Opthalmology

Question 1

Preorbital Cellulits

Answer 1

An eyelid and skin infection in front of the orbital septum where the inflammation and infection remains confined to the soft tissue layers superficial to the orbital septum. - It is important to differentiate this from orbital cellulitis which is where the muscles of the orbit are affected and is usually due to bacterial sinusitis and is a life threatening condition

Question 2

Risk Factors for Preorbital Cellulits

Answer 2

Boys - Previous sinus infection - Lack of Hib infection - Recent eyelid injury

Question 3

Symptoms of Preorbital Cellulits

Answer 3

Swelling, redness and hot skin around the eyelids and the eye

Question 4

Ix for Preorbital Cellulits

Answer 4

Clinical examination - CT sinus and orbits with contrast will help to differentiate between periorbital and orbital

Question 5

Managment of Preorbital Cellulits

Answer 5

Empirical antibiotics either an inpatient or outpatient depending on severity e.g Cefotaxime/Clindamycin

Question 6

Squint

Answer 6

Also known as strabismus, this is misalignment of the eyes - When the eyes are not aligned, the images on the retina will not match and the patient will experience double vision

Question 7

Pathophysiology of Squint

Answer 7

In childhood, as the eyes have not fully established their connections with the brain, the brain copes with this by reducing the signal from the less dominant eyes. - This results in one dominant eye and one eye which will be ignored (lazy eye)

Question 8

What happens to untreated Squint

Answer 8

When left untreated, this lazy eye becomes more and more disconnected from the brain and the problem worses - this is known as amblyopia

Question 9

Name different types of Squint

Answer 9

Concomitant, Esotropia, Exotropia. Hypertropia. Hypotropia

Question 10

Concomitant Squint

Answer 10

differences in the control of the extra ocular muscles

Question 11

Esotropia Squint

Answer 11

• inward position squint -> affected eye deviated towards the nose

Question 12

Exotropia Squint

Answer 12

outward position quint -> affected eye deviated towards the ear

Question 13

Hypertropia Squint

Answer 13

upward moving affected eye

Question 14

Hypotropia Squint

Answer 14

downward moving affected eye

Question 15

Aetiology of Squint

Answer 15

Idiopathic - Hydrocephalus - Cerebral palsy - Space occupying lesion e.g retinoblastoma - Trauma

Question 16

Ix for Squint

Answer 16

gations - Eye movements and inspection - Fundoscopy - Visual acuity - Hrischberg’s test - Cover test

Question 17

What is Hrischberg’s Test?

Answer 17

: shine a pen torch at the patient from 1 metre away, when they look at it, observe the reflection of the light source on their cornea - this should be central and symmetrical.

Question 18

What is the Cover Test?

Answer 18

cover one eye and ask the patient to focus on an object in front of them. Move the cover to the opposite eye and watch the movement of the other eye and observe for any exo/esotropia.

Question 19

Managment of Squint must start before the age of ____

Answer 19

e 8 years of age

Question 20

Management of Squint

Answer 20

Occlusive patch can be used to cover the good eye and force the weak eye to develop - Atropine drops can be used in the good eye causing blurry vision and again forcing the bad eye to develop.