CataractNCT05323526
Validation of the Catquest-9SF Questionnaire in Greek Language
An observational study of Cataract and Catquest-9SF, run by Democritus University of Thrace at 2 sites in Greece.
Trial summary
Primary objective of this study is the validation of the Catquest-9SF questionnaire in the Greek population. Read more about this study
- Who is it for?
- Ages 18 to 85 years
- Conditions the study is for
- Cataract, Catquest-9SF
- What is being tested?
- Catquest-9SF questionnaire and Demographics and clinical parameters
- How many people
- 100 participants
- Where
- 2 sitesGreece
- Study dates
- 15 Feb 2020to 15 Dec 2021
- How long will I take part?
- 2 Months
- 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 to 85 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Patients diagnosed with cataract who will undergo cataract surgery.
Who may be able to join
- Patients with unilateral or bilateral senile cataract with stage 2 nuclear opalescence according to the Lens Opacities Classification System III (LOCS-3) grading scale, and no severe cognitive impairment during their preoperative examination.
Who cannot join
- Patients with difficulty with the Greek language or dementia, Alzheimer's disease, severe stroke with mental disorder and conditions with the onset of mental retardation.
Trial locations and contacts
2 sites in 1 country.
Greece2 sites
Department of Ophthalmology, University Hospital of Alexandroupolis
Alexandroupoli, Evros, 68100
General Hospital of Kalamata
Kalamata, Messinia, 24100
About this study
Primary objective of this study is the validation of the Catquest-9SF questionnaire in the Greek population.
Read the detailed description
The present study aims to validate the Catquest-9SF questionnaire in the Greek population. The Catquest-9SF is a questionnaire for assessing the quality of vision of patients with cataract. It consists of 9 questions, two of which concern the subjective assessment of the patient's vision and the other seven the patient's ability to perform various daily activities.
The Catquest-9SF questionnaire were translated into the Greek language by a translation team consisting of five members: one translation coordinator, two professional native English-speaking translators, one professional native Greek-speaking translator and one native Greek ophthalmologist fluent in English.
Patients participating in the study are asked to complete a questionnaire in Greek before and after cataract surgery. Upon completion of the data collection, data are processed and analyzed through Rasch analysis to determine whether the questionnaire can be used in clinical practice in this translated version.
The following clinical parameters are evaluated: age, gender, preoperative and postoperative monocular distance uncorrected visual acuity (UVA), distance best spectacle-corrected visual acuity (BSCVA) of the eye for cataract surgery, binocular distance UVA and BSCVA, refraction, spherical equivalent (SE), and intraocular pressure.
- Conditions
- Cataract, Catquest-9SF
- Being tested
- Catquest-9SF questionnaire, Demographics and clinical parameters
- Keywords
- cataract, catquest, validation, questionnaire, Rasch Analysis
- Medical subject headings
- Cataract
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Catquest-9SF questionnaireDiagnostic test
Patients complete the questionnaire preoperatively and postoperatively.
Demographics and clinical parametersDiagnostic test
The following clinical parameters are evaluated: age, gender, ocular and systemic comorbidities, educational level, preoperative and postoperative monocular distance uncorrected visual acuity (UVA), distance best spectacle-corrected visual acuity (BSCVA) of the eye for cataract surgery, binocular distance UVA and BSCVA, refraction, spherical equivalent (SE), and intraocular pressure.
| Study group | Role | What they receive |
|---|---|---|
| Study Group | 100 patients who will undergo cataract surgery Receives: Diagnostic Test: Catquest-9SF questionnaire; Diagnostic Test: Demographics and clinical parameters |
What is being measured
The primary outcome is the main question the study is designed to answer.
Rasch Analysis: Response category ordering
Response category ordering is evaluated graphically with category probability curves by observing whether the four response categories - omitting 'Cannot decide' as missing - (three category thresholds) are utilized in ascending order.
Measured: 3 months
Rasch Analysis: Item fit statistics [infit and outfit mean square (MNSQ)]
Item fit statistics are used for the evaluation of the unidimensionality. When data fit well, the items should contribute to a single construct (visual disability) indicating the unidimensionality of the questionnaire (or the subscale). Both infit and outfit mean squares have an expected value of 1.0, with an ideal range of 0.7 to 1.3, and an acceptable range of 0.5 to 1.5) A value < 0.7 indicates too little variance and easily predicted questions, while > 1.3 indicates too much variance.
Measured: 3 months
Rasch Analysis: Principal components analysis (PCA)
PCA is used for the evaluation of the unidimensionality. Two criteria are used; the PCA assessment is performed by comparing the amount of variance explained empirically and by the model, and the amount of variance explained by the first contrast (additional dimension). For unidimensionality, the unexplained variance in the first contrast of the residuals should be < 2.0 eigenvalue units, and ≥ 60% of variance should ideally be explained by the measure, while a percentage of ≥ 50% is acceptable.
Measured: 3 months
Rasch Analysis: Person Separation Index (PSI)
PSI contributes to the assessment of the measurement precision of the Greek Catquest-9SF. PSI implies the questionnaire's ability to differentiate along its scale. The greater the value of person separation, the greater the questionnaire precision (acceptable person separation > 3.0).
Measured: 3 months
Rasch Analysis: Person Reliability (PR)
PR contributes to the assessment of the measurement precision of the Greek Catquest-9SF. PR (ranging from 0 to 1) should be > 0.9 to be considered adequate, indicating a high ability to distinguish between the strata of person ability.
Measured: 3 months
Rasch Analysis: Differential Item Functioning (DIF)
DIF indicates the differences between different subgroups of patients, since the questionnaire item calibration should be comparable across different patient groups. DIF occurs if patients from different subgroups with the same underlying true ability have an unequal probability of giving of a response to an item. DIF is assessed by evaluating age, gender, existence of ocular comorbidities, first vs second eye cataract surgery and binocular distance BSCVA. DIF of >1.0 logits is significant, DIF with values between 0.5 and 1.0 is minimal, and DIF <0.5 logits is considered absent.
Measured: 3 months
Rasch Analysis: Τargeting
Τargeting of the questions to the patient sample, which indicates how well the items' difficulties match the person ability, is assessed to establish if the questions are appropriate for patients before and following cataract surgery. This can be assessed graphically by observing the spread along the person-item map and by the difference between the item and the person mean values. A well-targeted instrument requires the ability of the patients and the difficulty of the questions to be centered on the same mean (targeting of 0). In general, a mean difference in magnitude of ≥1 logit indicates significant mistargeting, while a difference of <1.0 logit indicates good targeting, with targeting of 0 being ideal. A positive value indicates that the items are too difficult relative to person's ability, while a negative value indicates that the items are too easy. A person-item map also visualizes the item hierarchy of difficulty, ranging from a minimum to maximum difficulty of performance.
Measured: 3 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Apr 2022
- Study start15 Feb 2020
- Primary completion15 Apr 2021
- Study completion15 Dec 2021
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for CataractStudies of the same condition, open and under way.
- 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
- 100 participants (actual)
- Target duration
- 2 Months
Sponsor and investigators
- Lead sponsor
- Democritus University of Thrace
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Georgios Labiris, Democritus University of Thrace
- Investigators
- Georgios Labiris, MD, PhD, Study chair, Department of Ophthalmology, University Hospital of Alexandroupolis, Alexandroupolis, Greece
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05323526
- Sponsor's protocol ID
- ES1/Th7/30-01-2020
- Status last verified
- Apr 2022
- First submitted
- 5 Apr 2022
- Last updated
- 19 Apr 2022
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
Nanos P, Kouteliari V, Panagiotopoulou EK, Papadopoulos N, Ntonti P, Labiris G. Catquest-9SF questionnaire: Validation in a Greek-speaking population using Rasch analysis. PLoS One. 2022 Dec 7;17(12):e0278683. doi: 10.1371/journal.pone.0278683. eCollection 2022.
PubMed 36477289
Study at a glance
From the registry record, last updated by the sponsor on 19 Apr 2022. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Validation of the Catquest-9SF Questionnaire in Greek Language
- ClinicalTrials.gov ID
- NCT05323526
- Acronym / sponsor ID
- ES1/Th7/30-01-2020
- Conditions
- Cataract, Catquest-9SF
- Keywords
- cataract, catquest, validation, questionnaire, Rasch Analysis
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 100 participants (actual)
- Lead sponsor
- Democritus University of ThraceUniversity, hospital or other
- Study start
- 15 Feb 2020 (actual)
- Primary completion
- 15 Apr 2021 (actual)
- Study completion
- 15 Dec 2021 (actual)
- First posted
- 12 Apr 2022 (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.
Primary objective of this study is the validation of the Catquest-9SF questionnaire in the Greek population.
Detailed description
The present study aims to validate the Catquest-9SF questionnaire in the Greek population. The Catquest-9SF is a questionnaire for assessing the quality of vision of patients with cataract. It consists of 9 questions, two of which concern the subjective assessment of the patient's vision and the other seven the patient's ability to perform various daily activities.
The Catquest-9SF questionnaire were translated into the Greek language by a translation team consisting of five members: one translation coordinator, two professional native English-speaking translators, one professional native Greek-speaking translator and one native Greek ophthalmologist fluent in English.
Patients participating in the study are asked to complete a questionnaire in Greek before and after cataract surgery. Upon completion of the data collection, data are processed and analyzed through Rasch analysis to determine whether the questionnaire can be used in clinical practice in this translated version.
The following clinical parameters are evaluated: age, gender, preoperative and postoperative monocular distance uncorrected visual acuity (UVA), distance best spectacle-corrected visual acuity (BSCVA) of the eye for cataract surgery, binocular distance UVA and BSCVA, refraction, spherical equivalent (SE), and intraocular pressure.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Target follow-up
- 2 Months
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Study Group | – | Diagnostic Test: Catquest-9SF questionnaire, Diagnostic Test: Demographics and clinical parameters100 patients who will undergo cataract surgery |
Who may qualify
- Ages
- 18 to 85 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Patients diagnosed with cataract who will undergo cataract surgery.
Key inclusion criteria (1 listed)
- Patients with unilateral or bilateral senile cataract with stage 2 nuclear opalescence according to the Lens Opacities Classification System III (LOCS-3) grading scale, and no severe cognitive impairment during their preoperative examination.
Key exclusion criteria (1 listed)
- Patients with difficulty with the Greek language or dementia, Alzheimer's disease, severe stroke with mental disorder and conditions with the onset of mental retardation.
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 |
|---|---|---|
| Catquest-9SF questionnairePatients complete the questionnaire preoperatively and postoperatively. | Diagnostic test | Study Group |
| Demographics and clinical parametersThe following clinical parameters are evaluated: age, gender, ocular and systemic comorbidities, educational level, preoperative and postoperative monocular distance uncorrected visual acuity (UVA), distance best spectacle-corrected visual acuity (BSCVA) of the eye for cataract surgery, binocular distance UVA and BSCVA, refraction, spherical equivalent (SE), and intraocular pressure. | Diagnostic test | Study Group |
Primary outcome
Rasch Analysis: Response category ordering
Time frame: 3 months
Response category ordering is evaluated graphically with category probability curves by observing whether the four response categories - omitting 'Cannot decide' as missing - (three category thresholds) are utilized in ascending order.
Rasch Analysis: Item fit statistics [infit and outfit mean square (MNSQ)]
Time frame: 3 months
Item fit statistics are used for the evaluation of the unidimensionality. When data fit well, the items should contribute to a single construct (visual disability) indicating the unidimensionality of the questionnaire (or the subscale). Both infit and outfit mean squares have an expected value of 1.0, with an ideal range of 0.7 to 1.3, and an acceptable range of 0.5 to 1.5) A value < 0.7 indicates too little variance and easily predicted questions, while > 1.3 indicates too much variance.
Rasch Analysis: Principal components analysis (PCA)
Time frame: 3 months
PCA is used for the evaluation of the unidimensionality. Two criteria are used; the PCA assessment is performed by comparing the amount of variance explained empirically and by the model, and the amount of variance explained by the first contrast (additional dimension). For unidimensionality, the unexplained variance in the first contrast of the residuals should be < 2.0 eigenvalue units, and ≥ 60% of variance should ideally be explained by the measure, while a percentage of ≥ 50% is acceptable.
Rasch Analysis: Person Separation Index (PSI)
Time frame: 3 months
PSI contributes to the assessment of the measurement precision of the Greek Catquest-9SF. PSI implies the questionnaire's ability to differentiate along its scale. The greater the value of person separation, the greater the questionnaire precision (acceptable person separation > 3.0).
Rasch Analysis: Person Reliability (PR)
Time frame: 3 months
PR contributes to the assessment of the measurement precision of the Greek Catquest-9SF. PR (ranging from 0 to 1) should be > 0.9 to be considered adequate, indicating a high ability to distinguish between the strata of person ability.
Rasch Analysis: Differential Item Functioning (DIF)
Time frame: 3 months
DIF indicates the differences between different subgroups of patients, since the questionnaire item calibration should be comparable across different patient groups. DIF occurs if patients from different subgroups with the same underlying true ability have an unequal probability of giving of a response to an item. DIF is assessed by evaluating age, gender, existence of ocular comorbidities, first vs second eye cataract surgery and binocular distance BSCVA. DIF of >1.0 logits is significant, DIF with values between 0.5 and 1.0 is minimal, and DIF <0.5 logits is considered absent.
Rasch Analysis: Τargeting
Time frame: 3 months
Τargeting of the questions to the patient sample, which indicates how well the items' difficulties match the person ability, is assessed to establish if the questions are appropriate for patients before and following cataract surgery. This can be assessed graphically by observing the spread along the person-item map and by the difference between the item and the person mean values. A well-targeted instrument requires the ability of the patients and the difficulty of the questions to be centered on the same mean (targeting of 0). In general, a mean difference in magnitude of ≥1 logit indicates significant mistargeting, while a difference of <1.0 logit indicates good targeting, with targeting of 0 being ideal. A positive value indicates that the items are too difficult relative to person's ability, while a negative value indicates that the items are too easy. A person-item map also visualizes the item hierarchy of difficulty, ranging from a minimum to maximum difficulty of performance.
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 19 Apr 2022.
- Derived from this study: PubMed 36477289Nanos P, Kouteliari V, Panagiotopoulou EK, Papadopoulos N, Ntonti P, Labiris G. Catquest-9SF questionnaire: Validation in a Greek-speaking population using Rasch analysis. PLoS One. 2022 Dec 7;17(12):e0278683. doi: 10.1371/journal.pone.0278683. eCollection 2022.
- Individual participant dataSharing planned: Undecided
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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.
Georgios Labiris, MD, PhD study chair
Department of Ophthalmology, University Hospital of Alexandroupolis, Alexandroupolis, Greece
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Cataract and Catquest-9SF, run by Democritus University of Thrace at 2 sites in Greece.
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 1 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 19 Apr 2022. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Greece. 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?
Rasch Analysis: Response category ordering (time frame: 3 months). The study lists 7 primary outcomes in all. 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 NCT05323526, which also lists 1 linked publication.
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 19 Apr 2022.