medicine presentation

1. 1
Cornea & Sclera

2. 2
Cornea Gross anatomy

3. 3
Microscopic Anatomy

4. Anatomy
4
-five layers.
-Function and role of collagen fibers
compaction(regular arrangement
,avascularity and dehydration)
-Functions of cornea: major refractive
surface ,protection of intraocular
contents.
-Thickness & diameters:CCT 0.55mm ,
average diameter 11-12mm.
- Nutrition :perilimbal vessels , aqueous
humor and atmospheric air for oxygen.

5. Infective corneal disorders
5
-Viral keratitis :
Herpes simplex
Herpes Zoster
-Bacterial keratitis
-Fungal keratitis
-Acanthameba keratitis

6. Herpes Simplex Keratitis
6
-Type 1 HSV is the important cause of ocular
symptoms .
-Type 2 HSV is more common to cause genital
disease but can cause keratitis and chorioretinitis
in infants .
Infection can be : primary
-
secondary

7. HSV keratitis
Primary
7
As a viral infection it is associated with fever .
-
Vesicular rash
-
Follicular conjunctivitis .
-
Pre-auricular lymphadenopathy .
-
And can be asymptomatic .
-
-Corneal involvement is usually with punctate
epithelial damage ,and may not be involved .

8. HSV keratitis
Secondary
8
-Recurrent infections results from reactivation of the
the dormant virus in the dorsal root ganglion and
her in the trigeminal ganglion .
-Virus travels down in the nerves till it reaches the
final structures as the cornea .
-Usually occurs in a debilitated patients

9. 9

10. HSV keratitis
Secondary
10
-Dendritic epithelial ulcers usually heals without
scars .
-Stromal involvement : can lead to edema and
scaring that may require PKP
Uveitis
-
-Disciform keratitis : which is thought to be an
immunological reaction to the virus antigens .(
no epithelial ulceration )
-Necrotizing stromal keratitis : rare ,stromal
necrosis and melting , ant.Uveitis and corneal
scarring.

11. HSV treatment
11
Topical anti virals as :
-
Acyclovir (zovirax )
Idoxuridine
Vidarabine
Triflurothymidine
Avoid topical steroids if epithelial ulcer is
present .
-
Stromal keratitis needs cautious steroid use .
-

12. Herpes Zoster Ophthalmicus
12
-Caused by varicella –zoster virus the cause of
chickenpox
-The ophthalmic division of the trigeminal nerve
is involved .
-Ocular involvement is higher if the nasociliary
branch of the nerve is involved .(hutchinson
sign)
-Usually there is a prodromal phase and the
patient is unwell .

13. HZO
ophthalmic manifestations
13
-Usually preceded by vesicular rash at the area of
the trigeminal distribution
-Lid swelling
-Keratitis
-Iritis
-Secondary glaucoma

14. 14

15. 15

16. HZO treatment
16
-Systemic antiviral will reduce the chance of
post-herpetic neuralgia .
-Topical steroids and antiviral
-Glaucoma treatment if it occurred .
-Both HSV & HZO will cause corneal
anesthesia

17. 17
Bacterial keratitis

18. Protective factors of the
cornea
18
-Blinking
-Tears washing the debris
-FB entrapment by mucus
-Antimicrobial effect of the tears .
-Epithelium protective mechanism

19. Predisposing factors for bacterial
keratitis
19
-Dry eye
-Epithelial disturbance
-Contact lens wear
-Prolonged use of steroids

20. Causative Bacteria
20
-Staph .Epidermidis
-Staph .Aureus
-Strep.pneumoniae
-Coliforms
-Pseudomonas
-Hemophilus

21. Bacterial Keratitis
symptoms &signs
21
-Severe pain
-Redness
-Purulent discharge
-Ciliary injection
-Visual impairment
-Corneal infiltrate
-Hypopion

22. 22

23. Bacterial keratitis
management
23
-Culture & sensitivity
-Corneal scraps
-Gram stains
-Intensive topical AB
-If complications as corneal perforation happen
it may needs tissue adhesives and some
times urgent grafting .

24. Acanthameba Keratitis
24
A freshwater ameba is the causative factor .
-
Increased incidence in swimming with contact
lenses
-
- Non-nutrient agar with E-coli.
Very painful keratitis
-
-Treatment with chlorhexidine &
polyhexamethelene biguanide
-Grafting may be required

25. 25

26. Fungal Keratitis
26
-More common in worm climates
-Suspect it when :
No response to antibacterial
History of vegetable matter trauma
Prolonged use of steroids
-The corneal opacity is fluffy and satellite
lesions may be seen .
-Special(sabouraud agar) & prolonged cultures
Treatment with anti fungals
-

28. Corneal dystrophies
-Congenital, progressive, abnormal material accumulation
(cells are creating something that they shouldn’t be
creating) in one of the layers of the cornea which disrupts
the transparency of the cornea
-Rare inherited (usually autosomal dominant): its helpful to
ask about a family history since usually one of the parents
or both had it
-Non-inflammatory: symptoms usually present as halos due to
corneal haze, foreign body sensation or decrease in visual
acuity. The symptoms are chronic in nature
Even though they’re syndromes they do not affect other areas
of the body

29. Corneal dystrophies types:
-anterior of cornea
-Stromal
-Posterior of cornea

31. Corneal shape disorders
-Keratoconus : a form of corneal ectasia (dilatation) that
results in central corneal thinning and different degrees
of astigmatism
-Usually painless and progressive and appears during
puberty
-May be associated with ocular & systemic diseases
(vernal kertaoconjuctivitis, down’s syndrome, marfan’s
syndrome)
-Keratoglobus :disorder of the eye in which structural
changes within the cornea cause it to become
extremely thin and change to a more globular shape
than its normal gradual curve.

34. Central corneal degenerations
Band keratopathy :
is a corneal degeneration that is most often composed of
fine dust-like calcium deposits in the sub-epithelium,
Bowman’s layer and the anterior stroma. It is typically a
band-shaped, horizontal opacity that grows from the
peripheral cornea towards the central cornea

36. Band keratopathy
associations
Hypercalcemia
Chronic intraocular inflammation
Glaucoma

37. Band keratopathy presentation and
treatment
Discomfort
Visual loss
Treated by chemical chelation or eximer laser

39. Peripheral corneal degenerations
-Mooren”s ulcer : immunological painful periphral corneal
thinning. A type of keratitis (inflammation of the edge of
corne)
-Connective tissue disease associated as Rheumatoid
Arthritis
& Wegner granulomatosis.
-Treatment requires immunosuppressive treatment .

41. Arcus senalis
A lipid deposition that is separated from the limbus by
clear cornea ..
It may be a sign of hyperlipidemia .
No treatment is needed.

43. Corneal Grafting
A surgical procedure where a damaged or diseased cornea is replaced by
donated corneal tissue
Indications : Restore corneal clarity
Removal of infected cornea
Restore corneal regularity
Highly privileged avascular tissue
HLA typing may help to increase success rate .
Contraindications:
-in an eye that has no perception of light and is not painful or would not
respond to other treatments for pain relief,
in an eye which is phthisical (end stage ocular response to injury) and will
not recover function

46. Corneal grafting
technique
Recipient preparation
Donor preparation
Suturing
Follow up
Complication & treatment .
-Rejection
-Glaucoma
-High astigmatism

47. Refractive surgeries
Will be discussed in the Optics & Refraction secession

48. Episcleritis
-Inflammation of the episclera ,the superficial layer of the
sclera
-Rarely associated with systemic diseases
-Usually cause mild discomfort
-Self limiting and may respond to topical anti-
inflammatory .

50. Scleritis
-More serious and severe disease
-Usually associated with connective tissue diseases as
RA
-Can be ischemic and inflammatory
-Usually shows a swollen red areas that can be diffuse or
focal
-Can be anterior and posterior .

53. Scleritis
complications
Scleromalacia ( thinning of the sclera )
Keratitis
Uveitis
Cataract
Glaucoma

54. Scleritis
treatment
High dose steroids
Immunosuppressive agents .
Treatment of complications .

55. Thank you