Pilot Study on Ambulatory Intraocular Pressure and Blood Pressure Monitoring in Glaucoma
Condition: Normal-Tension Glaucoma
MeSH terms: Glaucoma; Low Tension Glaucoma
Study type: Interventional

Summary: 
      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.
    

Detailed description: 
      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.
    

Intervention name(s): Sensimed Triggerfish; Blood Pressure
Intervention type(s): Device; Device
Intervention description(s): 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.; Patients in both groups will be fitted with a blood pressure cuff that will measure pressures for 24 hours.
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Diagnostic
Keywords: Glaucoma; Intraocular Pressure; Blood Pressure