Certified Paraoptometric (CPO) Practice Exam 2025

What typically causes flashes or floaters in vision?

1. Mechanical stimulation of the nerves in the retina

2. Increased ocular pressure

3. Absence of the lens in the eye

4. Inflammation in the eyelid

The correct answer is: Mechanical stimulation of the nerves in the retina

Flashes and floaters in vision are primarily caused by mechanical stimulation of the nerves in the retina. When the vitreous gel, which fills the eye, shrinks or becomes more liquid with age, it can pull away from the retina. This pulling can create sensations of flashes of light or the appearance of floaters, which are small spots or cobweb-like structures that drift in the field of vision. This phenomenon occurs because the retina is sensitive to mechanical changes. Therefore, when the vitreous changes shape or structure, it can impact the retina, leading to the visual disturbances of flashes and floaters that many individuals experience, particularly as they age. The other factors listed, such as ocular pressure and the absence of the lens, do not typically contribute to the sensation of flashes and floaters. While inflammation in the eyelid may cause other visual issues or discomfort, it is not related to the mechanical changes affecting the retina that lead to these specific visual symptoms.