Summary Neuro week 2

Week 2 – The eye

Anatomy of the eye & pathology

Anterior segment of the eye

- Everything anterior to the lens

 Cornea
 Anterior chamber with aqueous humour
 Iris
 Pupil
 Posterior chamber with aqueous humour
 Lens
 Ciliary bodies with ciliary processes
 Zonular fibres

- Accommodation of vision

 PNS stimulation from the PNS division of CN 3 > Contraction of the ciliary bodies > Decreased tension on the
Zonular fibres connected to the lens > Lens becomes thicker & more spherical > Near vision (Accommodation)
 Normally, the natural tension on the Zonular fibres > Lens thinner > Distant vision
 Lose the ability to accommodate & focus on near objects with age & older people therefore hold objects further
away in order to see

- Some anterior segment pathologies

Area of the eye affected Pathology

Eyelid - Chalazion
 Due to blockage of the Meibomian glands
- Hordeolum
 Due to blockage of the Meibomian glands
Conjunctiva - Viral
- Bacterial (Gonococcal)
- Allergic
 Giant papillae will be present on palpebral conjunctiva with eversion
of eyelid
Cornea - Corneal ulcers
 Bacterial
 Viral (HSV)
- Endothelial deposits in Wilsons disease
Anterior chamber of eye - Hyphaema (Blood in anterior chamber)
- Hypopyon (Pus in anterior chamber)
Lens - Cataract
 When lens protein becomes opaque therefore reducing vision
 Loss of red reflex occurs


Posterior segment of the eye

- Everything posterior to the lens

- Some posterior segment pathologies: