This Study Examines Whether Personality Traits Influence the Frequency or Severity of Ocular Adverse Effects Reported by Patients Using Glaucoma Medications. The Findings May Identify Patients at Greater Risk of Intolerance and Support More Personalized Treatment and Counselling.

Glaucoma is a chronic eye disease that can cause irreversible vision loss. Lowering intraocular pressure is the principal strategy used to reduce the risk of disease progression. Topical medications are commonly used as first-line or adjunctive treatment, either alone or in combination with laser or surgical therapy. Although effective, glaucoma medications may cause ocular adverse effects such as dryness, irritation, redness, allergic reactions, inflammation, eyelash growth, changes in iris or periocular skin pigmentation, and changes in the tissues surrounding the eye. These adverse effects may affect comfort, adherence to treatment, and the need to modify or discontinue therapy.

The type and severity of adverse effects vary considerably among individuals. This variability may be related to the medication used, its preservatives, the duration of treatment, patient characteristics, or differences in how symptoms are perceived and reported. Personality traits may influence a person's awareness, interpretation, reporting, and tolerance of medication-related symptoms. However, the possible relationship between personality traits and ocular adverse effects from glaucoma medications has not been well studied.

The primary objective of this observational study is to evaluate the relationship between personality traits and ocular adverse effects in adults who are currently being treated, or were previously treated, with one or more glaucoma medications. The study will examine whether particular personality traits are associated with the occurrence and severity of ocular adverse effects. It will also compare the personality profiles of participants who have experienced specified medication-related ocular adverse effects with those of participants who have not.

Personality will be assessed using a questionnaire based on the Five-Factor Model. This widely used model describes personality across five domains: openness, conscientiousness, extraversion, agreeableness, and neuroticism. The study will investigate whether scores in these domains are associated with the type, frequency, or severity of ocular adverse effects and with treatment changes made because of these effects.

Approximately 352 adults aged 18 years or older will be recruited. Eligible participants must have a diagnosis of glaucoma and must currently be using, or have previously used, at least one glaucoma medication. Individuals with serious anxiety or depression that was present before the initiation of glaucoma treatment will not be eligible, as these conditions may affect the assessment of personality traits or the reporting of medication-related symptoms.

This is an observational case-control study. Participants will not be assigned to a treatment, and their glaucoma care will not be changed as part of the research. Participants who have experienced ocular adverse effects related to glaucoma medications will be compared with participants who have not experienced the adverse effects of interest.

Participation will involve one study session lasting approximately 30 minutes. The session may be completed remotely through Qualtrics, a secure web-based survey platform, or in person at the McGill Academic Eye Centre, according to the participant's preference. Questionnaires will be available in English and French.

During the study session, participants will complete the Five-Factor Model personality questionnaire by rating their agreement or disagreement with statements about their usual thoughts, feelings, and behaviours. Participants will also complete a brief demographic questionnaire that collects information such as age, gender, and ethnicity.

The research team will review relevant information from participants' medical records. Information collected will include the glaucoma medications used, medication type, dosage, duration of treatment, documented ocular adverse effects, the type and frequency of these effects, and any related changes to treatment. Questionnaire responses will be analyzed together with the clinical information to identify possible associations between personality traits and medication-related ocular adverse effects.

The study does not involve an experimental medication, additional clinical testing, or any change to the participant's usual treatment. There is no expected direct medical benefit to participants. The principal foreseeable risk is a potential breach of confidentiality. Participants will be identified in the research database by a study code, and identifying information will be stored separately from study data. Study information will be retained for seven years and may be presented at scientific meetings or published in scientific journals in a form that does not identify individual participants.

The findings may improve understanding of why patients differ in their experience and reporting of glaucoma medication side effects. If meaningful associations are identified, the results could support future research into more individualized approaches to medication counselling, monitoring, treatment selection, and management of adverse effects.