Certified Ophthalmic Assistant Practice Exam

What is a consequence of an improperly measured inter pupillary distance (PD)?

1. Blurred vision in low light

2. Induced prism in spectacle lenses

3. Increased eye strain

4. Difficulty focusing

The correct answer is: Induced prism in spectacle lenses

An improperly measured inter pupillary distance (PD) can lead to induced prism in spectacle lenses. This is because the PD is crucial for ensuring that the optical centers of the lenses align properly with the wearer’s pupils. When the PD is inaccurately measured, the optical centers of the lenses may not be positioned correctly over the pupils. This misalignment can result in unwanted prism effects, causing the images seen through the lenses to appear distorted or misaligned. Induced prism can lead to discomfort and visual disturbances, making it essential for ophthalmic assistants and technicians to measure PD accurately to prevent these issues. While other consequences like blurred vision in low light, increased eye strain, and difficulty focusing can occur due to various factors related to vision and eye health, they are not direct results of an incorrect PD measurement. Induced prism specifically relates to how lens alignment impacts vision directly, making it the most relevant consequence in the context of a mismeasured inter pupillary distance.