Why in Argyll Robertson pupil light reflex is lost?
The Argyll Robertson pupil occurs when a disease interferes with the light reflex pathway, thereby inhibiting the pupil’s natural response to bright light. Specifically, Argyll Robertson pupils don’t constrict in response to light but do constrict to focus on a nearby object.
What causes Marcus Gunn pupil?
Marcus Gunn pupil refers to the unequal pupillary response to light due to damage or disease in the retina or optic nerve. Examples include retinal detachment, retinal ischemia, optic neuritis, severe glaucoma, trauma, and tumor of the optic nerve, among other causes.
Why is the PUIL black?
The pupil is a hole located in the center of the iris of the eye that allows light to strike the retina. It appears black because light rays entering the pupil are either absorbed by the tissues inside the eye directly, or absorbed after diffuse reflections within the eye that mostly miss exiting the narrow pupil.
How do you test for Argyll Robertson?
They are a highly specific sign of neurosyphilis; however, Argyll Robertson pupils may also be a sign of diabetic neuropathy….
| Argyll Robertson pupil | |
|---|---|
| Diagnostic method | Pupillary light reflex and accommodation reflex tests |
What is Marcus Gunn phenomenon?
Marcus Gunn phenomenon is a rare genetic disorder that is usually present at birth. It is characterized by the movement of one upper eyelid in a rapid rising motion each time the jaw moves. Other eye abnormalities and vision difficulties may also occur. The exact cause of this phenomenon is not known.
What do black pupils mean?
There’s an eye disorder known as aniridia which makes the eye appear to have “no iris.” In truth, there is a small ring of iris tissue but it is so small and the pupil is so large that it can look like the eyes are completely black. It is due to a chromosome mutation.
Why is it called Marcus Gunn syndrome?
Marcus Gunn syndrome, named for the doctor who described the condition in 1883, is usually only found in one eye. But in rare cases, both eyes may be affected. Treatment for Marcus Gunn syndrome is not always needed, as it causes no complications and tends to get less noticeable with age.