Charles Bonnet SyndromeCBSNCT07563101
Charles Bonnet Syndrome in Low Vision Patients
An observational study of Charles Bonnet Syndrome, run by Fondazione Policlinico Universitario Agostino Gemelli IRCCS at 1 site in Italy.
Trial summary
Among patients with chronic and degenerative ocular diseases that cause visual limitations, the presence of Charles Bonnet Syndrome (CBS) may be detected as a comorbidity. CBS is as a phenomenon of complex visual hallucinations occurring in individuals with reduced visual function, in the absence of cognitive… Read more about this study
- Who is it for?
- Ages 40 to 70 years
- Conditions the study is for
- Charles Bonnet Syndrome
- How many people
- 640 participants
- Where
- 1 siteItaly
- Study dates
- 15 Jan 2025to 31 Jan 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
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 40 to 70 years
- All sexes
- Adult, Older adult
Study population: Visually impaired individuals with central and peripheral defects who access the center for visual rehabilitation.
Who may be able to join
- Best corrected visual acuity between 1/20 (1.0 LogMAR) and 3.2/10 (0.5 LogMAR) in cases of central vision impairment.
- Residual binocular visual field ≤ 60% in cases of peripheral vision impairment.
- Patients with age-related macular degeneration, Stargardt's disease, or glaucoma.
- Age between 40 and 70 years.
- Signed informed consent.
Who cannot join
- Age under 40 years.
- Clear cognitive impairments that reduce patient reliability.
- Psychiatric disorders.
- Refusal to sign informed consent to participate in the study.
- Mental State Examination (MMSE) score below 22.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Italy1 site
fondazione Policlinico Universitario A. Gemelli IRCCS, Polo Nazionale Ipovisione
Roma, 00168
About this study
Official title: Charles Bonnet Syndrome (CBS): Prevalence and Characteristics of Visual Hallucinations. Psychological Profile of the Visually Impaired Patient With CBS
Among patients with chronic and degenerative ocular diseases that cause visual limitations, the presence of Charles Bonnet Syndrome (CBS) may be detected as a comorbidity. CBS is as a phenomenon of complex visual hallucinations occurring in individuals with reduced visual function, in the absence of cognitive alterations, psychiatric and/or neurological conditions. It is estimated that 15.8% of patients with age-related macular degeneration and 13.5% among glaucoma patients have CBS. Prevalence rates vary widely, and this may depend on inconsistent diagnostic criteria, variability in the questions used to determine if an individual has visual hallucinations, and the reluctance of people to admit to having strange visions for fear of being considered mentally ill. Visual hallucinations can be invasive and debilitating, compromising mental health, quality of life, and rehabilitation in visually impaired individuals. Patients may experience confusion, anxiety, anger, paranoia, and social isolation. Regarding psychological aspects, about a third of patients report experiencing distress and fear,higher anxiety and social dysfunction particularly during the initial onset of symptoms and in the terminal stage of the disease.Screening questionnaires will be used.
Read the detailed description
As part of our clinical practice, screening questionnaires will be used to assess the mental health and psychological profile of enrolled patients:
PHQ-9 (Patient Health Questionnaire): A 9-question tool for screening depression, with scores ranging from 0-27 to assess depression severity. Scores above 5 require referral to a clinical psychologist; scores 15+ suggest psychiatric evaluation.
GAD-7 (General Anxiety Disorder): A 7-item tool to screen for generalized anxiety disorder, with scores from 0-21. Scores 10+ require clinical psychologist referral, and 15+ indicate the need for psychiatric evaluation.
SCL-90R (Symptom Checklist-90): A 90-item questionnaire assessing a range of psychological symptoms, including depression, anxiety, and aggression, rated on a Likert scale from 0 to 4.
NEI VFQ25 (National Eye Institute Visual Function Questionnaire): A tool to assess the quality of life related to vision.
GSES (Generalized Self-Efficacy Scale):A 10-item scale to measure perceived self-efficacy and coping mechanisms for stressful life events, rated on a 4-point Likert scale.
PSS (Perceived Stress Scale):A tool to measure how individuals perceive their life as stressful, focusing on unpredictability, uncontrollability, and overwhelm.
GHQ-12 (General Health Questionnaire-12):A 12-item questionnaire to identify general mental health problems, focusing on the past two weeks.
- Conditions
- Charles Bonnet Syndrome
- Medical subject headings
- Charles Bonnet Syndrome
What is being measured
The primary outcome is the main question the study is designed to answer.
Prevalence of the Charles Bonnet Syndrome
Prevalence of Charles Bonnet Syndrome, calculated as the ratio between the number of visually impaired patients affected by CBS and the total number of patients attending the visual rehabilitation center, multiplied by 100 (%).
Measured: From baseline through study completion, up to 24 months.
Secondary outcomes (6)
Change in Generalized Anxiety Disorder-7 (GAD-7). 7 items score.
Scale range: 0 to 21 Interpretation: higher scores indicate a worse outcome (greater severity of anxiety symptoms) Cut-off: greater than 5
Measured: 3 hours
Change in Patient Health Questionnaire-9 (PHQ-9). 9 Items score
Scale range: 0 to 27 Interpretation: higher scores indicate a worse outcome (greater severity of depressive symptoms) Cut-off: greater than 5
Measured: 3 hours
Change in Symptom Checklist-90 (SCL-90) . 90 items score
Scale range: 0 to 4 (mean score across items) Interpretation: higher scores indicate a worse outcome (greater psychological distress) Cut-off: greater than 1.5
Measured: 3 hours
Change in Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25). 25 items score
Scale range: 0 to 100 Interpretation: higher scores indicate a better outcome (better visual function and quality of life) Cut-off: less than 60
Measured: 3 hours
Change in General Self-Efficacy Scale (GSES) score.
Scale range: 10 to 40 Interpretation: higher scores indicate a better outcome (greater perceived self-efficacy) Cut-off: less than 30
Measured: 3 hours
Change in Perceived Stress Scale (PSS) score.
Scale range: 0 to 40 Interpretation: higher scores indicate a worse outcome (greater perceived stress) Cut-off: less than 15
Measured: 3 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 May 2026
- Study start15 Jan 2025
- Primary completion31 Aug 2026 (estimated)
- Study completion31 Jan 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Charles Bonnet SyndromeStudies of the same condition, open and under way.
- More trials run by Fondazione Policlinico Universitario Agostino Gemelli IRCCSThe 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
- 640 participants (estimated)
Sponsor and investigators
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Stefania Fortini, MD, Principal investigator, Fondazione Policlinico Universitario Agostino Gemelli IRCCS
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07563101
- Sponsor's protocol ID
- ID 6502
- Acronym
- CBS
- Status last verified
- Dec 2025
- First submitted
- 20 Dec 2024
- Last updated
- 1 May 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 1 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Charles Bonnet Syndrome (CBS): Prevalence and Characteristics of Visual Hallucinations. Psychological Profile of the Visually Impaired Patient With CBS
- ClinicalTrials.gov ID
- NCT07563101
- Acronym / sponsor ID
- CBS / ID 6502
- Conditions
- Charles Bonnet Syndrome
- Study type
- Observational
- Recruitment status
- Enrolling by invitation
- Enrolment
- 640 participants (estimated)
- Lead sponsor
- Fondazione Policlinico Universitario Agostino Gemelli IRCCSUniversity, hospital or other
- Study start
- 15 Jan 2025 (actual)
- Primary completion
- 31 Aug 2026 (estimated)
- Study completion
- 31 Jan 2027 (estimated)
- First posted
- 1 May 2026 (actual)
- 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.
Among patients with chronic and degenerative ocular diseases that cause visual limitations, the presence of Charles Bonnet Syndrome (CBS) may be detected as a comorbidity. CBS is as a phenomenon of complex visual hallucinations occurring in individuals with reduced visual function, in the absence of cognitive alterations, psychiatric and/or neurological conditions. It is estimated that 15.8% of patients with age-related macular degeneration and 13.5% among glaucoma patients have CBS. Prevalence rates vary widely, and this may depend on inconsistent diagnostic criteria, variability in the questions used to determine if an individual has visual hallucinations, and the reluctance of people to admit to having strange visions for fear of being considered mentally ill. Visual hallucinations can be invasive and debilitating, compromising mental health, quality of life, and rehabilitation in visually impaired individuals. Patients may experience confusion, anxiety, anger, paranoia, and social isolation. Regarding psychological aspects, about a third of patients report experiencing distress and fear,higher anxiety and social dysfunction particularly during the initial onset of symptoms and in the terminal stage of the disease.Screening questionnaires will be used.
Detailed description
As part of our clinical practice, screening questionnaires will be used to assess the mental health and psychological profile of enrolled patients:
PHQ-9 (Patient Health Questionnaire): A 9-question tool for screening depression, with scores ranging from 0-27 to assess depression severity. Scores above 5 require referral to a clinical psychologist; scores 15+ suggest psychiatric evaluation.
GAD-7 (General Anxiety Disorder): A 7-item tool to screen for generalized anxiety disorder, with scores from 0-21. Scores 10+ require clinical psychologist referral, and 15+ indicate the need for psychiatric evaluation.
SCL-90R (Symptom Checklist-90): A 90-item questionnaire assessing a range of psychological symptoms, including depression, anxiety, and aggression, rated on a Likert scale from 0 to 4.
NEI VFQ25 (National Eye Institute Visual Function Questionnaire): A tool to assess the quality of life related to vision.
GSES (Generalized Self-Efficacy Scale):A 10-item scale to measure perceived self-efficacy and coping mechanisms for stressful life events, rated on a 4-point Likert scale.
PSS (Perceived Stress Scale):A tool to measure how individuals perceive their life as stressful, focusing on unpredictability, uncontrollability, and overwhelm.
GHQ-12 (General Health Questionnaire-12):A 12-item questionnaire to identify general mental health problems, focusing on the past two weeks.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
Who may qualify
- Ages
- 40 to 70 years
- Sex
- All
- Age groups
- Adult, Older adult
- Study population
- Visually impaired individuals with central and peripheral defects who access the center for visual rehabilitation.
Key inclusion criteria (5 listed)
- Best corrected visual acuity between 1/20 (1.0 LogMAR) and 3.2/10 (0.5 LogMAR) in cases of central vision impairment.
- Residual binocular visual field ≤ 60% in cases of peripheral vision impairment.
- Patients with age-related macular degeneration, Stargardt's disease, or glaucoma.
- Age between 40 and 70 years.
- Signed informed consent.
Key exclusion criteria (5 listed)
- Age under 40 years.
- Clear cognitive impairments that reduce patient reliability.
- Psychiatric disorders.
- Refusal to sign informed consent to participate in the study.
- Mental State Examination (MMSE) score below 22.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Prevalence of the Charles Bonnet Syndrome
Time frame: From baseline through study completion, up to 24 months.
Prevalence of Charles Bonnet Syndrome, calculated as the ratio between the number of visually impaired patients affected by CBS and the total number of patients attending the visual rehabilitation center, multiplied by 100 (%).
6 secondary outcomes
Change in Generalized Anxiety Disorder-7 (GAD-7). 7 items score.
Time frame: 3 hours
Change in Patient Health Questionnaire-9 (PHQ-9). 9 Items score
Time frame: 3 hours
Change in Symptom Checklist-90 (SCL-90) . 90 items score
Time frame: 3 hours
Change in Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25). 25 items score
Time frame: 3 hours
Change in General Self-Efficacy Scale (GSES) score.
Time frame: 3 hours
Change in Perceived Stress Scale (PSS) score.
Time frame: 3 hours
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 1 May 2026.
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.
Stefania Fortini, MD principal investigator
Fondazione Policlinico Universitario Agostino Gemelli IRCCS
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 Charles Bonnet Syndrome, run by Fondazione Policlinico Universitario Agostino Gemelli IRCCS at 1 site in Italy.
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 5 inclusion and 5 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: enrolling by invitation, as of the sponsor's last update on 1 May 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 Italy. 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?
This study is still under way. Results are not available in the source record yet.
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?
Prevalence of the Charles Bonnet Syndrome (time frame: From baseline through study completion, up to 24 months.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 1 May 2026.