What Is Buphthalmos? Causes, Symptoms, and Treatment Options for Enlarged Eyes in Infants
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer
Buphthalmos is an eye condition present at birth in which one or both eyeballs are abnormally enlarged, usually from glaucoma-related high pressure inside the eye. [4] It occurs in about 1 in 30,000 births and can cause watery eyes, light sensitivity and a cloudy cornea. [4] Treating the pressure early with drops or surgery gives the best chance of preserving vision. [4]
Key takeaways
Buphthalmos is a congenital (present at birth) enlargement of one or both eyes, often noticeable within the first months of life. [4]
The most common cause is primary congenital or infantile glaucoma — fluid build-up that raises pressure inside the eye. [4]
Other causes include aniridia, neurofibromatosis type 1, Sturge-Weber syndrome, and birth injury. [4]
It occurs in about 1 in 30,000 births and is more common in people from Slovakia, Saudi Arabia, and South India. [4]
Signs include large eyeballs, watery or irritated eyes, light sensitivity, eye twitching, and a cloudy, stretched, or cracked cornea. [4]
Treatment uses medicated eye drops or surgery to drain fluid; early treatment gives the best chance of preventing vision loss. [4]
What the research says
Buphthalmos is usually genetic, and CYP1B1 is the gene most often involved. A systematic review of childhood glaucoma genetics (196 studies, 53 genes) found that CYP1B1 was the most-discussed gene (109 studies, 55.6%), with CYP1B1 variants present in 5% to 86% of people with primary congenital glaucoma depending on region and population (Kumar et al., PLoS One, 2024) [1].
It affects boys and girls alike, and inbreeding raises the risk. A meta-analysis covering 161 CYP1B1 mutations in 1,641 tested patients found no significant difference by sex, involvement of both eyes in most patients, and an important role for inbreeding in how the condition is passed on (Haddad et al., Eur J Ophthalmol, 2021) [2].
Surgery lowers eye pressure, and the technique matters. In a meta-analysis of 12 studies (778 eyes) in primary congenital glaucoma, 360-degree trabeculotomy lowered eye pressure by 2.10 mm Hg more and reduced medication use by 0.47 drops more than traditional angle surgery, with a higher complete-success rate (odds ratio 5.07, 95% CI 3.43–7.50) (Abbas et al., J Glaucoma, 2026) [3].
What Is Buphthalmos?
Buphthalmos is the medical term for an inherited congenital enlargement of your eye. Congenital means something that is present when you're born. The size of your eye is apparent at birth or in the first few months of life. It can happen in one eye (unilateral) or both eyes (bilateral). [4]
Buphthalmos (sometimes called buphthalmia) is most often caused by primary congenital glaucoma, which is usually passed down in an autosomal recessive pattern. [4] Autosomal recessive describes a pattern of inheritance in which both parents need to pass an altered gene onto their child for the child to inherit the condition or trait.
Inheritance term | What it means for buphthalmos |
Autosomal recessive | Both parents must pass an altered gene to the child |
Carriers | Parents may not know they carry these genes |
Risk when both parents carry the gene | 1 in 4 of their children will inherit the condition |
Where does the name come from?
Buphthalmos comes from the Greek words for "ox" and "eye." It refers to having big eyes like those of an ox or a cow. The ancient Greek physician Hippocrates was the first to identify the condition. [4]
How common is buphthalmos?
Buphthalmos happens in about 1 in 30,000 births. [4] It doesn't seem to happen more often in one sex (Haddad et al., 2021) [2]. Some groups may be more at risk of developing buphthalmos, including people in Slovakia, Saudi Arabia, and South India. [4]
What Are the Signs and Symptoms of Buphthalmos?
The most visible sign of buphthalmos is having large eyeballs when you're an infant. [4] Either one or both of your eyes might be big. Depending on what's causing the buphthalmos, you may have other symptoms:
Sign or symptom | What it looks like |
Large eyeballs | One or both eyes appear abnormally big as an infant |
Watery or irritated eyes | Eyes water, tear up, or become irritated easily |
Light sensitivity (photophobia) | Eyes are sensitive to light |
Eye twitching or blinking | Excessive blinking or eyelid fluttering |
Cloudy cornea | Haziness of the cornea, which is normally clear and acts as the "window" of your eye |
Corneal damage | Stretching, thinning, and possible breaks in the cornea |
What Causes Buphthalmos?
The most common cause of buphthalmos is primary congenital glaucoma or primary infantile glaucoma. [4] Glaucoma causes damage to your optic nerve and can cause vision loss. It's thought that this damage happens because of fluid build-up and increased pressure within your eye (intraocular pressure, or IOP). [4]
Glaucoma type | When it starts |
Primary congenital glaucoma | Starts at birth |
Primary infantile glaucoma | Starts after birth until a child is three years old |
Other causes of buphthalmos
Cause | How it leads to enlarged eyes |
A rare condition affecting your iris (the colored part of your eye); the iris is partially or completely missing and may affect vision | |
Mostly an inherited condition; tumors can grow on nerves, causing problems with your eyes | |
A congenital condition that causes blood vessels to grow too much, producing angiomas; it can affect your skin, brain, and eyes | |
Birth injury | An injury that happens during delivery can harm your eyes |
How Is Buphthalmos Diagnosed?
Parents may be the first to notice an issue with their child's eye and should ask a healthcare provider about any concerns. A pediatrician may recommend a visit to an eye care specialist. [4] In the case of buphthalmos and congenital glaucoma, this is especially important — early treatment will lead to better vision.
To diagnose buphthalmos, the provider may need to use anesthesia to do some of the following tests: [4]
Test | What it checks |
Thorough eye exam | Whether the cornea is cloudy, torn, or swollen; measurement of the eye; whether there is cupping of the optic disk where the optic nerve leaves the eye |
Retinoscopy | Refraction errors, such as myopia (nearsightedness) |
Gonioscopy | The eye's drainage system — healthy eyes continually make and drain fluid, but in glaucoma fluid backs up, raising pressure and damaging the optic nerve |
Ultrasound biomicroscopy | Detailed noninvasive images of the front part of the eye; can show drainage problems in more detail than a plain ultrasound (sonogram) |
How Is Buphthalmos Treated?
It's important to treat ocular pressure in treating buphthalmos. There are a number of ways to reduce pressure.
Medications
Eye drops or other topical treatments contain one of the following:
Medication type | How it helps |
Beta blockers | Eye drops or topicals that reduce fluid production and lower eye pressure |
Prostaglandin analogs | Eye drops that increase fluid drainage from the eye |
Carbonic anhydrase inhibitors | Eye drops that reduce the amount of fluid the eye makes |
Surgical procedures
Surgical procedures treat ocular pressure by helping fluid to drain: [4]
Procedure | What is done |
Drainage implants | Placing implants in your eye to help fluid drain |
Making cuts in your eye structures to open the drainage pathway | |
Tissue removal | Removing tissue from your eye to relieve pressure |
Of course, if you have buphthalmos, you may have other conditions that need treatment. The provider will help with treating neurofibromatosis type 1, Sturge-Weber syndrome, or aniridia. [4]
What Can I Expect If I Have Buphthalmos?
Buphthalmos is treatable. The best outcome in terms of preventing vision loss is finding and treating the condition early. [4]
Can Buphthalmos Be Prevented?
You really can't prevent buphthalmos, but you can prevent a bad outcome by finding and treating buphthalmos early in your child's life. [4]
How Do I Take Care of My Child?
It's important for everyone to have regular eye examinations, but it's especially important for anyone who has a congenital eye condition. Ask questions about changes in vision and when you should contact a care provider.
In addition to the exams, do what you can to have healthy eyes. Proper eye care includes:
Healthy eye habit | Why it helps |
Eating healthy and drinking enough water | Supports overall eye health |
Getting enough sleep and physical activity | Keeps the body — and eyes — healthy |
Wearing protective eyeglasses in the sun, at work, and during sports | Shields eyes from UV light and injury |
Reduces long-term risk to eye health |
A note worth remembering
If you feel like something isn't quite right about the way your child's eye looks, contact a healthcare provider. If buphthalmos is present, glaucoma and high pressure in the eye are likely present as well. [4] It's best to deal with this early.
Conclusion
Buphthalmos is a congenital eye condition in which one or both of an infant's eyeballs are visibly enlarged, usually because fluid buildup inside the eye raises pressure and stretches the flexible infant eye. Named after the Greek words for "ox" and "eye," it occurs in about 1 in 30,000 births and is most often caused by primary congenital or infantile glaucoma, though aniridia, neurofibromatosis type 1, Sturge-Weber syndrome, and birth injury can also be responsible.
The condition itself can't be prevented, but its outcome is highly controllable. Medicated eye drops and drainage surgery can lower intraocular pressure and protect the optic nerve — and the single most important factor is timing. Parents who notice unusually large, watery, light-sensitive, or cloudy eyes in a newborn should seek an eye care evaluation right away, because early treatment gives children the best chance of preserving vision for life. Visual diagrams of eye anatomy and pressure pathways make these concepts far easier to teach. Explore Rinnit's medical infographics to build engaging visuals for pediatric eye health and other medical topics.
Frequently Asked Questions
What is buphthalmos?
Buphthalmos is an inherited congenital (present at birth) enlargement of one or both eyes, usually noticeable at birth or within the first few months of life.
What does the word buphthalmos mean?
The word buphthalmos comes from the Greek words for "ox" and "eye," referring to big eyes like those of an ox or cow. Hippocrates was the first to identify the condition.
Is buphthalmos the same as buphthalmia?
Yes. Buphthalmia is simply another name for the same condition.
When does eye enlargement become visible?
The eye size is apparent at birth or in the first few months of life.
Can it affect one or both eyes?
Yes. It can happen in one eye (unilateral) or both eyes (bilateral).
Is buphthalmos genetic?
Often. Its most common cause, primary congenital glaucoma, is usually autosomal recessive, meaning both parents must pass an altered gene to the child; other causes, such as birth injury, are not inherited.
What does autosomal recessive mean?
Autosomal recessive describes a pattern of inheritance in which both parents need to pass an altered gene onto their child. Parents may not even know they carry these genes.
What is the risk if both parents carry the gene?
One out of four of their children will inherit the condition.
How common is buphthalmos?
Buphthalmos happens in about 1 in 30,000 births.
Is it more common in boys or girls?
No — it doesn't seem to happen more often in one sex.
Are any populations at higher risk?
Yes. People in Slovakia, Saudi Arabia, and South India may be more at risk.
What is the main sign of buphthalmos?
The most visible sign is large eyeballs in an infant — either one or both eyes.
Do watery eyes indicate buphthalmos?
Watery, irritated eyes are a possible symptom, though they can have many other causes.
What is photophobia?
Photophobia is sensitivity to light — a symptom that can accompany buphthalmos.
Can buphthalmos cause eye twitching?
Yes. Eye twitching or excessive blinking can occur depending on the underlying cause.
What happens to the cornea?
The cornea may become hazy or cloudy, and can stretch, thin, and possibly break under pressure.
What is the cornea?
The cornea is the normally clear "window" of your eye that covers the front.
What is the most common cause of buphthalmos?
Primary congenital glaucoma or primary infantile glaucoma — fluid build-up that raises pressure inside the eye.
What is intraocular pressure (IOP)?
Intraocular pressure is the pressure within the eye, which rises when fluid builds up.
How does glaucoma damage vision?
Glaucoma is thought to damage the optic nerve because of fluid build-up and increased pressure inside the eye, and it can cause vision loss.
What is the difference between congenital and infantile glaucoma?
Primary congenital glaucoma starts at birth, while primary infantile glaucoma starts after birth and can develop until a child is three years old.
What is aniridia?
A rare condition affecting the iris (the colored part of your eye), in which the iris is partially or completely missing and may affect vision.
How does neurofibromatosis type 1 relate?
Neurofibromatosis type 1 causes tumors to grow on nerves, which can cause problems with the eyes.
What is Sturge-Weber syndrome?
A congenital condition that causes blood vessels to grow too much, producing angiomas, and can affect the skin, brain, and eyes.
Can birth injury cause buphthalmos?
Yes. An injury that happens during delivery can harm the eyes and contribute to buphthalmos.
Who should I contact if my baby's eyes look abnormal?
Parents who notice an issue should ask their healthcare provider, who may recommend a visit to an eye care specialist.
Is anesthesia needed for diagnosis?
Yes — the provider may need to use anesthesia to perform some of the diagnostic eye tests on an infant.
What does an eye exam check for?
Whether the cornea is cloudy, torn, or swollen; the size of the eye; and whether there is cupping of the optic disk where the optic nerve leaves the eye.
What is retinoscopy?
A test that tells the provider if you have refraction errors, such as myopia (nearsightedness).
What is gonioscopy?
A test that checks the eye's drainage system — in glaucoma, fluid backs up instead of draining, raising pressure and damaging the optic nerve.
What is ultrasound biomicroscopy?
A noninvasive test that gives detailed images of the front part of the eye and can show drainage problems better than a plain ultrasound.
Is there a cure for buphthalmos?
The condition is treatable — ocular pressure can be controlled with medications and surgery, and early treatment can prevent vision loss.
What eye drops are used?
Topical treatments containing beta blockers, prostaglandin analogs, or carbonic anhydrase inhibitors.
What surgeries treat buphthalmos?
Surgeries that help fluid drain, including placing implants in the eye, making cuts in eye structures, and removing tissue from the eye.
Do the other conditions need treatment too?
Yes — the provider will also help treat neurofibromatosis type 1, Sturge-Weber syndrome, or aniridia if present.
What is the outlook for a child with buphthalmos?
Buphthalmos is treatable, and the best outcome for preventing vision loss comes from finding and treating the condition early.
Can it be prevented?
The condition itself can't be prevented, but a bad outcome can be prevented by finding and treating buphthalmos early in your child's life.
How can I protect my child's eye health?
Regular eye exams, healthy eating and hydration, enough sleep and physical activity, protective eyeglasses in the sun, at work, and during sports, and quitting smoking.
When should I contact a provider about my child's eyes?
If something doesn't look quite right about how your child's eye looks — if buphthalmos is present, glaucoma and high eye pressure are likely present too, and it's best to deal with this early.
What should I do now?
If your infant has unusually large, watery, light-sensitive, or cloudy eyes, ask a pediatrician for a referral to an eye care specialist promptly. Early diagnosis and pressure-lowering treatment give your child the best chance at a lifetime of healthy vision.
Related Reading
References
Kumar A, Han Y, Oatts JT. Genetic changes and testing associated with childhood glaucoma: a systematic review. PLoS One. 2024;19(2):e0298883. PMID: 38386645. https://doi.org/10.1371/journal.pone.0298883
Haddad A, Ait Boujmia OK, El Maaloum L, et al. Meta-analysis of CYP1B1 gene mutations in primary congenital glaucoma patients. Eur J Ophthalmol. 2021;31(6):2796-2807. PMID: 34020567. https://doi.org/10.1177/11206721211016308
Abbas J, Haider F, Arooj H, et al. Comparison of 360-degree trabeculotomy versus traditional angle surgery in primary congenital glaucoma: a systematic review and meta-analysis. J Glaucoma. 2026;35(7):e86-e94. PMID: 41875194. https://doi.org/10.1097/IJG.0000000000002705
Cleveland Clinic. Buphthalmos. Accessed October 15, 2026. https://my.clevelandclinic.org/health/diseases/24074-buphthalmos
Medical disclaimer
This article is for general informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for diagnosis and treatment decisions. Parents who notice unusually large, watery, cloudy, or light-sensitive eyes in an infant should seek prompt evaluation by an eye care specialist.
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