Childhood Glaucoma ✅ Flashcards
Is childhood glaucoma common?
No, it is rare
Why is childhood glaucoma significant?
It is a potentially blinding condition
What is childhood glaucoma characterised by?
Raised IOP and optic disc cupping
What is the optic cup?
The pale central area of the optic disc
What produces the optic cup?
In the normal optic nerve head, the retinal ganglion cell (RGC) axons are concentrated around the circumference of the optic disc, leaving a pale central area relatively devoid of axons
What happens to the optic cup in glaucoma?
The relative size of the optic cup (cup:disc ratio) gradually enlarges
Why does the cup:disc ratio enlarge in glaucoma?
The raised IOP causes retinal ganglion cell death, so the number of axons passing through the optic nerve head opening reduces
What will uncontrolled glaucoma lead to clinically?
Peripheral visual field loss
What is the problem with the presentation of uncontrolled glaucoma?
Peripheral visual field loss is difficult to detect in children
How does the presentation of glaucoma differ to that of optic neuritis or optic atrophy?
The optic neuropathy of glaucoma is not characterised by the early loss of visual acuity or colour vision that is seen with optic neuritis or optic atrophy
Why do you not get early loss of visual acuity or colour vision in glaucoma?
Because the RGCs serving the macula are the last to be damaged
What is the normal intra-ocular pressure in children?
6-18mmHg
In what setting can intra-ocular pressure in children be measured?
In eye clinic
What causes raised IOP?
Impaired aqueous outflow through the trabecular meshwork
What will happen with raised IOP in children under 3?
It will result in globe expansion (buphthalmos)
Why will raised IOP lead to globe expansion in children under 3?
Because they have low scleral rigidity
What does the increase in axial length in globe expansion caused by raised IOP in under 3’s lead to?
A shift towards myopia (or loss of hypermetropia) and an increasing corneal diameter
What is the normal corneal diameter?
11mm
Why does primary congenital glaucoma present?
Within the first year of life
Is primary congenital glaucoma unilateral or bilateral?
Usually bilateral
What does primary congenital glaucoma result from?
Abnormal development of the drainage angle
What is the incidence of primary congenital glaucoma?
1/10,000 live births
What are the majority of causes of primary congenital glaucoma due to?
A gene mutation in the CYP1B1 gene
What happens in primary congenital glaucoma?
The globe enlarges due to the raised pressure, and splits occur in the deeper layers of the cornea, leading to photophobia and corneal opacification
What are the splits in the deeper layers of the cornea in primary congenital glaucoma called?
Haab’s striae
What is the treatment for primary congenital glaucoma?
Early surgical division of the abnormal ‘Balkan membrane’ (which obstructs fluid flow to the drainage angle)
What are the causes of secondary glaucoma?
- Anomalies of the anterior segment
- Sturge-Weber syndrome
- Following congenital cataract surgery
- Topical, inhaled, or oral steroid therapy
Give an example of an anomaly of the anterior segment?
Aniridia
How can Sturge-Weber syndrome lead to secondary glaucoma?
If the capillary malformation involves the eyelids, the episcleral venous pressure may be raised, reducing aqueous outflow and causing glaucoma in 50% of cases
What is the lifetime risk of secondary glaucoma following cataract surgery?
30%
Why can glaucoma develop following cataract surgery?
Possibly due to the release of vitreous derived factors or inflammatory cells into the drainage angle in infancy
How can topical, inhaled, or oral steroid therapy lead to glaucoma?
Due to the increased accumulation of glycosaminoglycans or trabecular meshwork-induce bile glucocorticoid response protein (TIGR) in the trabecular meshwork
