Ocular anatomy

Question 1

How to image the eye

Answer 1

Plain film and x-rays look at fractures and metallic foreign bodies

CT used for trauma (bone anatomy) and mass lesions

MRI used for inflammatory changes and lesions

Question 2

How do you identify a T2 weighted image?

Answer 2

Water and fat are white but soft tissue is darker/grey

Question 3

Corneal laceration

Answer 3

Loss of volume in anterior chamber

Question 4

Ruptured globe

Answer 4

Open globe injury with loss of volume and haemorrhage

Question 5

Penetrating globe injury

Answer 5

Foreign body with loss of globe volume

Question 6

post vs pre septal cellulitis

Answer 6

septum is a thin, fibrous membrane between eye lids and orbit - infections anterior to septal are preseptal; and infections posterior to septum are postseptal

Question 7

Cellulitis complications

Answer 7

• Ethmoid sinusitis - infection crosses lamina papyracea
• Can cause subperiosteal or orbital abscess
• Loss of vision
• Intercranial complications - cavernous sinus thrombosis, epidural abscess empyema, meningitis, brain abscess

Question 8

Orbital melanoma

Answer 8

• Most common primary intra-ocular malignancy
• US, CT, MRI, PET all diagnose and stage
• PET CT used to stage and identify metastases

Question 9

Acoustic neuroma/schwannoma

Answer 9

Sensorineural hearing loss and tinnitus
Benign tumours drom CN8
Solid mass