Cataract fixed.pptx

8/9/2019 Cataract fixed.pptx

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Cataract

Deasy Mirayashi

(I11110003)


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Lens

Essential refractive media of the eyeand focuses incident rays of light on the

retina

Lies in the posterior chamber of the eye

between the posterior surface of the iris

and the vitreous body

purely epithelial structure without any

nerves or blood vessels.

nourished by diffusion from the aqueous humor.


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The epithelium of the lens -> maintain

the ion equilibrium and permit

transportation of nutrients minerals

and water into the lens.

Lens

The water content of the lens is

normally stable

The water content of the lens

decreases with age. The lens becomes

harder less elastic and less

transparent.


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Cataract

Cataract is present when the

transparency of the lens is reduced to

the point that the patient!s vision is

impaired.

The term cataract comes from the "ree#

word katarraktes$down-rushing% waterfall&

' cataract is any opacity in the lens.


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Etiology

Age-related cataract is a common cause of visual impairment.

Agingis the most common cause of cataract but many other

factors can be involved including trauma, toxins, systemic

disease (such as diabetes), smoking, and heredity


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Classification

Cataract can be classified according to

several different criteria %

a. (orphology

b. (aturity

c. Time of occurance $acquired or

congenital&


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)enile Cataract

the most frequent form of cataract

accounting for *+, of all cataracts

'bout , of all +-year-olds and /+, of all 0+-

year-olds suffer from a cataract requiring surgery


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)enile Cataract

Etiology

The precise causes of senile cataract have

not been identified

's occurrence is often familial it is importantto obtain a detailed family history

0


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)enile Cataract%

1uclear cataract

2n the fourth decade of life 3ressure of

peripheral lens fiber production causes

hardening of the lens especially the nucleus.

The nucleus ta#es on a yellowish brown color(brunescent nuclear cataract).

refractive power 2ncreasenuclear cataracts

lead to lenticularmyopia and monocular diplopia

(orphology


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)enile Cataract%

1uclear cataract

(orphology


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%ortical cataractsare opacities in the lens corte4.

Changes in the hydration of lens fibers create clefts in a

radial pattern around the equatorial region.

tend to be bilateral but often asymmetric.

5isual function is variably affected depending on how

near the opacities are to the visual a4is.

)enile Cataract%

Cortical cataract

(orphology


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)enile Cataract%

Cortical cataract(orphology


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located in the corte4 near the central posterior capsule.

6eginning a a small cluster of granular opacities this

form of cataract e4pands peripherally in a disc-li#e

pattern.

's opacity increases the rest of thecorte4 and nucleus

become involved.

)enile Cataract%

3osterior subcapsular cataract

(orphology


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Lens is partially opaque 2ris shadow can be seen on the opacity

with oblique illumination. Lens appears grayish white in color

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(aturity)enile Cataract%

2mmature cataract


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The lens is diffusely whitecomplete

opacification of the corte4.

' yellow lens nucleus is often faintly

discernible.

8 the ris# of angle closure glaucoma.

)enile Cataract%

(ature cataract

(aturity


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)enile Cataract%

(ature cataract

(aturity


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' mature cataract progresses to the point of

complete liquification of the corte4 the dense

brown nucleus will subside within the capsule its

superior margin will then be visible in the pupilas a dar# brown silhouette against the

surrounding grayish white corte4.

)enile Cataract%

9ypermature cataract

(aturity


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)enile Cataract%

9ypermature cataract

(aturity


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(orgagni!s cataractthe final stage in a

cataract that has usually developed over

the course of two decades

' hypermature cataract in which the lens

nucleus floats freely in the capsular bag is

called a morgagnian cataract&

)enile Cataract%

(orgagnian cataract

(aturity


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)enile Cataract%

(orgagnian cataract

(aturity


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:eatures 2mmature (ature 9ypermature

'nterior Chamber 1ormal $shallow inintumescent&

1ormal $shallow inintumescent&

to deep

Color of Lens "rayish white 3early white (il#y white $withbrown crescent ofnucleus& or chal#y

white

2ris shadow )een 1ot seen 1ot seen

'ierentiating arious *tages o %ataract


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'iabetic cataract diabetes mellitus9yperglycemia causes

glucose $sorbitol&. )orbitol accumulates in the

lens fiber;ater correct the osmoticimbalancethe lens fibers swellrupture


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+alactosemic %ataract "alactosemia is a rare cause of early cataract in children

"alactosemia is an autosomal recessive disorder where

a lac# of one of the three en?ymes involved in theconversion of galactose into glucose causes a rise in

serum galactose levels.

There is an accumulation of galactitol within the lens and

in a similar process to diabetes

Cataract with

systemic disease

Time of ccurance

$'cquired cataract&


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:requent traumatic cataracts% Contusion cataract% Contusion of the eyeball

will produce a rosetteshaped subcapsular

opacity on the anterior surface of the lens 2t will normally remain unchanged but will

migrate into the deeper corte4 over time due

to the apposition of new fibers

Traumatic Cataract Time of ccurance$'cquired cataract&


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Traumatic Cataract Time of ccurance$'cquired cataract&


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3rolonged topical or systemic therapy with

corticosteroids can results in a posterior

subcapsular opacity.

To4ic Cataract Time of ccurance$'cquired cataract&


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To4ic Cataract Time of ccurance$'cquired cataract&


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Congenital Cataract

Congenital cataracts% 9ereditary

'cquired through the placenta.

:amilial forms of congenital cataracts may

be autosomal dominant autosomal

recessive sporadic or @-lin#ed

diagnosed on the basis of theircharacteristic symmetric morphology.

phtalmology ' )hort Te4tboo#

Time of ccurance

$Congenital cataract&


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:orms of hereditary

congenital cataract

amellaror onularcataract. pacities are located in

one layer of lens fibers often as AridersB only in the

equatorial region

.uclear cataract. This is a variant of the lamellar

cataract in which initially only the outer layer of the

embryonic nucleus is affected

%oronary cataract. This is characteri?ed by fine radial

opacities in the equatorial region.

%erulean cataract. This is characteri?ed by fine roundor club-shaped blue peripheral lens opacities.

Time of ccurance



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Page 3$phtalmology ' )hort Te4tboo#

Time of ccurance



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Page 31phtalmology ' )hort Te4tboo#

Time of ccurance



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Cataract from Transplacental This infection occurred during the fifth to

eighth wee# of pregnancy the phase in which

the lens develops the protective lens

capsule has not yet been formed at this time

viruses can invade and opacify the lens tissue. The cataract is bilateral and total and may be

diagnosed by the presence of leu#ocoria

$white pupil& and chorioretinal scarring

secondary to choroiditis

phtalmology ' )hort Te4tboo#


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)igns and )ymptoms


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)igns )ymptoms)igns

'n abnormally dim red reDe4 educed contrast sensitivity

;hite pupil.

)lit lamp e4amination shows whether the cataract is

cortical nuclear or posterior subcapsular and allows

fundus e4amination.

Cataract in children is unusual but may be associated

with a white pupil inability to F4 on a target $e.g. light&

and the development of a squint.

phtalmology at a "lance


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Treatment

Essentially a surgical problem

/hen is surgery indicated0

Earlier surgical techniques were

dependent upon the maturity of the

cataract


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Cataract )urgery

The operation is performed on only one

eye at a time. The procedure on the fellow

eye is performed after about a wee# if

once the first eye has stabili?ed There are = techniques%

2ntracapsular method

E4tracapsular method


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2ntracapsular Cataract

E4traction

2n this method the entire lens is removed

within its capsule $with a cryoprobe&

The suspensory ligaments of the lens are

dissolved by the en?yme chymotrypsin

a hole cut in the iris $iridectomy& allows the

aqueous to bypass the pupil.

'6C of Eyes 7th Edition


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2ntracapsular (ethod

The incidence of postoperative retinal

detachment and cystoid macular edema is

significantly higher than after

e4tracapsular surgery but intracapsularsurgery is still a useful procedure

particularly when facilities for

e4tracapsular surgery are not available


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E4tracapsular (ethod

The anterior capsule is opened $capsulorrhe4is& incision in the

eye $about /+mm in length&anterior capsule is cut open with the

tip of a sharp needle

Then only the corte4 and nucleus of the lens are removed

$e4tracapsular e4traction&G the posterior capsule and ?onule

suspension remain intactprovides a stable base for implantation

of the posterior chamber intraocular lens.

The large nucleus is then e4pressed whole and the remaining soft

lens fibres aspirated. ' non-folding lens is then inserted into the

empty lens capsular bag and the incision closed with fine sutures.

'6C of Eyes 7th Edition


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E4tracapsular Cataract E4traction

The surgical techniques of ECCE presently in vogue are%

Conventional e4tracapsular cataract e4traction

$ECCE&

(anual small incision cataract surgery $)2C)&

3hacoemulsification


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Coventional ECCE


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)2C))urgical steps of manual small incision cataract surgery $)2C)&% ' )uperior rectus bridle

sutureG 6 ConHunctival flap and e4posure of scleraG C < E E4ternal )cleral incisions

$straight frown shaped and chevron respectively& part of tunnel incisionG : )clero-corneal tunnel with crescent #nifeG " 2nternal corneal incisionG 9 )ide port entryG

)2C)


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)2C)2 Large CCCG

I 9ydrodissectionG

J 3rolapse of nucleus

into anterior chamberG

L 1ucleus delivery with

irrigating wire vectisG

( 'spiration of corte4G

1 insertion of inferior

haptic of posterior

chamber 2LG

2nsertion of superior

haptic of 3C2LG

3


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