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Diurnal Intraocular Pressure and the Relationship With Swept-Source OCT–Derived Anterior Chamber Dimensions in Angle Closure: The IMPACT Study
摘要： PURPOSE. To evaluate diurnal intraocular pressure (DIOP) among individuals with primary angle closure (PAC) or primary angle-closure suspect (PACS). Additionally, the hypothesis that greater DIOP ?uctuation is related to smaller angle parameters was investigated. METHODS. Forty Caucasian newly referred untreated patients with bilateral PAC or PACS were recruited. Intraocular pressure (IOP) was measured hourly between 9 AM and 4 PM with Goldmann applanation tonometry. Diurnal IOP ?uctuation was de?ned as difference between maximum and minimum IOP. Angle opening distance (AOD), trabecular–iris angle (TIA), angle recess area (ARA), and trabecular–iris space area (TISA) were measured with anterior segment optical coherence tomography (AS-OCT) in dark (0.3–0.5 lux) and light (170–200 lux) on the same day as DIOP measurements in eight angle sections. RESULTS. Intraocular pressure declined as the day progressed (P < 0.001), unrelated to presence of peripheral anterior synechiae (PAS). At each time point, eyes with PAS (n ? 31) had signi?cantly higher IOPs than eyes without PAS (n ? 49; P ? 0.043). Diurnal IOP ?uctuation varied from 1.50 to 14.50 mm Hg (mean 5.99 mm Hg, SD 2.70 mm Hg). Diurnal IOP ?uctuation was unrelated to PAS. Multiple-predictor models investigating association of angle dimensions and greater DIOP ?uctuation were statistically signi?cant for AOD 750 (light), ARA 750 (light and dark), TISA 500 (light), TISA 750 (light), TIA 500 (light), and TIA 750 (light and dark). CONCLUSIONS. Diurnal IOP variation has clinical implications given that IOP level is used to distinguish between diagnostic categories of PACS and PAC. Optical coherence tomography angle parameter measurements may predict for magnitude of IOP diurnal ?uctuations in at-risk patients, which may be clinically useful when a clinical intervention is being considered.
关键词： glaucoma,intraocular pressure,angle closure
更新于2025-09-09 09:28:46
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Automated, Noncontact Intraocular Pressure Home Monitoring after Implantation of a Novel Telemetric Intraocular Pressure Sensor in Patients with Glaucoma: A Feasibility Study
摘要： Purpose. Reliable and regular assessment of intraocular pressure (IOP) is important for the monitoring of patients with glaucoma. The purpose of this study was to evaluate the feasibility of a novel system for the automated, noncontact measurement of IOP. Patients and Methods. A first-generation telemetric IOP sensor was previously implanted in the ciliary sulcus of six patients with open-angle glaucoma during cataract surgery. Using this technology, automated noninvasive tonometry may be performed in a home setting. In the present study, a modified sleep mask and a modified eyepatch with incorporated coil antennae for measurements during nighttime and daytime, respectively, were tested on a single patient. Results. In this feasibility study, the 24 h wear of the prototype measuring apparatus was well tolerated. Three sequences of 24 h IOP measurements with at least 200 IOP measurements per day were performed (Sequence 1: mean 19.6 ± 2.7 mmHg, range 13.4–28.7 mmHg; Sequence 2: mean 21.0 ± 3.0 mmHg, range 13.1–30.5 mmHg; Sequence 3: mean 19.9 ± 2.4 mmHg, range 12.6–27 mmHg). Conclusions. For the first time, repeated and automated 24-hour measurements are possible using a prototype noncontact reading system after implantation of a novel telemetric IOP sensor in patients with glaucoma.
关键词： noncontact tonometry,glaucoma,intraocular pressure,automated measurement,telemetric sensor
更新于2025-09-09 09:28:46
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Quantitative Analysis of Fundus-Image Sequences Reveals Phase of Spontaneous Venous Pulsations
摘要： Spontaneous venous pulsation correlates negatively with elevated intracranial pressure and papilledema, and it relates to glaucoma. Yet, its etiology remains unclear. A key element to elucidate its underlying mechanism is the time at which collapse occurs with respect to the heart cycle, but previous reports are contradictory. We assessed this question in healthy subjects using quantitative measurements of both vein diameters and artery lateral displacements; the latter being used as the marker of the ocular systole time.
关键词： retina,pulsation,intraocular pressure,blood flow,intracranial pressure,spontaneous venous pulsation
更新于2025-09-04 15:30:14
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Guide to the slit lamp
摘要： The slit lamp biomicroscope allows examination of the eye using varying illumination and magnification powers to give a detailed stereoscopic view of the anterior segment. It can also be used in conjunction with other instruments or lenses for checking the intraocular pressure or viewing the posterior segment (vitreous and retina). This article works best if it is re-visited with a slit lamp at hand.
关键词： intraocular pressure,slit lamp,anterior segment,biomicroscope,posterior segment
更新于2025-09-04 15:30:14
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Experimental Application of Piezoelectric Actuator-Driven Pulsed Water Jets in Retinal Vascular Surgery
摘要： To report on the effectiveness and safety of an ophthalmic piezoelectric actuator-driven pulsed water jet (ADPJ) system adapted for intraocular use. Methods: First, we determined the highest ADPJ flow rate that did not cause an unsafe rise in intraoperative intraocular pressure (IOP) in rabbits (n ? 4). Next, we determined the most effective ADPJ frequency (in hertz) at that flow rate. Finally, we visualized the ADPJ stream, measured its pressure, and determined the minimum voltage and distance between the ADPJ needle and retinal veins to induce intravenous displacement of the blood column (DBC) through massage of the outer retinal vessels (n ? 3) while not causing retinal tearing or hemorrhage. Results: We found that a 0.05 mL/min ADPJ flow rate caused IOP to rise above 40 mm Hg after 1 minute, but that at 0.025 mL/min, IOP stayed below 40 mm Hg even after 3 minutes. Moreover, we found that a 0.025 mL/min ADPJ stream was stable at a pulse frequency of 10 Hz and that at this flow rate/frequency the ADPJ pressure was closely correlated with the applied voltage (P , 0.001, r2 ? 0.9991). The minimum voltage and distance to achieve intravenous DBC without causing retinal tearing or hemorrhage were 40 V and 0.5 mm, respectively. Conclusions: With an appropriate flow rate and surgical time, ADPJ successfully induced massage of the retinal vessels and intravenous DBC while maintaining safe IOP and not causing retinal complications. Translational Relevance: The ADPJ system has promise as a safe and minimally invasive instrument for the intraocular surgical treatment of human retinal vascular diseases.
关键词： intraocular pressure,retinal complication,retinal vascular surgery,piezoelectric actuator-driven pulsed water jet,retinal vein occlusion
更新于2025-09-04 15:30:14
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Shape Changes of the Anterior Lamina Cribrosa in Normal, Ocular Hypertensive, and Glaucomatous Eyes Following Acute Intraocular Pressure Elevation
摘要： PURPOSE. The purpose of this study was to estimate and compare changes in anterior lamina cribrosa (LC) morphology in normal, ocular hypertensive (OHT), and glaucomatous eyes following acute elevations in intraocular pressure (IOP). METHODS. The optic nerve heads (ONHs) of 97 subjects (17 OHT, 19 primary open-angle glaucoma [POAG], 31 primary angle-closure glaucoma [PACG], and 30 normal subjects) were imaged using optical coherence tomography (OCT). Intraocular pressure was raised twice by applying forces to the anterior sclera, using an ophthalmodynamometer. After each IOP elevation, IOP was held constant and measured; each ONH was rescanned with OCT. In each OCT volume, the anterior LC was enhanced, delineated, and its global shape index (GSI) calculated and compared across groups. RESULTS. The baseline IOP was 17.5 6 3.5 mm Hg and was increased to 38 6 5.9 mm Hg and then to 46.5 6 5.9 mm Hg. At the ?rst IOP increment, mean GSI was signi?cantly smaller than that at baseline in normal subjects and glaucoma subjects (P < 0.05) but not in OHT subjects (P ? 0.12). For the second IOP increment, the mean GSI was signi?cantly smaller than that at baseline in normal subjects and in OHT eyes (P < 0.05). After adjusting for age, sex, and baseline IOP, the LC of POAG eyes was found to be signi?cantly more posteriorly curved than that of normal subjects (P ? 0.04). CONCLUSIONS. Acute IOP elevations altered anterior LC shape in a complex nonlinear fashion. The LC of POAG eyes was more cupped following acute IOP elevations compared to that of normal subjects.
关键词： morphometry,glaucoma,elevation,global shape index,intraocular pressure,lamina cribrosa,adaptive compensation
更新于2025-09-04 15:30:14
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Diurnal Variation in Intraocular Pressure Measured by Ocular Response Analyzer in Korean Patients with Normal Tension Glaucoma
摘要： Purpose: To analyze the diurnal change in intraocular pressure (IOP) and corneal biomechanical properties measured using the Ocular Response Analyzer (ORA; Reichert Inc., Depew, NY, USA) in Korean patients with normal tension glaucoma (NTG) patients. Methods: Intraocular pressure (Goldmann applanation tonometer IOP [GAT IOP], Goldmann-correlated IOP [IOPg], corneal-compensated IOP [IOPcc]) and corneal hysteresis (CH), corneal resistance factor (CRF) and central corneal thickness (CCT) were measured in 21 eye of NTG patients (12 males, 9 female) at 3 hour intervals for 48 hours using ORA. We recorded the time of each parameter that showed the lowest and the highest values of during the 48 hour testing period (Day 1 and Day 2) and evaluated the change of diurnal variation using Repeated measures analysis of variance (Re-ANOVA). Results: Peak IOP measured with GAT and ORA occurred at 6 AM-9 AM, 3 PM-6 PM and the trough IOP at 9 PM-12 AM during the 48 hour period. CCT, GAT IOP, IOPcc and IOPg measurements showed statistically significant variations (p<0.05). CH and CRF variations were not statistically significant (p>0.05). Conclusions: In Korean NTG patients, IOP exhibits significant diurnal variation, with higher values during the dawn and afternoon and lower values before retiring. Clinically, measurements of IOP performed in the afternoon could aid in the detection of relatively elevated IOP.
关键词： Diurnal variation,Ocular response analyzer,Intraocular pressure,Biomechanical properties
更新于2025-09-04 15:30:14