Optical coherence tomography is a technique to examine the cell layers of the retina and the optic nerve on a microscopic level. The technique uses the scattering of light to peruse the diagnosed area to provide a better description of the disease.
OCT can detect the conditions on its early stages. Conditions such as macular oedema, macular hole, diabetic retinopathy, and age related macular degeneration, etc.
Just a flash of light, not even touching is involved in this technique. The flash of light may lead you to a small point of discomfort but except the test is entirely a speed itself and can be performed within a few minutes.
No, except a few seconds of discomfort, there are no side effects of the test.