Fluorescent lifetime microscopy has emerged as a useful tool to study fluorescent lifetimes in vitro. Fluorescence lifetime represents the average amount of time a fluorophore remains in the excited state following excitation and depends on the fluorophores molecular environment. Fluorescence lifetime ophthalmoscopy (FLIO) is a technique which can quantify fluorescence lifetimes in the human retina in vivo. The purpose of this study is to investigate fluorescence lifetime characteristics in the human retina by using a FLIO. The investigators hypothesize that FLIO will allow to identify areas of retinal metabolic stress such as ischemia by detecting changes in fluorescence lifetimes.

Background

Ophthalmic imaging has made considerable progress in the last years. Especially the introduction of optical coherence tomography and the scanning laser ophthalmoscope has helped to understand the structural changes underlying various retinal diseases. However, the appearance of structural changes during retinal disease often represents irreversible functional loss with only limited treatment options. In order to prevent loss of vision, retinal diseases should ideally be diagnosed before structural changes occur. This can be achieved by imaging metabolic changes of the retina as most retinal diseases such as age related macular degeneration or diabetic retinopathy are associated with distinct metabolic changes, mainly related to oxidative stress.

Recently, a novel device for imaging fluorescent lifetimes of the retina in vivo, the fluorescent lifetime ophthalmoscope (FLIO), has been developed. This device is able to measure fluorescence lifetimes in the retina on a macroscopic level and may be able to shed new light on metabolic diseases of the retina.

Objective

To define fluorescence lifetime characteristics in healthy patients and patients with various retinal diseases.

Methods

The investigators will use a novel device, the fluorescence lifetime ophthalmoscope (FLIO) to investigate fluorescence lifetimes in the human retina.

Inclusion Criteria:

• Subject must be willing to give written informed consent
• Healthy volunteers 18 years of age or greater
• Patients 18 years of age or greater
• No significant media opacities

Exclusion Criteria

• Opacities of ocular media excluding detailed observation of the retina

The study population will consist of patients and healthy subjects attending the department of ophthalmology at the University of Bern