Test-retest repeatability

Multiple tests (same test/variable) have been carried out on 20 different subjects by the same investigator. Each subject was tested 1, 2 or 3 times (most of them). How do I measure repeatability of the test result within each subject and overall based on the results from the 20 subjects? i.e.: how do I make sure that the outcome of the test is repeatable?
Intraclass Correlation Coefficient (ICC), Coefficient of Repeatability (CoR), Coefficient of Variation (CoV), graphical method through Bland-Altman plots, ...? Any idea on which coefficient/method should be preferred over another one in such a case and why? I have excluded Pearson's as more than two tests were performed on most of the subjects.

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Thanks Karabiner,
A physiological parameter of the visual system is measured under near-identical conditions using the same procedure, operator, and measuring system. Repeatable meaning: how close to each other are the already performed measurements and how likely is for a new measurement taken in the same conditions on the same patient to be as close as possible to the already performed measurements?