Autofluorescence ImagingFLIO-GroupNCT01981148
Measurement of Retinal Auto Fluorescence With a Fluorescence Lifetime Imaging Ophthalmoscope
An observational study of Autofluorescence Imaging and Neuroimaging, run by Insel Gruppe AG, University Hospital Bern at 1 site in Switzerland.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Autofluorescence Imaging, Neuroimaging
- What is being tested?
- Fluorescence lifetime ophthalmoscope
- Type of treatment
- Medical device
- How many people
- 892 participants
- Where
- 1 siteSwitzerland
- Study dates
- Feb 2013to 31 Dec 2025
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: The study population will consist of patients and healthy subjects attending the department of ophthalmology at the University of Bern
Who may be able to join
- 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
Who cannot join
- Opacities of ocular media excluding detailed observation of the retina
Trial locations and contacts
1 site in 1 country.
Switzerland1 site
Department of Ophthalmology, Bern University Hospital, Bern, 3010 Bern, Switzerland
Bern, 3010
About this study
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.
Read the detailed description
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.
- Conditions
- Autofluorescence Imaging, Neuroimaging
- Being tested
- Fluorescence lifetime ophthalmoscope
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Fluorescence lifetime ophthalmoscopeDevice
All patients and healthy subjects will be imaged with the fluorescence lifetime ophthalmoscope
| Study group | Role | What they receive |
|---|---|---|
| Healthy patients | Healthy patients Receives: Device: Fluorescence lifetime ophthalmoscope | |
| Patients with various retinal diseases | Various retinal diseases (vascular, hereditary, degenerative) Receives: Device: Fluorescence lifetime ophthalmoscope |
What is being measured
The primary outcome is the main question the study is designed to answer.
Fluorescence lifetime measured by a fluorescence lifetime imaging ophthalmoscope
Measured by fluorescence lifetime variable (TAU). Measured once; in some patients, up to 4 measurements within 2 years will be done
Measured: at baseline
Secondary outcomes (1)
Repeatability of FLIO
Two independent measurements
Measured: at baseline
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Nov 2013 (estimated)
- Study startFeb 2013
- Primary completion31 Dec 2025
- Study completion31 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (8)Papers the sponsor has linked to this study.
- Other trials for Autofluorescence ImagingStudies of the same condition, open and under way.
- More trials run by Insel Gruppe AG, University Hospital BernThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 892 participants (actual)
Sponsor and investigators
- Lead sponsor
- Insel Gruppe AG, University Hospital Bern
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Martin Zinkernagel, Prof.Dr.Dr., Study chair, Inselspital, University Clinic Ophthalmology
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01981148
- Sponsor's protocol ID
- FLIO
- Acronym
- FLIO-Group
- Status last verified
- Jun 2026
- First submitted
- 4 Nov 2013
- Last updated
- 11 Jun 2026
- Results posted
- No
- Data monitoring committee
- Yes
Publications
Klemm M, Dietzel A, Haueisen J, Nagel E, Hammer M, Schweitzer D. Repeatability of autofluorescence lifetime imaging at the human fundus in healthy volunteers. Curr Eye Res. 2013 Jul;38(7):793-801. doi: 10.3109/02713683.2013.779723. Epub 2013 Mar 26.
PubMed 23530995Schweitzer D, Gaillard ER, Dillon J, Mullins RF, Russell S, Hoffmann B, Peters S, Hammer M, Biskup C. Time-resolved autofluorescence imaging of human donor retina tissue from donors with significant extramacular drusen. Invest Ophthalmol Vis Sci. 2012 Jun 8;53(7):3376-86. doi: 10.1167/iovs.11-8970.
PubMed 22511622Schweitzer D, Quick S, Klemm M, Hammer M, Jentsch S, Dawczynski J. [Time-resolved autofluorescence in retinal vascular occlusions]. Ophthalmologe. 2010 Dec;107(12):1145-52. doi: 10.1007/s00347-010-2195-7. German.
PubMed 20552361Dysli C, Quellec G, Abegg M, Menke MN, Wolf-Schnurrbusch U, Kowal J, Blatz J, La Schiazza O, Leichtle AB, Wolf S, Zinkernagel MS. Quantitative analysis of fluorescence lifetime measurements of the macula using the fluorescence lifetime imaging ophthalmoscope in healthy subjects. Invest Ophthalmol Vis Sci. 2014 Apr 3;55(4):2106-13. doi: 10.1167/iovs.13-13627.
PubMed 24569585Dysli C, Dysli M, Wolf S, Zinkernagel M. Fluorescence lifetime distribution in phakic and pseudophakic healthy eyes. PLoS One. 2023 Jan 6;18(1):e0279158. doi: 10.1371/journal.pone.0279158. eCollection 2023.
PubMed 36608033Lincke JB, Dysli C, Jaggi D, Solberg Y, Wolf S, Zinkernagel MS. LONGITUDINAL FOVEAL FLUORESCENCE LIFETIME CHARACTERISTICS IN GEOGRAPHIC ATROPHY USING FLUORESCENCE LIFETIME IMAGING OPHTHALMOSCOPY. Retina. 2021 Nov 1;41(11):2391-2398. doi: 10.1097/IAE.0000000000003222.
PubMed 34282069Dysli C, Dysli M, Lincke J, Jaggi D, Wolf S, Zinkernagel MS. IMAGING ARTIFACTS IN FLUORESCENCE LIFETIME IMAGING OPHTHALMOSCOPY. Retina. 2021 Nov 1;41(11):2378-2390. doi: 10.1097/IAE.0000000000003235.
PubMed 34111887Dysli C, Wolf S, Hatz K, Zinkernagel MS. Fluorescence Lifetime Imaging in Stargardt Disease: Potential Marker for Disease Progression. Invest Ophthalmol Vis Sci. 2016 Mar;57(3):832-41. doi: 10.1167/iovs.15-18033.
PubMed 26934141
Study at a glance
From the registry record, last updated by the sponsor on 11 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Measurement of Retinal Auto Fluorescence With a Fluorescence Lifetime Imaging Ophthalmoscope
- ClinicalTrials.gov ID
- NCT01981148
- Acronym / sponsor ID
- FLIO-Group / FLIO
- Conditions
- Autofluorescence Imaging, Neuroimaging
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 892 participants (actual)
- Lead sponsor
- Insel Gruppe AG, University Hospital BernUniversity, hospital or other
- Study start
- Feb 2013 (actual)
- Primary completion
- 31 Dec 2025 (actual)
- Study completion
- 31 Dec 2025 (actual)
- First posted
- 11 Nov 2013 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
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.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Healthy patients | – | Device: Fluorescence lifetime ophthalmoscopeHealthy patients |
| Patients with various retinal diseases | – | Device: Fluorescence lifetime ophthalmoscopeVarious retinal diseases (vascular, hereditary, degenerative) |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- The study population will consist of patients and healthy subjects attending the department of ophthalmology at the University of Bern
Key inclusion criteria (4 listed)
- 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
Key exclusion criteria (1 listed)
- Opacities of ocular media excluding detailed observation of the retina
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Fluorescence lifetime ophthalmoscopeAll patients and healthy subjects will be imaged with the fluorescence lifetime ophthalmoscope | Device | Healthy patients, Patients with various retinal diseases |
Primary outcome
Fluorescence lifetime measured by a fluorescence lifetime imaging ophthalmoscope
Time frame: at baseline
Measured by fluorescence lifetime variable (TAU). Measured once; in some patients, up to 4 measurements within 2 years will be done
1 secondary outcome
Repeatability of FLIO
Time frame: at baseline
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 11 Jun 2026.
- Results publication: PubMed 23530995Klemm M, Dietzel A, Haueisen J, Nagel E, Hammer M, Schweitzer D. Repeatability of autofluorescence lifetime imaging at the human fundus in healthy volunteers. Curr Eye Res. 2013 Jul;38(7):793-801. doi: 10.3109/02713683.2013.779723. Epub 2013 Mar 26.
- Results publication: PubMed 22511622Schweitzer D, Gaillard ER, Dillon J, Mullins RF, Russell S, Hoffmann B, Peters S, Hammer M, Biskup C. Time-resolved autofluorescence imaging of human donor retina tissue from donors with significant extramacular drusen. Invest Ophthalmol Vis Sci. 2012 Jun 8;53(7):3376-86. doi: 10.1167/iovs.11-8970.
- Results publication: PubMed 20552361Schweitzer D, Quick S, Klemm M, Hammer M, Jentsch S, Dawczynski J. [Time-resolved autofluorescence in retinal vascular occlusions]. Ophthalmologe. 2010 Dec;107(12):1145-52. doi: 10.1007/s00347-010-2195-7. German.
- Results publication: PubMed 24569585Dysli C, Quellec G, Abegg M, Menke MN, Wolf-Schnurrbusch U, Kowal J, Blatz J, La Schiazza O, Leichtle AB, Wolf S, Zinkernagel MS. Quantitative analysis of fluorescence lifetime measurements of the macula using the fluorescence lifetime imaging ophthalmoscope in healthy subjects. Invest Ophthalmol Vis Sci. 2014 Apr 3;55(4):2106-13. doi: 10.1167/iovs.13-13627.
- Derived from this study: PubMed 36608033Dysli C, Dysli M, Wolf S, Zinkernagel M. Fluorescence lifetime distribution in phakic and pseudophakic healthy eyes. PLoS One. 2023 Jan 6;18(1):e0279158. doi: 10.1371/journal.pone.0279158. eCollection 2023.
- Derived from this study: PubMed 34282069Lincke JB, Dysli C, Jaggi D, Solberg Y, Wolf S, Zinkernagel MS. LONGITUDINAL FOVEAL FLUORESCENCE LIFETIME CHARACTERISTICS IN GEOGRAPHIC ATROPHY USING FLUORESCENCE LIFETIME IMAGING OPHTHALMOSCOPY. Retina. 2021 Nov 1;41(11):2391-2398. doi: 10.1097/IAE.0000000000003222.
- Derived from this study: PubMed 34111887Dysli C, Dysli M, Lincke J, Jaggi D, Wolf S, Zinkernagel MS. IMAGING ARTIFACTS IN FLUORESCENCE LIFETIME IMAGING OPHTHALMOSCOPY. Retina. 2021 Nov 1;41(11):2378-2390. doi: 10.1097/IAE.0000000000003235.
- Derived from this study: PubMed 26934141Dysli C, Wolf S, Hatz K, Zinkernagel MS. Fluorescence Lifetime Imaging in Stargardt Disease: Potential Marker for Disease Progression. Invest Ophthalmol Vis Sci. 2016 Mar;57(3):832-41. doi: 10.1167/iovs.15-18033.
Related trials for Autofluorescence Imaging
Recruiting
NIRAF-Guided Parathyroid Identification During Thyroidectomy
Hypocalcemia, Hypoparathyroidism
RecruitingObservational study
Intra-operative Detection of Positive Margins and Lymph Nodes in Breast Surgery
Breast Cancer Invasive
Active, not recruitingObservational study
A Snapshot Adaptive Optics and Hyperspectral Autofluorescence Fundus Camera for Age-Related Macular Degeneration (AMD)
Age Related Macular Degeneration
Recruiting
Surgery for Thyroid Cancer With or Without Autofluorescence to Prevent Hypoparathyroidism
Thyroid Cancer
Not yet recruiting
Use of the PTEye Device to Reduce Inadvertent Parathyroidectomy During Thyroid Surgery
Thyroid Surgery, Inadvertent Parathyroidectomy
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Martin Zinkernagel, Prof.Dr.Dr. study chair
Inselspital, University Clinic Ophthalmology
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Autofluorescence Imaging and Neuroimaging, run by Insel Gruppe AG, University Hospital Bern at 1 site in Switzerland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 11 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Fluorescence lifetime measured by a fluorescence lifetime imaging ophthalmoscope (time frame: at baseline). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT01981148, which also lists 8 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 11 Jun 2026.