Circadian Macular Volume Changes in the Choroid (CVdi)

Pilotstudy: Diurnal Changes in Choroidal Volume

Choroidal volume measured fluctuates significantly over a 24 hour time frame.

Study Overview

• Status: Completed
• Conditions: Choroid Physiology

Detailed Description

All patients undergo enhanced depth imaging (EDI) by the Spectralis SD-OCT device (Heidelberg Spectralis HRA2, Heidelberg Engineering, Heidelberg, Germany). SD-OCT measurements will be performed in both eyes after pupil dilation.

Scanning Protocol: This studies choroidal volume measurement protocol has been previously published. In short, 31 high resolution B-scans centered at the fovea will be obtained by a single investigator. To optimize image quality each B-scan will be averaged from at least 25 individual scans using the build in eye tracking software (TrueTrack, Heidelberg Engineering, Heidelberg, Germany). Scan length will be set to 9.3mm and spacing to 240µm, resulting in a 30x25 degree area around the fovea.

Each individual will undergo SD-OCT measurement every 3 hours within a 24 hour timeframe (at 0, 3, 6, 9 12, 15, 18, and 21 o'clock; 8 times total). Additionally, automated blood pressure measurement and Goldmann applanation tonometry will be performed every 3 hours. Subject will be instructed to sleep in erect position from 21 to 6 o'clock, and will be awoken for examination at 0 and 3.

OCT Analysis: Two retinal specialists will manually adjust the segmentation lines for automated choroidal volume calculation by the devices build in software. Choroidal thickness is defined as the layer between the outer boarder of the retinal pigment epithelium (RPE) and the hyper reflective layer behind the large vessels of the choroid (chorio-scleral interface). The devices Software thus generates a three-dimensional choroidal thickness map, divided according to the Early Treatment Diabetic Retinopathy Study (EDTRS) grid. In addition to this, subfoveal choroidal thickness will be measured manually using the SD-OCTs integrated caliper tool, drawing a perpendicular line to the RPE within the aforementioned bounds.

This is considered a pilot study, so explorative data analysis will be performed.

• Study Type: Observational
• Enrollment (Actual): 15

Contacts and Locations

Study Locations

• Austria
  • Styria
    • Graz, Styria, Austria, 8036
      • Department of Ophthalmology, Medical University of Graz

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Helathy human subjects

Description

Inclusion Criteria:

• age 18-65, signed informed consent form,

Exclusion Criteria:

• any ocular pathology, including history of ocular surgery or trauma, use of ocular medication, elevated intraocular pressure (IOP), or significant vitreous floaters. Further exclusion criteria were current use of any systemic medications, history of cardio-vascular disease, diabetes mellitus, or hypertension

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
healthy subject; healthy subject, every 3 hour measurement

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Macular Choroidal Volume	macular choroidal volume in the central 6mm	daily average out of measurements every 3 hours within a 24 hour timeframe

Secondary Outcome Measures

Outcome Measure	Time Frame
Subfoveal Choroidal Thickness	daily average out of measurements every 3 hours within a 24 hour timeframe

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mean Ocular Perfusion Pressure	mean arterial pressure (MAP) is defined as DBP + 1/3(SBP - DBP); mean ocular perfusion pressure results from 2/3(MAP - IOP).	every 3 hours within a 24 hour timeframe

Collaborators and Investigators

• Sponsor: Medical University of Graz
• Investigators: Principal Investigator: Gerald Seidel, MD, Medical University of Graz

Publications and helpful links

Helpful Links

• PMID 25447108

Study record dates

Study Major Dates

• Study Start: October 1, 2013
• Primary Completion (Actual): January 1, 2014
• Study Completion (Actual): February 1, 2014

Study Registration Dates

• First Submitted: August 21, 2014
• First Submitted That Met QC Criteria: August 21, 2014
• First Posted (Estimate): August 22, 2014

Study Record Updates

• Last Update Posted (Actual): September 24, 2020
• Last Update Submitted That Met QC Criteria: September 1, 2020
• Last Verified: September 1, 2020

More Information

Terms related to this study

• Other Study ID Numbers: CVdi