Retinal Neuro-vascular Coupling in Patients With Non-arteritic Anterior Ischemic Optic Neuropathy

Study Overview
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Brief Summary
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Ischemic optic neuropathy is among the most common causes of serious impaired vision in the middle-aged and elderly population in the western world. The current study focuses on a subgroup of ischemic optic neuropathy, the so-called non-arteritic ischemic optic neuropathy (NAION). Although the exact pathogenesis of NAION has not been fully clarified it is known that patients with cardio-vascular risk factors such as hypertension, diabetes mellitus and dyslipidemia have also an increased risk to develop NAION. Along this line of thought it has been shown that patients with a history of NAION in one eye have an increased risk to develop NAION also on the contralateral eye. However, clinical studies investigating ocular perfusion abnormalities in patients with NAION are sparse and even contradicting. Thus, the current study seeks to measure ocular blood flow parameters in patients with a history of NAION and compare it to healthy age-matched subjects.

Official Title
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Retinal Neuro-vascular Coupling in Patients With Non-arteritic Anterior Ischemic Optic Neuropathy

Conditions
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Anterior Ischemic Optic Neuropathy

Intervention / Treatment
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* Device: Dynamic Vessel Analyzer (DVA)
* Device: Fourier Domain Doppler Optical Coherence Tomography (FDOCT)
* Device: Optical coherence tomography (OCT)


Participation Criteria
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Eligibility Criteria
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Inclusion criteria for healthy subjects: Men and women aged over 18 years Non-smokers Normal findings in the medical history unless the investigator considers an abnormality to be clinically irrelevant Normal ophthalmic findings, ametropy < 6 Dpt. Inclusion criteria for patients with NAION: Men and women aged over 18 years History of NAION in one eye Normal ophthalmic findings, ametropy < 6 Dpt. Adequate visual acuity to allow participation in the ocular blood flow measurements A potential participant has to be on stable doses of all medications he/she is taking because of consisting illnesses according to medical history for at least 30 days prior inclusion, if considered relevant by the investigator. Any of the following will exclude a healthy subject from the study: Current ocular disease or history of NAION Presence or history of a severe medical condition as judged by the clinical investigator Untreated Arterial hypertension History or family history of epilepsy Presence of any abnormalities preventing reliable measurements in the study eye as judged by the investigator Best corrected visual acuity < 0.5 Snellen Ametropy ≥ 6 Dpt Pregnancy or planned pregnancy Alcoholism or substance abuse Any of the following will exclude a patient from the study: Presence or history of a severe medical condition other NAION as judged by the clinical investigator Untreated Arterial hypertension History or family history of epilepsy Presence of any abnormalities preventing reliable measurements in the study eye as judged by the investigator Best corrected visual acuity < 0.5 Snellen in the non-affected eye Ametropy ≥ 6 Dpt Pregnancy, planned pregnancy Alcoholism or substance abuse

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Patients with a history of NAION<br>patients with a history of non-arteritic anterior ischemic optic neuropathy (NAION) in one eye | Device: Dynamic Vessel Analyzer (DVA)<br>* Retinal vessel diameters and oxygen saturation will be measured with the DVA device.<br>Device: Fourier Domain Doppler Optical Coherence Tomography (FDOCT)<br>* Retinal blood flow will be assessed using FDOCT.<br>Device: Optical coherence tomography (OCT)<br>* Nerve fiber layer thickness and central retinal thickness will be measured using OCT.<br>|
| Experimental: Healthy control subjects<br>healthy age-and sex- matched control subjects | Device: Dynamic Vessel Analyzer (DVA)<br>* Retinal vessel diameters and oxygen saturation will be measured with the DVA device.<br>Device: Fourier Domain Doppler Optical Coherence Tomography (FDOCT)<br>* Retinal blood flow will be assessed using FDOCT.<br>Device: Optical coherence tomography (OCT)<br>* Nerve fiber layer thickness and central retinal thickness will be measured using OCT.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Flicker light induced hyperemia in retinal vessels | Response of retinal vessels to increased neuronal activity assessed with flicker light | 1 day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Retinal vessel diameters | Response of retinal vessel diameters to flicker light assessed with DVA | 1 day | 
| Retinal oxygen saturation | Retinal oxygen saturation measured with DVA | 1 day | 
| Retinal blood flow | Response of retinal blood flow to flicker light assessed with FDOCT | 1 day | 
| Retinal nerve fiber layer thickness | Retinal nerve fiber layer thickness measured using OCT | 1 day | 
| Central retinal thickness | Central retinal thickness using OCT | 1 day |