Retinal Biomarkers in Parkinson´s Disease

Retinal Biomarkers in Parkinson´s Disease: Retinal Oximetry, Pattern Electroretinography (PERG), Visual Evoked Potentials (VEP) and Optical Coherence Tomography (OCT)

The goal of this observational study is to determine whether oxygen content of the retinal vessels of the eye may serve as a biomarker in Parkinson´s disease. The main questions it aims to answer are:

1. Is retinal vessel oxyhemoglobin saturation and vessel width altered in people with Parkinson´s disease?
2. Is the thickness of the retinal nerve fiber layer altered in people with Parkinson´s disease?
3. Is the response of ganglion cells of the inner retina and the visual cortex altered in people with Parkinson´s disease?

The study procedure is threefold. The participants will:

A. Sit in front of a screen and focus on a red dot of its middle. A simple recording electrodes are applied on the cornea, forehead and scalp for the electrophysiological measurements. Prior to this procedure a topical anesthetic gel is applied to numb the eye to prevent discomfort from placement of the corneal electrodes.

B. Undergo general eye examination and optical coherence tomography (OCT) to measure the retinal tissue thickness. Prior to eye examination,eye drops are applied into the eyes to enlarge the pupils C. Sit in front of a fundus camera for obtaining images of the retinal vessels to measure oxygen saturation and the vessel width

Researchers will compare the obtained measurements with age- and gender matching of healthy controls.

Study Overview

• Status: Active, not recruiting
• Conditions: Parkinson Disease

• Study Type: Observational
• Enrollment (Estimated): 60

Contacts and Locations

Study Locations

• Iceland
  • Reykjavik, Iceland, 101
    • Ophthalmic Outpatient Department Landspitali UH

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

People with confirmed parkinsons disease Stage 0-3 on the Hohen and Yahr scale

Description

Inclusion Criteria:

• Confirmed Parkinson Disease

Exclusion Criteria:

• Eye disease
• Diabetic Mellitus
• Chronic Obstructive Pulmonary Disease (COPD)
• Other Neurological Disease
• Smoking on a daily basis

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Retinal vessels oxyhemoglobin saturation	Obtained by retinal oximetry	Baseline. On the visit to the ambulatory Opthalamic department at Landspitali

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Vessel width of retinal arterioles and venules	Obtained by retinal oximetry	Baseline. On the visit to the ambulatory Opthalamic department at Landspitali
Retinal nerve fiber layer thickness	Obtained by cross-sectional imaging of the retinal tissue (OCT)	Baseline. On the visit to the ambulatory Opthalamic department at Landspitali
Components and waveform of VEPs	Pattern electroretinogram (PERG)	Baseline. On the visit to the ambulatory Opthalamic department at Landspitali
Pattern electroretinograms (PERGs)	Amplitude of the visual evoked potential response	Baseline. On the visit to the ambulatory Opthalamic department at Landspitali

Collaborators and Investigators

• Sponsor: Landspitali University Hospital
• Collaborators: University of Iceland; Reykjalundur Rehabilitation
• Investigators: Principal Investigator: Thorunn S Eliasdottir, PhD, CRNA, University Hospital of Iceland and University of Iceland. Reykjalundur; Principal Investigator: Thorunn S Eliasdottir, PhD, CRNA, Landpitali the University Hopital of Iceland; Principal Investigator: Thorunn S Eliasdottir, PhD, CRNA, University of Iceland; Principal Investigator: Soley Thrainsdottir, MD, PhD, Reykjalundur

Study record dates

Study Major Dates

• Study Start (Actual): March 10, 2023
• Primary Completion (Estimated): December 31, 2026
• Study Completion (Estimated): December 31, 2026

Study Registration Dates

• First Submitted: March 31, 2025
• First Submitted That Met QC Criteria: April 8, 2025
• First Posted (Actual): April 15, 2025

Study Record Updates

• Last Update Posted (Actual): April 15, 2025
• Last Update Submitted That Met QC Criteria: April 8, 2025
• Last Verified: April 1, 2025

More Information

Terms related to this study

• Keywords: Optical Coherence Tomography; Visual Evoked Potentials; Retinal oximetry; Pattern Electroretinography; Oxyhemoglobin saturation
• Additional Relevant MeSH Terms: Synucleinopathies; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Neurodegenerative Diseases; Movement Disorders; Parkinsonian Disorders; Basal Ganglia Diseases; Parkinson Disease
• Other Study ID Numbers: VSN-22-129

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No