cornea stricture and disorders in the eye

cornea stricture and disorders in the eye

1. 9/9/2022
1
CORNEA
STRUCTURE & DISORDERS
Sudeep Chaturvedi
MBBS; MS(Ophtho), Cert. Basics of Health Economics(WBI)
Consultant Ophthalmologist, Government Inst. of Medical S ciences, Greater Noida
Consultant Ophthalmologist Promhex Multispecialty Hospi tal, Greater Noida
Consultant Ophthalmologist GA One Med.Consult, Greater No ida
General Manager NTPC Ltd (CMO CC-Retd.)
EMAIL- [email protected]
The word cornea has come from “Kerato”.
The term “Kerato” in greek means horn or shield like.
Ancient Greek used to believe that cornea is derived
from same material like that of thinly sliced horn of
animal.

2. 9/9/2022
2
THECORNEA
9
The cornea is a transparent avascular
tissue with smooth, convex outer surface
and concave inner surface, which
resembles a small watch-glass.
9
Radius of curvature of sclera 12mm and
that of cornea is 8mm
9
It forms anterior 1/6
th
of the globe
9
To meet the diverse functional demands
the cornea must be:
- Transparent
- Refract light
- Sustain the intraocular pressure
- Provide a protective interface
DIMENSIONS
9
Microcornea:when HCD is less than 10mm
9
Macrocornea: when HCD is more than 13 mm

3. 9/9/2022
3
Shape :
- Prolate
Surface area:
- About 1.3 cm² (one-sixth of the globe)
9
Radius of curvature:
-Anterior surface – about 7.8
mm
- Post. Surface – about 6.5
mm
9
Refractive power: +43.1 D
9
Refractive index:1.376

4. 9/9/2022
4
COMPOSITION OF HUMAN CORNEA 9
Water: 78 %
9
Collagen: 15 %
of which:
Type-I : 50-55 % Type-III : 1 %
Type-IV : 8-10 %
Type-VI : 25-30 %
9
Other protein: 5 %
9
Keratan sulphate: 0.7 %
9
Condroitin/dermatan sulphate: 0.3 %
9
Hyaluronic acid:+
9
Salts: 1 %
STRUCTURE
TO REMEMBER
A- ANTERIOR EPITHELIUM
B- BOWMAN’S LAYER
C- CORNEAL STROMA
D- DESCEMET’S MEMBRANE
E- ENDOTHELIUM

5. 9/9/2022
5
DEVELOPMENT ANTERIOR EPITHELIUM DEVELOPS FROM
SURFACE ECTODERM
THE NEURAL CREST CELLS MIGRATE TOWARDS
SURFACE ECTODERM TO DEVELOP INTO
KERATOCYTES AND ENDODERM
Layers
Thickness
(in µm)
Composition
Epithelium (Ep) 50
Stratified
Squamous
Epithelium
Bowman's
Membrane (BM)
8-14
Compact layer of
unorganised
collagen fibres
Stroma (SP) 500
Orderly
arrangement of
collagen lamellae
with keratocytes
Descemet's
Membrane (DM)
10-12
Consists of
basement
membrane
materials
Endothelium (En) 5
single layer of
simple squamous
epithelium

6. 9/9/2022
6
EPITHELIUM: /
Stratified, squamous and
nonkeratinized
/
Three types of cells are seen a.
Superficial cells
b.
Wing cells
c.Basal cells
- Germinative layer of the
epithelium
-only epithelial layer with mitotic
activity
-
Adhesion is achieved by –
desmosomes And
hemidesmosomes
-
Desmosomes are tight
junctions between cells -
Hemidesmosomes are tight
junctions between cell and
basal lamina
-
- Langerhans cells (cells of
immune system) present
near periphery. They are
almost absent at central
cornea but aggregate in
response to infection
9
Epithelial Turnover: -Early studies suggested that the epithelium replac ed
approximately weekly by division of basal cells and the oldest
shed from the surface
-It is now recognized that the germinative region l ies at the limbus,
the stem cells, and cells migrate at a very slower rate (123
µm/week) to the center of the cornea which may be a s long as a
year

7. 9/9/2022
7
The XYZ hypothesis:
Thoft R. and Friend J.
(1983) proposed that both
limbal basal and corneal
basal cells are the source
for corneal epithelial cells,
and there is a balance
among division, migration
& shedding.
9
Bowman’s layer: (Ant. Limiting lamina) - Modified region of anterior stroma
- Acellular homogeneous zone
- 8 – 14 µm thick
- It delineates the anterior junction between cornea and lim bus
9
Compact arrangement of collagen gives it great
strength and relatively resistant to trauma both
mechanical and infective.

8. 9/9/2022
8
S
TROMA
: (S
UBSTANTIA PROPRIA
)
9
Stroma: (Substantia propria)
-About 500 µm thick (about 90% of
corneal thickness)
-Consists of regularly arranged
lamellae of collagen bundles, lie in
proteoglycan ground substance
with –
- 200 – 300 bundles – centrally
- 500 bundles – peripherally
- Small population of cells –
keratocytes present
-The keratocytes occupy 2.5 – 5 % of total
stromal volume and is responsible for synthesis
and maintaining of collagen & proteoglycan
substance of stroma.
-There are stellate processes extending for great
distance and frequent contacts are made with other
keratocytes in same horizontal plane forming
gap
junctions

9. 9/9/2022
9
D
ESCEMET
’
S
MEMBRANE : (P
OST
.
L
IMITING LAYER
)
L
- It is the basal lamina of
corneal endothelium
- First appears at 2nd month
of gestation and synthesis
continue throughout adult
life
Thickness
at birth :- 3 – 4 µm
at childhood :- about5µm
at adult :- 10 – 12 µm
-It is a strong resistant sheet
-It thickens with age and in some corneal
degenerative conditions
- The peripheral rim of DM is the internal
landmark of corneal limbus and also it is
the anterior limit of drainage angle,
called Schwalbe’ line
- This if too prominent is called posterior
Embryotoxan , condition in which a
thickened and anteriorly displaced
Schwalbe's line is visible on external
examination
L
Endothelium:
-It is a single layer of hexagonal,
cuboidal cells attached to the
posterior aspect of DM
-It is mesenchymal in origin
-Corneal endothelial cells
production is relatively fixed and
limited
-There is about 0.3% to 0.6%
loss per year
-Cell count keeps reducing with
age and trauma

10. 9/9/2022
10
Endothelial cells density
- If cells density falls below 500 cells/mm² corneal oedema devlops
and transparency reduced
Endothelium is rich in subcellular organeles –
-large number of mitochondria, both rough and smoot h endoplasmic
reticulum, free ribozomes, these reflects that endo thelium is extremely
active metabolically
Nutrition to endothelium:
-Endothelium gets its nutrition & O 9/from aqueous
-Essential nutrients (such as glucose & amino acids ) pass across
its surface to supply the cellular needs of all the corneal layers
-It maintains deturgescence of cornea through an act ive pump
mechanism
-When the hydration of the stroma is ~3.5mg H2O/mg dry tissue or
less, the stroma is relatively transparent

11. 9/9/2022
11
9
Endothelial Repair:
- Physical & chemical damage to endothelium results in
loss of cells
- Neighboring cells move over to fill the gap by sliding
process and enlargement of cells occur (polymegathism)
- Thus, after injury, the endothelial cell density fal ls, the cell
area increases and the cell height decreases
L
IMBAL
S
TEM
C
ELLS
:
9
Only 5% to 15% of the cells in the limbus are stem c ells
9
The basal cells of limbal epithelium comprises the limbal
stem cells.
2
They are the precursor for all other cells of the ti ssue
2
They have a self maintaining population
2
They account for only a small portion of total cell s of the
tissue
2
In vivo,they show slow cycling,but when placed in cell
culture,they demonstrate high potential to prolifera te.
2
They can not be differentiated from rest of the cells
of tissue.

12. 9/9/2022
12
B
LOOD SUPPLY TO CORNEA
:
9
In normal condition, cornea does not contain any blood
vessels
9
Anterior ciliary artery
, a branch of ophthalmic
artery forms a
vascular arcade in the limbal
region
and helps in corneal metabolism and
wound repair by providing nourishment.
9
Absence of blood vessel in cornea is one of the
contributing factors for its transparency.
NERVE SUPPLY OFCORNEA: 9
Density of the nerve ending in
cornea is about 300 times of
that of skin.
9
The ophthalmic division of the
trigeminal nerve has three
parts: the frontal nerve, the
lacrimal nerve, and the
nasociliary nerve.
9
The nasociliary nerve provides
sensory innervation to
cornea.

13. 9/9/2022
13
CORNEAL NUTRITION & METABOLISM 9
Cornea requires energy for normal metabolic
activities as well as for maintaining
transparency and dehydration
9
Energy is generated by the breakdown of
glucose in the form of ATP
9
Most actively metabolizing layers are
epithelium & endothelium
9
Sources of Nutrients: -Oxygen – mainly from atmosphere through
tear film, with minor amounts supplied by the aqueo us
and limbal vasculature
- Glucose, amino acid, vitamins, and other nutrients
supplied to cornea by aqueous humor, a lesser amounts
from tears or limbal vessels.
- Glucose also derived from glycogen stores in corneal
epithelium.
- Epithelium consumes O9/10 times faster than stroma.

14. 9/9/2022
14
CORNEALTRANSPARENCY The cornea transmits nearly
100% of the light that enters
it. Transparency achieved by
1. Arrangement of stromal
lamellae
Two theories –
i)Maurice (1957):The transparency
of the stroma is due to the lattice
arrangement of collagen fibrils.
He explained, because of their
small diameter and regularity of
separation, back scattered light
would be almost completely
suppressed by destructive
interference
ii)Goldman et al. (1968):
Proposed that lattice
arrangement is not a
necessary factor for stromal
transparency . Cornea is
transparent because fibrils
are small in relation to light
and do not interfere with light
transmission unless they are
larger than one half of a
wavelenght of light(2000 A).
/
Both theories failed to explain
why there is corneal clouding
with raised IOP and why there
is corneal clearing on
reduction of IOP.
Other factors of corneal transparency –
2. Corneal epithelium & tear film
• Epithelial non-keratinization
• Regular & uniform arrangement of corneal epithelium
•Junctions between cells & its compactness and also
tear film maintain a homogenicity of its refractive index
3. Relative deturgescence state of normal cornea.
4. Corneal avascularity
5. Non myelenated nerve fibres

15. 9/9/2022
15
Signs of Corneal Disease
Superficial
1.Punctate epithelial erosions
Tiny ,slightly depressed, epithelial
defects which stain with flourescein but
not with Rose Bengal
PEE are non specific and may develop in
a wide variety of keratopathies like
Rosacea.
Dry-eye syndrome.
Blepharitis.
Acute bacterial conjunctivitis.
Trauma.
Exposure keratopathy from poor eyelid
closure.
Ultraviolet or chemical burn.
Contact lens-related disorder such as
toxicity or tight lens syndrome
2.Punctate epithelial keratitis
It is the hallmark of viral infections.
Swollen epithelial cells
Stains with Rose Bengal, till break
down occurs
Can occur in
1. A viral infection.
2. A bacterial infection (including
trachoma)
3. Dry eyes.
4. Strong chemicals splashed in the
eye.
5. Exposure to ultraviolet light
(sunlight, sunlamps, or welding
arcs)
6. Prolonged use of contact lenses.
7. An allergy to eye drops.

16. 9/9/2022
16
3. Corneal Ulceris relatively
acornealepithelial defect
with underlying inflammation
(which soon results in
necrosis ofcornealtissue)
due to invasion by bacteria,
fungi, viruses, or
Acanthamoeba. It can be
initiated by mechanical
trauma or nutritional
deficiencies
Signs of Corneal Disease
4. Epithelial Oedema
Sign of Endothelial
decompensation
Severe acute elevation of IOP
Endothelial Dystrophy
5. Filaments
Small coma shaped mucus
strands lined with epithelium.
One end attached with
epithelium
Common in Dry eye disease

17. 9/9/2022
17
6. Pannus( Chronic
Superficial Keratitis)
Inflammatory or
degenerative in-growth of
fibro vascular tissue from
limbus
No known cause for its
formation
May be caused by chronic
inflammation like in Contact
Lens wearers, Viral
Keratitis, Trachoma and as
congential abnormality.
Signs of Corneal Disease
Stromal Lesions
1.Infiltrates
Focal areas of active stromal
inflammation
2. Oedema
Increased corneal thickness
Decreased transparency
3. Vascularization
Lesions of Endothelium
Endothelial Dystrophy/
Degeneration
Reduced cell count
Epithelial oedema

18. 9/9/2022
18
“STUMPED” Classification
(Congenital)
9
S – Sclerocornea
9
T – Tears in descemet’s membrane
9
U – Ulcer
9
M – Metabolic (rarely present at birth)
9
P – Posterior corneal defect
9
E – Endothelial dystrophy- usually
effects at a later age
9
D- Dermoid
SCLEROCORNEA
TEARS IN DESCEMETS
MEMB
POSTERIOR CORNEAL
DEFECT
LIMBAL DERMOID

19. 9/9/2022
19
9/20134T2O 3421T1TR
9EMBA2O 3421T1TR
9-T42O 3421T1TR
Microbial Keratitis
Predisposing Factors
The pathogens able to produce corneal  infection 
in the presence of an intact epithelium  are 
Neisseria gonorhoae, 
Corynebacterium  diphtheriae, 
Listeria sp. and 
Haemophilus sp.
Other bacteria are capable of producing  
keratitis only after loss of corneal epithelial  
integrity
Bacterial Keratitis

20. 9/9/2022
20
Predisposing Factors for Epithelial breaks
1.
Contact lens wear.The infection is often caused  by 
pseudomonas aeruginosa which requires an  epithelial 
defect for corneal invasion.Such defects  occur in all 
contact lens wearers at times.
2.
Ocular surface disease which disrupts defence  
mechanisms, such as
trauma, 
bullous  keratopathy, 
corneal exposure, 
dry eye and  
diminished corneal sensation.
Bacterial Keratitis
Clinical Features 1.
Staph. aureus and 
Strep.pneumoniae tend to  
produce oval, yellow-white, 
densely opaque  stromal 
suppuration surrounded by 
relatively  clear cornea.
2.
Pseudomonas typically causes 
thick  mucopurulent exudate, diffuse 
liquefactive  necrosis and semi-
opaque “ground-glass”  appearance 
of adjacent stroma. The infection 
may  progress rapidly and result in 
corneal perforation  within 48 hours
3.
Enterobacteriacea usually 
causes a shallow  ulceration, 
grey-white pleomorphic 
suppuration  and diffuse stromal
opalescence.
Bacterial Keratitis

21. 9/9/2022
21

22. 9/9/2022
22
Management
A bacterial corneal ulcer is a sight-thereatening
condition demanding urgent identification and
eradication of the causative organism. This is best
performed with the patient hospitalized
Bacterial Keratitis
Clinical Features 1.
Flamentous fungal keratitis is most 
prevalent in  agricultural areas and
typically preceded by ocular trauma, 
most frequently involving organic  
matter such as wood.
2.
Candida keratitis usually develops in  
association with pre-existing chronic 
corneal  disease or in an 
immunocompromised or  debiliated 
patient. It is characterized by a yellow-
white ulcer associated with dense
suppuration
Fungal Keratitis

23. 9/9/2022
23
Viral Keratitis
9Herpes Simplex Keratitis
9Herpes Zoster Keratitis
Herpes simplex virus
(HSV) is a DNA virus with
humans as the only host.
Infection with HSV is extremely
common and about 90% of the
population are seropositive for HSV
antibodies.
Primary ocular infection
Recurrent ocular infection
-Dendritic ulcer
-Disciform keratitis(endothelitis )
Herpes Simplex Keratitis

24. 9/9/2022
24
Herpes simplex keratitis
9Primary ocular infection
9Recurrent ocular infection
-Dendritic ulcer
-Disciform keratitis(endothelitis )
Primary ocular infection
typically occurs in children
between the ages of 6 months
and 5 years 1.
Blepharoconjunctivitis is usually
benign and self limited and, in
children, it may be the only
manifestation of primary herpetic
infection.
2.
Keratitis is uncommon. It is
characterized by fine epithelial
punctate keratitis which may be
transient.
Herpes Simplex Keratitis
Primary Ocular Infection

25. 9/9/2022
25
Sign in chronological order
a)Early cases shows opaque cells
arranged in a coarse, punctate
or stellate pattern
b)Following central
desquamation a linear-
branching ulcer begins to form.
The bed of the ulcer stains with
fluorescein.
c)Occasionally, the continued
enlargement of a dendritic ulcer
leads to much larger epithelial
defect which has a geographical
or “amoeboid” configuration
Herpes Simplex Keratitis
Dendritic Ulcer
Disciform Keratitis
Herpetic disciform keratitis is a
primary endotheliitis resulting in
both stromal and epithelial edema
in a round (disciform) distribution
with keratic precipitates underlying
the area of edema. The corneal
edema and keratic precipitates
appear to be out of proportion to
the degree of anterior chamber
inflammation, in contrast to uveitis
with secondary corneal
decompensation.
Disciform keratitis may be caused
by both herpes simplex and
herpes zoster viruses.

26. 9/9/2022
26
Herpes zoster is a common infection caused by human herpes
virus
Usually occurs in infected individuals who have had ChickenPox in
past
Virus lies dormant in Ganglions and erupts in compromised
individuals
Approximately 15% of all cases of herpes zoster affect the
ophthalmic division of the trigeminal nerve
Herpes Zoster Ophthalmicus
1.The Rash (one side of midline)
2.Conjunctivitis 
3.Acute Epithelial Keratitis,
4.Dendritic Epithelial  Lesions
5.Nummular Keratitis
5.Disciform Keratitis
6.Anterior Uveitis
6.Secondary Glaucoma
Serious Eye involvement if 
nasociliary branch affected-
Vesicle on side of nose/ 
Hutchinson’s Sign
Peripheral Corneal Lesions
Dellen: saucer like thinning of peripheral cornea
causes: raised limbal lesion, use of hard
contact lenses/ dehydration, ideopathic in
elderly
Necrotising Keratitis: Herpes Simplex, Rare in
Zoster
Marginal Keratitis ( Catarrhal Ulcer): supposed to
be hypersensitivity reaction to staph exotoxins
Common with chronic ulcerative blepharitis
Starts as subepithelial infiltrate spreading
circumferentially and finally epithelium breaks
down to form an ulcer

27. 9/9/2022
27
PRINCIPLES OF TREATMENT OF CORNEAL ULCER 1. IDENTIFICATION OF CAUSATIVE AGENT-
CLINICAL & PATHOLOGICAL(C&S DISCHARGE/
SCRAPING)
2. ANTIBIOTICS/ CAUTERISATION
3. REST TO PART- RELIEVE PAIN- PROTECT
FROM PERFORATION- P&B, CYCLOPLEGIA,
BCL(BANDAGE CONTACT LENS)
4. RESTORATION OF VISION-
GLASSES/TATTOOING/CORNEAL GRAFT
5. THERAPEUTIC CORNEAL GRAFTING FOR
NON HEALING ULCERS
Rosacea keratitis:
•In association with skin lesion on face
•Usually between 30-50 yr age,
•In females commonly
•Symmetrical distribution on face
•Unknown reason
•Increases with stress, alcohol and tobacco
consumption
•Common in fair skin persons
•Three stages:
•1- Erythema;
•2- papules/pustules;
•3- nodules and furunculoid lesions;
•Rhinophyma(rare, most advanced form)
•Corneal involvement: Punctate
keratitis/Peripheral vascularisation/gross
ulceration/ thinning
•Emollients, Immune modulators,
vasoconstrictors applied locally
•
Oral antibiotics Doxy/
Metronidazole

28. 9/9/2022
28
Phlyctenular keratoconjunctivitis:
•also known asphlyctenulosis
•is an inflammatory syndrome
caused by a delayed hypersensitivity
reaction to one or more antigens.
•The triggering antigen is usually a
bacterial protein particularly from
Staphylococcus aureus but may also
be a virus, fungus (particularly
Candida albicans or Nematode.
•Initially was considered a
hypersensitivity reaction to tubercular
protein alone.
•It may be in association with
conjunctival lesion or may occur
astride limbus
•May ulcerate rarely
KERATITIS IN SYSTEMIC COLLAGEN DISEASES
Cornea is affected in systemic
collagen diseases like
Rheumatoid Arthritis, SLE,
Polyartritis Nodosa, Wegner
Granulomatosis
Presentation can be Sclerosing
Keratitis, Peripheral Corneal
Thinning, Stromal Keratitis,
Peripheral Ulcerations, Corneal
Melting
A tongue shaped corneal opacity
with apex towards center, and a
clear margin from limbus,
corresponding scleritis nodule
present

29. 9/9/2022
29
Keratoconus (conical
cornea) is a fairly
common, progressive
disorder in which the
cornea assumes an
irregular conical shape.
The hallmark of keratoconus is
central or paracentral stromal
thinning, apical protrusion and
irregular astigmatism.
The onset is at around puberty and
progresses slowly thereafter,
although it may become stationary
at any time
Corneal Ectasias
Keratoconus
1. SPECTACLE CORRECTION
2. CONTACT LENSES
3. PENETRATING KERATOPLASTY
FOR PROGRESSIVE LESION
AND SCARRING
4. C3R( CROSS LINKING WITH
RIBOFLAVIN) PROCEDURE
Treatment
Decreased visual acuity
Rizutti’s sign
Munson sign
Fleischer ring
Corneal scarring
Features
Keratoglobus(from Greek kerat
o-horn, cornea;
and Latin: globusround), is a
degenerative non-
inflammatory 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. It
causes corneal thinning, primarily
at the margins, resulting in a
spherical, slightly enlarged eye.

30. 9/9/2022
30
Chemical Burn
: Acid or Alkali
Corneal Burns- Chemical
Corneal Burns- Chemical

31. 9/9/2022
31
Flash Burn
:
•caused by ultraviolet light from
various sources
•sunlamp in salon
•reflection of the sun off the
snow at high elevation (snow
blindness)
•photographer's flood lamp
•lightning that strikes close to
you
•halogen lamp
•welding torch
•direct sunlight
•many times presentation is pain
redness and diminished vision,
after 6-8 hrs of exposure leading
to
SPK
CORNEAL DEGENERATION corneal degeneration refers to the condition in
which the normal cells undergo some
destructive changes under the influence of age
or some pathological/metabolic conditions.

32. 9/9/2022
32
The corneal dystrophies are a group of
progressive, usually bilateral and mostly
genetically determined corneal opacifying
disorders which develop in the absence of
inflammation.
Corneal Dystrophies
DEGENERATION VS DYSTROPHY
• Non - Hereditary and Non -Familial
• UsuallyUnilateral to start
• MostlyPeripheral
• Commoner than Dystrophy
• Vascularity and Inflammation may be
present

33. 9/9/2022
33
Corneal  
degenerations
Depending  
upon  
etiology
Age -Related
Pathological  
Degeneration
Depending  
upon  
location
Axial
Peripheral
6
5
Corneal Degeneration
Depending upon Location
2. Axial CornealDegenerations
a) FattyDegenerations
b) Hyaline Degenerations
c) Amyloidosis
d) Calcific Degenerations
(Band Keratopathy)
e) Salzmann’s Nodular
Degeneration
1. Peripheral Degenerations
a) ArcusSenilis
b) Vogt’s White LimbalGirdle
c) Hassall –Henle Bodies
d) Terriens’s Marginal Degeneration
e) Mooren’s Ulcer
f) Pellucid MarginalDegeneration
g) Furrow Degeneration(Senile
MarginalDegeneration)

34. 9/9/2022
34
Depending upon Etiology
I. Age Related Degenerations
a) ArcusSenilis
b) Vogts White LimbalGirdle
c) Hassal - Henle Bodies
d) MosaicDegenerations
II. PathologicalDegenerations:
a) FattyDegeneration
b) Amyloidosis
c) Calcific Degenerations (
Band Shaped
Keratopathy)
d) Salzmann’s Nodular
Degeneration
e) Terrien’sMarginal
Degeneration
f) Mooren’s Ulcer
g) Pellucid Marginal
Degeneration
h) FurrowDegenerations
i) SpheroidalDegeneration
•ARCUS SENILIS
•It is the annular lipid infiltrations of
the corneal periphery seen in the
elderly.
Age – related degeneration occurring
bilaterallyin60% ofpeopleaged40to60
years.
•Andalmostallindividuals agedover
80years.
•
Doesnot
affect
vision
AGE RELATED
• Commences as a crescentric grey or
white arc in the superior and
inferior quadrant and progresses to
form a ring around thecornea,
• 1mm wide ring
• Lucid interval of Vogt’s –the clear
zonewhich separatesthe ring of
opacityfrom the limbus.
• Peripheral border is sharp and inner
borderis diffuse.
• Lipid deposits are found

35. 9/9/2022
35
ARCUS JUVENELIS
•Similar to Arcus Senilis but occurs in individual s agedless
than 40years.
•Rarecondition
•Associated with Hypercholesterolemia
•Diagnostic feature: Presenceof a line of clear co rnea
between opacity andlimbus.
Vogt’s White Limbal Girdle
Agerelated which appearsasa
• Bilateral
• Chalky white opacities in the
inter - palpebral area both
nasally andtemporally.
• Opacity in the Bowman's
Membrane.

36. 9/9/2022
36
• Drop shaped excrescences of
hyalinematerial projecting
into the anterior chamber
around the corneal
periphery
• Arise from Descemet’s
membrane
• Commonest senile change.
• In pathological changes, they
become larger and invade the
central area and theconditions
is called ‘CornealGuttata’.
Hassal - HenleBodies
Mooren’s Ulcer:
Mooren’s ulceration is characterized by painful
peripheral corneal ulceration of unknown
etiology.
The disease generally begins with intense limbal
inflammation and swelling in the episclera and
conjunctiva.
Corneal changes begin 2-3 mm from the limbus,
first appearing as grey swellings that rapidly
furrow, affecting the superficial one-third of the
cornea and then proceeding circumferentially
and centrally over 4-12 months.
The bed of the furrow becomes vascularized,
with vessels advancing into the base of the
undermined edges of the ulcers
These ulcers are crescent-shaped and can
leave behind either an opaque, edematous
central cornea or alternatively, they can
completely consume the corneal stroma and
replacing it with a thin fibrovascular membrane

37. 9/9/2022
37
Pellucid marginal degeneration(PMD),
is a degenerative corneal condition,
often confused with keratoconus.
It is typically characterized by a clear,
bilateral thinning in the inferior and
peripheral region of the cornea
Although some cases affect only one
eye.
The cause of the disease remains
unclear.
The term "pellucid marginal
degeneration" was first coined in 1957
by the ophthalmologist Schalaeppi.
The word "pellucid" means clear,
indicating that the corneas retain clarity
in pellucid marginal degeneration
1.
Anterior dystrophies
-Microcystic (Cogan)
-Reis-Büclers
-Meesmann
-Schnyder
2.
Stromal dystrophies
-Lattice I,II, III
-Granular I,II, III
-Macular I, II
3.
Posterior dystrophies
-Fuchs endothelial
-Posterior polymorphous
Corneal Dystrophies

38. 9/9/2022
38
CORNEAL TRANSPLANT/ GRAFTING
Corneal transplantation, also known
ascorneal grafting, is a surgical
procedure where a damaged or diseased
cornea is replaced by donated corneal tissue
(the graft).
The graft is taken from a recently dead
individual with no known diseases or other
factors that may affect the chance of
survival of the donated tissue or the health
of the recipient or can be a Bioengineered
Graft Tissue.
When the entire cornea is replaced it is
known asPenetrating Keratoplastyand
when only part of the cornea is replaced it is
known asLamellar Keratoplasty.
Keratoplasty simply means surgery to the
cornea.
Lamellar Keratoplasty can also beDeep
Anterior Lamellar Keratoplasty(DALK)or
Endothelial Keratoplasty(EK).
There are three forms of EK.
Deep Lamellar Endothelial
Keratoplasty (DLEK)in which the
posterior part of the recipient
cornea is replaced by donor tissue.
Descemet's Stripping (Automated)
Endothelial Keratoplasty
(DSEK/DSAEK)in which the
diseased Descemet’s membrane is
removed and replaced by a healthy
donor posterior transplant.
Descemet Membrane Endothelial
Keratoplasty (DMEK)is the most
recent EK technique in which an
isolated Descemet membrane is
transplanted.

39. 9/9/2022
39
Examination Of Corneal opacity -
Overview
Clinical History
Clinical Evaluation Of Cornea And External Eye
Bedside Tests
Laboratory Investigations And Corneal Imaging
Evaluation Of Visual Potential And Prognostication
APPROACH TO A CASE OF CORNEAL
OPACITY
HISTORY 9
Congenital or Acquired
9
Onset and duration
9
Unilateral or bilateral
9
Trauma or chemical injury
9
Recurrent episodes of pain and redness
9
Long term topical medication
9
Contact lens use
9
Previous ocular surgery
9
Systemic illness

40. 9/9/2022
40
Symptoms 9
Diminution of vision
9
Pain,
9
Redness
9
Photophobia
Examination
Adenexa
Congestion- Presence/absence/Conjunctival/Corneal
Grading
Appearance: demarcated/ diffuse/sharp/dirty
Sensations/ Tenderness
Depth of Opacity
Anterior Chamber Reaction
Pupil Size/reaction
Lens for Cataract/ Position
Intra ocular Pressure

41. 9/9/2022
41
Grading the Opacity Nebular: faint opacity due to
superficial scar involving bowman’s
layer and superficial stroma
Macular: Semi dense opacity d/t scar
involving half of stroma.
Leucomatous: Dense white opacity
d/t scarring of more than half of stroma
Examination of Corneal Opacity- Tear
Film Evaluation
Tear Film
Function Test
TBUT
Schirmer’s test
Tear Meniscus
Height
Tear Clearance
rate
Tear Osmolarity
And
Composition

42. 9/9/2022
42