Normal-Tension Glaucoma Clinical Trial
Official title:
Pilot Study on Ambulatory Intraocular Pressure and Blood Pressure Monitoring in Glaucoma
Purpose: To study the feasibility of a larger study by determining the tolerability of
measuring blood pressure (BP) and intraocular pressure (IOP) over 24 hours in an ambulatory
fashion with automatic devices.
Participants: 20 patients with moderate to severe normal tension glaucoma and 20
non-glaucomatous patients.
Procedures (methods): Both BP and IOP will be measured automatically in each participant in
an ambulatory fashion during a 24-hour period. BP will be monitored using an appropriately
sized cuff Oscar 2 (Suntech Medical, Morrisville, NC), which will be placed by a person
trained in ambulatory BP monitoring devices. The device will be set up to automatically
inflate every 30 minutes during the day and every hour during the night to measure and
record the BP. IOP will be measured using Sensimed Triggerfish contact lens (Sensimed AG,
Lausanne, Switzerland); the measurements will be taken and recorded every 10 minutes. The
contact lens will be inserted by eye doctors (investigators). Both monitoring devices will
be removed the following day.
Chart review will be performed to select potential glaucoma participants. These potential
participants will be invited to participate in the study, either by phone or face-to-face
during scheduled visits.
Control participants will be invited from a registry that contains names of prior research
participants who have agreed to be contacted about future studies (participants have worn
ambulatory blood pressure monitor or ABPM in the past).
Invited persons who agree to participate in the study will be scheduled for a screening
visit at the eye clinic, during which they will learn more about the study. On the day of
the screening visit, they will be provided with detailed information about the study, after
which they will decide whether or not to participate. If they agree, they will sign the
consent form. The screening visit will then be conducted by the research personnel and will
take place at the eye clinic in a designated closed office and will include measurement of
visual acuity, assessment of the anterior and posterior segments of the eye, measurement of
IOP by Goldmann applanation tonometry. If after the screening exam it is determined that
they do not qualify for the study, they will be told why they are being excluded. Healthy
controls as well as glaucomatous patients not on treatment will be fitted with the BP and
IOP monitoring devices. Those who are on glaucoma medication will be asked to stop their
medication starting the day following the screening visit for the duration detailed in the
inclusion criteria, and be given an appointment for the for IOP and BP measurement. On the
appointment day, they will be fitted the BP and IOP monitoring devices. The BP monitor will
be set up to take the measurements automatically every 30 min during the day and every hour
at night until the next morning. The IOP monitor will take measurements every 10 minutes
during the 24-hour period. Both devices are computerized and record all the measurements and
reading times. Patients will be required to return to the clinic the next morning for
removal of the devices, after which there will be no further visits.
1. This study will provide for the first time information on the safety, tolerance, and
acceptability of the two devices used together. It will also provide preliminary
information on the reasons why people may drop out of the study, and information about
the relationship between IOP, BP, and OPP in patients with normal tension glaucoma and
in healthy controls.
2. IOP will be measured with the Sensimed Triggerfish, which is a disposable silicone
contact lens embedded with a wireless sensor. The sensing resistive gauge in the device
is circular around the center of the lens and is placed over a circumference of 11.5 mm
in diameter. This corresponds to the corneoscleral junction position, where maximum
corneal deformation occurs as a result of changes in IOP. A soft patch containing the
receiving antenna will be applied around the eye and transmits the information via wire
to the recorder that the patient will wear around the waist. The patient can continue
to wear spectacles during monitoring. The device records a total of 144 measurements
over a 24-hour period. Measurements are taken every 10 min for a total duration of 1
min. The results obtained are presented in an arbitrary unit and not mm Hg. In this
study, tonometry will be performed using radiofrequency waves at 27 MHz from the
external antenna, which is embedded in the patch applied around the patient's eye.
;
Allocation: Non-Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Open Label, Primary Purpose: Diagnostic