Certified Ophthalmic Assistant Practice Exam

What is the most common cause of halos around lights?

1. Mucous deposits on the cornea

2. Glaucomatous damage

3. Cataract formation

4. Retinal detachment

The correct answer is: Mucous deposits on the cornea

The most common cause of halos around lights is cataract formation. As cataracts develop, they can cause the light entering the eye to scatter and create a halo effect, particularly around bright lights at night or in low-light conditions. This scattering occurs due to the clouding of the lens, which disrupts the normal pathways of light and alters how images are perceived. While mucous deposits on the cornea could affect vision and potentially cause distortions, they are not the primary reason for halos that patients report. Glaucomatous damage can lead to vision changes, but it is not typically associated with halos. Retinal detachment represents a more serious condition that also generally does not manifest as halos, but rather may come with symptoms like a curtain effect or sudden vision loss. Cataracts, particularly in elderly populations or those with prolonged exposure to certain risk factors, are indeed the leading cause of halo perception, making it the most likely correct answer in this context.