Limits...
Noninvasive intraocular pressure monitoring: current insights.

De Smedt S - Clin Ophthalmol (2015)

Bottom Line: The current practice of punctual measuring the IOP during office hours is therefore a suboptimal approach, which does not take into account the natural fluctuation of IOP.Phasing means monitoring a patient's IOP during the daytime or over a 24-hour period.Invasive techniques using an implantable sensor are beyond the scope of this review.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, AZ St Maarten, Mechelen, Belgium.

ABSTRACT
Glaucoma is the second leading cause of blindness worldwide and intraocular pressure (IOP) is currently its only modifiable risk factor. Peak IOP has for a long time been considered as a major contributor to glaucoma progression, but its effects may depend not only on its magnitude, but also on its time course. The IOP is nowadays considered to be a dynamic parameter with a circadian rhythm and spontaneous changes. The current practice of punctual measuring the IOP during office hours is therefore a suboptimal approach, which does not take into account the natural fluctuation of IOP. Because of its static nature a single IOP measurement in sitting position fails to document the true range of an individual's IOP, peak IOP, or variation throughout the day. Phasing means monitoring a patient's IOP during the daytime or over a 24-hour period. This can provide additional information in the management of glaucoma patients. This review focuses on the current insight of non-invasive IOP monitoring as a method of obtaining more complete IOP profiles. Invasive techniques using an implantable sensor are beyond the scope of this review.

No MeSH data available.


Related in: MedlinePlus

The sensor transmits the information to an antenna which is connected to a portable recorder. Reproduced with permission from Sensimed AG © 2014.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4525787&req=5

f2-opth-9-1385: The sensor transmits the information to an antenna which is connected to a portable recorder. Reproduced with permission from Sensimed AG © 2014.

Mentions: An alternative technique is a disposable contact lens sensor (CLS) (SENSIMED Triggerfish®; Sensimed AG, Lausanne, Switzerland) that has been developed to register corneal curvature changes (Figure 1).58 The corneal curvature in human eyes correlates well with IOP, in which an IOP change of 1 mmHg causes a change of central corneal radius of curvature of approximately 3 µm.60,61 In vitro studies using a sensor with an embedded micro-fabricated strain gauge on porcine eyes have demonstrated a very good correlation between the IOP variations and the changes in the corneal curvature measured in the corneoscleral area, where it is believed IOP changes induce maximum corneal deformation.62,63 Any ocular dimensional changes in the corneoscleral area are transmitted to the recorder expressed as an equivalent of the electric voltage (mV equivalents) (Figure 2). Recorded profiles are visual-ized graphically on a computer interface with approximately 300 data points acquired during a 30-second period, every 5 minutes, resulting in a total of 288 measurements over a 24-hour period. As IOP fluctuates synchronically with heart rate, this 24-hour registration of IOP rhythm can be inspected for ocular pulsation, including systolic and diastolic peaks and ocular pulsation frequency (Figure 3). The noise could be significantly allowing the detection an artificially induced IOP change over a 10-minute interval in four human volunteers, correlating well with the expected GAT-values.64 IOP can be measured by GAT before and after CLS wear, but GAT is not possible during the CLS wear, making simultaneous validation of the registered spikes difficult.65


Noninvasive intraocular pressure monitoring: current insights.

De Smedt S - Clin Ophthalmol (2015)

The sensor transmits the information to an antenna which is connected to a portable recorder. Reproduced with permission from Sensimed AG © 2014.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525787&req=5

f2-opth-9-1385: The sensor transmits the information to an antenna which is connected to a portable recorder. Reproduced with permission from Sensimed AG © 2014.
Mentions: An alternative technique is a disposable contact lens sensor (CLS) (SENSIMED Triggerfish®; Sensimed AG, Lausanne, Switzerland) that has been developed to register corneal curvature changes (Figure 1).58 The corneal curvature in human eyes correlates well with IOP, in which an IOP change of 1 mmHg causes a change of central corneal radius of curvature of approximately 3 µm.60,61 In vitro studies using a sensor with an embedded micro-fabricated strain gauge on porcine eyes have demonstrated a very good correlation between the IOP variations and the changes in the corneal curvature measured in the corneoscleral area, where it is believed IOP changes induce maximum corneal deformation.62,63 Any ocular dimensional changes in the corneoscleral area are transmitted to the recorder expressed as an equivalent of the electric voltage (mV equivalents) (Figure 2). Recorded profiles are visual-ized graphically on a computer interface with approximately 300 data points acquired during a 30-second period, every 5 minutes, resulting in a total of 288 measurements over a 24-hour period. As IOP fluctuates synchronically with heart rate, this 24-hour registration of IOP rhythm can be inspected for ocular pulsation, including systolic and diastolic peaks and ocular pulsation frequency (Figure 3). The noise could be significantly allowing the detection an artificially induced IOP change over a 10-minute interval in four human volunteers, correlating well with the expected GAT-values.64 IOP can be measured by GAT before and after CLS wear, but GAT is not possible during the CLS wear, making simultaneous validation of the registered spikes difficult.65

Bottom Line: The current practice of punctual measuring the IOP during office hours is therefore a suboptimal approach, which does not take into account the natural fluctuation of IOP.Phasing means monitoring a patient's IOP during the daytime or over a 24-hour period.Invasive techniques using an implantable sensor are beyond the scope of this review.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, AZ St Maarten, Mechelen, Belgium.

ABSTRACT
Glaucoma is the second leading cause of blindness worldwide and intraocular pressure (IOP) is currently its only modifiable risk factor. Peak IOP has for a long time been considered as a major contributor to glaucoma progression, but its effects may depend not only on its magnitude, but also on its time course. The IOP is nowadays considered to be a dynamic parameter with a circadian rhythm and spontaneous changes. The current practice of punctual measuring the IOP during office hours is therefore a suboptimal approach, which does not take into account the natural fluctuation of IOP. Because of its static nature a single IOP measurement in sitting position fails to document the true range of an individual's IOP, peak IOP, or variation throughout the day. Phasing means monitoring a patient's IOP during the daytime or over a 24-hour period. This can provide additional information in the management of glaucoma patients. This review focuses on the current insight of non-invasive IOP monitoring as a method of obtaining more complete IOP profiles. Invasive techniques using an implantable sensor are beyond the scope of this review.

No MeSH data available.


Related in: MedlinePlus