Sclera

Question 1

Where is the sclera?

Answer 1

It starts anteriorly at the limbus and terminates posteriorly at the optic nerve.
Makes up 5/6ths of the globe

Question 2

What are the 3 parts of the sclera from outer to inner?

Answer 2

Episclera
Substantia propria
Lamina fusca

Question 3

What is the Episclera?

Answer 3

Outermost point, thin, vascularised connective tissue found anterior to the sclera and posterior to the tenon capsule

Question 4

What is the substantia propria?

Answer 4

This is made up of irregularly arranged type 1 collagen fibres

Question 5

What is the lamina fusca?

Answer 5

This is composed of loosely arranged connective tissue and is separated from the choroid by the suprachoroidal space

Question 6

What innervates the anterior and posterior sclera?

Answer 6

Anterior - Long posterior ciliary nerves

posterior - short posterior ciliary nerves

Question 7

Define episcleritis?

Answer 7

This is inflammation of the Episclera, which is a common self limiting condition typically affecting middle aged females. Often idiopathic

Question 8

How long does simple episcleritis usually last?

Answer 8

Acute onset, peaks around 12-24 hours then slowly fades after a few days.
Often a localised triangular redness and discomfort.

Question 9

What is nodular episcleritis?

Answer 9

This is a less common form of episcleritis which has an insidious onset and a longer recovery time. Red eye and discomfort commonly seen, with tender vascular nodules often seen in the interpalpebral fissure.

Question 10

What is the most appropriate investigation for episcleritis?

Answer 10

Instillation of 10% phenylephrine blanches the redness in episcleritis.

Question 11

How is episcleritis managed?

Answer 11

Cool compress

Oral NSAIDs

Question 12

What is scleritis?

Answer 12

This is full thickness inflammation of the sclera which is commonly associated with certain autoimmune conditions.

Question 13

What conditions are associated with scleritis?

Answer 13

Rheumatoid arthritis
Relapsing polychondritis
Polyangiitis and granulomatosis
infection: herpes zoster, Lyme disease, syphilis

Question 14

What are the different types of anterior scleritis?

Answer 14

Diffuse (most common)
Nodular
Necrotising with inflammation
Scleromalacia perforans (necrotising without inflammation)

Question 15

What causes a blue sclera and list some conditions associated with it:

Answer 15

Blue sclera is a result of underlying uvea due to scleral thinning.

• Osteogenesis imperfecta
• Ehlers-Danlos syndrome

Question 16

What is the investigation and management for anterior scleritis?

Answer 16

Instillation of 10% phenylephrine does not cause blanching
Oral NSAIDs
Systemic steroids and immunomodulatory therapy for severe or necrotising scleritis

Question 17

What are the signs/symptoms of diffuse scleritis?

Answer 17

Most common
Dull pain radiating to forehead and jaw
Gradual onset of redness of the eye
Oedematous sclera that often resolve leaving a bluish tinge

Question 18

What is seen in nodular scleritis?

Answer 18

Redness, gradual onset of pain. Single or multiple erythematous tender nodules.

Question 19

What is necrotising scleritis?

Answer 19

This is the most severe form of anterior scleritis. It can result in vision loss and causes subacute, severe ocular pain, often radiating to jaw and forehead. Causes redness and lacrimation and can lead to white patches of scleral oedema that block the overlying Episclera and conjunctiva vasculatures, causing low perfusion - this is what leads to the necrosis of the scleral tissue.

Question 20

What is Scleromalacia perforans?

Answer 20

This is necrotising scleritis without the inflammation, and is commonly seen in patients who are elderly, with advanced RA.
It is characterised by an asymptomatic gradual onset of necrotic patches leading to scleral thinning and exposure of the underlying uvea.

Question 21

What are the features of posterior scleritis?

Answer 21

Severe pain 
Choroidal folds
retinal detachment
Diplopia and mild ptosis
Optic disc swelling and vision loss

Question 22

What investigations should be done for posterior scleritis?

Answer 22

B-scan USS shows increased scleral thickness and fluid accumulation in the sub-tenon space, giving rise to the characteristic T sign

Question 23

What is the management for posterior scleritis?

Answer 23

Oral NSAIDs and corticosteroids