Certified Ophthalmic Medical Technologist (COMT) Practice Exam

Which diagnostic test measures the resting potential between the cornea and retina using dark adaptation and light?

1. Electroretinogram (ERG)

2. Electro-oculogram (EOG)

3. Visual Evoked Potential (VEP)

4. Fluorescein Angiography (FA)

The correct answer is: Electro-oculogram (EOG)

The electro-oculogram (EOG) is the correct choice because it specifically measures the resting potential difference between the cornea and the retina, which is an indicator of the function of the retinal pigment epithelium. The EOG is particularly focused on capturing the changes in the electrical potential as the eye undergoes dark adaptation, followed by light exposure. During dark adaptation, the cells in the retina are responding to low levels of light, and the EOG can track how the electrical potential changes in response to these varying illumination conditions. The resting potential reflects the health and functionality of the retinal layers, making EOG a useful tool in assessing certain retinal conditions. In contrast, other choices do not focus primarily on this specific aspect. The electroretinogram (ERG) is concerned with the electrical responses of retinal cells to light stimuli but does not specifically measure the resting potential difference. The visual evoked potential (VEP) assesses the brain's electrical activity in response to visual stimuli rather than retinal potential. Fluorescein angiography is a diagnostic procedure that uses a fluorescent dye to visualize blood vessels in the retina and does not pertain to measuring electrical potentials. Therefore, the option that accurately fits the description given in the question is