Marcus Gunn Pupil: Causes, Diagnosis, and Treatment

Marcus Gunn pupil is an eye problem characterized by the eye responding differently to light. This is a rare condition that affects a person’s eye health. Here we will talk about the causes of Marcus Gunn pupil, how to diagnose and how to treat it.

Differences in the light response of each eyeball indicate dysfunction or disease in the optic nerve or in the retina of the eye. The problem known as the Marcus Gunn pupil is a type of pupillary defect or Relative Afferent Pupil Defect (RAPD).

When exposed to bright light, normal pupils will shrink. While on the other hand, Marcus Gunn’s pupils continued to dilate so that the two pupils of a person were of different sizes. Well, someone with a Marcus Gunn pupil, he is not at risk to himself, but this could be a sign that his eyes have problems that need to be treated.

Symptoms and Types Marcus Gunn Pupil

Marcus Gunn pupil was the name given by an ophthalmologist to Scottish ophthalmologist in the 1800s.

Usually, people who suffer from this disease will complain of one eyeball. So when conducting an examination, a doctor needs to determine whether the difference in the eyeballs is caused by Marcus Gunn pupils or because of cataracts.

There are many types of RAPD, and non-RAPD conditions that then cause Marcus Gunn pupil symptoms. So, we will determine the symptoms of Marcus Gunn pupil based on RAPD or non-RAPD.

– No RAPD: There are other conditions such as hippus (fluctuation in pupil size) and non-reactive pupils, this makes RAPD difficult to recognize.

– Mild RAPD: The pupil of the affected eye shows an initial narrowing, then dilates to a greater size.

– Moderate RAPD: A person with moderate RAPD shows symptoms where the infected pupil shows a stable narrowing that does not change.

– Severe RAPD: The affected pupil is immediately dilated to a larger size.

Those are some of the symptoms that appear in people with an eye disease known as “Marcus Gunn pupil”.

Causes

Seeing the causes of this disease, there are many reasons behind it, including:

Loss of vision or unilateral optic neuropathy.
Optic neuritis
Severe glaucoma, which causes damage to the optic nerve
Traumatic optic neuropathy, this includes direct ocular trauma, head injuries that damage the optic nerve and orbital trauma.
Optic nerve tumor, this is rare
Orbital disease, including compression damage to the optic nerve, orbital tumors, thyroid-associated orbitopathy, optic atrophic vascular malformations, and including optic nerve degeneration.
Optic nerve inflammation or infection
Optic atrophy, and optic nerve degeneration
Ischemic retinal disease, such as ischemic central retinal vein occlusion, sickle cell retinopathy, and central retinal artery occlusion.
Retinal detachment
Severe unilateral macular degeneration
retinal infection
Severe lazy eye (amblyopia)

How to Diagnose

When light is emitted into two eyeballs, they should narrow simultaneously and evenly. This is because the two eyes are interconnected. This condition is called the consensual light reflex and this test is known as the Marcus Gunn test or also known as the swinging flashlight test.

The pupil of the eye reacts to the light shining on it by this method because of the light reflex pathway, it is divided into two parts:

The afferent pathway: Pupils send messages to the brain along the optic pathway
The efferent pathway: Messages are sent back from the brain to the pupils via the nerve cells. This then causes the pupil to constrict.

This test is performed by an ophthalmologist by shining a light on the patient’s eyes in a semi-dark room. The doctor will hold the light in front for 3 seconds and transfer it to the other eye.

Well, when light shines on the eyes of a Marcus Gunn Pupil, then his eyes will not narrow like what happens in normal eyes. So, these eyes indicate a problem.

Because Marcus Gunn Pupil’s disease does not have much effect, many people sometimes do not realize that he is experiencing this problem in his eyeballs.

Treatment

Marcus gunn pupil is a symptom of another problem, so when a person is diagnosed with this disease, it is not treated right away. The treatment of marcus gunn pupil depends on the underlying cause (see again causes of marcus gunn pupil above)

Some eye conditions that can cause Marcus Gunn Pupil can be treated in the following ways.

Optic neuritis

This condition can be treated with steroids but often gets better on its own without any treatment. While the pain that arises can be alleviated with pain relievers that appear.

Severe glaucoma

If Marcus Gunn Pupil occurs due to severe glaucoma problems, the treatment can be done with eye drops, laser treatment, or eye surgery (surgery).

Optic nerve tumor

There is also a Marcus Gunn pupil occurring due to a tumor of the optic nerve. Conditions like this can be treated according to the type of tumor, whether it is a benign tumor or a malignant tumor.

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Optic atrophy

If it occurs due to optic atrophy then the type of treatment can be an attempt to stop its development.

Retinal detachment

Marcus Gunn pupil that occurs due to retinal detachment, the type of treatment that can be done only by surgery. Using this surgical treatment has a cure rate of about 80 to 90 percent. Sometimes, one operation is not enough, but a second operation is needed.

Surgery is not always successful in improving vision, as it depends on the reconnection of the retina. If the retina cannot be reattached, the patient will experience blindness in this eye.

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Severe unilateral macular degeneration

If this is the background, until now there is no cure. But doctors can help to slow its progress.

Retinal infection

If the Marcus Gunn pupil is due to an infection in the retina, the treatment model is to give the eye an injection of medication and sometimes require an oral medication called intravenous. It could also be a doctor suggest treatment with laser or surgery.