An observational study in Quality Control and Validation Study, sponsored by Aalen University. Completed at 1 site in Germany. Open to participants aged 18 Years to 80 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2023-07-20.
Sponsored by Aalen University · Observational
The aim of this study is to investigate and compare the validity of four different input methods for Landolt Cs, i.e. the proportion of correct gap positions in relation to the total number of performances. The four input methods are a numeric keypad, an eight-positions rocker switch, a remote control and voice feedback.
The measurement of visual acuity is the most frequent and one of the most important ophthalmological functional investigations. Therefore, it is particularly important to find a measuring procedure with as little input errors as possible.
The 8-position Landolt C (LC) is the internationally accepted, well-standardised optotype for the determination of visual acuity.
Usually, the subjects informs the examiner verbally about the perceived position of each LC. According to the current literature, about 20 to 30 % of the population suffers from a right/left weakness. Furthermore, language barriers are an additional considerable hurdle.
Therefore, it is important to find an input method for the LC gap positions with minimal entry mistakes. In oder to avoid the thresholding procedure and its inherent difficulties, highly supra-threshold (10 times above the previously determined individual central visual acuity threshold) 8-position LCs are presented.
The study compares four input methods for entering of the Landolt C gap positions: a modified numeric keypad, an 8-position rocker switch, a modified TV remote control and voice/verbal feedback.
Each subject will perform all four input methods, with 2 test runs of 16 Landolt C presentations, each. A forced-choice method will be applied, i.e. the test is not continued until the test person has responded ot each single presentation. Regardless of whether the entry was correct or incorrect, the next Landolt C is displayed.
The optotypes are presented using modified version of the Freiburg Visual Acuity and Contrast Test (FrACT), which allows to present the 8-position Landolt Cs in a standardized way on a video display unit (VDU).
The sequence of the input methods is randomized. This study is carried out in a "within-subject design", i.e. all test persons go through all test conditions and serve as their own controls.
Aalen University is the lead sponsor of 4 studies on the registry; none are open to participants now.
Counted across the registry records on this site, refreshed daily.
Healthy, young subjects recruited for the students and or co-workers of the Aalen University of Applied Sciences
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Four different methods for entering the Landolt C gap position are compared
validity
Proportion of correct gap position entries in relation to the total number of LC presentations by the four different entry methods
Time frame: Through study completion, an average of 3 months
retest reliability
Comparison of the correct gap position entry between first and second test run by the four different entry methods
Time frame: Through study completion, an average of 3 months
Examination duration
Comparison of the examination duration of the the four different entry methods and by the first and second run
Time frame: Through study completion, an average of 3 months
Subjects´ satisfaction
Subjects´ evaluation (using a questionnaire) for the four different entry methods
Time frame: Through study completion, an average of 3 months
Plan to share: No
No publications or documents are linked to this record.
Ran from Jul 2022 to primary completion in Mar 2023, 7 months.
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This study is completed, as verified in Jul 2023. You cannot join it, but the record below documents what was studied.
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