Setting sun eye phenomenon in infants
What are sunset eyes?
Setting sun eyes, also called “sunset eyes” or “setting sun sign,” refers to a phenomenon in infants and young children in which the eyes are focused downward, and the upward gaze is inhibited.
There is a visible white space between the top portion of the sclera (white part of the eye) and the iris (colored part of the eye) in babies with setting sun eyes. Sometimes, the lower eyelid may also cover a portion of the pupil due to the eyes gazing downward.
The condition is often a sign of a neurological problem and should be evaluated as soon as possible.
What causes setting sun eyes?
Sunset eyes are commonly caused by neurological conditions that cause an increase in intracranial pressure and affect the part of the brain that controls eye movement. One such condition is hydrocephalus, a condition in which there is excessive fluid in the brain.
Babies who have hydrocephalus may also experience Parinaud syndrome, a condition that can restrict upward eye movement. Hydrocephalus can sometimes lead to Parinaud syndrome, and setting sun eyes can be present with both conditions.
In rare cases, setting sun eyes can also appear without any underlying health concerns. This is known as the “benign setting sun” phenomenon. Doctors believe the benign variety may be caused by underdeveloped ocular reflexes. Changes in light levels can trigger the downward gaze of a child who experiences benign setting sun eyes.
Benign setting sun eyes may resolve on their own by the time a child reaches 6 months of age. Children with sunset eyes due to hydrocephalus need brain surgery to relieve the pressure created in order for the eye problem to go away.
What are the signs of setting sun eyes?
The most prominent sign of setting sun eyes is its outward appearance. A child with setting sun eyes presents with a fixed downward gaze and an inability to look upward. A large portion of the sclera (the white part of the eye) is visible between the upper eyelid and the iris. The lower eyelid may also cover a portion of the pupil.
If a baby’s setting sun eyes are the result of infantile hydrocephalus, they may have other clinical signs or eye movement disorders. These signs could point to the underlying condition and may include:
An unusually large head size
Crossed eyes (strabismus)
Shaky eyes (nystagmus)
Vision issues like blurry or double vision can also happen alongside sunset eyes. Some babies with vision symptoms may not follow moving objects with their eyes.
Keep an eye out for these symptoms and be careful to observe whether your child’s downward gaze is constant or if it is triggered by changes in light levels. If it’s persistent, there’s a greater chance that it is associated with hydrocephalus.
Doctors often perform neurological assessments if they suspect a serious problem like hydrocephalus. They may order tests like ultrasounds, MRI scans or CT scans to help them diagnose the underlying cause of sunset eyes.
SEE RELATED: Everything you need to know about your baby’s vision
Do sunset eyes only occur in infants?
No — older children can also have setting sun eyes associated with hydrocephalus. It’s actually one of the most significant indicators that hydrocephalus may be present.
An older child’s head would not appear enlarged the same way an infants would when hydrocephalus occurs, because the bones in the skull are already fused together at their older age. Once the bones have fused, they prevent the head from growing in size.
Since a larger head is one of the primary symptoms of hydrocephalus, doctors must look to other symptoms to identify the condition in older children. The setting sun eyes phenomenon is one of the key symptoms that they look for.
Other signs can include:
Seizures
Lethargy
Uncontrollable vomiting
It is possible that setting sun eyes may not be related to hydrocephalus. Regardless, it is important to have your child examined right away if any of the above symptoms occur.
Note: Neurological problems like Parinaud syndrome can also cause sunset eyes in adults. However, the sign is more often associated with babies and children, especially with hydrocephalus.
Treatment for setting sun eyes
When sunset eyes occurs in a newborn, it sometimes resolves on its own by the time a baby is 6 months old. However, it is always important to have it checked by a doctor to make sure it isn't caused by something else.
For babies and children who have sunset eyes caused by an underlying condition, the treatment depends on the cause.
If setting sun eyes occurs with hydrocephalus, the hydrocephalus would need to be treated surgically. Treatment must be initiated promptly, or brain damage may occur.
Hydrocephalus can be treated with two different surgical procedures: shunt surgery or endoscopic third ventriculostomy (ETV).
Shunt surgery involves placing a tube (shunt) in the brain and connecting it to another tube that is placed under the skin. Together, these tubes help drain excess fluid from the brain to other parts of the body, such as the abdomen or chest cavity. If a shunt becomes defective, it needs to be replaced as soon as possible. Some people may require several shunt replacements over time.
Endoscopic third ventriculostomy (ETV) involves creating a small hole in the third ventricle of the brain (one of four fluid-filled cavities in the brain) so that the excess fluid can make its way out and relieve pressure.
These procedures may also be performed when the patient has Parinaud syndrome, as hydrocephalus is a major underlying cause of both Parinaud syndrome and setting sun eyes. Setting sun eyes and increased head circumference resolve following surgery.
Are setting sun eyes permanent?
In many cases, setting sun eyes go away when the underlying cause is treated properly. But there are some circumstances that may cause symptoms like setting sun eyes to return.
Sometimes, a shunt placement for hydrocephalus can malfunction or cause an infection. If a shunt issue occurs, fluid can build up in the brain again and cause your child to experience the same symptoms they had before surgery (setting sun eyes, growing head size, etc.).
Monitor your child’s developing vision
Talk to an eye doctor right away if you think your child has sunset eyes. They can help diagnose or rule out serious causes and recommend treatment if needed.
They can also refer you to another medical professional if they need to, such as an eye doctor who specializes in pediatric ophthalmology.
If your child has had a procedure that affects their vision, be sure to monitor any changes (positive or negative) and report them back to your doctor.
