CATARACT (lens) REVISION NOTES

LENS
• Shape - Biconvex
• Diameter – 10mm
• Refractive power – 18-20D
• Highest refractive index 1.386
• The refractive index increases from 1.386 in the peripheral cortex to 1.41 in
the central nucleus of the lens
TONY SCARIA 2010 KMC

Lens capsule Lens epithelium Lens fibres
Transparent membrane
• Thickest @ preequatorial
region
• Thinnest @ posterior pole
• Single layer of epithelium
on anterior surface of lens
• Lens fibres arranged closely in concentric
layers
• Formed through out life
Nucleus Embryonic In first
3months of
gestation
Fetal 3months till
birth
Infantile Birth to
puberty
Adults From
puberty to
rest of life
Cortex Peripheral part containing youngest
fibresTONY SCARIA 2010 KMC

Arrangement of fibres in fetal nucleus

Antioxidants in lens
• Glutathione
• Superoxide dismutase
• Catalase
• Vitamin C
• Vitamin E Enzymatic Nonenzymatic
• Glutathione
• Superoxide dismutase
• Catalase
• Vitamin C
• Vitamin E

Anterior fibres  strongest &
thickest

Metabolism in lens
• Glucose is main source of nutrition to lens
• mainly obtained from aqueous humour (mainly ) & vitreous

Source of energy
• Anaerobic glycolysis (80%)
• Krebs cycle
• HMP shunt
• Sorbitol pathway

• Lens capsule  thickest membrane of our body

MIP 26/ AQP0
• Help in
• Transport of water across lens
• Transport of glycerol across lens

Crystallins
α crystallin β crystallin γ crystallin
Alpha crystallin has the largest
mass
Gamma crystallin has the smallest
mass
about 35% of crystallins. most common and accounts for
55% of crystallins
10% of crystallins
α-Crystallins have chaperone-like
functions that enable them to
prevent the heat-denatured
proteins from becoming insoluble
and facilitate the renaturation of
proteins that have been denatured
chemically.
They also act as chaperones under
conditions of oxidative stress and,
therefore, may help to maintain
lens transparency
correlates with the hardness of
the lens

• Vitamin C is absorbed in to lens with help of Na+-K+ ATPase

cataract
• Senile
• MC form of cataract
• Congenital form & developemental

Congenital & developmental
cataract

Congenital & developmental cataract Present at birth Either embryonic or fetal nucleus
Developmental cataract From infancy to
adolescence
Deeper parts of cortex or capsule

Congenital cataract types
Punctate
cataract
Zonular
cataract
Fusiform
cataract
Nuclear
cataract
Coronary
cataract
Anterior
capsular
cataract
Posterior
capsular
cataract
• Blue dot
cataract
• Most
common
type of
congenital
cataract
• Donot cause
visual
disturances
• most
common
cause of
congenital
catract with
dimished
vision
• Anteroposte
rior spindle
shaped
opacity.
Familial
• Embryonic
nucleus is
affected
• RUBELLA IN
PREGNANCY

Punctate cataract
• Blue dot cataract
• Most common type of congenital
cataract
• Donot cause visual disturances
• When crowded in the Y sutures  sutural
cataract

ZONULAR CATARACT
• MOST COMMON CAUSE OF
CONGENITAL CATRACT WITH
DIMISHED VISION
• ZONE IN FETAL NUCLEUS IS
OFTEN AFFECTED
• HYPOCALCEMIA IN
PERGNANCY IS AN
IMPORTANT CAUSE
• HYPOCALCEMIA
• HYPOVITAMINOSIS DTONY SCARIA 2010 KMC

Zonular cataract
• Usually bilateral
• May affect vision

RIDERS ARE SEEN IN ZONLAR CATARACT

NUCLEAR CATARACT
• AFFECTS EMBRYONIC NUCLEUS
• RUBELLA IN PREGNANCY IS AN
IMPORTANT CAUSE

CORONARY CATARACT
• AROUND PUBERTY
• OPACITIES IN PERIPHERY OF THE LENS
• CLUB SHAPED PERIPHERAL OPACITIES

CORONARY CATARACT

ANTERIOR CAPSULAR CATARACT
• IN DEVELOPMENTAL DELAY OF ANTERIOR CHAMBER
• IN OPTHALMIA NEONATORUM
THICKENED WHITE
OPAQUE
ANTERIOR PYRAMIDAL
CATARACT
REDUPLICATE
(DOUBLE CATARCAT)
ALSO SEEN IN
PERFORATING INJURY

POSTERIOR CAPSULAR CATARACT
• PERSISTENCE OF hyaloid artery

RUBELLAR CATARACT
• NUCLEAR CATARACT
• A/W MATERNAL INFECTION IN 2ND OR 3RD TRIMESTER
• VIRUS CAN BE CULTURED FROM LENS
• A/W SALT & PEPPER RETINOPATHY
• CHD  PDA
• MICROPHTHALMOS
• MENTAL RETARDATION
• DEAFNESS
• MOST COMMON OCULAR COMPLICATION
• IN INDIA IS CATARACT
• IN WORLD IS SALT & PEPPER RETINOPATHY

Rx options in children
• Needling (discission) obsolete
• Lensectomy if child less than 2 years
• Lens Aspiration done if child more than 2 years

Senile cataract
Commonest type of acquired cataract

Pathophysiology Types
Cortical senile cataract
(soft cataract)
• Decreased level of total
protein , aa & K+
• Increased concn of Na+ &
hydration
• Coagulation & denaturation
of lens protein
Cuneiform
cataract (wedge
shaped
opacities in the
cortex)
Most common senile
(70 %)
Posterior
subcapsular
cataract (saucer
shaped opacity
beneath
posterior
capsule)
5% of cataract
Nuclear cataract (senile
cataract)
d/t intensification of age related
nuclear sclerosis
25% of senile cataract

Cuneiform senile cataract

Posterior subcapsular cataract

Senile nuclear cataract

Pathogenesis of Cortical senile cataract

Stages of
cortical senile
cataract
Stage of lamellar
separation
Stage of incipient
cataract (cuneiform or
cupuliform)
Stage of immature
senile cataract
Stage of mature senile
cataract
Stage of hypermature
senile cataract
(Morgagnian or sclerotic
type) TONY SCARIA 2010 KMC

Stage of lamellar sepraration • Fluid accumulation demarcation of cortical fibres  separation
• demonstrated by slit-lamp examination only.
• reversible.
Stage of incipient cataract Cuneiform senile cataract • wedge-shaped opacities with clear areas in between
• extend from equator towards centre and in early stages can only be demonstrated after
dilatation of the pupil. They are first seen in the lower nasal quadrant
Cupuliform senile cataract • in the central part of posterior cortex (posterior subcapsular cataract)
• Cupuliform cataract lies right in the pathway of the axial rays and thus causes an early loss of
visual acuity.
Immature senile cataract (ISC) • Cuneiform or cupyliform pattern can be recognised until late stage
• In late stage  diffuse & irregular
• Iris shadow still visible (because of clear cortex)
• ‘intumescent cataract'.
 lens may become swollen due to continued hydration.Due to swollen lens anterior chamber
becomes shallow
Mature senile cataract (MSC) • Lens becomes pearly white in colour. Such a cataract is also labelled as ‘ripe cataract’
Hypermature senile cataract
(HMSC)
Morgagnian cataract • after maturity the whole cortex liquefies &converted into a bag of milky Fluid
• small brownish nucleus settles at the bottom, altering its position with change in the position of
the head.
• calcium deposits may also be seen on the lens capsule
Sclerotic type • the cortex becomes disintegrated and the lens becomes shrunken due to leakage of water.
• wrinkled anterior capsule
• dense white capsular cataract may be formed in the pupillary area.
• shrinkage of lens anterior chamber becomes deep and iris becomes tremulous (iridodonesis)TONY SCARIA 2010 KMC

Intumuscent cataract
Shallow anterior
chamber

Morgagnian cataract Cortex converted to
milky fluid in HMSC
Nucleus sinks down shift position with
respect change in position of head

Sclerotic type HMSC
• the cortex becomes
disintegrated and the lens
becomes shrunken due to
leakage of water.
• wrinkled anterior capsule
• dense white capsular cataract
may be formed in the pupillary
area.
• shrinkage of lensanterior
chamber becomes deep and
iris becomes tremulous
(iridodonesis) TONY SCARIA 2010 KMC

Sclerotic type HMSC
wrinkled anterior capsule

Maturation of nuclear senile cataract
• In it, the sclerotic process renders the lens inelastic and hard,
decreases its ability to accommodate and obstructs the light rays.
• begin centrally and slowly spread peripherally almost up to the
capsule when it becomes mature; a very thin layer of clear cortex may
remain unaffected

Nuclear cataract
• become diffusely cloudy (greyish) or tinted (yellow to black) due to
deposition of pigments
• commonly observed pigmented nuclear cataracts
• amber, brown (cataracta brunescens) or
• black (cataracta nigra)
• reddish (cataracta rubra) in colour

CF
• Glare
• Coloured halos
• Frequent change of glasses
• Visual field loss

CF of nuclear cataract
Index myopia d/t increased refractive index of nucleus
Second sight
Day blindness Bright light  constriction of pupil
Loss of ability to see objects in bright light
Coloured halos around light d/t irregularity of refractive index in different part of
lens

CF of cortical cataract
NIGHT BLINDNESS d/t dilation of pupil in bright light
Index hypermetropia
Monocular polyopia (diplopia ) • It occurs due to irregular refraction by the lens
owing to variable refractive index as a result of
cataractous process
• In incipient stage of cortical cataract

CF of intumescent cataract
•RAPID LOSS OF VISON IN CATARACT

Complications of senile cataract
Phacoanaphylactic uveitis Leakage of lens proteins into anterior chamber from
hypermature cataract
may act as antigens  induce antigen antibody
reaction leading to uveitis
Lens-induced glaucoma phacomorphic glaucoma due to intumescent lens
phacolytic glaucoma leakage of proteins
into the anterior chamber from a hypermature
cataract
Phacotopic glaucoma Dislocated lens  block pupil or anterior chamber of
eye
Subluxation or dislocation of lens due to degeneration of zonules in hypermature
stage

Diabetes cataract
Glucose Sorbitol
NADPH dependant aldolase
reductase
Accumalates in lensglycation carbamylation of crystallins &increased oxidative
damage  osmotic changes hydropic lens fibres  SNOW FLAKE CATARACT
Fluctuating refractive error

Snowflake cataract

Complicated cataract
• Lens opacification secondary to some other cataract
• Disturbance in nutrition of lens due to inflammatory or degenerative disease of
other parts of the eye
• Cause
• Anterior uveitis
• iridocyclitis,
• ciliary body tumours,
• choroiditis,
• degenerative myopia,
• anterior segment ischaemia,
• retinitis pigmentosa,
• gyrate atrophy or
• retinal detachment
• Fibrous metaplasia of the fibresTONY SCARIA 2010 KMC

Complicated cataract may be of 2 types
Posterior cortical complicated cataract Anterior cortical complicated cataract
d/t affection of posterior segment  In posterior part
of cortex in the axial region
d/t affection of anterior segment like glaucoma
(glacucomflecken)or anterior uveitis
Bread crump appearance
Polychromatic lusture
c/c anterior uveitis  mc cause of complicated cataract

Toxic cataract
Systemic corticosteroids Posterior subcapsular cataract
Chlorpromazine Star shaped cataract
Miotics Anterior subcapsular cataract
Amiodarone Anterior subcapsular cataract

Chlorpromazine  star shaped cataract

Pre-senile cataract
• Myotonic dystrophy
• Down’s
• Werner’s
• Syndermatotic cataract
• NF

Systemic diseases a/w cataract
Galactosemia • Bilateral ‘oil droplet’ cataract in early life.
• Reversible cataract
• d/t seficiency of galactose 1 phosphate uridyl
transferase
Fabrys disease • cornea verticillate
• Spoke like lens opacities
Lowes syndrome • Posterior lentoconus
• Cataract
• Microspherophakia
Wilson disease • KF ring
• Sunflower cataract  pseudocataract  no visual
impairement
Hypocalcemia • Spike or riders on surfaceTONY SCARIA 2010 KMC

Oil droplet cataract

Radiation cataract: Heat, X rays, Gamma rays, UV rays cause posterior
subcapsular cataract
Infrared radiation cataract (Heat) specifically seen in
glass blowers
and iron workers. Associated with pseudoexfoliation
of the lens capsule.
Down syndrome punctate subcapsular cataracts.
Atopic cataract Cataract appears frequently in those suffering from
severe and widespread skin diseases—-atopic eczema,
poikiloderma vasculare atrophicans, scleroderma,
keratosis follicularis, and others

Mx of cataract

Indications for cataract Sx
Optical indication Medical indication Cosmetic indication
• In visually handicapped patients
• MC indication
• Lens induced glaucoma / uveitis
• Dislocated / subluxated lens
• RD or diabetic retinopathy
• Phacoanaphylactivc
endophthalmitis

Pre operative evaluation
Visual acuity • Snellens chart
Pupil • RAPD
• Pupillary reactin
Cornea • Keratometry
• Corneal topography
IOP • Tonometry
• If high  gonioscopy
Slit lamp examination • Anterior segment evaluation
B scan Usg • posterior segment assessment
Retinal / macular function test • Light perception
• Maddox rod test
• Colour perception
• Laser inferometry
• ERG EOG VER
Contrast sensitivity functions • Vison contrast test system
• Pelli robston contrast system
• FACTS

For IOL power calculation

IOL calculation
Hypermetropic eye (axial
length <22mm)
Emmetropic eye (axial
length 22-25mm)
Myopic eye (axial length
>25 mm)
Post refractive Sx cases
HOFFER Q formula SRK II formula SRK T formula Haigis / holladay formula

Operative techniques
Extracapsular cataract extraction (ECCE) Intracapsualr cataract extraction (ICCE)
Central part of Anterior capsule & lens are removed
leaving behind peripheral part of anterior capsule &
posterior capsule
Lens is removed along with whole capsule after
breaking zonules
IOL is placed in capsular bag IOL is kept iris fixed/ sclera fixed /placed in AC
SX of choice for all cataract Sx
C/I in subluxated or dislocate dlens
Only indication  subluxated lens

Variations of ECCE
ECCE Small incision cataract Sx Phasecoemulsification Microincision cataract Sx
Large limbal incision of 8-
9mm
Corneoscleral tunnel is
used instead of limbal
inciosn of size 6-7mm
Incision of size to allow US
probe (3.2mm)
Lens is emulsified &
aspirated by by US probe
after making circular
opening in anterior capsule
Foldable IOL implanted in
to capsular bag
Incision is even smaller 
1.8-2.2mm
Rollable IOL  ultrathin
IOL are used after phakonit
technique microincision of
1mm

phacoemulsification

IOL implantation
• Indicartion
• Correction of aphakia
• Unilateral cataract extraction  commonest indication
• Best position is with in capsular bag in posterior chamber

Types OF IOL based on foldability
Nonfoldable (rigid) Foldable Rollable
Made up of PMMA Silicon / acrylic acid /hydrogel Hydrogel
PCIOL / ACIOL /iris fixated iOL
/sclera fixed IOL
PCIOL IN phacoemulsification PCIOL in phokonit technige(MCIS)

Types of IOL based on focal length
Monofocal IOL Multifocal IOL Accomodative IOL
Provide good distance vison
Accomodation is lost  poor near
vision  glasses are used for near
visions
• Separate zone for focussing for
far & near vison
• Disadvantage  glare & halos
Can move in accommodation to
provide good vision for both
distance & near with out glasses

Complications of cataract Sx
Complications related to Sx Complications related to IOL
• Aftercataract (opacification of capsule)
• Vitreous prolapse & loss
• CME
• Endophthalmitis
• Aphakic glaucoma
• Anterior uveitis
• RD
• Pseudophakic bullous keratopathy
• Corneal endothelial damage
• Sunset syndrome
• Sunrise syndrome
• Lost lens syndrome
• Windhield wiper syndrome
• Toxic lens syndrome (d/t ethylene gas treated IOL)
• UGH syndrome (uveitis glaucoma hyphaemia )

Aftercataract
• Most common complication of ECCE
• Postopertaive proliferation of capsular lens  opacification
Ring of soemmering Elschnng pearls
the cubical cells which line the anterior
capsule
also persist; they continue to fulfil their
function of
forming new lens fibres, although those
formed under
these abnormal conditions are abortive
and opaque.
Sometimes these fibres, enclosed
between the two layers of capsule, form
a dense ring behind the iris
the subcapsular cells proliferate
and instead of forming lens fibres,
develop into large
balloon-like cells which some-times fill
the pupillary
Aperture
RX with NdYAG laser

ring of soemmering

Elschning pearls

Elschning operation

Endopthalmitis in cataract Sx
• Suppurative inflammation strating from vitreous which extend all
parts of eye except sclera
• If sclera is involved  panopthalmitis
• Rx of panopthalmitis is evisceration
Early onset (with in 7 days ) Late onset
Staphylococcus epidermidis Fungi & Propionibacterium acne

Prevention of endopthalmitis
• Pre operative Abx strated 3 days prior to cataract Sx
• Topical antiseptic povidone iodine 5% instilled as single drop 10 -30
minute before Sx
• Intraoeprative injection of Abx subconjunctivally
• Postoperative intracameral injection of Abx
• Post operative topical Abx fo 1-2 weeks

Disease Cataract
Myotonic dystrophy Christmas tree cataract
Wilson disease /chalcosis Sunflower cataract
DM/ down syndrome Snow flake cataract
Atopic dermatitis Blue dot cataract
Posterior subcapsular cataract
Congenital rubella Nuclear cataract
Galactosemia Oil drop cataract
Complicated cataract (iridocyclitis/high myopia) • Posterior cortical breads crumb appearance e
• Polychromatic lusture
• Rainbow cataract
Blunt trauma • Vossius ring on anterior surface of lens
• Rossette shaped cataractTONY SCARIA 2010 KMC

Sunflower cataract in Wilson ds

Snow flake cataract in DM

Bread crumb cataract in complicated cataract

Vossius ring d/t blunt trauma

Rosette shaped cataract

ECTOPIA LENTIS
• MARFANS SYNDROME
• EHLERS DANLOS SYNDROME
• HOMOCYSTINURIA
• WEIL MARCHESANI SYNDROME
• SULPHITE OXIDASE DEFICIENCY
• HYPERLYSINEMIA
• STICKLER SYNDROME
• TRAUMA

DISEASE LENS DISLOCATION
MARFAN SYNDROME SUPEROTEMPORAL
HOMOCYSTINURIA INFERONASALLY
WEIL MARCHESANI SYNDROME FORWARD

C/F
• Uniocular diplopia
• Slit lamp examination
• Phacodonesis  lens moving with eye movement
• Shining golden brighjt crescent
• direct ophthalmoscopy
• Dark crescent line
• Retinoscopy 
• aphakic area is hypermetropic
• Phakic area ia myopic
• 2 discs on fundoscopy
• Larger through aphakic area
• Smaller through phakic area

Golden bright shining crescent in slit lamp oblique
illumination

Golden bright crescent

Congenital spherophakia
• Congenital small speherical lens --> increased risk for phacomorphic
glaucoma

Iris shadow to detect cataract

Contact lens

Hard contact lens Rigid gas permeable Soft contact lens
Made up of polymethylmethacrylate
(PMMA)
firm, durable plastic that
transmits oxygen, e.g. a
copolymer of PMMA and
silicone and cellulose
acetate
butyrate
hydroxyethylmethacrylate
(HEMA)
Oxygen delivery Poor Moderate to high High
Visual clarity Good Clear vision Need to refocus after a
blink
Use in astigmatism Possible Possible Less suitable
Adaptation Required Required Not required
Deposits Few few Accumulate over time
Durability May scratch Do not scratch or tear Tend to tear

• Contact lens keratitis
• MC organism is pseudomonas
• Acanthameba can also cause from tap water
• In case of contact lens keratitis avoid wearing contact lens for 48-72
hrs

CATARACT (lens) REVISION NOTES

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CATARACT (lens) REVISION NOTES