was not higher than 21mmHg in all groups. In multivariable analysis, PAC and PACG eyes showed significantly higher peak IOP ( P =0.020 and 0.006, respectively) and 24-hour IOP fluctuation ( P =0.048 and 0.001, respectively) compared with PACS eyes. In comparison between combined PACS and PAC eyes versus PACG eyes, PACG eyes revealed significantly higher 24-hour IOP fluctuation. The degree of PAS was associated with peak and mean IOP values and with 24-hour IOP fluctuation in PAC and PACG eyes. Twenty-four-hour IOP fluctuation was highest in PACG eyes. Although PAC and PACG eyes showed higher peak IOP and 24-hour IOP fluctuation values, compared with PACS eyes, trough IOP in PAC and PACG eyes were mostly below 21mmHg. In addition, the degree of PAS was associated with a 24-hour IOP pattern in either PAC or PACG eyes.

Intraocular pressure changes following small-incision cataract surgeries in a tertiary care center: a prospective study

Aim This study aims to identify the pattern of intraocular pressure (IOP) changes after uneventful small-incision cataract surgery (SICS) in previously normotensive eyes, to know the cause for these postoperative changes, and to correlate the preoperative anterior chamber depth (ACD) to the postoperative IOP change. Patients and methods A prospective study was conducted at Yenepoya Medical College, Mangalore, India on 87 non-glaucomatous eyes that underwent an uneventful SICS with posterior chamber intraocular lens implantation. The IOP was measured preoperatively and postoperatively on days 1, 3, and weeks 1, 3, and 6. We tried to identify the cause of the IOP change. The preoperative and postoperative ACD change was also noted and correlated with the IOP change. Results The mean preoperative IOP was 14±1.81 mm Hg. On the first postoperative day (POD-1), 54% of the eyes showed a statistically significant rise in IOP (mean IOP=17.03±7.17 mm Hg, P=0.0002), and 28% showed a mean fall in IOP of 9.28 mm Hg. On the third postoperative day (POD-3), the IOP showed a statistically significant rise (14.82±3.93 mm Hg, P=0.028) compared with the preoperative value. At the end of the first postoperative week (POW-1), the IOP showed a statistically nonsignificant rise (P=0.66). By the third postoperative week (POW-3), the IOP decreased to 13.82±2.83 mm Hg, with a statistically nonsignificant difference compared with the preoperative IOP (P=0.45). However, there was a statistically significant decrease in the IOP (P=0.0001) in the sixth postoperative week (POW-6). Postoperatively, there was a statistically significant increase in ACD from 3.01±0.31 to 3.23±0.36 mm (P=0.0001) by the POW-3. The preoperative ACD showed a statistically significant moderate negative correlation with late postoperative IOP (r=−0.7394, P&lt;0.0001). Conclusion After SICS, at the end of 6 weeks, there was a statistically significant decrease in the mean IOP with an increase in the ACD. A moderate negative correlation existed between the preoperative ACD and late postoperative IOP. It was found that 2.3% of the eyes were steroid responders and showed a rise in IOP at POW-3.

Intraocular Pressure Spikes Following iStent Inject and the Relationship to Aqueous Outflow in Open Angle Glaucoma.

Adding trabecular bypass surgery (TBS) to phacoemulsification creates unpredictable short-term intraocular pressure (IOP) control that may be undesirable for patients with advanced glaucoma. Aqueous outflow (AO) responses after TBS are complex and probably multifactorial. To assess IOP spikes in patients with open angle glaucoma up to 1 month after iStent inject and their relationship to AO patterns measured by hemoglobin video imaging (HVI). We studied IOP for 4 weeks after TBS with iStent inject in 105 consecutive eyes with open angle glaucoma (6 TBS only and 99 combined with phacoemulsification). The change in IOP after surgery at each time point was compared with baseline measurements and the prior postoperative visit. IOP-lowering medications were stopped on the day of surgery in all patients. A smaller pilot study of 20 eyes (TBS only = 6 and combined = 14) underwent concurrent HVI to observe and quantify perioperative AO. Aqueous column cross-sectional area (AqCA) of one nasal and one temporal aqueous vein was calculated at each time point, and qualitative observations were documented. An additional 5 eyes were studied after phacoemulsification only. Mean IOP for the entire cohort (preoperative 17.3 ± 5.6 mm Hg) was lowest the day after TBS (13.1 ± 5.0 mm Hg) and peaked at 1 week (17.2 ± 8.0 mm Hg), before stabilizing by 4 weeks (15.2 ± 5.2 mm Hg; P < 0.00001). The same IOP pattern was seen when separating the group into a larger cohort without HVI (respectively 15.9 ± 3.2 mm Hg, 12.8 ± 4.9 mm Hg, 16.4 ± 7.4 mm Hg, and 14.1 ± 4.1 mm Hg; N = 85, P < 0.00001) and the smaller HVI pilot study (respectively 21.4 ± 9.9 mm Hg, 14.2 ± 4.9 mm Hg, 20.2 ± 9.7 mm Hg, and 18.9 ± 7.6 mm Hg; N = 20, P < 0.001). More than 30% IOP elevation above baseline occurred in 13.3% of the entire cohort at 1 week after surgery. This increased to 46.7% when IOP was compared with 1 day after surgery. Inconsistent AqCA values and patterns of aqueous flow were demonstrated after TBS. AqCA after phacoemulsification alone was maintained or increased within 1 week in all 5 eyes. After iStent inject surgery in patients with open angle glaucoma, intraocular spikes were most commonly seen at 1 week. AO patterns were variable and additional studies are needed to understand the pathophysiology underlying IOP responses after this procedure.

The Pattern of Intraocular Pressure After Phacoemulsification Surgery In Senile Cataract

Phacoemulsification is a surgical procedure for cataracts, which can increase intraocular pressure (IOP) and cause blindness due to glaucoma. It was known that the pattern of IOP changes after phacoemulsification surgery in senile cataracts. This study was an observational analytic study without a control group design. The study population was male and female senile cataract patients over 40 years of age who underwent phacoemulsification surgery at Kebumen Eye Centre Clinic in 2020. Intraocular pressure measurements using a Noncontact Tonometry by a nurse were carried out before surgery (D-0) and postoperatively on day 2 (D-2), day 9 (D-9), day 16 (D-16), and day- 23 (D-23). The data were analyzed using the Friedman test followed by the Post Hoc LSD test. The Friedman test results showed significant differences (p 0.05) in the IOP measurement at D-0, D-2, D-9, D-16, and D-23. Wilcoxon post hoc test showed IOP measurements on D-2 increased and then decreased normally. There was a change in the IOP pattern after phacoemulsification surgery, in which the IOP increased significantly on D-2 and then decreased normally.

The safety and validity of contact lens sensor (Triggerfish) in measuring diurnal variation of intraocular pressure (IOP)

With the current understanding of pathophysiology of glaucoma, the reduction of intraocular pressure (IOP) is the main evidence-based treatment which can prevent the progression of visual field defect (1). Several studies have shown that IOP varies throughout the day and night and patients with different glaucoma subtypes can have different circadian IOP patterns (2-4). In clinical practice, most ophthalmologists rely on the single measurement of IOP in clinic at each patient visit to monitor the control of IOP and thereby monitor the control of glaucoma. The peak IOP during after-hours is frequently underestimated by this form of measurement because it can only provide a single temporal value. Therefore, it is clear that in order to better manage glaucomatous patients, it is necessary to keep track of how their IOP changes over time.

Effects of medetomidine/ketamine and xylazine/ketamine anesthesia and their reversal by atipamezole on ocular parameters and monitored anesthesia care in cats

The aim of this study was to investigate the impact of the general anesthetic drug ketamine and premedication agents medetomidine and xylazine, and their reversal by atipamezole, on monitored anesthesia care values and ocular parameters such as intraocular pressure, horizontal pupillar diameter, and Schirmer tear test in cats. A randomized, single-blinded study was conducted. Twenty intact female cats (weiging between 2.2 and 3.6 kg, and 0.5 to 5.5 years of age) referred for ovariohysterectomy (OHE) procedure by the owners at regular intervals over 4 months were included in the study. The cats were randomly divided into two groups containing 10 animals in each group. The cats were premedicated with medetomidine 80 µg/kg intramuscular in group 1 while the cats in the 2nd group were premedicated with xylazine hydrochloride 2 mg/kg intramuscular. After the OHE procedure was ended, anesthesia regimes were reversed by using atipamezole 200 µg/kg intramuscularly. Monitoring of respiration rate, heart rate, mean arterial pressure, peripheral arterial oxygen saturation, and body temperature were conducted using a patient monitor at T0, T1, T2, T3, and T4 time points. Both groups showed declines in intraocular pressure and increases in horizontal pupil diameter after anesthesia induction (T0 vs. T1, all, P&amp;lt;0.05); however, the chancing and recovery pattern of intraocular pressure and horizontal pupil diameter showed intergroup difference. In conclusion, xylazine/ketamine is more effective than medetomidine/ketamine in attenuating the intraocular pressure, increasing the horizontal pupil diameter, and alteration the monitored anesthesia care response in the general anesthesia.

Clinical Audit on the Effectiveness of Clinic-Based Intraocular Pressure Phasing for Patients With Glaucoma and Glaucoma Suspect.

Introduction: Glaucoma is a complex disease with intraocular pressure (IOP) playing an important role in its diagnosis and management. IOP has shown diurnal and nocturnal variations, which may affect the course of the disease.Objective: The objective of this study was to determine the effectiveness of clinic-based office hour phasing in the diagnosis and management of glaucoma and glaucoma suspect (GS).Methods: A retrospective clinical audit was conducted on patients who were subjected to office hour phasing in a glaucoma clinic, Hospital Universiti Sains Malaysia, Kelantan, Malaysia, between January 2015 and December 2019. The office hour phasing was conducted for various indications such as confirmation of diagnosis, screening, and effectiveness of treatment. IOP was recorded every two hours between 0800 and 1600 using an air puff tonometer by a trained nurse. Measurement of IOP was repeated with Goldmann applanation tonometer at sitting position by a trainee when the IOP ≥ 20 mmHg or discrepancy of IOP > 2 mmHg between two eyes. Other investigations including a Humphrey visual field and gonioscopy were conducted in between the IOP measurements. Diagnosis and clinical decisions on management were made at the end of the office hour clinic phasing.Results: A total of 83 patients (163 eyes) were included in this clinical audit. Their mean age was 59.3 (16.5) years with 59% of male patients. Both eyes showed an almost similar pattern of mean IOP over five daytime readings in the clinic. A total of 35 eyes (21.5%) showed fluctuation ≥ 6 mmHg, and 128 eyes (78.5%) showed stable IOP during the clinic hour phasing. There was a significant difference in the mean IOP pattern between groups with stable and fluctuating IOP based on repetitive measure analysis of variance (RM ANOVA) (p = 0.008). The final diagnosis was made for 39 eyes (21 OD [right eye] and 18 OS [left eye]) out of 131 eyes (29.8%) with GS. Confirmation of diagnosis was achieved in all eyes (100%) with suspected ocular hypertension (OHT) and normal-tension glaucoma (NTG). Progression of glaucoma was confirmed in four eyes (2 OD and 2 OS) out of 17 eyes (23.5%) with suspected progression.Conclusion: Clinic hour IOP phasing provides a practical approach in confirmation of diagnosis and adjustment in the management of patients with glaucoma and GS.

Intraocular Pressure Elevation Following the Use of Topical Dexamethasone Ointment After Squint Surgery.

Purpose:To describe the pattern of intraocular pressure (IOP) changes after squint surgery in eyes of black Africans at the University College Hospital, Ibadan, Nigeria.Materials and Methods:This was a retrospective review of the clinical records of patients who underwent squint surgery between 2010 and 2019. Data on demographic characteristics, preoperative and postoperative intraocular pressure values, co-existing ocular pathology, type of strabismus, surgery performed, frequency and duration of postoperative topical steroid use and treatment received for elevated intraocular pressure were collected and descriptively summarised.Results:Thirty-six (39.1%) out of 92 patients who had squint surgery during the study period met study inclusion criteria. Mean age was 20.5 ± 13.6 years. All patients were administered Maxitrol® ointment postoperatively. Baseline, peak and net change in IOP were 12.9 ± 2.6 mmHg, 21.3 ± 6.8 mmHg and 8.39 ± 7.2 mmHg respectively. Thirty-one (86.1%) patients had elevation in IOP from baseline; 21 (67.7%) of these had significant IOP elevation. Topical steroid therapy was tailed off rapidly for all patients with significant IOP elevation. Twelve patients were commenced on topical IOP lowering medications, with normalization of intraocular pressure in majority of them by three months after surgery.Conclusion:Elevated intraocular pressure with the use of topical dexamethasone ointment after squint surgery was common in this study and majority of the patients had significant elevation in intraocular pressure. Close monitoring of the intraocular pressure of black patients, especially children, on topical steroid medication after squint surgery is strongly recommended.

The relationship between 24‐hour mean, peak, trough and clinic intraocular pressure in glaucoma patients

AbstractPurposeFor years, ophthalmologists have been relying on clinic intraocular pressure (IOP) to manage glaucoma patients. There are studies which have shown that IOP can vary substantially throughout the day. This prospective observational study is to evaluate the relationship between the 24‐hr mean IOP, peak IOP, trough IOP and clinic IOP and the timing of peak and trough IOP in glaucoma patients.Methods23 patients diagnosed with glaucoma were recruited and all of them were fitted with a contact lens sensor for 24 hours. The 24‐hr mean IOP of each patient was recorded. The peak, trough and clinic IOP of each patient were recorded as well. The Pearson correlation coefficient between 24‐hr mean IOP and peak IOP, trough IOP and clinic IOP were calculated and analysed. The circadian IOP pattern of glaucoma patients was constructed and analysed to determine the peak and trough.ResultsThe Pearson correlation coefficient of 24‐hr mean IOP and peak IOP among our subjects are r(23) = 0.8419 (p &lt; 0.00001). The correlation coefficient between 24‐hr mean IOP and trough IOP is r(23) = 0.8258 (p &lt; 0.00001). However, the correlation coefficient between 24‐hr mean IOP and clinic IOP is r(23) = 0.3608 (p = 0.091). The overall circadian IOP pattern showed peak IOP at 0730 and 1730 and showed trough IOP at 2130.ConclusionsThe 24‐hr mean IOP showed significantly strong positive correlation with peak and trough IOP among glaucoma patients. However, the 24‐hour mean IOP only showed weak positive correlation with the clinic IOP. We can possibly predict the 24‐hour mean IOP in patients based on single peak or single trough IOP reading but measuring a single IOP in clinic might not tell us the 24‐hour mean IOP of glaucoma patients. The best time to pick up peak or trough IOP to correlate with the 24‐hour mean IOP is at 0730/1730 and 2130 respectively.

Melatonin, circadian rhythms and glaucoma: current perspective.

Melatonin, circadian rhythms and glaucoma: current perspective.

Time-of-Year Variation in Intraocular Pressure.

In this study conducted in Chicago, IL, intraocular pressure (IOP) level was found to have a subtle, but measurable, annual pattern. Reasonable evidence is presented for a time-of-year variation in IOP. Adequate numbers of subjects must be studied to detect this small variation. The aim was to investigate the relationship between IOP and time of year. During a separate investigation, patients from 2011 to 2018 (dataset A, N=3041) in an urban, academic facility in Chicago, IL received an examination that included Goldmann applanation tonometry. Regression analyses assessed the relationship between time of year and IOP. Two additional datasets, 1 collected in a similar manner during 1999 and 2002 (dataset B, N=3261) and another consisting of all first visits during 2012 and 2017 (dataset C, N=69,858), were used to confirm and further investigate trends. For dataset A, peak mean IOP occurred in December/January (15.7±3.7/15.7±3.8 mm Hg) and lowest in September (14.5±3.1 mm Hg). The analysis suggested conventional quarterly analysis (January to March, etc.) can conceal time-of-year relationships because of inadequate statistical power and timing of IOP variation. Multiple linear regression analysis, with a November-to-October reordering, detected an annual, downward IOP trend (P<0.0001). Analysis of dataset B confirmed this trend (P<0.001). Fourier analysis on datasets A and B combined supported a 12-month IOP cycle for right/left eyes (P=0.01/P=0.005) and dataset C provided stronger evidence for an annual periodicity (P<0.0001). Harmonics analysis of dataset C showed a repeating pattern where IOP trended downward around April, and then back upward around October. This analysis strongly supports a demonstrable annual, cyclical IOP pattern with a trough to peak variation of ≈1 mm Hg, which has a seasonal relationship.

Triggerfish Recording of IOP Patterns in Combined HFDS Minimally Invasive Glaucoma and Cataract Surgery: A Prospective Study.

Background: The aim of the study is to investigate whether the circadian IOP rhythm can be influenced by combined cataract surgery with high frequency deep sclerotomy (HFDS) and whether intraocular pressure (IOP) can be significantly reduced by HFDS. Methods: In our study 10 patients were included, in whom 24 h IOP monitoring was installed before and after HFDS/cataract surgery using a Triggerfish. HFDS is a minimally invasive glaucoma surgery (MIGS). Results: After performed HFDS combined with cataract surgery, the IOP was reduced from 27.7 ± 2.11 mmHg to 14.4 ± 2.59 mmHg, which is highly significant (p < 0.001). The contact lens sensor (CLS) cosinor analysis pre- and postoperatively showed that the circadian rhythm is not influenced by the surgery, i.e., the circadian IOP rhythm did not show significant differences before and after surgery. Conclusions: HFDS combined with cataract surgery is a potent surgical method that can significantly reduce the IOP. However, the circadian rhythm cannot be changed by the surgery. The acrophase remained during the night in all patients.

24-h intraocular pressure patterns measured by Icare PRO rebound in habitual position of open-angle glaucoma eyes.

To measure the 24-h intraocular pressure (IOP) by Icare PRO rebound in healthy and primary open-angle glaucoma (POAG) eyes and compare it with non-contact tonometry (NCT). Thirty POAG patients, who were under IOP-lowering treatment, and 30 healthy subjects were included. Participants were hospitalized overnight for the 24-h IOP measurement. IOPs were measured by Icare PRO and NCT according to a standard protocol every 2h during 24h. The 24-h IOP curve and IOP-related parameters were compared between Icare PRO and NCT groups in POAG and healthy eyes. The IOPs measured by Icare PRO in habitual position increased notably at 22:00 in the normal group and at 20:00 in the POAG group, reached peak at 0:00, stayed high until 4:00, and then decreased in both groups (all p < 0.05). The POAG patients had higher mean 24-h IOP, peak IOP, IOP fluctuation, and greater IOP change from supine to sitting position in the nocturnal period than those in the normal subjects even after adjusting for eyes, age, gender, CCT, and axial length (all p < 0.05). The Icare PRO provides a well-tolerated approach for 24-h IOP monitoring in habitual position. Twenty-four-hour IOP in habitual position is more sensitive for detecting high nocturnal IOP peaks and greater IOP fluctuation for POAG patients.

Circadian Variation of Ocular Perfusion Pressure in Primary Open Angle Glaucoma- A Cross-sectional Study

Introduction: Various haemodynamic factors have been implicated as pathophysiological mechanisms in Primary Open Angle Glaucoma (POAG) other than raised Intraocular Pressure (IOP). However, the exact relationship still remains unclear. Aim: To examine the circadian pattern of Blood Pressure (BP), IOP and Ocular Perfusion Pressure (OPP) with the aim of understanding their relationships in a cohort of patients with POAG. Materials and Methods: A cross-sectional study was conducted in which 44 cases of newly diagnosed, non-hypertensive patients with POAG were enrolled and categorised based on the severity of glaucoma. Recording of BP and IOP were done every 4th hourly during a 24 hour hospital stay. The Mean OPP (MOPP) was calculated as 2/3×Mean Arterial Pressure (MAP)-IOP. Systolic OPP (SOPP) was calculated as Systolic BP-IOP and Diastolic OPP (DOPP) was calculated as Diastolic BP-IOP. The diurnal, nocturnal and 24 hour fluctuations were derived from the difference between the highest and lowest values within each period. Data was analysed using Statistical Package for the Social Sciences (SPSS) version 16.0. Univariate and multivariate regression analysis of the variables with age and severity of POAG were performed Results: Significant positive correlation of the nocturnal fluctuations in MAP (r=0.533), SOPP (r=0.835), DOPP (r =0.768), MOPP (r=0.685) and 24 hour fluctuation in MOPP (r=0.636) were noted with severity of glaucoma on multivariate analysis. No significant correlation of these parameters with age was noted on multivariate analyses. Conclusion: Nocturnal dip in OPP was an important observation among patients with POAG, potentially contributing to its pathophysiology.

Icare Home Tonometer: A Review of Characteristics and Clinical Utility.

The Icare HOME (TA022, Icare Oy, Vanda, Finland) is rebound tonometer recently approved by the US Food and Drug Administration in March 2017 designed for self-measurement of intraocular pressure (IOP). IOP remains a major modifiable risk factor for glaucoma progression; however, IOP measurements typically occur through single office measurements on Goldmann applanation tonometry (GAT) and do not always reveal the complete picture of patient’s IOP patterns and daily fluctuations, which are important for accurate diagnosis and evaluation. Numerous studies have now compared the efficacy of the Icare HOME to that of GAT. The objective of this article is to review the existing literature surrounding the Icare HOME tonometer and its efficacy as a self-tonometer in comparison to GAT. The available literature has shown promising results in its accuracy of measuring IOP but suggests cautious usage in patients with central corneal thicknesses or IOP ranges that are outside of a certain range. This article will also provide details and example cases for when the Icare HOME may be most clinically useful.

Transient changes in refractive error and corneal tomography after 24-h continuous monitoring of intraocular pressure patterns with a contact lens sensor

To evaluate changes in refractive error and corneal tomographic measurements after 24-h monitoring of intraocular pressure patterns with a contact lens sensor (CLS). Prospective, longitudinal, observational study. Fourteen eyes of 14 consecutive patients who underwent 24-h CLS monitoring were enrolled. The objective spherical equivalent (SE) refractive error was measured using automated refraction and keratometry. The axial power, instantaneous power, and corneal thickness at the central, paracentral, midperipheral, and peripheral cornea were measured with swept-source anterior-segment optical coherence tomography. Measurements were performed at baseline, immediately after monitoring, and at follow-up visits 2-4days after monitoring. The myopic SE increased significantly (P < 0.001) from - 5.1 ± 4.2 to - 6.0 ± 4.0, D after 24-h monitoring with a CLS and returned to the premonitoring level at the second visit (- 5.3 ± 4.4 D, P = 0.315). Decreases in the midperipheral and peripheral axial powers and the paracentral instantaneous power and increases in the central instantaneous power and peripheral corneal thickness occurred after CLS monitoring. Twenty-four-hour monitoring with a CLS resulted in significant increases in the myopic refractive error and corneal central steepening and midperipheral flattening. Although these changes are transient and do not negate the clinical merits of the CLS, clinicians should be aware of these potential adverse events. Three-dimensional evaluation of corneal deformation with anterior segment optical coherence tomography is a powerful tool for assessing and improving the safety, tolerability, and accuracy of CLS devices.

Role of 24-Hour Intraocular Pressure Monitoring in Glaucoma Management.

Glaucoma is the leading cause of irreversible blindness worldwide and the prevalence is on the rising trend. Intraocular pressure (IOP) reduction is the mainstay of treatment. The current practice of IOP monitoring is based on spot measurements during clinic visits during office hours. However, there are up to 50% of glaucoma patients who had normal initial IOP, while some treated patients continued to have progressive glaucomatous optic nerve damage even with a low IOP. Recent studies have shown that the IOP of glaucoma patients fluctuated during the day with different patterns, and some of them had peak IOP outside office hours. These findings provided us with new insights on the role of 24-hour IOP monitoring in managing normal tension glaucoma and patients with progressive deterioration despite apparently well-controlled IOP. Nevertheless, results to date are rather inconsistent, and there is no consensus yet. In this review, we briefly highlighted the current modalities of 24-hour IOP monitoring and summarized the characteristic 24-hour IOP pattern and the clinical relevance of IOP parameters in predicting glaucomatous progression in different glaucoma subtypes. We also discussed the therapeutic efficacy of current glaucoma treatment modalities with respect to the mentioned 24-hour IOP profiles, so as to strengthen the role of 24-hour IOP monitoring in identifying and stratifying the risks of progression in glaucoma patients, as well as optimizing treatments according to their IOP profiles.

Cyclic Pattern of Intraocular Pressure (IOP) and Transient IOP Fluctuations in Nonhuman Primates Measured with Continuous Wireless Telemetry

ABSTRACTPurpose: Most studies on intraocular pressure (IOP) to monitor IOP “fluctuations” in glaucoma patients have been performed with snapshot tonometry techniques that obtain IOP measurements at single time points weeks to months apart. However, IOP telemetry has shown that IOP varies from second-to-second due to blinks, saccades, and systolic vascular filling. The purpose of this study was to characterize the cyclic pattern of baseline IOP and transient IOP fluctuations in 3 nonhuman primates (NHPs).Methods: Bilateral IOP was measured using a proven implantable telemetry system and recorded 500 times per second, 24 hours a day, up to 451 continuous days in 3 male rhesus macaques aged 4 to 5 years old. The IOP transducers were calibrated every two weeks via anterior chamber cannulation manometry and all data were continuously corrected for signal drift via software, filtered for signal noise and dropout, and peaks and troughs were quantified and counted using a finite impulse response filter; waking hours were defined as 6:00–18:00 hours based on room light cycle.Results: Fourier transform analyses of baseline IOP and the hourly mean frequency of transient IOP fluctuations > 0.6 mmHg, 0.6–5 mmHg and > 5 mmHg above baseline during waking hours exhibited an approximate 16- to 91-day cyclic pattern in all NHPs. There were no measured environmental or experimental factors associated with this cyclical pattern.Conclusions: While the importance of the cyclic pattern identified in IOP and its fluctuations is unknown at this time, it is plausible that this pattern is relevant to both homeostasis and pathophysiology of the ONH, corneoscleral shell, and aqueous outflow pathways.

The effects of topical dorzolamide 2% and brinzolamide 1%, either alone or combined with timolol 0.5%, on intraocular pressure, pupil diameter, and heart rate in healthy cats.

ObjectiveTo investigate the effects of topical dorzolamide 2% q8h and brinzolamide 1% q8h, administered either alone (A and B, respectively) or in combination with topical timolol 0.5% q12h (C and D, respectively), on the circadian pattern of intraocular pressure (IOP), the pupil size, and heart rate in healthy cats.MethodsIn this prospective, randomized, double‐blinded study, 10 healthy, adult cats were randomly assigned to one of four groups and the eye to be medicated was randomly assigned. IOP, pupil diameter, and heart rate were measured at 3‐hour intervals. A 5 days’ adjustment period was followed by a 5 days’ placebo (baseline) period. Then, all groups of cats received all four treatments (A‐D) according to a Latin square‐based rotating schedule. Five days’ medication periods were alternated with 3 days’ washout periods.ResultsMean baseline IOP was 13.6 ± 2.7 mm Hg. All treatments resulted in a statistically significant decrease in mean IOP in the treated eye: A: −2.33 mm Hg (95% CI: −2.71, −1.94), B: −1.91 mm Hg (95% CI: −2.30, −1.53), C: −2.36 mm Hg (95% CI: −2.74, −1.97), and D: −2.37 mm Hg (95% CI: −2.76, −1.98) and the nontreated eye: A: −0.19 mm Hg (95% CI: −0.28, −0.11), B: −0.18 mm Hg (95% CI: −0.27, −0.10), C −0.31 mm Hg (95% CI: −0.40, −0.23), and D: −0.24 mm Hg (95% CI: −0.32, −0.15). Timolol resulted in an additional, significant decrease in IOP of 4% and 5%, respectively, compared to A and B, and in mild bradycardia and miosis.ConclusionsTopical administration of dorzolamide 2% and brinzolamide 1% q8h significantly decreased IOP in healthy cats. Supplemental timolol 0.5% eye drops q12h resulted in an additional, statistically significant reduction of IOP.