L6: Opaque eye pt II

Describe the anatomy of the lens

What are the clinical signs of lens instability

• Decreased transparency

• Phacodonesis

• Iridodonesis

• Aphakic crescent

Define phacodonesis

Wobbly lens

Define Iridodonesis

Wobbly iris

Define aphakic crescent

Clear crescent shape in the pupil where the lens has moved out of the way

(seeing directly though pupil into vitreous)

How do you diagnose lens instability

• clinical appearance

• Tonometry

  • Intraocular pressure may be high

What are the causes of primary lens luxation

Genetic mutation

esp in terrier breeds

What are the causes of secondary lens luxation

• Chronic uveitis (zonular degradation)

• Glaucoma (stretches zonules)

• Cataract (secondary uveitis)

• Trauma (mechanical rupture, uveitis)

• Intraocular neoplasm

How do you treat lens luxation

Surgical emergency

Describe aqueous humour flow in the anterior chamber

Ciliary body→ pupil → iridocorneal angle (drainage angle)

Describe blood aqueous barrier in the anterior chamber

• Epithelial barrier located in the ciliary body and iris which separates the eye from the systemic circulation

• Becomes leaky when inflamed

  • Uveitis, trauma, neoplasia

What are the clinical signs of uveitis

• Aqueous humour flare

• Hyphaema

• Hypopyon

How do you diagnose uveitis

• clinical signs

• Tonometry

What are some diseases that cause vitreal opacities

• Liquefaction

• persistent hyaloid artery

• PHTVL/PHPV

• Vitreal degeneration

• Haemorrhage

• Vitritis

• Asteroid hyalosis

• Synchysis scintillans

What does this show

persistent hyaloid artery

What does this show

PHTVL/PHPV

What does this show

vitreal degeneration

What does this show

haemorrhage

What does this show

vitritis

What does this show

Asteroid hyalosis

What is the anatomy and physiology of glaucoma

What is the anatomy and physiology of glaucoma

Anatomy and Physiology of Glaucoma: Glaucoma is a group of eye conditions that damage the optic nerve, often due to increased pressure in the eye. This can lead to vision loss and blindness if not treated. The main structures involved are the optic nerve, the trabecular meshwork, and the drainage angle in the eye.

What are the acute clinical signs of glaucoma

• Corneal oedema

• Episcleral congestion

• Conjunctival hyperaemia

• Epiphora

• Mydriasis

• Aqueous flare

• Absent menace

What are the chronic clinical signs of glaucoma

• Signs of acute glaucoma

• Optic nerve head cupping

• Haab’s stria

• Buphthalmia

• Lens subluxation/luxation

What are the diagnostic tests for glaucoma

• Tonometry

  • interpret alongside clinical signs

• Gonioscopy

What are the types of glaucoma

• Congenital

• primary

• secondary

What are the types of primary glaucoma

• Open angle

• Closed angle

How do you manage glaucoma

Medical

• Carbonic anhydrase inhibitors

• Prostaglandin analogues

• Adrenergic agents

  • B blockers and alpha agonists

• Cholinergic agonists

• Osmotic agents

surgical

• Referral level

• Select patients

If there is corneal oedema can you see into the eye?

no, so remember other diagnostic tests like tonometry

If you see something wobbling inside the eye what should you think

Lens luxation

What does this show

Lens luxation ± glaucoma