Changes in Regional Retinal Oxygen Extraction and Function After Radiation Therapy
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Enrollment
- 32
- Locations
- 1
- Primary Endpoint
- Abnormalities in regional retinal oxygen extraction after incidental irradiation of the retina.
Study Overview
Brief Summary
The investigators propose using retinal oximetry to assess for abnormalities in regional retinal oxygen consumption in previously- irradiated patients, and relate these abnormalities to changes in regional retinal function (i.e. visual field abnormalities). Since different regions of retina receive different radiation doses, the investigators will assess for a dose response as well.
Detailed Description
Radiation therapy (RT) is a common treatment for patients with cancers of the sinonasal area, orbit, skull base, nasopharynx, and brain. Because of the close proximity of these targets to the eyes, the retina is often incidentally and unavoidably irradiated. As a result, some patients develop radiation retinopathy and possibly vision loss. Clinicopathologic studies suggest similar microvascular mechanisms for both radiation- and diabetic retinopathy: small vessel occlusion and ischemia that can lead to neovascularization, increased capillary permeability, and visual loss in the regions of retina perfused by damaged vasculature. UNC has a novel, non-invasive retinal imaging technology called a Retinal Oximeter which measures hemoglobin oxygen saturation of retinal vessels. The difference in oxygen saturation between a retinal arteriole and venule pair reflects the oxygen consumption of the retinal region supplied by that vessel pair.
Study Design
- Study Type
- Observational
- Observational Model
- Case Only
- Time Perspective
- Prospective
Eligibility Criteria
- Ages
- 18 Years to 99 Years (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •≥ 18 years of age at the time of radiation therapy (no upper age limit)
- •History of radiation therapy delivered at UNC-CH or Rex Hospital to the vicinity of the retina(s) ≥ 2 months prior to enrollment
- •Estimated average dose to at least one quadrant of one retina ≥ 30 Gy
Exclusion Criteria
- •History of diabetes, retinal vascular occlusions, glaucoma, retinitis pigmentosa, occipital stroke or any other ophthalmologic or systemic problem that may confound visual field results.
- •Residual tumor within the visual pathway: retina, optic nerves, optic chiasm, optic radiations and brain.
Outcomes
Primary Outcomes
Abnormalities in regional retinal oxygen extraction after incidental irradiation of the retina.
Time Frame: 2 months
To identify abnormalities in regional retinal oxygen extraction in patients who have had previous incidental irradiation of the retina.
Prevalence of vision loss in patients with previous incidental irradiation of the retina
Time Frame: 2 months
To determine the prevalence of regional retinal dysfunction (i.e. vision loss) in patients with previous incidental irradiation of the retina.
Secondary Outcomes
- Vision loss amount versus radiation dose.(2 months)
- Changes in retinal oxygen extraction as compared to vision loss.(2 months)
- Changes in retinal oxygen extraction compared to radiation dose(2 months)