scholarly journals Evaluation of a novel method to measure the intraocular pressure based on a mechanical eye model

2012 ◽  
Vol 57 (SI-1 Track-P) ◽  
Author(s):  
K. Saleh ◽  
V. Unger ◽  
A. Dietzel ◽  
D. Heydenreich ◽  
R. Großjohann ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Eye Model ◽  
Novel Method

Tactile Eye Pressure Measurement Through the Eyelid

2015 ◽  
Author(s):  
Eniko T. Enikov ◽  
Péter P. Polyvás ◽  
Gholam Peyman ◽  
Sean Mccafferty
Keyword(s):  
Intraocular Pressure ◽  
Human Subjects ◽  
Statistical Error ◽  
Applanation Tonometry ◽  
Tactile Sensors ◽  
Non Invasive ◽  
Digital Palpation ◽  
Early Results ◽  
Novel Method ◽  
Eye Pressure

This article presents the early results from a 10-person human subject study evaluating the accuracy of a novel method of indirect estimation of intraocular pressure using tactile sensors. Manual digital palpation tonometery is an old method used to estimate the eye pressure through palpation with ones fingers. Based on this concept, we present an instrumented measurement method, where multiple tactile stiffness sensors are used to infer the intraocular pressure of the eye. The method is validated using experimental data gathered from human subjects with eye pressures from 15 to 22 mmHg and determined by Goldman applanation tonometry (GAT). Bland-Altman plots comparing the GAT measurements and the proposed through-the-eye-lid tonometry indicate a statistical error of 5.16 mmHg, within the 95% confidence interval, which compares favorably with the FDA-mandated error bound of 5 mmHg. Details on the unit operation and data filtering are also presented. Due to its indirect and non-invasive nature, the proposed new tactile tonometry method can be applied at home as a self-administered home tonometer for management of glaucoma.

scholarly journals A Novel Method for the Localization and Management of Traumatic Cyclodialysis Cleft

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Mingling Wang ◽  
Shufang Hu ◽  
Zhenquan Zhao ◽  
Tianlin Xiao
Keyword(s):  
Optical Coherence Tomography ◽  
Visual Acuity ◽  
Intraocular Pressure ◽  
Clinical Study ◽  
Ultrasound Biomicroscopy ◽  
Slit Lamp ◽  
Normal Range ◽  
Postoperative Visual Acuity ◽  
Novel Method ◽  
Cyclodialysis Cleft

Purpose.To propose a novel surgical method for the localization and management of traumatic cyclodialysis clefts.Methods.Five patients with traumatic cyclodialysis clefts who underwent the innovative surgery were retrospectively reviewed. The new method was introduced to repair a cyclodialysis cleft with two running sutures from the middle to each end of the cleft under the guidance of a probe. Preoperative and postoperative visual acuity (VA), intraocular pressure (IOP), slit lamp and gonioscopic results, ultrasound biomicroscopy (UBM), and optical coherence tomography (OCT) findings were recorded.Results.Cyclodialysis clefts were completely closed postoperatively in four patients (four eyes); this was confirmed by progressively improved VA, restoration into the normal range of the IOP, disappearance of suprachoroidal fluid, and reduced macular edema. Only one patient with multiple clefts had an incomplete reattachment.Conclusions.This clinical study offers a novel and efficient method to localize and repair the cyclodialysis clefts.

Mechanical eye model for evaluating intraocular pressure measurements

2014 ◽  
Vol 4 (4) ◽  
pp. 396-402
Author(s):  
Kutaiba Saleh ◽  
Volkmar Unger ◽  
Alexander Dietzel ◽  
Detlef Heydenreich ◽  
Rico Großjohann ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Pressure Measurements ◽  
Eye Model

SIMULATING THE EFFECTS OF ELEVATED INTRAOCULAR PRESSURE ON OCULAR STRUCTURES USING A GLOBAL FINITE ELEMENT MODEL OF THE HUMAN EYE

2017 ◽  
Vol 17 (02) ◽  
pp. 1750038 ◽  
Author(s):  
PEISHAN DAI ◽  
YALI ZHAO ◽  
HANWEI SHENG ◽  
LING LI ◽  
JING WU ◽  
...  
Keyword(s):  
Finite Element ◽  
Intraocular Pressure ◽  
Element Model ◽  
Global Model ◽  
Eye Model ◽  
Human Eye ◽  
Anterior Eye Segment ◽  
Elevated Intraocular Pressure ◽  
Biomechanical Responses ◽  
Iop Elevation

Elevated intraocular pressure (IOP) may be the primary risk factor to the development of glaucoma. Finite element (FE) modeling is commonly considered as an effective method to quantitatively analyze pathogenesis of glaucoma. Recent researches focus on establishing partial human eye models. A refined global human eye model was developed using ANSYS software to investigate the correlation between IOP elevation and biomechanical responses. First, the pressure transferring process according to IOP elevation in the whole eye was analyzed to simulate the effects of IOP elevation on glaucoma. Then, the biomechanical responses of the anterior eye segment under various pressure differences between the anterior and posterior chambers (AC and PC) were analyzed to simulate posterior nonadhesion of iris and posterior synechia. This global eye model not only simulated the responses of elevated IOP on ocular structures, but also revealed the process of pressure transferring among each tissue from the anterior eye segment to the optic nerve head (ONH) region. The local mechanical characteristics of the ocular structures obtained from the global model agreed with previous findings. This global model may shed light on the studies of multifactorial glaucoma.

scholarly journals A Water Balloon Eye Model for Teaching about the Human Eye

2020 ◽  
Vol 82 (5) ◽  
pp. 341-343
Author(s):  
Kwok-chi Lau
Keyword(s):  
Intraocular Pressure ◽  
Eye Model ◽  
Human Eye ◽  
Convex Lens

A physical eye model made of a water balloon and a convex lens is described. It can be used to model how an image is formed in the eye as well as shortsightedness and farsightedness. The model is unique in featuring a fluid-filled “eyeball” with “intraocular pressure,” making it a useful tool for teaching about accommodation and glaucoma. Instructional ideas for the model are suggested.

scholarly journals Experimental glaucoma model with controllable intraocular pressure history

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kayla R. Ficarrotta ◽  
Youssef H. Mohamed ◽  
Christopher L. Passaglia
Keyword(s):  
Intraocular Pressure ◽  
Time Course ◽  
Ganglion Cells ◽  
Brown Norway ◽  
Peripheral Retina ◽  
Significant Finding ◽  
Experimental Glaucoma ◽  
Progressive Degeneration ◽  
Novel Method ◽  
First Time

AbstractGlaucoma-like neuropathies can be experimentally induced by disturbing aqueous outflow from the eye, resulting in intraocular pressure (IOP) changes that are variable in magnitude and time course and permanent in duration. This study introduces a novel method of glaucoma induction that offers researchers round-the-clock measurement and reversible control of IOP for the first time. One eye of Brown-Norway rats was implanted with a cannula tethered to a pressure sensor and aqueous reservoir. IOP was raised 10 mmHg for weeks-to-months in treated animals and unaltered in control animals. Counts of Brn3a-expressing retinal ganglion cells (RGCs) in implanted eyes were indistinguishable from non-implanted eyes in control animals and 15 ± 2%, 23 ± 4%, and 38 ± 4% lower in animals exposed to 2, 4, and 9 weeks of IOP elevation. RGC loss was greater in peripheral retina at 2 weeks and widespread at longer durations. Optic nerves also showed progressive degeneration with exposure duration, yet conventional outflow facility of implanted eyes was normal (24.1 ± 2.9 nl/min/mmHg) even after 9-weeks elevation. Hence, this infusion-based glaucoma model exhibits graded neural damage with unimpaired outflow pathways. The model further revealed a potentially-significant finding that outflow properties of rat eyes do not remodel in response to chronic ocular hypertension.

scholarly journals Non-invasive Intraocular pressure monitoring with contact lens

2019 ◽  
pp. bjophthalmol-2018-313714 ◽  
Author(s):  
Angelica Campigotto ◽  
Stephane Leahy ◽  
Guowei Zhao ◽  
Robert J Campbell ◽  
Yongjun Lai
Keyword(s):  
Intraocular Pressure ◽  
Contact Lens ◽  
Continuous Monitoring ◽  
Vision Loss ◽  
Contact Lenses ◽  
Fluid Movement ◽  
Eye Model ◽  
Non Invasive ◽  
Cyclical Fluctuations ◽  
Pressure Catheter

BackgroundGlaucoma is the second leading cause of blindness in the world and the first leading cause of irreversible vision loss. Currently, the primary methodology of testing for the intraocular pressure (IOP) is during clinical office hours, which only provide a limited amount of information on the trends and fluctuations of the IOP. Therefore, a continuous monitoring system is required to properly determine the peaks of pressure and to negate any false results obtained by sparse, clinic hour testing. The objective of this study is to determine the ability of a newly designed contact lens with an embedded microchannel, to accurately measure the fluctuations in the IOP.MethodsExperimentation was completed on fresh enucleated porcine eyes. The contact lens was placed on the porcine eye and utilising a camera the fluid movement, within the microchannel in the contact lens, was recorded. A micro-pressure catheter, threaded into the centre of the vitreous chamber, recorded the true IOP and was compared with the displacement of the indicator fluid within the microchannel.ResultsThe contact lenses showed a consistent linear responsiveness to changes in IOP and robust to the effects of anatomical differences among eyes. The indicator fluid had an average fluid movement of 28 um/mm Hg between all the trials. Additionally, the devices showed the ability to measure both increases and decreases in IOP during cyclical fluctuations.ConclusionThe described inexpensive and non-invasive sensor is able to reliably monitor the IOP changes based on porcine eye model.

Sign in / Sign up

Export Citation Format

Share Document