Glaucomas

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Overall yield:

V >

Clinical exam:

Viva:

Essay:

MCQ:

-V-V-V

What are the causes of congenital glaucomas?

"Congenital glaucoma can be classified as primary or secondary." "Secondary causes include..."

Classification of congenital glaucoma

1. Primary

• Congenital (birth), infantile (1-2), juvenile (2-16)

2. Secondary

• Systemic disorders

• Chromosomal disorders

• Metabolic disorders (Lowe's, Zellweger's)

• Phakomatoses (Sturge-Weber's)

• Ocular developmental disorders

• Anterior segment dysgenesis, aniridia

• Congenital ectropian uvea, nanophthalmos

• Ocular diseases

• Retinoblastoma, ROP, persistent hyperplastic primary vitreous, trauma, uveitis

<S> What are causes of cloudy cornea at birth?

"Cloudy corneas can be caused be many different disorders." "A useful way of classifying is by the size of the eye."

Cloudy cornea at birth

1. Large eye

• Congenital glaucoma

• Mesenchymal dysgenesis

2. Small eye

• Microphthalmos

• Severe prenatal infection

• Mesenchymal dysgenesis

3. Normal size eye

• Diffuse opacity

• Congenital hereditary endothelial dystrophy

• Congenital hereditary stromal dystrophy

• Sclerocornea

• Mucopolysaccharidosis

0 Exam tips:

• The classification is exactly the same as for congenital cataracts (page 9)!

• Mucolipidosis

• Interstitial keratitis

• Congenital glaucoma Regional opacity

Round

Forceps injury

Congenital glaucoma (Haab's straie)

Infective keratitis Peter's anomaly

Localized mesenchymal dysgenesis

Howdo you manage congenital glaucomas?

"The management of congenital glaucoma is difficult." "And involves a multidisciplinary team approach." "The important issues include ..."

"A complete history and physical examination, usually under anesthesia is needed."

O Exam tips:

» Like management of congenital cataracts (page 9), a fairly difficult question to handle • Provide precise opening statements to capture spectrum of related problems

Management of congenital glaucoma

1. Issues in management

• Assessing etiology and inheritance of congenital glaucoma

• Managing systemic problems of secondary congenital glaucoma

• Deciding on type of surgery (corneal diameter as a guide)

• < 13mm: goniotomy/trabeculotomy

• > 14mm: trabeculotomy/trabeculectomy/valve implant

• > 16mm: cyclodestructive procedures (usually very poor prognosis)

• Managing associated ocular problems and amblyopia

• Refractive errors

• Corneal opacity

2. Physical examination

Photophobia Blepharospasm

Signs

NOTES

The clinical signs can be remembered as "ABCDE"

• D iameter of cornea enlarged

• E xamination under anesthesia Examination under anesthesia

• Ketamine anesthetic (other agents like isoflurane, halothane give falsely low IOP)

• Opthalmoscopy (disc)

• Refraction (retinoscopy)

■ Corneal diameter (horizontal and vertical)

What is goniotomy and trabeculotomy?

"Goniotomy and trabeculotomy are surgical operations for congenital glaucoma."

Treatment options for congenital glaucoma

1. Goniotomy

• Establish communication between AC and Schlemm's canal

• Indications

• Common conditions: primary congenital glaucoma, Sturge-Weber's syndrome, Lowe's syndrome

• Requires clear cornea

• Incision made at superficial layer of meshwork, midpoint of trabecular band (midpoint of Schwalbe's line and scleral spur)

• Each sweep for 120 degrees,

• Iris should drop posteriorly

• Repeat from opposite side

• Good initial results (85% success)

• However, 40% need re-operation

2. Trabeculotomy

• Establish communication between AC and Schlemm's canal by removal of portion of trabecular meshwork (goniotomy ab externo)

• Indications

• Common conditions: juvenile glaucoma, Axenfeld's anomaly, Peter's anomaly

• Poor corneal visibility

• Scleral flap fashioned, usually inferotemporal region (preserve superotemporal conjunctiva for trabeculectomy later)

• Radial incision made over Schlemm's canal until it is entered

• Check location of Schlemm's canal by threading 5/0 nylon into canal

• Trabeculotome inserted into canal and rotated into AC, tearing meshwork

• Withdraw trabeculotome and introduce in opposite direction

• Similar results as goniotomy but conjunctiva is violated

3. Trabeculodialysis

• Similar to goniotomy

• Usually for children with secondary glaucoma from inflammation (juvenile chronic arthritis)

• Differs from goniotomy in that knife cuts at Schwalbe's line

• Meshwork is pushed interiorly using flat side of blade and is disinserted from scleral spur

4. Trabeculectomy

• Needs mitomycin C/5 fluorouracil application

• Problems with trabeculectomy in children

• Difficulty in identifying limbus

• Higher rates of scarring and trabeculectomy failure

• Risk of endophthalmitis

5. Medical therapy

• Not very effective

• Compliance

• Toxicity, especially systemic toxicity (e.g. bradycardia and asthma with beta blockers)

• Side effects are usually very different from adults (e.g. failure to thrive, bed wetting, abnormal school behavior)

^■SL? What are the mesodermal dysgeneses?

"Mesodermal dysgeneses are a group of congenital disorders." "Which involves the cornea, iris and AC angle." "And frequently associated with congenital glaucoma."

Mesodermal dysgeneses and aniridia

CO Exam tips:

• Another name is iridocorneal dysgenesis Do not confuse with the iridocorneal endothelial syndromes (ICE)

• Aniridia is NOT part of the spectrum, but included in the table for comparison

• Remember that Wilm's tumor is associated with AR type of aniridia

Axenfeld's anomaly

Rieger's anomaly

Peter's anomaly

Aniridia

and syndrome

Inheritance • AD

• AD

AD

AD

AR (mental retardation)

Sporadic (Wilm's)

Iris • Posterior

• Posterior

Posterior

Aniridia

embryotoxon

embryotoxon

embryotoxon

• Iris strands

• Iris hypoplasia,

Iris hypoplasia,

corectopia, polycoria,

corectopia, polycoria,

ectropian uvea

ectropian uvea

Cornea

Corneal opacity

Corneal opacity

Keratoienticuiar

Keratoienticuiar

adhesions

adhesions

Corneal plana,

Corneal plana,

sclerocornea

Cataract

Others

Cataract

Cataract

Foveal hypoplasia Nystagmus Choroidal coloboma

Glaucoma • Glaucoma in 50%

Glaucoma in 50%

Glaucoma in 50%

Glaucoma in 50%

Systemic • None

Dental and facial malformations in Reiger's syndrome

None

Wilm's tumor in AR trait

^y- CliniCdl approach to mesodermal dysgenesis

"The most obvious abnormality is the presence of posterior embryotoxon." "There are also diffuse areas of iris atrophy, corectopia, ectropian uvea."

Look for

• Lenticular opacities — Anterior polar cataracts (Peter's)

• Keratoienticuiar adhesions (Peter's)

• Check fellow eye (bilateral condition)

• Check maxillary hypoplasia, teeth (hypodontla, microdontia)

This young patient has mesodermal dysgenesis."

I'll like to

• Perform gonioscopy

• Assess optic disc

• Look at the visual fields

• Assess the family members for similar condition

"The most obvious abnormality is the absence of iris..." Look for

• Corneal opacity, microcornea, sclerocornea

• Limbal dermoid

• Lenticular opacities

• Keratoienticular adhesions

• Check fellow eye (bilateral condition)

"This young patient has aniridia."

I'll like to

• Perform gonioscopy

• Check fundus (foveal and disc hypoplasia, choroidal coloboma)

• Assess the family members for similar condition

• If this is sporadic, need to refer to renal physician to exclude Wilm's tumor

Clinical approach to aniridia

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