What kinds of eye problems are seen in children with PHACE syndrome?
Eye problems with PHACE syndrome are somewhat rare, but there are certain abnormalities that are seen more commonly than others. The problems most often seen in PHACE syndrome are: microphthalmia, optic nerve hypoplasia, persistent fetal vasculature, and morning glory discs.
- Microophthalmia is the term used when the eye is smaller than normal and has not formed correctly.
- Optic nerve hypoplasia refers to an underdeveloped or small optic nerve. The optic nerve conducts the images we see and transfers them to the brain as electrical impulses. This can be seen on examination by an ophthalmologist (eye doctor). Underdevelopment of the optic nerve can also be a sign that there are other brain abnormalities.
- Persistent fetal vasculature is where blood vessels in the retina that should disappear as the fetus develops inside the womb do not disappear. This can lead to vision problems.
- Morning glory disc anomaly is seen when the blood vessels that supply nutrients to the retina of the eye do not radiate from a normal central point. The optic nerve also does not develop correctly when the child is in the womb. The result is an excess of white tissue in the back of the eye and looks like the center of the morning glory flower.
- Peripapillary staphyloma is likely due to a lengthening of the globe of the eye (eyeball), which causes a thinning and a stretching of the sclera (the white tissue around the iris that surrounds the eye). This allows certain layers inside of the eye to protrude through other layers.
- Coloboma is a developmental problem that happens before a child is born. A layer of tissue called the choroidal fissure does not fuse properly, resulting in an opening in the tissue. This can happen anywhere in the eye – the iris, the lens, or the tissue in the middle of the eyeball. The visual problems can be minimal to severe depending on where the incomplete fusion of tissue happened.
- Congenital third nerve palsy is a paralysis of the third cranial nerve, which affects the movement of the eyelid and eye muscles.
- Horner's syndrome is a condition where there is a disturbance in the nerves of the eye and face. The nerve dysfunction can cause ptosis (droopy eyelid), myosis (small pupil when compared to the other), and anhidrosis (lack of sweating) on one side of the face. This can be present at birth, or it can develop later. If a hemangioma begins pressing on a nerve or if there is a carotid artery dissection (a splitting of the artery that feeds the brain), Horner's syndrome can develop.
- Ptosis is an eyelid that does not open fully. In PHACE syndrome, it may be caused by a hemangioma crowding the eyelid and keeping it from opening fully. This can affect the developing vision and needs to be watched closely by a physician.
- Amblyopia, otherwise known as lazy eye, is a disorder of the visual system that is characterized by poor vision or lack of vision in an eye that is otherwise physically normal. In this condition, visual stimulation either fails to transmit or is poorly transmitted through the optic nerve to the brain for a continuous period of time. It often occurs during early childhood, resulting in poor or dim vision. Detecting the condition in early childhood increases the chance of successful treatment. Amblyopia normally affects only one eye, but it is possible to be amblyopic in both eyes. It has been estimated to affect around 1 to 5 percent of the normal population.
- Proptosis is the forward protrusion, or bulging of the eyeball. Usually, it is a sign of a severe orbital disorder, such as a tumor, inflammation, or thyroid eye disease. In PHACE syndrome, a growing hemangioma could cause the eye to be displaced.
- Astigmatism refers to the cornea (the clear tissue covering the front of the eye) being abnormally curved, causing vision to be out of focus.
What are the signs and symptoms of eye problems and what specialist should be seen?
Vision is a sense that is not well developed in children at birth and it takes weeks to months for their vision to improve and sharpen. Therefore, eye problems could go unnoticed by parents for some time. However, there are certain other findings that could provide clues about potential eye development issues. One sign would be if a child has a weak eyelid (ptosis) or wandering eye. A wandering eye (strabismus) means that the eyes may be looking in different directions.
All children with PHACE syndrome should have an eye exam by an ophthalmologist who has expertise in PHACE syndrome. The ophthalmologist will make sure the child is seeing in an age-appropriate manner (an infants' vision grows sharper as they age), which can be difficult since the child cannot tell anyone how well they are seeing. The eye doctor will also check to see if both eyes are seeing equally. The eye doctor will examine the muscles of the eye, the back of the eye (the retina), and the outer parts of the eye, looking for any changes in growth or development. If a child has a hemangioma located around the eye, an ophthalmologist that has experience with hemangiomas should be seen.
The eye doctor might also use visual evoked potentials to test differences in visual sensation between the eyes. This is a test where the physician checks to see how well the nerves of the eye are functioning and it can be very helpful in detecting differences in the eyes.
How are eye abnormalities treated?
The best treatment is prevention for certain eye problems. While there are certain developmental changes in the eye that can affect vision before the child is even born, there are certain times when treatment may be necessary to prevent a problem down the road. For example, a wandering eye is often correctable if noticed early enough in the child's growth.