Buphthalmos

Inspection:

Port wine stain

Signs of Neurofibromatosis

Measure IOP – using Perkins, tono-pen, iCare

Slit lamp examination:

Look for a trabeculotomy scar at the superior limbus.

Check the cornea edge on the temporal side for goniotomy scar

Check corneal diameters – both horizontal and vertical - (>12mm before the age of 1 year is highly suspicious)

Haab’s Striae – multiple horizontal or Oblique lines in Descemet’s membrane; retro-illumination may enhance their visualization.

Clarity of Cornea – The corneal may be clear or hazy due to edema.

Anterior chamber – deep anterior chamber

Iris – aniridia – hypoplastic iris, Peters anomaly - iridocorneal contact, NF 1 – Lisch Nodule, mammillations.

Iridodonesis

Peripheral iridectomy

Lens – phacodonesis, Cataract (Rubella)

Gonioscopy – signs of trabeculodysgenes

Optic disc for glaucomatous changes. Cupping of the optic nerve head – Asymmetry or a cup/disc ratio of 0.3 is suspicious – in the case of cloudy corneas, severe cupping may be seen on B-Scan.

Visual Acuity – check for amblyopia

Cycloplegic Retinoscopy – myopia due to elongation and enlargement of the eyeball, astigmatism from Haab striae and corneal stretching, anisometropia

Investigations

Axial length measurement – better by immersion technique

Pachymetry - Pachymetry serves as a tool for assessing the central corneal thickness. While corneal edema can contribute to increased thickness, it's noteworthy that in individuals with primary congenital glaucoma (PCG) who lack corneal edema, the central cornea has been observed to be thinner, possibly attributable to tissue stretching

ASOCT -

Clinical genetics consultation may be advised.

Questions:

What is the classic triad of Buphthalmos?

In addition to raised IOP, buphthalmos is characterized by the presence of a triad of photophobia, epiphora, and blepharospasm,

List the causes of congenital glaucoma.

Primary congenital glaucoma

Anterior cleavage syndromes such as Axenfeld's, Reiger's, and Peter's. Rubella

Phakomatoses such as Sturge-Weber's Syndrome and neurofibromatosis Aniridia

Persistent hyperplastic primary vitreous

Briefly describe features of Aniridia, NF1, and Sturge-Weber Syndrome.

Aniridia: This condition is marked by either complete or partial iris hypoplasia, with an autosomal dominant inheritance pattern. The glaucoma associated with it is believed to stem from angle-closure.

Neurofibromatosis type 1: This condition is defined by the presence of multiple neurofibromas, cafe au lait spots, iris Lisch nodules, and freckling in the axillary and inguinal regions. It has an AD inheritance pattern, and glaucoma is believed to result from developmental anomalies affecting the anterior chamber angle.

Sturge-Weber syndrome: This condition is marked by nevus flammeus on the face and meningeal angiomas. Around 60% of cases exhibit glaucoma with associated angle anomalies. The proposed causes of glaucoma include developmental anomalies in the angle and elevated episcleral venous pressure.

What do you know about the corneal diameters?

The corneal diameter of a newborn is typically in the range of 9.5-10.5 mm and expands to 10.0-11.5 mm by the age of 1. An abnormality may be indicated if the diameter exceeds 12.0 mm before the first year, particularly if there is a noticeable asymmetry between the two eyes. A corneal diameter surpassing 13 mm at any age raises suspicion for glaucoma.

What is the mechanism of eyeball enlargement?

In the presence of elevated intraocular pressure (IOP), not only does the cornea undergo stretching, but the scleral wall and all internal eye tissues also experience this phenomenon, resulting in buphthalmos. The enlargement of the cornea typically halts around the age of three, while the sclera may continue to stretch until the age of 10.

How does cupping in congenital glaucoma differ from that in adult glaucoma?

In very young children, optic nerve cupping might be solely attributed to the stretching of the optic canal and posterior bowing of the lamina cribrosa, without a concurrent decrease in the neuroretinal rim. Normalizing intraocular pressure (IOP) can lead to a significant reversal of cupping. However, it's important to note that while cupping may resolve, any damage to the retinal nerve fiber layer, if already present, tends to be permanent.

How often the A-scan should be repeated?

A scan should be repeated 3-4 monthly.

What special precautions must be taken in the measurement of IOP?

It's crucial to consider the impact of anesthetic agents on intraocular pressure (IOP), as they can variably alter it, with most agents tending to lower IOP. Therefore, it's recommended to obtain IOP measurements promptly after the induction of anesthesia and before intubation.

In infants and young children, the average IOP is generally lower compared to adults. Newborns typically have an average IOP ranging from 10 to 12 mm Hg, which increases to around 14 mm Hg by the age of 7 or 8. Understanding these variations is essential for accurate assessments in the pediatric population.

How gonioscopy is performed in infants?

Performing gonioscopy in a clinic setting is recommended if the corneal view allows. When dealing with young children, a Sussman (or a similar) indirect gonioscopy lens is often preferable due to its easy fit within their small palpebral fissure

Notably, infants diagnosed with primary congenital glaucoma (PCG) typically do not exhibit a visible scleral spur. This is distinct from normal infants, where the peripheral iris and ciliary body have receded to the scleral spur or positioned posterior to it. In PCG, the peripheral iris inserts directly into the trabecular meshwork. Understanding these nuances is crucial for accurate diagnosis and management.

How is perimetry performed in children?

Initiating perimetry around the age of 7-8 is feasible, provided the patient doesn't exhibit nystagmus, cognitive impairment, or severe vision loss. Employing quicker testing algorithms like SITA-FAST can enhance the reliability of results in children. Additionally, Goldman perimetry has proven to be highly beneficial in evaluating visual fields in young children.

What is the differential diagnosis of Primary congenital Glaucoma?

Epiphora	Nasolacrimal duct obstruction, conjunctivitis, corneal abrasion, keratitis, uveitis. (Photophobia and blepharospasm are unlikely with nasolacrimal duct obstruction and conjunctivitis; however, they may be seen with corneal abrasion/injury, keratitis, or uveitis.)
Corneal Clouding or Opacification	birth trauma (generally involving forceps causing Descemet tears that are vertical or oblique (unlike Haab striae, which are usually more horizontal or curvilinear)), corneal dystrophies (such as congenital hereditary endothelial dystrophy or posterior polymorphous dystrophy), congenital or developmental abnormalities (such as sclerocornea, Peters anomaly), keratitis (from intrauterine infection or inflammation such as herpetic infection, congenital syphilis, and maternal rubella, and Riley-Day syndrome), storage diseases & inborn errors of metabolism (such as mucopolysaccharidoses, mucolipidoses, cystinosis, and oculocerebrorenal (Lowe) syndrome) choristomas.
Corneal Enlargement	high axial myopia Megalocornea. (Megalocornea is an inherited disorder in which infants have clear corneas with diameters > 14 mm, deep anterior chambers, and iridodonesis. There have been reports within one family of megalocornea coexistent with congenital glaucoma.)
Optic Disc Cupping	physiologic cupping, optic nerve coloboma, optic nerve atrophy, optic nerve hypoplasia, and optic nerve malformation