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Enrolling by Invitation

NCT Number: NCT07563101

Charles Bonnet Syndrome in Low Vision Patients

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.

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Key information

Conditions

Charles Bonnet Syndrome Hallucinations Nervous System Diseases Neurobehavioral Manifestations Neurologic Manifestations Pathological Conditions, Signs and Symptoms Perceptual Disorders Signs and Symptoms

Age range

40 year–70 year

Sex eligibility

All sexes

Study type

Observational

Primary location

fondazione Policlinico Universitario A. Gemelli IRCCS, Polo Nazionale Ipovisione

Roma, 00168, Italy

About this study

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.

Who can participate

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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.

Exclusion criteria

  • 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.

Treatment and study plan

Primary outcomes

  1. 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 (%).

Secondary outcomes

  1. Change in Generalized Anxiety Disorder-7 (GAD-7). 7 items score.

    Time frame: 3 hours

    Scale range: 0 to 21 Interpretation: higher scores indicate a worse outcome (greater severity of anxiety symptoms) Cut-off: greater than 5

  2. Change in Patient Health Questionnaire-9 (PHQ-9). 9 Items score

    Time frame: 3 hours

    Scale range: 0 to 27 Interpretation: higher scores indicate a worse outcome (greater severity of depressive symptoms) Cut-off: greater than 5

  3. Change in Symptom Checklist-90 (SCL-90) . 90 items score

    Time frame: 3 hours

    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

  4. Change in Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25). 25 items score

    Time frame: 3 hours

    Scale range: 0 to 100 Interpretation: higher scores indicate a better outcome (better visual function and quality of life) Cut-off: less than 60

  5. Change in General Self-Efficacy Scale (GSES) score.

    Time frame: 3 hours

    Scale range: 10 to 40 Interpretation: higher scores indicate a better outcome (greater perceived self-efficacy) Cut-off: less than 30

  6. Change in Perceived Stress Scale (PSS) score.

    Time frame: 3 hours

    Scale range: 0 to 40 Interpretation: higher scores indicate a worse outcome (greater perceived stress) Cut-off: less than 15

Sponsors and collaborators

Lead sponsor

Fondazione Policlinico Universitario Agostino Gemelli IRCCS

Other

Registry information

Official study title

Charles Bonnet Syndrome (CBS): Prevalence and Characteristics of Visual Hallucinations. Psychological Profile of the Visually Impaired Patient With CBS

Acronym: CBS

Important dates

Study start
2025
Primary completion
2026
Study completion
2027
First posted
May 1, 2026
Registry last updated
May 1, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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