Clinical Trial: Retinal Oxygen Function After Radiation Therapy

Study Status: Completed
Recruit Status: Completed
Study Type: Observational

Official Title: Changes in Regional Retinal Oxygen Extraction and Function After Radiation Therapy

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 Summary: 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.
Sponsor: UNC Lineberger Comprehensive Cancer Center

Current Primary Outcome:

• 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.

Original Primary Outcome: Same as current

Current Secondary Outcome:

• Changes in retinal oxygen extraction compared to radiation dose [ Time Frame: 2 months ]
  To correlate changes in retinal oxygen extraction to radiation dose.
• Vision loss amount versus radiation dose. [ Time Frame: 2 months ]
  To correlate retinal dysfunction (i.e. vision loss) to radiation dose.
• Changes in retinal oxygen extraction as compared to vision loss. [ Time Frame: 2 months ]
  To correlate changes in retinal oxygen extraction to retinal dysfunction (i.e. vision loss).

Original Secondary Outcome: Same as current

Information By: UNC Lineberger Comprehensive Cancer Center

Dates:
Date Received: January 13, 2014
Date Started: March 2011
Date Completion:
Last Updated: May 15, 2017
Last Verified: May 2017