Primary congenital glaucoma is a rare eye condition that is present at birth or develops early in childhood. It occurs due to improper drainage of the eye's fluids, which leads to increased pressure inside the eye, known as

intraocular pressure Intraocular pressure (IOP) is the fluid pressure inside the eye. Tonometry is the method eye care professionals use to determine this. IOP is an important aspect in the evaluation of patients at risk of glaucoma. Most tonometers are calibrated t ...

. This elevated pressure can damage the

optic nerve In neuroanatomy, the optic nerve, also known as the second cranial nerve, cranial nerve II, or simply CN II, is a paired cranial nerve that transmits visual system, visual information from the retina to the brain. In humans, the optic nerve i ...

which will result in permanent vision loss. It is also known as pediatric glaucoma or childhood glaucoma, and was previously known as trabeculodysgenesis or goniodysgenesis.

Types

Primary congenital glaucoma is classified into three subtypes: * true congenital glaucoma, which causes signs of increased intraocular pressure within the first month of life, * infantile glaucoma, which presents between one month and three years, and * juvenile glaucoma, which becomes clinically apparent after three years of age and before age 40.

Primary juvenile glaucoma

Primary juvenile glaucoma becomes apparent between the ages of 3 and 40. It develops due to

ocular hypertension Ocular hypertension is the presence of elevated fluid pressure inside the eye (intraocular pressure), usually with no optic nerve damage or visual field loss. For most individuals, the normal range of intraocular pressure is between 10 mmHg and ...

and is diagnosed between three years of age and early adulthood. It is caused due to abnormalities in the

anterior chamber angle The anterior chamber angle is a part of the eye located between the cornea and iris which contains the trabecular meshwork. The size of this angle is an important determinant of the rate aqueous humour flows out of the eye, and thus, the intraocu ...

development that obstruct aqueous outflow in the absence of systemic anomalies or other ocular malformation.

History

In the late 19th and early 20th centuries, the disease was commonly referred to by terms such as ''trabeculodysgenesis'' and ''goniodysgenesis'', emphasizing the developmental anomalies in the eye's drainage structures. It was considered untreatable at the time, with most cases resulting in inevitable vision loss and blindness due to elevated

. In the early 20th century, Dr. Paul Chandler identified congenital glaucoma as a distinct medical condition. Later, Dr. Janey Wiggs, a researcher at

Harvard Medical School Harvard Medical School (HMS) is the medical school of Harvard University and is located in the Longwood Medical and Academic Area, Longwood Medical Area in Boston, Massachusetts. Founded in 1782, HMS is the third oldest medical school in the Un ...

, conducted studies identifying new genetic mutations associated with congenital glaucoma, such as the

thrombospondin-1 Thrombospondin 1, abbreviated as THBS1, is a protein that in humans is encoded by the ''THBS1'' gene. Thrombospondin 1 is a subunit of a disulfide-linked homotrimeric protein. This protein is an adhesive glycoprotein that mediates cell-to-cell ...

(THBS1) gene.

Causes and symptoms

The condition is often caused by developmental anomalies in the eye's drainage system. Genetic factors play a significant role, with several mutations identified like

that contribute to the development of congenital glaucoma. Common symptoms of primary congenital glaucoma include. * Enlarged eyes (

Buphthalmos Buphthalmos (plural: buphthalmoses) is enlargement of the eyeball and is most commonly seen in infants and young children. It is sometimes referred to as buphthalmia (plural buphthalmias). It usually appears in the newborn period or the first 3 mo ...

) * Sensitivity to light (

Photophobia Photophobia is a medical symptom of abnormal intolerance to visual perception of light. As a medical symptom, photophobia is not a morbid fear or phobia, but an experience of discomfort or pain to the eyes due to light exposure or by presence o ...

) * Tearing ( Epiphora) * Cloudy cornea * Bluish discoloration of the eyeball.

Presentation

The typical infant who has congenital glaucoma usually is initially referred to an

ophthalmologist Ophthalmology (, ) is the branch of medicine that deals with the diagnosis, treatment, and surgery of eye diseases and disorders. An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Following a ...

because of apparent corneal edema. The commonly described triad of epiphora (excessive tearing),

blepharospasm Blepharospasm is a neurological disorder characterized by intermittent, involuntary spasms and contractions of the orbicularis oculi muscle, orbicularis oculi (eyelid) muscles around both eyes. These result in abnormal twitching or blinking, an ...

and photophobia may be missed until the corneal edema becomes apparent.

Systemic associations

Two of the more commonly encountered disorders that may be associated with congenital glaucoma are

Aniridia Aniridia is a condition characterized by the absence or near absence of the iris, the colored, muscular ring in the eye that controls the size of the pupil and regulates the amount of light entering the eye. This absence results in a primarily b ...

and

Sturge–Weber syndrome Sturge–Weber syndrome, sometimes referred to as encephalotrigeminal angiomatosis, is a rare congenital neurocutaneous disorder (also known as phakomatoses). It is often associated with port-wine stains of the face, glaucoma, seizures, intellect ...

Diagnosis

The diagnosis is clinical. The

(IOP) can be measured in the office in a conscious swaddled infant using a Tonopen or hand-held Goldmann tonometer. Usually, the IOP in normal infants is in the range of 11-14 mmHg.

and

Haab's striae Haab's striae, or Descemet's tears, are horizontal breaks in the Descemet membrane associated with congenital glaucoma Primary congenital glaucoma is a rare eye condition that is present at birth or develops early in childhood. It occurs due to i ...

can often be seen in case of congenital glaucoma. Its diagnosis process typically involves an eye examination, including measurement of

, corneal diameter, and

assessment. Goniotomy is one surgical option, where surgeons cut into the eye's drainage angle to access the trabecular meshwork, using a gonioscope for visibility. If the drainage angle isn't clearly visible through the

cornea The cornea is the transparency (optics), transparent front part of the eyeball which covers the Iris (anatomy), iris, pupil, and Anterior chamber of eyeball, anterior chamber. Along with the anterior chamber and Lens (anatomy), lens, the cornea ...

, a trabeculotomy is performed, cutting into the

sclera The sclera, also known as the white of the eye or, in older literature, as the tunica albuginea oculi, is the opaque, fibrous, protective outer layer of the eye containing mainly collagen and some crucial elastic fiber. In the development of t ...

with an electrocautery device called a trabeculotome. If these approaches are ineffective, a trabeculectomy may be considered, removing part of the trabecular meshwork through the sclera to create a new drainage pathway. Alternatively, a glaucoma drainage device (tube shunt) may be implanted to drain fluids onto a plate beneath the

conjunctiva In the anatomy of the eye, the conjunctiva (: conjunctivae) is a thin mucous membrane that lines the inside of the eyelids and covers the sclera (the white of the eye). It is composed of non-keratinized, stratified squamous epithelium with gobl ...

. Early detection of this medical condition is important for prevention of vision loss.

Differential diagnosis

Corneal cloudiness may have myriad of causes.

Corneal opacity Corneal opacification is a term used when the human cornea loses its transparency. The term corneal opacity is used particularly for the loss of transparency of cornea due to scarring. Transparency of the cornea is dependent on the uniform diamete ...

that results from hereditary dystrophies is usually symmetric. Corneal enlargement may result from megalocornea, a condition in which the diameter of the cornea is larger than usual and the eye is otherwise normal.

Treatment

The preferred treatment of congenital glaucoma is surgical, not medical. The initial procedures of choice are goniotomy or trabeculotomy if the cornea is clear, and trabeculectomy ab externo if the cornea is hazy. The success rates are similar for both procedures in patients with clear corneas. Trabeculectomy and shunt procedures should be reserved for those cases in which goniotomy or trabeculotomy has failed. Cyclophotocoagulation is necessary in some intractable cases but should be avoided whenever possible because of its potential adverse effects on the lens and the retina.

Epidemiology

In the United States, the incidence of primary congenital glaucoma is about one in 10,000 live births. Worldwide, the incidence ranges from a low of 1:22,000 in Northern Ireland to a high of 1:2,500 in Saudi Arabia and 1:1,250 in Romania. In about two-thirds of cases, it is bilateral. The distribution between males and females varies with geography. In North America and Europe, it is more common in boys, whereas in Japan it is more common in girls. * Incidence: one in every 10000-15000 live births. * Bilateral in up to 80% of cases. * Most cases are sporadic (90%). However, in the remaining 10% there appears to be a strong familial component.

Genetics

Primary congenital glaucomas most commonly occur sporadically. Juvenile open-angle glaucoma is typically an

autosomal dominant In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the Phenotype, effect of a different variant of the same gene on Homologous chromosome, the other copy of the chromosome. The firs ...

, inherited condition. A primary cause is myocilin protein dysfunction. Myocilin gene mutations are identified in approximately 10% of patients affected by juvenile glaucoma.

References

External links

* * ; MYOC * ;

CYP1B1 Cytochrome P450 1B1 is an enzyme that in humans is encoded by the ''CYP1B1'' gene. Function CYP1B1 belongs to the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved ...

* on

eMedicine eMedicine is an online clinical medical knowledge base founded in 1996 by doctors Scott Plantz and Jonathan Adler, and computer engineers Joanne Berezin and Jeffrey Berezin. The eMedicine website consists of approximately 6,800 medical topic revi ...

Glaucoma for Children
on AAPOS. * Congenital Primary Glaucoma on patient.info
GeneReview/NCBI/NIH/UW entry on Primary Congenital Glaucoma

Glaucoma entry on PGCFA
{{Congenital malformations and deformations of eye, ear, face and neck Congenital disorders of eyes Blindness Pediatrics