What is often a characteristic sign in patients with a significant afferent pupillary defect?

What is often a characteristic sign in patients with a significant afferent pupillary defect?

• A. Relative pupillary defect
• B. Fixed pupils
• C. Pupil dilation in dark
• D. Excessive tearing

Answer: (A)

A characteristic sign in patients with a significant afferent pupillary defect is the relative pupillary defect. This condition typically indicates that there is an issue with the sensory (afferent) pathway of the eye that may lead to an unequal response of the pupils to light. When light is shone in the eye with the defect, the affected pupil does not constrict as much as the unaffected pupil, demonstrating a relative defect. When a light source is moved between the two eyes, the affected pupil will appear to dilate compared to the unaffected eye, which is known as the Marcus Gunn pupil phenomenon. This relative response highlights the dysfunction in the afferent pathway rather than in the efferent response of the pupil muscles, which remain intact. Other choices, such as fixed pupils, pupil dilation in the dark, and excessive tearing, do not adequately represent the key features of an afferent pupillary defect. Fixed pupils can suggest severe neurological damage or disruption in the autonomic pathways, while pupil dilation in the dark is a normal response and can occur in many situations. Excessive tearing typically is related to other ocular issues and not specifically to afferent pupillary defects.

A characteristic sign in patients with a significant afferent pupillary defect is the relative pupillary defect. This condition typically indicates that there is an issue with the sensory (afferent) pathway of the eye that may lead to an unequal response of the pupils to light.

When light is shone in the eye with the defect, the affected pupil does not constrict as much as the unaffected pupil, demonstrating a relative defect. When a light source is moved between the two eyes, the affected pupil will appear to dilate compared to the unaffected eye, which is known as the Marcus Gunn pupil phenomenon. This relative response highlights the dysfunction in the afferent pathway rather than in the efferent response of the pupil muscles, which remain intact.

Other choices, such as fixed pupils, pupil dilation in the dark, and excessive tearing, do not adequately represent the key features of an afferent pupillary defect. Fixed pupils can suggest severe neurological damage or disruption in the autonomic pathways, while pupil dilation in the dark is a normal response and can occur in many situations. Excessive tearing typically is related to other ocular issues and not specifically to afferent pupillary defects.