Common Conditions of the Eye

Question 1

What is the consequence of the bony orbit having very thin walls?

Answer 1

Can get herniation of contents into surrounding sinuses usually maxilla - due to fractures
Muscles are tethered so eye does not move

Question 2

How is a blow out fracture diagnosed?

Answer 2

CT scan - teardrop sign

Question 3

What does orbital fat hypertrophy lead to?

Answer 3

Leads to staring appearance - proptosis
Can be due to thyroid diseases
Can also cause scleral show

Question 4

What can infection spread from emissary veins to cavernous sinus cause?

Answer 4

Can lead to cavernous sinus thrombosis as travelled from danger area of face
CN4,5,6 affected and causes swelling
Blindness can be caused due to lack of blood supply

Question 5

What are the symptoms of CN VI palsy?

Answer 5

LR affected as abducent nerve
Eye can adduct but cant abduct

Question 6

What are the symptoms of CN III palsy?

Answer 6

Eyelid drooping and all muscles affected except SO and LR
Pupillary reflex is tested - large and unreactive
Ptosis

Question 7

What are the symptoms of CN IV palsy?

Answer 7

SO affected as trochlear nerve
Eye shoots up as result
As adducting the IR is over reacting
SO muscle is paralysed

Question 8

What can blunt trauma to the eye cause?

Answer 8

Peripheral retina to tear
Vitreous gel gets liquefied
Liquid vitreous pushes through retinal tear which detaches it

Question 9

What is coloboma?

Answer 9

Congenital malformation of eye causing defects in iris, retina and optic disc

Question 10

What is the conjunctivae?

Answer 10

Thin vascular membrane covering inner surface of eyelids and loops back over sclera
Does not cover the cornea

Question 11

Describe conjunctivitis

Answer 11

Self limiting bacterial or viral infection of conjunctivae
Red, watering eye with discharge
No loss of vision as long as the infection does not spread to cornea

Question 12

What is the treatment for conjunctivitis?

Answer 12

Antibiotic eye drops if likely to be bacterial

Question 13

What might cause drooping eyelid (ptosis)?

Answer 13

CNIII dystrophy or paralysis

Question 14

What could cause inability to close eyelid?

Answer 14

CN VII facial nerve palsy
Check other facial nerves
Causes extreme drying and conjunctivitis - ulceration of cornea

Question 15

Describe a stye/ hordeolum

Answer 15

External stye - hordeolum externum
Infection of hair follicle of eyelash
Internal stye - hordeolum internum
Blockage and infection of Meibomian gland

Question 16

What is the treatment for a stye?

Answer 16

Warm compress, eyelid hygiene and may need surgical incision and curettage

Question 17

What do corneal pathologies lead to?

Answer 17

Opacification of cornea
Can be treated with keratoplasty

Question 18

Describe corneal ulcer

Answer 18

Inflammatory pathology - infectious and needs aggressive management to prevent spread and scarring
If non-infectious then can be trauma, degeneration or dystrophy

Question 19

What are corneal dystrophies?

Answer 19

Non-inflammatory - bilateral, opacifying, mostly genetically determined and can be due to accumulation of substances in cornea

Question 20

What is the clinical presentation of corneal dystrophies?

Answer 20

First to fourth decade
Most commonly decreased vision
Starts in one layer of cornea and spreads to others

Question 21

Describe the occurrence of cataracts in population

Answer 21

30% of people over 65 have some opacity
Each year 225000 new cases
330000 cases operated a year

Question 22

How do cataracts develop?

Answer 22

Older fibres are never shed so compacted in the middle
No blood supply to lens so depends on diffusion for nutrition
Absorbs harmful UV rays to prevent damage to retina but damages lens so gets opacification

Question 23

What are immature cataracts?

Answer 23

Seen as spoke like opacities and only cause issues in dull light where pupil naturally dilates so opacities stop light into retina

Question 24

What is a mature cataract?

Answer 24

No light is let into the retina and nearly blind

Question 25

What could cause a cataract?

Answer 25

Complication of steroid eye drops in anterior part of lens, blunt trauma or childhood - sutural and zonular (opacification in certain zones in utero)

Question 26

Describe the management for cataracts

Answer 26

Eye drops do not treat Surgery - small incision so lens capsule opened and cataract lens is removed by emulsification then plastic lens placed (PCIOL)

Question 27

What is PCIOL?

Answer 27

Posterior Chamber Intra Ocular Lens Lens implant after cataract surgery

Question 28

What is the 2nd most commonest cause of blindness?

Answer 28

Glaucoma

Question 29

What is glaucoma?

Answer 29

Raised intraocular pressure Most common form - primary open angle glaucoma Can be asymptomatic for long period

Question 30

What are the consequences of raised IOP?

Answer 30

Pressure on nerve fibres on surface of retina so they die out and cause visual field defects On ophthalmoscopy - optic disc is unhealthy, pale and cupped Ultimately gets blindness

Question 31

What are the triad signs of glaucoma?

Answer 31

Raised IOP Visual field defects Optic disc changes on ophthalmoscopy

Question 32

Describe the management of primary open angle glaucoma

Answer 32

Eye drops to decrease IOP - prostaglandins, beta blockers, carbonic anhydrase inhibitors Laser trabeculoplasty Trabeculectomy surgery

Question 33

Describe the presentation of angle closure glaucoma

Answer 33

Sudden onset, painful, vision blurred, headaches, red eye, cornea often opaque, AC shallow, angle closed, pupil mid-dilated and IOP severely raised

Question 34

What are the mechanisms causing angle close?

Answer 34

Functional block in small eye - large lens Mid-dilated pupil - periphery of iris crowds angle and outflow obstructed Iris sticks of pupillary border prevents reaching of AC - iris balloons anteriorly and obstructs angle

Question 35

How can IOP be decreased for management of acute episode of angle closure glaucoma?

Answer 35

IV infusion with or without oral therapy - carbonic anhydrase inhibitors Analgesics and antiemetics Constrictor eye drops - pilocarpine Beta blockers - timolol is contraindicated Steroid eye drops - dexamethasone

Question 36

What surgery is given for management of acute episode of angle closure glaucoma?

Answer 36

Iridotomy laser of both eyes to bypass the blockage

Question 37

In open angle glaucoma what increases IOP?

Answer 37

Trabecular meshwork is blocked so leads to gradual and painless build up of IOP This is POAG

Question 37

What are the types of uveitis?

Answer 37

Anterior - iris or with/without ciliary body is inflamed Intermediate - ciliary body inflamed Posterior - choroid inflamed

Question 38

In angle closed glaucoma what increases IOP?

Answer 38

Event of predisposed eye leads to peripheral iris blocking the angle therefor AH can't drain Sudden increase in IOP so sudden red and severe pain Usually emergency

Question 39

What are the causes of uveitis?

Answer 39

Isolated illness, non-infectious autoimmune cause, infectious and associated with systemic diseases (ankylosing spondylosis)

Question 40

Describe pathophysiology of uveitis

Answer 40

Inflamed anterior uvea (iris) leaks plasma and white blood cells into AH Hazy anterior chamber and cells deposited at back of cornea Red, painful and vision loss Cell in AC may settle inferiorly - hypopyon