RightFit
RecruitingPhase 4

Retinal Blood Flow and Autoregulation

Direct Measures of Retinal Blood Flow and Autoregulation as Robust Biomarkers for Early Glaucoma

Who can join

As published by the study on ClinicalTrials.gov. "Not stated" means the study hasn't said — ask the study team.

Age
18 Years to 88 Years
Sex
All sexes
Healthy volunteers
Accepted
Compensation
Not stated

Other requirements are listed under Eligibility below. Only the study team can confirm whether you can join.

What to expect

No one can promise a trial will help you personally — that is what the research is trying to find out.

What participation involves

Not stated in the study description — ask the study team about visits and procedures.

Compensation
Not stated
  • Study-related exams and procedures are typically provided at no cost. This is how many trials work in general — confirm the details for this study with the study team.
  • Participants are monitored closely by the research team throughout the study.
  • Some participants may receive access to an investigational treatment, which is still being studied.
  • Your participation helps researchers learn whether this approach could help future patients.

About this study

In plain language

This study looks at how small blood vessels in the retina, the light-sensing layer at the back of the eye, control blood flow. It tests whether this could be an early sign of primary open-angle glaucoma, a disease that damages the eye’s main nerve. It includes adults with early glaucoma, glaucoma damage before vision test changes, or healthy eyes.

The purpose of this study is to establish autoregulation of retinal blood flow in arterioles and capillaries as a biomarker for early primary open angle glaucoma.

Compensation is read from the study's own description and may be missing — always confirm with the study team.

Eligibility

Who can join

  • Be older than 18.
  • Have an open drainage angle in the eye, graded 3 or 4 on an eye exam.
  • Have an eye prescription between +3.00 and -8.00 diopters and vision of 20/25 or better with glasses or contacts.
  • Belong to one of the three groups below.
  • Early glaucoma group: Meet the study’s early glaucoma rules, with vision loss only above or below the middle of the field of view. Be off glaucoma medicines for 4 weeks.
  • Glaucoma before vision test changes group: Have glaucoma damage to the eye’s main nerve and nerve fiber layer, but no clear glaucoma-related vision loss on the last 3 vision field tests.
  • Healthy comparison group: Have no family history of glaucoma, normal eye scans and vision field tests, and eye nerve measurements within the study’s limits. Participants will be matched in age to the early glaucoma group.

Who can't join

  • Have a problem with the cornea, the clear front of the eye, or another condition that prevents accurate eye pressure testing.
  • Have a retinal disease that changes the thickness of the eye’s nerve fiber layer.
  • Have glaucoma caused by another condition, or past eye surgery other than cataract surgery without problems or laser treatment to improve eye drainage.
  • Cannot safely stop glaucoma medicines for 4 weeks.
  • Cannot get usable eye blood vessel scans because of eye movement or trouble keeping your gaze steady, or have unreliable vision field tests.
  • Have smoked in the past 6 months.
  • Have a cataract, or cloudy eye lens, above the study’s allowed severity limit.
  • Have diabetes, high blood pressure, or another known blood vessel disease, such as blood vessel inflammation.

Simplified for readability. The official criteria below are what the study team uses.

Official eligibility criteria

Inclusion Criteria: 1. age over 18 years 2. open angle in gonioscopy (grade 3 or 4 in Shaffer classification) 3. refractive error within the range of +3.00 to -8.00 diopters (4) best-corrected visual acuity 20/25 or better (5) Individuals recruited will be in one of the 3 groups: 1\) Early Glaucoma as per Hodapp-Anderson-Parrish Criteria (54). Early glaucoma subjects specifically with visual field defects restricted to one side of the horizontal midline will be selected to allow for comparison of rates of progression in both hemifields. Individuals will need to be off of glaucoma medications for four weeks to participate in the study. 2) Pre-perimetric glaucoma defined as the presence of glaucomatous optic nerve damage (e.g., focal notching, rim thinning), RNFL defect, and the absence of a definite glaucomatous visual field defect using standard automated perimetry at the three most recent consecutive examinations. A glaucomatous visual field defect is defined as either 3 or more abnormal points with a P\<0.05, of which at least 1 point has a pattern standard deviation (PSD) of P\<0.01; or a PSD of P\<0.05; or glaucoma hemifield test values outside the normal limits. (55,56) 3) Control group - A subject with no family history of glaucoma who has the following: a) OCT with all four quadrants within the normal range for age-matched controls, b) reliable visual fields with glaucoma hemifield test within normal limits and determined to be normal by a glaucoma specialist, and c) cup-to-disc ratio of 0.4 or lower and asymmetry of the cup to disc ratio no greater than 0.1 as determined by a glaucoma specialist. Control subjects will be age matched to the early glaucoma subjects. Exclusion Criteria: 1. corneal abnormalities or other conditions preventing reliable applanation tonometry 2. retinal disease affecting retinal nerve fiber layer thickness such as vitreomacular traction as determined by a glaucoma specialist 3. secondary glaucoma 4. history of prior ocular surgery other than uncomplicated cataract surgery or laser trabeculoplasty 5. inability to safely be off of glaucoma medications for 4 weeks 6. inability to obtain OCT angiography data due to excessive eye motion or inability to fixate 7. unreliable visual fields 8. any history of smoking in the past 6 months 9. cataract greater than lens opacity classification system (LOCS) II Grade≥2 10. diagnosis of diabetes, hypertension, or other known vascular disorder such as vasculitis

Study sites (4)

MD