Anterior Eye 2 - Sclera and Episclera Flashcards
What is the sclera?
• Outer tough shell of the eye
- Protects the delicate structures inside
• Anteriorly it becomes cornea (limbus)
• Posteriorly it form optic nerve dural sheath
• It serves as a conduit for blood vessels and nerves
• It provides attachment points for extra-ocular muscles
• Weakly attached to underlying Choroid
• Outermost layer is called Episclera
• Heals poorly due to poor blood supply
What is the thickness of the sclera, and how does it look for children/jaundiced patients?
• Thickness ranges from 0.3 mm to 1.00mm
• Thickest at optic nerve and thinnest behind the insertion of muscles
• Sclera is white but can look blue in children because it is transparent
• Can also look yellow in jaundiced patient
What are the diseases of a sclera and episclera?
• Scleritis versus Episcleritis
• Scleritis is rare (0.08%), Episcleritis is not rare
• Anterior scleritis versus posterior scleritis
• Inflammation (local or manifestation of systemic disease)
• Systemic diseases such as Rheumatoid arthritis or Systemic Lupus Erythematosus.
• 57% of patient have a disease association
• More common in women and more prevalent in 4th-6th decade
• Trauma
What are the symptoms or scleritis?
• Pain, tearing or photophobia, ocular tenderness, decreased visual acuity.
- Pain is the most common symptom; it is the best indicator of active inflammation. - -Pain results from both direct stimulation and stretching of the nerve endings by the inflammation.
• Severe, penetrating pain that radiates to the forehead, brow, jaw, or sinuses
• Awakens the patient during the night
• Exacerbated by touch; extremely tender
• Only temporarily relieved by analgesics
• Often misdiagnosed with conjunctivitis
How is scleritis examined/diagnosed?
• This redness does not blanche after topical applications of routine sympathomimetic dilating agents (Phenylephrine 10% eye drops)
• Need to perform a full eye examination and refer for systemic work up
• It can cause severe keratitis, glaucoma, uveitis and cataract
• Ultrasound or CT useful in posterior sclertitis
What is Anterior scleritis types?
• Diffuse, nodular, necrotizing (either with perforation or non perforating)
• Red and painful eyes and vision can also be affected
What is scleritis prognosis and treatment?
• Prognosis depends on the underlying disease
• Chronic versus episodic
• Treatment usually requires oral immunosuppression combined with aggressive topical steroids
• Oral Non-steroidal anti-inflammatory drugs can also be useful (Ibuprofen)
• Surgery for perforation (very rare)
• Usually needs review by Rheumatologists as well
What is episcleritis?
• Usually a mild, self-limiting, recurrent disease
• Most cases are idiopathic, although up to one third have an underlying systemic condition (Rheumatoid arthritis and connective tissue disorders). Foreign bodies can also cause episcleritis
• Diffuse versus nodular
• Nodular more prolonged and painful than diffuse
• Diffuse episcleritis (84% of cases) is more common than nodular scleritis (16% of cases), and the mean age of all patients with episcleritis is 47.4 years
What the prognosis for episcleritis?
• Prognosis is good
• Self limiting disease
• The injection in episcleritis blanches with instillation of 10% phenylephrine ophthalmic drops, but not in scleritis
• Episcleritis can cause uveitis and raised IOP
• Diagnosis is clinical. Good history taking is essential
• Full eye examination
• Sometime requires blood tests if systemic association is suspected
What is episcleritis treatment?
• Nothing
• Lubrication
• Topical Steroid
• Topical NSAID (Acular)
• Systemic Steroid (rarely)
