CONGENITAL

GLAUCOMA

By Shubham Vasudeva

CONGENITAL GLAUCOMAS

They are a group of diverse disorders in which abnormal high intraocular pressure results due to developmental abnormalities of the angle of anterior chamber obstructing the drainage of aqueous humour.

CLASSIFICATION

1. Primary congenital glaucoma(without asso. anomalies)

> True congenital glaucoma (IUL- birth)

> Infantile congenital glaucoma (up to 3 yrs)

> Juvenile glaucoma (>3yrs)

2. Developmental glaucoma(with asso. anomalies)

> Glaucoma asso. with iridocorneal dysgenesis

> Glaucoma asso. aniridia

> Glaucoma asso. with ectopia lentis syndromes

> Glaucoma asso. with phakomatosis

> Miscellaneous conditions

Pathogenesis

Primary congenital glaucoma is due to failure or abnormal development of the trabecular meshwork

Maldevelopment of trabeculum including the iridotrabecular junction (trabeculodysgenesis) is responsible for impaired aqueous outflow resulting in raised IOP.

Trabeculodysgenesis is characterized by absence of the angle recess with iris having a flat or concave direct insertion into the surface.

The iris may not completely separate from the cornea that the angle remains closed by persistent embryonic tissue.

Pathogenesis of Glaucomatous Ocular Damage

Main Theories are:

1 Mechanical changes due to the rise of IOP

2 Vascular perfusion of the optic nerve head

3 Defective autoregulation

Above is shown a typical nerve appearance with damage from glaucoma.  Note that the center of the nerve has an excavated or "scooped out" appearance.

CUPPING OF OPTIC DISC IN GLAUCOMA

CLINICAL FEATURES

1. Photophobia, blepharospasm, lacrimation & eye rubbing are often occur together.

These are thought to be caused by irritation of corneal nerves, which occurs as a result of the elevated IOP.

Photophobia is usually the initial sign, but is not enough by itself to arouse suspicion in most cases.

2. Corneal signs : Corneal signs include its oedema, enlargement and Descemet’s breaks.

Corneal oedema – It is frequently the first sign which arouses suspicion

Corneal enlargement- It occurs along with enlargement of globe-buphthalmos especially when the onset is before the age of 3yrs

.

Haab’s straie (Tears and break in Descement’s membrane)-

These occur because Descement’s membrane is less elastic than the corneal stroma. Tears are usually peripheral and concentric with the limbus.

3. Sclera becomes thin and appears blue due to underlying uveal tissue.

4. Anterior Chamber becomes deep.

5. Iris may show iridodonesis and atrophic patches in late stage

6. Lens becomes flat due to stretching of zonules and may even

subluxate. 7. Optic disc may show variable cupping and atrophy especially after third

year.

8. IOP is raised which is neither marked nor acute

9. Axial myopia may occur because of increase in axial length which may give rise to anisometropic ambylopia.

MANAGEMENT OF CONGENITAL GLAUCOMA

CLINICAL FEATURES

Symptoms

- Epiphora

- Photophobia

- Blepharospasm

Examination

- Reduced visual acuity

- Buphthalmos

- Corneal diameter > 12 mm

- Corneal edema

- Haab’s striae

- Elevated IOP

- Optic atrophy

The same infant as the previous photo. Although the red reflex from the flash can be partially seen, a whitish haze covers the entire corneal surface.

This infant presented with hazy bilateral corneal opacities on the initial newborn exam. The diagnosis of was relatively easy as there was a strong family history of congenital glaucoma.

Examination under General Anaesthesia

IOP

normal is 10-15 mm Hg under anaesthesia -

anaesthetics and preoperative dehydration lowers IOP.

Vernier callipers are used to measure the corneal diameter in infants.

Gonioscopy

anterior chamber deep with normal iris structure

angle open with concave or flat insertion of iris root with abnormal tissue

giving shagreen, glistening appearance

may also have absent angle recess, peripheral iris hypoplasia, tenting of

peripheral iris pigment epithelium, thickened uveal trabecular meshwork.

Stretch marks in the cornea (Haab’s striae) from the high

intraocular pressure in a patient with congenital glaucoma (need

cropping and arrows).

The left eye of this congenital glaucoma patient is noticeably larger than the right eye. The patient has buphthalmos of the left eye

Examination under General Anaesthesia

Optic nerve

- normally pink with small cup

- preferential neural loss of superior and inferior

poles

- cupping may be reversible if IOP lowered initially

Axial length

- enlarged but may reverse with reduced IOP

DIFFERENTIAL DIAGNOSIS

Nasolacrimal duct Obstruction

X-linked congenital megalocornea without

glaucoma

Birth trauma

Keratits or uveitis

Retinoblastoma

DIFFERENTIAL DIAGNOSIS

Corneal dystrophies and dysgenesis

Inborn errors of metabolism

Intrauterine inflammations (congenital syphilis

and rubella)

Optic nerve pit, coloboma, or physiologic cupping

TREATMENT

Surgical

mainstay treatment

goniotomy for clear corneas

trabeculotomy for hazy corneas ,success rates

similar

trabeculectomy and shunt procedures only when

goniotomy or trabeculotomy fails

GONIOTOMY

Involves making a horizontal incision at the

midpoint of the superficial layers of the trabecular

meshwork

May need to be repeated

Eventual success rate is about 85%

Results are poor if the corneal diameter is 14mm

or more because Schlemm’s canal obliterated.

The goniotomy surgery involves entering

the anterior chamber with a sharp

goniotomy knife and making an opening

incision through the abnormally

developed trabecular meshwork to allow

greater outflow of the aqueous fluid and

thereby, lower the IOP .

Often 120 degrees (out of 360 degrees

total) of the trabecular meshwork can be

treated with goniotomy in a single setting.

Goniotomy. A fine surgical knife is used to open the drainage angle (trabecular meshwork) in order to lower the intraocular pressure.

TRABECULOTOMY

If corneal clouding prevents visualization of

the angle or when repeated goniotomy has failed

Partial thickness scleral flap is fashioned

Schlemm canal is found and a trabeculotome is inserted into

Schlemm canal and then rotated into the anterior chamber

Technically highly demanding, requires previous experience, and

good anatomical landmarks to achieve predictable results

Schlemm canal may be difficult to canalize because of hypoplasia or

angle anomaly

Trabeculotomy surgery involves making an external incision and

identifying the Schlemm’s canal from the outside, inserting a fine

instrument into the Schlemm’s canal, and breaking through the

trabecular meshwork to increase the aqueous outflow .

Typically, 120-140 degrees of trabecular meshwork can be treated

by trabeculotomy in a single surgery.

If one surgical technique is unsuccessful in decreasing the IOP, the

other technique can be utilized in a fresh area of the trabecular

meshwork (the area not previously operated upon) to increase

the success of the surgery.

Even after initial control of the intraocular pressure is established

with surgery, a periodic monitoring is necessary to ensure the IOP

doesn’t increase again and the glaucoma go out of control.

Trabeculotomy. A trabeculotome instrument is used to open the drainage angle (trabecular meshwork) in

order to lower the intraocular pressure.

TREATMENT

Medical

Temporary measures to control IOP and to clear cloudy

cornea prior to surgery

Administer beta-adrenergic antagonists, CAI’s(carbonic

anhydrase inhibitors).

avoid alpha2-adrenergic agonists under 3 years

occlude nasolacrimal drainage system for 2 minutes

after administration.

•Medications can be used as an adjunct therapy either before or after

the surgical treatment.

• Medications may be utilized temporarily after the diagnosis until

surgery can be performed. If the initial surgery fails to completely

control the IOP, topical medications can be used to bring the glaucoma

under control.

• The systemic side effects of topical medications are greater in infants

than in adults because of the smaller body mass.

•Because of potential systemic side effects, the first line of

medications that are commonly employed is the topical carbonic

anhydrase inhibitors.

• After the CAI, the next choices are topical prostaglandin

analogs or beta-blockers .

•The prostaglandin analogs (e g.latanoprast) appear to be safe

in children; however, there are no long-term data on the safety

of these medications in children. Topical beta-

blockers(eg .timolol , carvedilol) should be used with caution

in children because of the well-known systemic side effects.

•Finally, topical alpha-2 agonist (brimonidine) should be

AVOIDED in infants because it’s been associated with severe

respiratory depression (breathing difficulty).

PROGNOSIS

Good in asymptomatic patients

diagnosed before 24 months.

Guarded in symptomatic patients diagnosed after

24 months even if IOP controlled after surgery.

Developmental Glaucoma Associated With Ocular Or Systemic Abnormalities

Microphthalmos

Corneal anomalies (microcornea, megalocornea, cornea

plana, sclerocornea, corneal staphyloma)

Anterior segment dysgenesis (Axenfield-Rieger syndrome, Peters anomaly, iridoschisis)

Aniridia

Lens anomalies (congenital cataracts, lens dislocation, microspherophakia)

Persistent hyperplastic primary vitreous Congenital ectropion-uvea syndrome ectropion

THANK

YOU