cataract.ppt

7/27/2019 cataract.ppt

http://slidepdf.com/reader/full/cataractppt 1/126

24 October 2013



24 October 2013



24 October 2013

Objectives:-

• Lens Anatomy• Lens Physiology

• Lens Functions• Definition of Cataract

• Pathology of Cataract• Etiology of Cataract



24 October 2013



• It is a highly organized,transparent, biconvex spheroid

structure.• It does not posses, nerve or

blood vessels .

24 October 2013

Ant Post



• Diameter varies from 8.8 to 9.2

• Antero-posterior thicknesschanges with accommodation.

• Circumference is known asequator

24 October 2013

Ant Post



• Lens is suspended in eye, byZonules, which are inserted

on anterior surface andequatorial lens capsule and

attached to ciliary body.

24 October 2013

Ant

Post

cbcb


http://slidepdf.com/reader/full/cataractppt 8/12624 October 2013

Lens

Zonulesciliary body



L

e

ns

An

a

t

o

m

y

Lens

Zonulesciliary body



24 October 2013

Lens

Zonules

Zonules

ciliary body

ciliary body



• Histologically, lens

consists of three major components

• 1)Capsule2) Lens Epithelium

3 Lens substance24 October 2013



1. Capsule – is a thick

membrane, which is transparent,elastic, acellular- envelop, thick

at anterior pre-equatorial region ,thinnest at the posterior pole .equator

Pre equatorial region

AntPost



-Anterior pole contains, theepithelial cells and fibres, as

a structural unit and allows,a passage of smallmolecules, both into and outof the lens.

24 October 2013



24 October 2013

-The lens capsule, regulate the

transport of metabolite, nutrientsand electrolytes, to the lens

fibres.

Can – opener ant

capsulotomy

Continuous curvilinear

capsulorrhexis ( CCC )



24 October 2013

2. Lens Epithelium – It is asingle layer of cells, liningthe anterior capsule andextends to the equator.



24 October 2013

Ant lens capsule Post lens capsule

epithelium



24 October 2013

These cells are actively dividing

and elongating to form new lensfibres throughout the life.



3. Lens substance: It

constitute, the main mass of the

lens.

It is divided into-a. Nucleus

b. Cortex

24 October 2013



Nucleus: consists of (i) Embryonic nucleus

(ii) Fetal nucleus(iii)Infantile nucleus

(iv)Adult nucleus

24 October 2013



24 October 2013

(i)Embryonic nucleus : It

contains primary lens fibres,that are formed in lens vesicle.

( 1 to 3 months of gestation )



24 October 2013

ii) Fetal nucleus: it contains

embryonic nucleus and all fibresadded to the lens before birth

( from 3 months gestation tillbirth )



24 October 2013

(iii) Infantile nucleus: it

contains embryonic , fetalnucleus together with all

the fibres added up-to theage of 4 years.



24 October 2013

(iv) Adult nucleus: composed of

all fibres added before puberty.



24 October 2013

The nucleus consists of, densely

compacted lens fibres and it has

higher refractive index than

cortex.



24 October 2013

c

a

i

f

E



• It is located peripherally, and iscomposed of secondary fibres formed

continuously after puberty. It is

further divided into: – Deep cortex

– Intermediate cortex

– Superficial cortex

24 October 2013

N

U

C

LE

U

S



– Lens fibres contain high

concentrations of crystalline protein.

– It is a major protein of the

lens24 October 2013



• The region between embryonic and fetal

nuclear core and soft cortex i.e. infantile

and adult nucleus is sometimes referred

to as epinucleus.

24 October 2013

Adult Nucleus

Infantile Nucleus

Cortex

epinucleus



• Are found both at anterior and posterior poles. They are formed by overlap of ends of secondary

fibres. These secondary fibresformed before birth (fetalnucleus). Anterior suture is

shaped as an erect Y, and a posterior suture shaped as an

inverted Y.24 October 2013



24 October 2013

Anterior Suture

( erect Y )

posterior sutureinverted Y



• Function of the Lens ,and it’s

transparency, is dependant on

the supply of appropriatenutrients to its various

structures. Metabolic needs of a adult lens, is met by the,

aqueous and vitreous.24 October 2013



• Lens function is dependent on the1) metabolism of glucose to

produce energy , and

2) protein synthesis.

• Glutathione – (anti-oxidant) is

found in high concentration inlens and it protect lens fromoxidative damage.

24 October 2013



24 October 2013

Lens - Physiology



• The transparency is

dependent on, highlyorganized structure of lens.

• By act of accommodation, it

changes focusing power.24 October 2013

L F i



24 October 2013

Lens - Functions



24 October 2013

• Age related changes in the structure.

• Overall light transmission decreases

with age, lens becomes less elastic.• Reducing its ability to accommodate

which leads to presbyopia.

I. Subluxation



24 October 2013

It is partial displacement in which lens is moved sideways (up,

down, medially or laterally), but remains behind the pupil. It

results from partial rupture or unequal stretching of the zonules

II. Dislocation or luxation of the lens

In it all the zonules are absent or destroyed. A dislocated lens

may be incarcerated into the pupil or present in the anterior

chamber or the vitreous



24 October 2013

Subluxation of the lens



24 October 2013

Dislocation or luxation of

the lens



24 October 2013



24 October 2013

Antero-posterior thickness

of Lens changes

1) In accommodation

2) While looking up

3) In sleep4) By rubbing the eyes

Ans :- 1) in accommodation



24 October 2013

Lens is suspended in the eye by

1) Capsule

2) Vitreous3) Iris

4) Zonules Ans :- 4) Zonules



24 October 2013

What are major 3 parts of Lens

1) Capsule

2) Epithelium3) Substance



24 October 2013

Lens substance is divided into

two parts -

1) Cortex2) Nucleus



24 October 2013

4 parts of the Nucleus

(i) Embryonic nucleus

(ii) Fetal nucleus(iii)Infantile nucleus

(iv)Adult nucleus

Which is the major protein of the



24 October 2013

Which is the major protein of the

lens :-

Crystalline protein.



24 October 2013

What is epinucleus ? ?

Adult &infantile

nucleustogether

called as

epinucleus



24 October 2013

Which anti-oxidant is

synthesized in the lens ?

Glutathione



24 October 2013

What are the functions of lens ?

1) Focusing the rays on the

fovea2) Protects the retina from

the UV radiation



24 October 2013

Sub-luxation



24 October 2013

Dis-location



24 October 2013

• Cataract Definition

• Classification of Cataract

• Cataract Etiology

•Cataract Pathology

• Cataract Symptoms



• Any opacity in the lens or

its capsule, whether developmental or acquired

is called cataract.

24 October 2013

Developmental opacities



24 October 2013

Developmental opacitiesare usually partial and

stationary, whereas

acquired opacities areprogressive.



2009 - 2010 Suhas Kulkarni 55

Cataract is caused by• 1.The degeneration and

opacification of existing lensfibres,

• 2.formation of aberrant lens fibres

• 3.deposition of other material intheir place.

24 October 2013



56

Any factor, physical or chemical,which disturbs the critical intra – and

extra-cellular equilibrium of water andelectrolytes or deranges the colloidsystem within the fibres tends to bring

about opacification.

24 October 2013




• Fibrous metaplasia of fibres mayoccur in complicated cataract)

• Epithelial cell necrosis leads tofocal opacification of the lens

epithelium as ‘Glaucomflecken’

in acute angle closure glaucoma.

24 October 2013



Abnormal products of metabolism,drugs or metals can be deposited in

storage diseases ( Fabry ),metabolic diseases ( Wilson )

and toxic reactions ( siderosis ).

24 October 2013




• Biochemically three factors are

evident in the Process of cataract

formation. – Hydration

– Denaturation of Lens Proteins – Sclerosis

24 October 2013



This process may be reversible and



This process may be reversible and

opacities thus formed, may clear up, as

in juvenile insulin dependent diabeticpatients whose lens becomes clearer

after control of hyperglycaemia.

Hydration may be due to osmotic

changes within the lens or due to

changes in the semipermeability of thecapsule. Traumatic cataract develops

by hydration process.24 October 2013

2. Denaturation of Lens Proteins



If the proteins are denatured, with an

increase in insoluble proteins, a denseopacity is produced, a process which is

irreversible . This occurs in young lens

or cortex of adult lens. This type of cataract is called as soft cataract.

3. SclerosisSlow degenerative process occurs in

nucleus of the lens. This type of cataract

is called as hard cataract.24 October 2013



24 October 2013

Part – II Cataract

--Etiology--Classification

--Symptoms



24 October 2013

Et io logy

-Age-related -Trauma -Metabolic or secondary

-Toxic due to drugs

-Complicated Cataract

-After cataract or PCO

-Syndromes associated with

cataract

A

B

C

D

E

F

G



2009 - 2010

• A. Age-related

1. Sub-capsular a. Anterior: due to fibrous

metaplasia of the anterior lens

epithelium b. Posterior: just in front

of the posterior capsule. It is

associated with the posterior migration of the anterior epithelium of the lens

24 October 2013

2. Nuclear Cataract



• -Exaggeration of the normal aging

involving the lens nucleus-Often associated with myopia due to

the increase in the refractive index .

- Some elderly patients with Nuclear Sclerosis may be able to read again without

their spectacles, due to the induced myopia:

this is called the "second sight ".

24 October 2013



Suhas Kulkarni 67

• B. Trauma : can cause cataract:

• concussion, penetrating injury,electric shock, lightening, orradiation

24 October 2013

Flower shaped

(rosette)cataract

C.. Metabolic or secondary



Suhas Kulkarni 68

1. Diabetes -Senile cataract isaccelerated

-True diabetic cataract: associatedwith over-hydration. Results in bilateralsnowflake posterior or anterior sub-

capsular opacities

24 October 2013



2. Galactosemia- multifocal whiteflakes are seen in lens (inborn error of galactose metabolism)

3. Wilson’s disease –

green sunflower cataract(inborn error of copper metabolism)

24 October 2013

• D Toxic due to drugs



• D. Toxic due to drugs

• -Steroids: systemic cause morecataract than topical.

causes anterior and posterior sub-

capsular lens opacities.

-Chlorpromazine: causes anterior lens

capsule opacities

24 October 2013



-Gold (used in Rheumatoid Arthritis):50% have posterior lens

opacities

-Miotics: cause anterior sub-capsular opacities

24 October 2013



Suhas Kulkarni 72

• E. Complicated Cataract(due to some other ocular disease)

-Chronic anterior uveitis

- Retinitis Pigmentosa- High Myopia

- Acute angle closure glaucoma(Glaukomfleckens)

24 October 2013



F. After cataract or PCO

posterior capsular opacity formed after

cataract surgery ( extra capsular cataractextraction )

It is white membranous

opacity formed by remains of anterior capsule and cortex.

24 October 2013



• G. Syndromes associated with cataract

Down’s ( mental retardation )

anterior, posterior subcapsular cataract

Lowe’s ( oculo-cerebro-renal )

total cataract

Wilson’s disease ( hepatolenticular degeneration )

green sunflower cataract

Congenital rubellatotal cataract

24 October 2013



1. Developmental2. Age related (senile)

3. Cataract associated with ocular diseases

4. Cataract associated with systemic

diseases

5. Traumatic Cataract

6. Drug induced cataract

24 October 2013

Classification of Cataract (2)



Suhas Kulkarni 76


1.Congenital2.Acquired- a) Senile b) Traumatic

c) Complicated d) secondary e) Toxic

f) Syndromes associated with cataract

3.After Cataract

24 October 2013



A. Morphologic

B. With respect to

maturity of Cataract

C. Age of onset


24 October 2013

• A. Morphologic:




1. Capsular Cataract2. Subcapsular Cataract

3. Nuclear Cataract

4. Cortical Cataract

5. Lamellar Cataract

6. Sutural Cataract

24 October 2013



2009 - 2010 Suhas Kulkarni 80 Anterior Capsular cataract24 October 2013

• 2. Subcapsular Cataract

P t i S b l




a. Posterior Subcapsular -Complicated (e.g. in Diabetes Mellitis,

Myotonic Dystrophy, steroids,irradiation)

b. Anterior Subcapsular -Acute angle closure glaucoma(Glaukomfleckens),

- miotics- Wilson's disease

24 October 2013




Anterior Subcapsular Posterior Subcapsular

24 October 2013



24 October 2013

Anterior Subcapsular



2009 - 2010 Suhas Kulkarni

Acute angle closure glaucoma

(Glaukomfleckens)

24 October 2013

3. Nuclear Cataract Age related




-Age-related

-Congenital: Rubella, Galactosemia

Nuclear Cataract

24 October 2013

4. Cortical CataractUsually spoke like can be anterior or




-Usually spoke-like, can be anterior or

posterior

-Can be congenital (very common)-Usually doesn't interfere with vision

Cortical Cataract

24 October 2013

Cortical Cataract on retroillmination




24 October 2013

5 Lamellar Cataract




5. Lamellar Cataract-Congenital.

Involves one lamella of the fetal or

nuclear zone

24 October 2013

6. Sutural CataractCongenital




-Congenital

-Very common

-Y-shaped opacity in the lens nucleus-No clinical significance

Anterior Sutural (erect Y )

24 October 2013

B. With Respect to Maturity of Cataract




p y

24 October 2013

1. Stage o f lamellar separat ion .

2. Stage of inc ipient catarac t.

3. Immature senile cataract (ISC).

4. Mature senile cataract (MSC).

5. Hypermature senile cataract (HMSC).

1 ). Lameller separation :- cortical fibres are

separated by fluid This phenomenon



separated by fluid. This phenomenon

(lamellar separation) can only be seen with a slit-lamp

and not with ophthalmoscope.The general increase in the refractive index of the cortex

in old people

gives a grey

appearance.

24 October 2013

2. Stage of inc ipient cataract.



24 October 2013

g p

In this stage early detectable opacities with

clear areas between them are seen.Two distinct types of senile cortical

cataracts can be recognized at this stage:

(a) Cuneiform senile cortical cataract.

(b) Cupuliform senile cortical cataract.

I i i t t d h d k fCuneiform Cataract



24 October 2013

Incipient stage:- wedge-shaped spokes of

opacity with clear areas between them

appear in the periphery of the lens and lie in

cortex, some in front of and some behind

the nucleus. Lens fibres, thus producing

irregularities in refraction, some visual

deterioration and polyopia. The bases of the

wedge-shaped opacities (cuneiform

Opacities) are peripheral and they are most

common in the lower nasal quadrant.



24 October 2013

Cuneiform senile cortical cataract



24 October 2013



Cupuliform




24 October 2013

Cupuliform

cataract

posterior

subcapsular

cataract

3. Immature Cataract tt d iti t d b l




-scattered opacities are separated by clear areas

24 October 2013

when opacification becomes more diffuse andirregular. The lens appears greyish white but

clear cortex is still present and so iris shadow is

visible.

Iris



24 October 2013

Shadow

Intumescent cataract The lens has become swollen by imbibed water




The lens has become swollen by imbibed water

-Can be mature or immature

24 October 2013

The progressive hydration of the cortical layersmay cause a swelling of the lens, thus making the

anterior chamber shallow (intumescent cataract).

4. Mature sen ile catarac t (MSC). Cortical



24 October 2013

In this stage, opacification becomes complete,

i.e., whole of the cortex is involved.Lens becomes pearly white in colour. Such a

cataract is also labelled as ‘ripe cataract.’

Mature cataract Cort ical




-Cortex is totally opaque

24 October 2013

Cort ical

Nuclear senile cataract.

degenerative changes are intensified and



24 October 2013

degenerative changes are intensified and

associated with dehydration this leads to

compaction of the nucleus resulting in formationof a hard cataract.

The nucleus may become diffusely cloudy

(greyish) or tinted (yellow to black) due todeposition of pigments. The commonly observed

pigmented nuclear cataracts are either

amber, brown (cataracta brunescens) or

black (cataracta nigra) and rarely

reddish (cataracta rubra) in colour



24 October 2013

5. Hypermature Cataract -Mature cataract that has become swollen and has




a wrinkled capsule as a result of leakage of water

out of the lens.

24 October 2013

A) Morgagnian Cataract: -Hypermature cataract leading to total liquefaction of




yp g q

the cortex making the nucleus sink inferiorly

24 October 2013

Some times cortexbecomes fluid and

nucleus may sink to

the bottom of thelens. The liquefied

cortex is milky, and

the nucleus is asbrown mass, altering

it’s position with

position of head.



24 October 2013

(b) Sclerotic type hypermature cataract:

S ti ft th t f t it th t



24 October 2013

Sometimes after the stage of maturity, the cortex

becomes disintegrated and the lens becomes

shrunken due to leakage of water. The anterior

capsule is wrinkled and thickened due to

proliferation of anterior cells and a dense white

capsular cataract may be formed in the pupillaryarea. Due to shrinkage of lens, anterior chamber

becomes deep and iris becomes tremulous

(iridodonesis).

C . Age of onset




1. Congenital Cataract -- Present at birth

2. Infantile Cataract --- up to 1 yr of age

3. Juvenile Cataract -------- Infancy to

adolescence4. Pre-senile Cataract ------ up to the

age of 40

5. Senile Cataract ------ after the age of 40

24 October 2013




1. Blurring of vision2. Frequent change of glasses due to rapid

change in refractive index of the lens

3. Painless, progressive gradual diminution of vision due to reduction in transparency of the lens

4. Second sight or myopic shift in case of

nuclear cataract causing index myopia,improving near vision.

24 October 2013




8. Colored haloes around the light as seen incortical cataract due to irregular refractive

index in different parts of the lens.

9. Color shift , reds are accentuated

10. Visual field loss, generalized reduction in

sensitivity due to loss of transparency

24 October 2013



24 October 2013

Cataract risk factorsDemographic RF



Demographic RF

Age- The strongest RF for cataract

The risk of cataract at age 70 is about 13-fold that at age 50

Race

Some types of cataracts (cortical & nuclear) are more

common in african americans

Sex

Women slightly greater risk than men

Geographic

Especially prevalent in developing countries in the tropical bel24 October 2013

Medical RF



Medical RF

Diabetes

Drugs

Miotic cholinergic compounds

Cancer chemotherapy agentsDiuretics

Various photosenthesitizing drugs

Major tranquillizers

Gout medications

Steroids

24 October 2013



• Chronic open angle glaucoma

• Macular degeneration

• Optic atrophy

• Corneal dystrophy

• Retinopathy associated with

systemic disorders (hypertension or

diabetes)24 October 2013



24 October 2013



24 October 2013

Grading of nucleus for



24 October 2013

g

Phaco-emulsification

Examination of the Eye



24 October 2013

Visual acuity for RE / LE With or without spects

For distance and near

Pin hole vision

Pupil dilatation

Slit-lamp examination

Fundus examination

B-Scan

A-Scan

Sac Syringing



24 October 2013

IOT

Other investigations

Urine and Blood Test

B.P. and ECG with Physicians fitness

Anaethetist’s examination and fitness



24 October 2013

cataract.ppt

Documents