Corneal edema in detail

1. 1AMITY UNIVERSITY GURGAON

2. Corneal edema
Rashad Ibn Muhammed
M.optom student
2nd sem
2AMITY UNIVERSITY GURGAON

3. CORNEAL HYDRATION
 Water content of cornea is 78% which is
highest of any connective tissue in body.
 If hydration becomes above 78% its
central thickness increases &
transparency reduces.
 Cornea is relatively in dehydrated state
for its transparency.
3AMITY UNIVERSITY GURGAON

4. Maintained by
A}Factors draw water in to the cornea:-
1) Swelling pressure of stromal matrix (
GAGs).
2) Intraocular pressure.
B} factors which prevent flow of water into
the cornea:-
1. Mechanical barriers.
2. Na+-K+ active pump of endothelium.
4AMITY UNIVERSITY GURGAON

5. Stromal swelling pressure
 Pressure exerted by corneal stromal
mainly GAGs is stromal pressure (SP).
 Sp is 60 mmHg, is a keystone of corneal
biophysics.
 Anionic charges on GAGs molecule
expands the tissue, draws fluid with
equal but negative pressure called
imbibation pressure.
5AMITY UNIVERSITY GURGAON

6. Barrier mechanism
• Both epithelium & endothelium acts as a
barrier for excessive flow of water &
diffusion of electrolytes into stroma.
• As compare to endothelium, epithelium
offers twice resistance.
• Endothelium allows diffusion of small
solutes like NaCl & urea, while
epithelium produces hyper tonicity of the
solution bathing the cornea.
6AMITY UNIVERSITY GURGAON

7. Na+- K+ pump
 Present in endothelium, several fold
more active than its epithelium
counterparts..
 It causes diffusion gradient for water.
 Na conc. in aqueous is more compare to
stroma, which draws water from the
stroma.
7AMITY UNIVERSITY GURGAON

8. EVAPORATION
 Evaporation of water from precorneal
tear film increases its osmolarity relative
to cornea.
 Hyper tonicity of tear film could draw
water from cornea.
 However this water loss is readily
replaced by aqueous, it results in only a
little corneal dehydration.
8AMITY UNIVERSITY GURGAON

9. EDEMA
 It is the condition in which the fluid
content is increases.
 Formerly known as dropsy or hydropsy
which means accumulation of excessive
fluid.
9AMITY UNIVERSITY GURGAON

10. 10AMITY UNIVERSITY GURGAON

11. Etiology
 PRIMARY
 SECONDARY
11AMITY UNIVERSITY GURGAON

12. Primary causes
A) Primary endothelial dystrophies:
dystrophies involving endothelium &
descemet’s membrane causes
symmetrical marked stromal edema
which is gradually progressive over a
period of years.
B) Primary endothelial dystrophy which
develop later in life are fuch’s
dystrophy.
12AMITY UNIVERSITY GURGAON

13. Primary Endothelial Dystrophy
 Congenital hereditary endothelial
dystrophy(CHED): characterised by diffuse
edema at birth or soon thereafter, without
significant anterior segment abnormalities.
 Posterior polymorphous dystrophy: B/L
vesicular or linear lesions at the level of
descemet’s membrane & endothelium is
present, it presents with congenital corneal
edema.
13AMITY UNIVERSITY GURGAON

14. FUCH’s dystrophy
 AD pattern of inheritance, Earliest
changes are limited To posterior cornea
& presents with central B/L asymmetrical
corneal Guttata.
 In fuch’s dystrophy endothelial cells
transform into fibroblast Like cells
capable of secreting collagen fibrils.
Contribute to BM thickening.
14AMITY UNIVERSITY GURGAON

15. 15AMITY UNIVERSITY GURGAON

16.  Progressive endothelial decompensation
leads to stromal & epithelial edema.
 Fluid in the stroma permeates the
epithelial layer causes microcystic
epithelial edema.
 Individual epithelial cells burst,
intercellular edema occurs & typical
blisters or bullae formed.
 These changes are confined to centre of
cornea initially. 16AMITY UNIVERSITY GURGAON

17. Bullous keratopathy
 It represents the terminal stage of severe or
Prolonged epithelial edema.
 In the affected area the epithelium is
steamy irregular & on its surface one or
more large bullae appears, raised in the
form of blebs.
17AMITY UNIVERSITY GURGAON

18. 18AMITY UNIVERSITY GURGAON

19. Secondary causes
 Mechanical trauma
 Glaucoma
 Contact lenses
 Metabolic disorders
AMITY UNIVERSITY GURGAON 19

20. [I] Mechanical trauma
1) Blunt non penetrating injury causes
edema by injury to endothelium, mostly it
is reversible.
2) Perforating injuries cause direct damage
to the cornea, IOFB in AC can cause
edema mainly in inferior periphery
where FB mainly settles.
3) Forceps delivery cause pressure on
globe, causes edema due to DM tear.
20AMITY UNIVERSITY GURGAON

21. 21AMITY UNIVERSITY GURGAON

22. 4) Noxious chemicals mainly alkalis which
penetrates cornea cause endothelium
damage.
5)Intraocular sx can cause acute
endothelial loss most notably in superior
& central cornea.
22AMITY UNIVERSITY GURGAON

23. 6) BROWN McLean syndrome:
peripheral edema with brown black
discolouration of underlying endothelium
seen in ICCE, ECCE, pars plana
vitrectomy.
7)Cold induced reversible corneal edema
has been reported in trigeminal nerve
dysfunction.
23AMITY UNIVERSITY GURGAON

24. 8) Certain systemic medications like
amantadine & cefaclor can cause
edema.
9) Lasers used for iridotomy can cause
focal corneal edema.
10) High altitude corneal decompensation
has been reported causing hypoxia
induced corneal edema.
24AMITY UNIVERSITY GURGAON

25. [ II ] GLAUCOMA
• Acute rise in IOP which exceeds swelling
pressure of stroma causes epithelial
edema.
• Hypoxic Endothelial decompensation
occurs due to diminished aqueous flow.
• When corneal endothelium is
compromised, edema occurs even @
lower level of IOP.
25AMITY UNIVERSITY GURGAON

26. 26AMITY UNIVERSITY GURGAON

27. [ III ] Contact lenses
• Most common cause of corneal edema is
prolonged use of contact lens.
• It is mainly due to insufficient supply of
oxygen to epithelium.
• Edema presents as microcystic epithelial
edema near the center of resting position
of the lens.
27AMITY UNIVERSITY GURGAON

28.  If allowed to continue, it‘ll cause stromal
edema, descemet’s membrane folds.
 Edema easily clears if contact lens is
removed.
 Even altering the fit of contact lens is
also successful in reducing edema if it
provides sufficient oxygen to the
epithelium.
 The response & recovery from edema is
independent of age. 28AMITY UNIVERSITY GURGAON

29. [IV] Metabolic disorders
 Some vague concepts suggested by
corneal edema occuring in some
metabolic conditions like myxedema.
 It has also seen in hypercholesterolemia.
 In malaria mainly in patients taking
mepacrine for its treatment, in this
condition edema is limited to basal layer
of epithelium & superficial layer of
stroma.
29AMITY UNIVERSITY GURGAON

30. Manifestations of edema
 Depends upon cause & degree of the
condition.
 Mild discomfort in conditions like fuch’s
dystrophy.
 Severe neuralgic pain is seen in Bullous
keratopathy.
 Colour haloes.
 Severe visual loss.
30AMITY UNIVERSITY GURGAON

31. Visual acuity
 Small amount of epithelial edema can
result in substantial reduction in visual
acuity.
 Although 70% stromal edema is
compatible with normal visual acuity.
 Decreased acuity is more severe in early
morning.
 IOP, iritis glaucoma & optic nerve
changes may contribute to reduced
acuity. 31AMITY UNIVERSITY GURGAON

32. Pain and discomfort
 As edema increases epithelium is
detached from basement membrane to
form bullae.
 This rupture of bullae causes severe
pain, photophobia, epiphora & narrowing
of palpebral fissure.
 Photophobia is due to light scattering in
the edematous cornea.
 Coloured haloes.
32AMITY UNIVERSITY GURGAON

33. Evaluation
 Slit lamp examination.
 Specular biomicroscopy.
 Pachymetry.
 Optical coherence tomography.
 Scheimpflug camera.
 Orbscan.
33AMITY UNIVERSITY GURGAON

34. Management
• In all cases high IOP, its control with
topical anti glaucoma drugs or systemic
CAE inhibitors are given.
• Even in moderately elevated IOP
patients control may significantly reduces
epithelial edema.
• If IOP remains elevated despite
maximum tolerated surgical intervention
must be considered.
34AMITY UNIVERSITY GURGAON

35. Local therapy
 Early morning reduced vision can be
improved by exposing eyes to warm air
eg: hair dryer.
 Topical application of hyper osmotic
agents like 5%NaCl solution or ointment
can reduce edema to an little extend.
 If inflammation is a contributory cause of
corneal edema topical application
steroids may be very helpful.
35AMITY UNIVERSITY GURGAON

36.  Therapeutic hydrophilic contact lens can
be used .
 If the aetiology of edema is not apparent
10 days course of topical steroids can
serve as diagnostic as well as
therapeutic purpose.
 In patients with early corneal
decompensation & mild edema a careful
refraction may improve vision.
36AMITY UNIVERSITY GURGAON

37. References
 Opthalmology-ak khurana 2nd edition page
no.142
 http://www.slideshare.net/KishoreKhade/corne
al-edema
 Ocular differential diagnosis ,9th edition .FH
Roy. page no.311-314
 Parsons diseases of the eye , 19th edition
,page no.186
 Cornea atlas 2nd edition, jack h palay,page no-
172-178
37AMITY UNIVERSITY GURGAON

38. THANKYOU
38AMITY UNIVERSITY GURGAON