The document provides information about the sclera, including its structure, thickness, apertures, nerve supply, inflammation conditions like episcleritis and scleritis, and other related topics. The sclera forms the posterior five-sixths of the outer fibrous tunic of the eyeball. It varies in thickness from 1mm posteriorly to 0.3mm at the muscle insertions. It contains three layers and is pierced by blood vessels and nerves. Inflammation of the sclera can cause episcleritis or scleritis, with the latter being a more serious condition sometimes associated with underlying systemic diseases.

1. Sclera
6th semester mbbs
Nischal Shrestha
8/14/2019 Nischal Shrestha 1

2. 8/14/2019 Nischal Shrestha 2

3. 8/14/2019 Nischal Shrestha 3

4. 8/14/2019 Nischal Shrestha 4

5. • Sclera forms posterior 5/6th opaque part of the external fibrous tunic of eyeball.
• Its whole outer surface is covered by Tenon’s capsule.
• In the anterior part , it is also covered by bulbar conjunctiva.
• Its inner surface lies in contact with choroid with a potential suprachoroidal space in between .
• In its anterior most part near limbus there is furrow which encloses the canal of schlemm.
8/14/2019 Nischal Shrestha 5

6. • Thickness: thin in children than adults. And females < males
• It is thickest posteriorly (1mm)and gradually becomes thin anteriorly.
• It is thinnest at the insertion of extraocular muscles (0.3 mm)
• Lamina cribrosa is a sieve-like sclera from which fibres of optic nerve pass.
• Sclera is thinnest at posterior to the attachment of superior rectus muscle.
8/14/2019 Nischal Shrestha 6

7. • Sclera is pierced by 3 sets of apertures (holes/gap):
1. Posterior aperture : situated around optic nerve and transmit long and short ciliary nerves and vessels.
2. Middle apertures (4 in number)are situated slightly posterior to the equator; through these pass the 4 vortex veins
(vena verticosae)
3. Anterior aperture are situated 3to4 mm away from limbus. Anterior ciliary vessels and branches from long ciliary
nerves pass through these.
8/14/2019 Nischal Shrestha 7

8. Microscopic structure
• Histologically, consists of 3 layers
1. Episcleral tissue: thin , dense vascularized layer of connective tissue which covers sclera proper. Fibroblasts ,
macrophages and lymphocytes are present here.
2. Sclera proper: avascular structure that contains collagen fibres.
3. Lamina fusca: innermost part which blends with suprachoroidal and supraciliary lamina of uveal tract. It is
brownish in color d/t presence of pigmented cells.
NERVE SUPPLY: supplied by branches from long ciliary nerves which pierce it 2-4 mm from limbus to form plexus.
8/14/2019 Nischal Shrestha 8

9. Inflammation of sclera
1. Episcleritis
2. scleritis
8/14/2019 Nischal Shrestha 9

10. Episcleritis
• Benign recurrent inflammation of episclera, involving the overlying Tenon’s capsule but not the underlying sclera.
• Affects young adults, women affected twice than men.
• Etiology :
idiopathic Systemic disease Hypersensitivity reaction infections
-Gout
-Psoriasis
-Rosacea
-Connective tissue
disorder
Endogenous tubercular
or streptococcal toxins
Herpes zoster virus
Syphilis
TB
Lyme disease
8/14/2019 Nischal Shrestha 10

11. Pathology
• There occurs localized lymphocytic infiltration of episcleral tissue associated with edema and congestion of overlying
Tenon’s capsule and conjunctiva.
8/14/2019 Nischal Shrestha 11

12. c/f
• Redness
• Mild ocular discomfort as gritty, burning or foreign body sensation
• Rarely mild photophobia and lacrimation
• Marked pain is absent
Symptoms
8/14/2019 Nischal Shrestha 12

13. Signs
• On examination, 2 clinical types of episcleritis may be recognized.
1. Simple episcleritis: characterized by sectorial (occasionally diffuse) inflammation of episclera. The engorged
episcleral vessels are large and run in radial direction beneath conjunctiva.
2. Nodular episcleritis: characterized by pink or purple flat nodule, usually situated 2-3 mm away from limbus. The
nodule is firm, tender ,can be moved separately from sclera and overlying conjunctiva also moves freely.
8/14/2019 Nischal Shrestha 13

14. 8/14/2019 Nischal Shrestha 14

15. Clinical course
• Limited course of 1o days to 3 weeks and resolves spontaneously.
• Recurrences are common.
• Rarely ,fleeting type of disease (episcleritis periodica) may occur. (fleeting= lasting for very short time)
8/14/2019 Nischal Shrestha 15

16. t/t
•
NSAIDs Artificial tears Cold compression Mild corticosteroid drops
Applied to closed lids
offer relief
Fluorometholone 2-3 hrly,
resolves it within a few days
0.5% carboxy
methyl cellulose
topical systemic
0.3%
ketorolac In recurrent cases,
e.g. indomethacin
8/14/2019 Nischal Shrestha 16

17. 8/14/2019 Nischal Shrestha 17

18. Scleritis
• Inflammation of the sclera proper.
• Comparatively serious disease which may cause visual impairment and even loss of eye if untreated.
• Incidence is much less than that of episcleritis.
• Usually occurs in elderly (40-70 years) involving female more than male.
8/14/2019 Nischal Shrestha 18

19. Etiology
• 50% cases are associated with some systemic diseases, most common being connective tissue diseases.
• Common conditions are:
1. Autoimmune collagen disorders, esp. rheumatoid arthritis, the most common association. About 0.5 % of pt. suffering from RA develop scleritis,
other disorders are Wegener’s granulomatosis, polyarteritis nodosa (PAN), SLE and ankylosing spondylitis.
2. Metabolic disorders like gout & thyrotoxicosis.
3. Some infections like herpes zoster ophthalmicus, chronic staph and strep infection
4. Granulomatosis diseases like TB, syphilis, leprosy , sarcoidosis
5. Irradiation, chemical burns, rosacea
6. Surgically induced scleritis (SIS), it occurs within 6 months postoperatively
7. Idiopathic. In many cases of scleritis, cause is unknown.
[nonpyogenic scleritis causes = TB, syphilis, leprosy]
8/14/2019 Nischal Shrestha 19

20. Pathology
• Histological changes are that of chronic granulomatous disorder.
• Fibrinoid necrosis, destruction of collagen together with infiltration of PMNs, lymphocytes, plasma cells &
macrophages.
• The granuloma is surrounded by multinucleated epithelioid giant cells
• vasculitis
8/14/2019 Nischal Shrestha 20

21. 8/14/2019 Nischal Shrestha 21

22. c/f
• Symptoms
- Pain :moderate to severe pain which is deep and boring type and wakes the patient early in morning . Ocular pain
radiates to jaw and temple.
- Redness may be localized or diffuse
- Photophobia and lacrimation
- Diminution of vision
8/14/2019 Nischal Shrestha 22

23. Signs
1. Non –necrotizing anterior diffuse scleritis:
- It is the commonest variety
- Widespread inflammation involving a quadrant (sector) or more of anterior
sclera
- Involved area is raised and pink to purple in color
8/14/2019 Nischal Shrestha 23

24. 2. Non –necrotizing anterior nodular scleritis:
- Characterized by 1 or 2 hard, purplish elevated immovable scleral nodules (in
contrast to episcleritis , where it is movable), usually situated near limbus.
- Sometimes , nodules are arranged in a ring around limbus (annular scleritis)
8/14/2019 Nischal Shrestha 24

25. 3. Anterior necrotizing scleritis with inflammation:
- It is acute severe form of scleritis
- Characterised by intense localized inflammation associated with areas of infarction d/t
vasculitis.
- The affected necrosed area is thinned out and sclera becomes transparent and ectatic with
uveal tissue shining through it.
- Usually associated with anterior uveitis.
8/14/2019 Nischal Shrestha 25

26. 4. Anterior necrotizing scleritis w/o inflammation (scleromalacia perforans):
- Typically occurs in elderly females usually suffering from long standing RA.
- Characterised by development of yellowish patch of melting sclera (d/t obliteration of arterial supply)
- Melting sclera with overlying episclera and conjunctiva completely separates from surrounding normal sclera. 
becomes dead white eventually absorbs leaving behind it a large punched out area of thin sclera through which
uveal tissue shines.
- Spontaneous perforation is rare.
- t/t is ineffective!!!
8/14/2019 Nischal Shrestha 26

27. 8/14/2019 Nischal Shrestha 27

28. 5. Posterior scleritis:
- Inflammation involving sclera behind equator
- The condition is frequently misdiagnosed
- Characterized by features of associated inflammation of adjacent structures, which include: exudative retinal
detachment, macular edema, proptosis and limitation of ocular movements.
8/14/2019 Nischal Shrestha 28

29. 6. Infectious scleritis
• If purulent, suspect infectious
• Signs:
- Formation of fistula
- Painful nodules
- Conjunctival and scleral ulcers
8/14/2019 Nischal Shrestha 29

30. Complications
• Mostly with necrotizing
• Includes:
- Sclerosing keratitis
- Keratolysis
- Complicated cataract
- Secondary glaucoma
8/14/2019 Nischal Shrestha 30

31. 8/14/2019 Nischal Shrestha 31

32. t/t
•
Non-infectious
infectious
Antimicrobial both topical
and oral
Don’t give steroids
Surgical debridement
Non-necrotizing necrotizing
Topical steroid Topical steroid
Systemic
indomethacin 75mg
BD
Oral steroid
Scleral patch graft
Immunosuppressive like methotrexate or
cyclophosphamide in non responsive cases
No subconjunctival steroid
8/14/2019 Nischal Shrestha 32

33. Blue sclera
• Asymptomatic condition
• Generalized blue discoloration of sclera d/t thinning
• It is typically associated with osteogenesis imperfecta.
• Other causes are:
- Marfan’s syndrome
- Ehler –Danlos syndrome
- Buphthalmos
- High myopia
8/14/2019 Nischal Shrestha 33

34. Staphyloma
• Localised bulging of weak and thin outer tunic of eyeball (cornea or sclera), lined by uveal tissue which shines
through the thinned out fibrous coat.
• Types:
1. Anterior
2. Intercalary
3. Ciliary
4. Equatorial
5. Posterior
8/14/2019 Nischal Shrestha 34

35. 8/14/2019 Nischal Shrestha 35

36. Anterior staphyloma
• An ectasia of pseudocornea (the scar formed from organised exudates and fibrous tissue covered with epithelium)
which results after total sloughing of cornea, with iris plastered behind it is called anterior staphyloma.
8/14/2019 Nischal Shrestha 36

37. Intercalary staphyloma
• localised bulge in limbal area lined by root of iris
• Treatment consists of localised staphylectomy under heavy doses of oral steroids
8/14/2019 Nischal Shrestha 37

38. Ciliary staphyloma
• it is the bulge of weak sclera lined by ciliary body.
• It occurs about 2–3 mm away from the limbus
• Its common causes are thinning of sclera following perforating injury, scleritis and absolute glaucoma. ( episcleritis does
not cause this)
8/14/2019 Nischal Shrestha 38

39. Equatorial staphyloma
• It results due to bulge of sclera lined by the choroid in the equatorial region
• Its causes are scleritis and degeneration of sclera in pathological myopia
• Occurs more commonly at the regions of sclera which are perforated by vortex veins
8/14/2019 Nischal Shrestha 39

40. Posterior staphyloma
• It refers to bulge of weak sclera lined by the choroid behind the equator
• Here again the common causes are pathological myopia, posterior scleritis and perforating injuries.
8/14/2019 Nischal Shrestha 40