Certified Ophthalmic Medical Technologist (COMT) Practice Exam

The phenomenon where patients with a damaged occipital lobe can perceive motion in the blind field is known as what?

1. Riddoch phenomenon

2. Schneider effect

3. Dobrow effect

4. Grunfeld effect

The correct answer is: Riddoch phenomenon

The Riddoch phenomenon refers specifically to the ability of some patients with damage to their occipital lobe, particularly those with hemianopia (a loss of vision in half of the visual field), to perceive movement within their blind field. This effect occurs because the visual pathways that convey motion information can remain functional even when the primary visual input is damaged. In patients experiencing the Riddoch phenomenon, while they may not consciously see static objects in their blind field, they can react to moving stimuli, indicating that some residual visual processing is still occurring. This phenomenon highlights the complexity of the visual system and how certain visual functions can be preserved despite the loss of other aspects of vision. Understanding this concept is crucial for those working in ophthalmology, as it helps inform both diagnosis and treatment of visual field deficits. The other options mentioned do not relate to the perception of motion in blind fields and involve different types of visual phenomena or effects that are unrelated to the specific circumstances described in the question.