Intraocular Pressure
Conditions
Brief summary
This study is to investigate the relationship between arterial carbon dioxide (CO2) concentration and vitreous pressure on the choroidal volume by integrated intraoperative OCT imaging under eye exams under anesthesia.
Detailed description
Children with normal eyes undergoing an exam under anesthesia or a non-intraocular eye procedure will have one eye examined after research consent is taken. Children have very elastic ocular tissues. When they are having an intraocular procedure positive vitreous pressure can cause the iris to prolapse out of the eye and this can cause intraoperative and postoperative complications. The causes of the positive vitreous pressure have been speculated to be due to an increase in choroidal volume. The Choroid is a layer of blood vessels sitting between the sclera and the retina. Ocular Coherence Tomography (OCT) is an imaging tool that allows an optical section of the retina, choroid and sclera to be examined. The subfoveal choroidal thickness has been shown to be a consistent area that can be measured with reliability that the anatomical site of measurement is consistent. By varying the end tidal CO2 the thickness of the choroid will be measured and at the same time the intraocular pressure taken using a pneumatonometer. The OCT is integrated into the operating microscope and is used to take a scan of the fovea. Three scans will be taken after 5minutes of the particular end tidal pCO2. In order to ensure the choroidal thickness is not being influenced by the axial length of the eye, the axial length will be measured using an ultrasound probe at the beginning of the measurements just once. In order to ensure that the position of the head and body is not influencing the choroidal thickness a spirit level will be used to ensure a flat operating bed at the beginning of the measurements.
Interventions
OTHERVentilation manipulation
Effects of ventilation manipulation to achieve desired levels of end tidal carbon dioxide
Sponsors
University of Pittsburgh
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Intervention model description
This is a descriptive case series.
Eligibility
Sex/Gender
ALL
Age
No minimum to 8 Years
Healthy volunteers
Yes
Inclusion criteria
* any child undergoing an eye exam under anesthesia for an ophthalmologic reason. * children between the ages newborn to 8 years of age.
Exclusion criteria
* children who are not having an eye exam under anesthesia. * children with a known medical diagnosis that affect the eye to be studied * \* children over the age of 8 years of age. * \* children with altered cerebral autoregulation, increased intracranial pressure, pulmonary hypertension, or any other condition deemed appropriate by the anesthesiologist. * children in whom a laryngeal mask airway will not be used
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Intraocular Pressure (IOP) (mmHg) | After induction of anesthesia end tidal CO2 will be manipulated to 40mmHg, then 30mmHg and then 50mmHg. The end tidal CO2 levels will be held for at least 5 minutes after each ventilation manipulation and at the end of this 5 minute period IOP measured | Measurement of intraocular pressure after maintenance of end tidal pCO2 for 5 minutes at three end tidal pCO2 values : 40mmHg, then 30mmHg and then 50mmHg |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Choroidal thickness ( microns) | After induction of anesthesia end tidal CO2 will be manipulated to 40mmHg, then 30mmHg and then 50mmHg. The end tidal CO2 levels will be held for at least 5 minutes after each ventilation manipulation;at the end of 5 minute period choroid images taken | After 5 minutes of maintenance of end tidal pCO2 at 40mmHg, then 30mmHg and then 50mmHg, ocular coherence tomography (OCT) will be used to capture the subfoveal choroid. The images of the choroid will be provided to blinded individuals who will measure their thickness using the integrated scale on the OCT image. |
Countries
United States
Contacts
Primary ContactAmy Monroe, MPH, MBA
Backup ContactAlisha Maslanka, BS, CCRC
Outcome results
None listed