What Are The Key Eye Features Of Fetal Alcohol Syndrome?

Fetal alcohol syndrome (FAS) causes a specific set of facial features, and the eyes are among the most telling signs. The key eye features include short palpebral fissures, which means the opening between the upper and lower eyelids is smaller than typical. Other common findings include drooping eyelids, an inner skin fold called epicanthal folds, and a flat or broad nasal bridge that alters the appearance of the eye area. These features are part of the diagnostic criteria for FAS and are caused by alcohol exposure during fetal development.

What Is the Most Distinctive Eye Feature of FAS?

The most distinctive eye feature is short palpebral fissures. Palpebral fissures are the horizontal openings of the eyes between the upper and lower lids. In FAS, this opening measures below the 10th percentile for the child’s age and sex, making it a primary diagnostic indicator.

This shortening happens because alcohol interferes with the development of the facial bones and tissues around the eyes during the first trimester. It is not a temporary effect — it is a permanent structural difference that remains recognizable from infancy through adulthood. When a clinician evaluates a child for FAS, measuring the palpebral fissure length is one of the first steps.

What Other Eye Features Are Seen in FAS?

Beyond short palpebral fissures, several other eye features appear frequently in FAS. These are not required for diagnosis but are common enough that they help support the clinical picture.

• Epicanthal folds — a vertical fold of skin that covers the inner corner of the eye.
• Ptosis — drooping of the upper eyelid, which can be mild or more pronounced.
• Flat nasal bridge — a low or absent bridge of the nose that changes how the eyes appear relative to the face.
• Short nose with a flat tip — often accompanies the flat nasal bridge and contributes to the overall facial appearance.
• Upward or downward slant of the eyelid opening — the palpebral fissures may tilt slightly.
• Strabismus — misalignment of the eyes, where one eye looks in a different direction than the other.

These features often appear together, but not every child with FAS has all of them. The combination and severity vary from person to person.

Why Does Alcohol Cause These Eye Features?

Alcohol is a teratogen, meaning it can cause birth defects when a developing fetus is exposed to it. The eyes and face form early in pregnancy, mostly during the first trimester. Alcohol disrupts the migration of neural crest cells, which are cells that help build the face, skull, and eyes.

When these cells do not move and develop normally, the bones and soft tissues of the face form differently. The result is the characteristic facial appearance of FAS, including the eye features described above. The severity depends on the timing, amount, and frequency of alcohol exposure, as well as genetic factors in both the mother and the fetus. There is no known safe amount of alcohol during pregnancy.

It is important to note that these facial features are not caused by damage to the eye itself, but by changes in the surrounding bones and skin. However, alcohol also affects the development of the optic nerve and other parts of the visual system, which is why vision problems are common in children with FAS.

Are These Eye Features Seen in Other Conditions?

Short palpebral fissures and other facial features of FAS can resemble findings in several genetic conditions. This is why diagnosis is never based on facial features alone.

Conditions that can look similar include:

• Williams syndrome — a genetic disorder with a broad forehead, short nose, and full cheeks.
• Noonan syndrome — characterized by drooping eyelids, wide-set eyes, and a short neck.
• Dubowitz syndrome — a rare condition with short palpebral fissures and a small face.
• Fetal hydantoin syndrome — caused by prenatal exposure to the seizure medication phenytoin.

Clinicians use a three-part diagnostic approach for FAS. They look for the characteristic facial features, growth problems (such as being small for gestational age), and evidence of central nervous system involvement, like developmental delays or intellectual disability. Only when all three are present is a diagnosis of FAS made. If the eye features appear without growth or brain findings, the child may be diagnosed with partial fetal alcohol syndrome or another condition entirely.

Do Children With FAS Have Vision Problems?

Yes. The structural eye features of FAS are often accompanied by functional vision problems. These are not cosmetic — they affect how the child sees and processes visual information.

Common vision issues in FAS include:

• Refractive errors — nearsightedness or farsightedness that requires glasses.
• Strabismus — misalignment of the eyes, which can lead to amblyopia (lazy eye) if untreated.
• Nystagmus — involuntary, rapid eye movements.
• Optic nerve hypoplasia — underdevelopment of the optic nerve, which can cause reduced visual acuity.

Some research suggests that up to 90% of children with FAS have some form of vision problem. This is why early eye examinations are recommended for any child diagnosed with FAS or suspected of having prenatal alcohol exposure. Early detection of strabismus or refractive errors allows for treatment that can prevent permanent vision loss.

Can These Eye Features Be Corrected?

The facial features of FAS, including short palpebral fissures, cannot be corrected with medication or therapy. They are permanent structural differences. Surgery is rarely performed for these features because they do not usually cause functional problems. The eyes work — they open and close — even if they look different from typical eyes.

Surgery may be considered in specific cases. Ptosis that is severe enough to block vision, for example, can be corrected with eyelid surgery. Strabismus can also be treated with surgery, glasses, or vision therapy. These treatments address the functional problem, not the appearance.

Parents and caregivers should know that the facial features of FAS are not a sign of pain or discomfort. They are simply a visible marker of the condition. The more pressing medical concerns are usually the neurological and behavioral effects of prenatal alcohol exposure, which require ongoing support and intervention.

What Should Parents Do If They Suspect FAS?

If you suspect your child may have FAS, the first step is a comprehensive evaluation by a clinician experienced in fetal alcohol spectrum disorders. This may be a developmental pediatrician, geneticist, or neurologist. Ask for a referral from your primary care provider.

During the evaluation, the clinician will measure the palpebral fissures, assess facial features, review growth charts, and evaluate developmental milestones. They will also take a detailed history of prenatal alcohol exposure, which is critical but not always available. Some children are diagnosed without a confirmed history of exposure because the facial features and brain findings are so characteristic.

An early diagnosis matters. Children with FAS who are diagnosed before age 6 are more likely to receive early intervention services, which improve outcomes in behavior, learning, and daily living skills. The facial features themselves do not change, but the support a child receives can make a significant difference in how they manage the challenges of FAS throughout life.