overview of cataract

1. Madhulika Ladha

2.  Definition: Any opacity in the lens or its capsule whether
developmental or acquired is called a cataract.
 Usually developmental opacities are stationary and
partial
 Acquired opacities progress till entire lens is involved
 Damage to the lens by trauma, toxins, hydration or UV
rays affect lens transparency.

3.  Cataract is due to degeneration and
opacification of formed lens fibres, formation
of aberrant lens fibres or deposition of other
materials in their space.
 This is due to
Hydration
Denaturation of lens proteins
Sclerosis

4. • Heredity
• Age
• UV radiation
• Dietary deficiencies of Vitamins A,C,E
• Severe diarrhoea
• Diabetes
• Smoking
• Corticosteroids

5. Classification:
 by cause: congenital, senile(age-related),
complicated, metabolitic, drug-induced, toxic,
traumatic, secondary
 by age:congenital, acquired
 by location: cortical, nuclear, subcapsular
 by shape: dot-like, coronary, lamellar
 by degree: immature, intumescent, mature,
hypermature

6. Symptoms:
 decreased vision: most obvious and important
because of reduced transparency of lens
 decreased contrast sensitivty
 refractive error like myopia due to change in RI of
nucleus and hence frequent change of glasses
 monocular diplopia and coloured halos due to
irregular refraction by different parts of lens
 Glare due to scattered light rays
 Change in color values ie red is accentuated

7. Grade’s standards of nuclear hardness:
Ⅰ transparent,no nucleus,soft
Ⅱ yellow-white or yellow,soft
Ⅲ dark yellow,moderate hard
Ⅳ brown or amber, hard
Ⅴ brown or black,extremely hard

9.  The Lens Opacity Classification System II (LOCS II)
photographic grading standards. N = Nuclear photographs.
Stage 0 = normal; I–III = various stages of nuclear cataract. For
nuclear opalescence, the average opalescence across the entire
nuclear region is used. An opalescence that is less than or
equal to Photographic Standard 0 = grade 0; if the opalescence
is less than or equal to Standard I, the grade is 1, and so on. For
Color Grading of the nucleus, only the N2 standard is used.
(<N2 for color=0, equal to N2 in color=1, and N2 for color = 2)
C = Cortical photographs. 0-Trace (Tr) = normal; I–IV =
various steps of cortical cataract (roughly CII ¼, CIII ½, CIV ¾.
CV > ¾). P = Posterior subcapsular photographs. 0 = normal;
I–III = various stages of posterior subcapsular cataracts

10. Most common type
Most patients are beyond their 50’s.
Occurs equally in men and women
Earlier in tropical countries
Considerable genetic influences

11.  The most common type
 Etiopathogenesis : Hydration followed by coagulation of
proteins in the cortex.
 Stages:
(1) Lamellar seperation
(2) Incipient cataract
(3) Immature stage
(4) Mature stage
(5) Hypermature stage

12.  Demarcation of cortical fibres owing to their
separation by fluid.
 Demonstrated by Slit-lamp examination only.
 Characteristic grey appearance of pupil due to
scattering of light
 Changes are reversible.

13.  Wedge shaped opacities with clear areas in
between( Lens striae).
 Most common in periphery and lower nasal
quadrant.
 Only seen in dilated pupil
 Irregularities in refraction, visual deterioration
and polyopia.

15.  Opacification becomes more diffuse and irregular.
 Lens is swollen.
 Iris shadow still visible.
 Anterior chamber becomes shallow.

17.  Complete opacification
 Whole cortex is involved
 Lens appears pearly white in colour
 Also known as ripe cataract
 No iris shadow

19. Cortex is disintegrated and transformed into pultaceous
material.
Usually occurs in two forms:-
1. Morgagnian hyper–mature cataract
2. Sclerotic hyper–mature cataract

20.  MORGAGNIAN CATARACT
Complete cortex is liquefied and appears milky
white in colour.
Nucleus settles at the bottom.
Calcium deposits may also be seen on the lens
capsule.
 SCLEROTIC HYPER–MATURE CATARACT
Disintegrated cortex.
Shrunken lens sometimes appears yellow
Wrinkled anterior capsule .
Dense white capsular cataract in pupillary area.
Deep Anterior-Chamber.
Tremulous Iris .

21. Morgagnian cataract
Shrunken cataract

22. Etio-pathogenesis:- Intensification of age related degenerative
changes associated with dehydration and compaction of
nucleus ie nucleur sclerosis
 Features:
 start earlier, generally on 40’s
 Hard cataract is formed.
 Significant increase in water insoluble protein.
 Lens becomes in-elastic and looses power of accommodation.
 Changes begin centrally and slowly spread to periphery.
 Cortex is clear

23.  slowly progressive, not likely to be mature.
 Deposition of tryptophan derived pigments that
gives characteristic colour to nucleus
cataracta brunescens- brown
cataracta nigra- black
Cataracta rubra- dusky red
 Vision: no vision damage early, myopia due to
increase in RI of nucleus
.

25. Features:
start earlier
Subcapsular opacities extending towards equator
posterior subcapsular cataract: cause obvious
vision defect early because near the nodal point
Best seen on retroillumination

27.  Congenital cataract
 (present at birth)
 Developmental cataract
 (develops soon after birth)
 Developmental opacity are usually partial & stationary
Etiology:
(1) Maternal and infantile malnutrition
(2) maternal infection
(3) defective oxygenation

28.  Punctate (blue dot) cataract
 Anterior Capsular cataract
 Anterior cortical cataract
 Pyramidal
 Reduplicated
 Posterior polar cataract
 Embryonal (nuclear) cataract
 Coronary cataract
 Fusiform cataract
 Zonular (Lamellar) cataract
 Total cataract

30. Punctate (blue dot/ cataracta coerulea) cataract:
Most common type
Appears as multiple, tiny blue dots
scattered all over the lens, especially
in the cortex.
Bluish color is due to the effects of
dispersion of light.
When near sutures- sutural cataract
Visual acuity is not affected

31. Anterior Polar Cataract
It is sharply demarcated opacity at the
anterior lens capsule.
Due to delayed formation of the anterior
chamber, during development due to
contact of capsule and cornea
It may project forwards into the anterior
chamber like a pyramid (pyramidal
cataract);
Or underlying cortex becomes opaque
(anterior cortical cataract)
When both are present ther is a clear
zone of subcapsular epithelium in
between (reduplicated cataract)
These opacities are stationary and rarely
interfere with vision.

32. Associated with persistent
hyaloid remnants(mittendorf
dots),posterior lenticonus &
persistent anterior fetal
vasculature
Common in minimal degree &
visually insignificant
With persistent hyaloid artery ,
lens deeply invaded by fibrous
tissue leading to total cataract
Posterior Capsular ( Polar) Cataract

33. Zonular (Lamellar) Cataract
Accounts for 50% of visually significant
cataract
Zone around embryonic nucleus (usually in
area of fetal nucleus) become opacified, area
around opacity is clear
Linear opacities like spokes of a wheel
(called riders) may run outwards
Usually bilateral,formed just before/shortly
after birth and affect vision
Often hereditary (autosomal dominant)
Associated with hypovitaminosis D or
hypocalcemia &maternal malnutrition

34. Coronary Cataract
Around puberty
Situated in deeper layers of
cortex &superficial layers of
adolescent nucleus
Corona or club shaped opacities
near periphery of lens ,usually
hidden by iris while rest areas
are free
Non progressive & does not
interfere with vision

35. Nuclear Cataract
Associated with rubella
Incidence more if infection
contracted in 2nd
month
Development of lens inhibited
at very early stage
Embyonal nuclear cataract
Progressive ,becomes total
cataract
Associated microphthalmos,
salt and pepper retinopathy,
deafness, heart defects

36. Fusiform Cataract
Anteroposterior spindle shaped opacities sometimes with
offshoots
Resemble coral hence called coralliform or spindle shaped
cataracts
Genetically determined
Discoid cataract- disc like opacity behind nucleus in posterior
cortex

37. Cataract that develops secondary to a primary ocular
disease.
Characterstic feature is polychromatic lustre and bread
crumb appearance
Chronic anterior uveitis:
most common
Polychromatic lustre at posterior pole
If persists anterior and posterior opacities
develop

38. Acute congestive angle closure: focal infarcts of lens
epithelium – small grey-white anterior subcapsular, or
capsular opacities- glaukomfecken
Pathological myopia: posterior subcapsular opacities and
early onset nucleur sclerosis that increase myopia
Heridity fundus dystrophies:
Lebers: total cataract
Stickler syndrome: cortical cataract

39.  Diabetic cataract:
Mech: hyperglycemia excess glucose to
metabolize into sorbitol in lens osmotic
overhydration
Is of 2 types
1) classic diabetic cataract : rare, fluid vacuoles in
capsule then dense white subcapsular opacities in
cortex : snowflake cataract
2) age-related cataract of diabetic patients: earlier and
rapid progression of senile cataract

40.  Myotonic dystrophy: fine dust like opacities with
tiny iridescent spots in cortex- christmas tree
cataract
May progress to stellate opacity at posterior pole
 Atopic dermatitis: shield like dense anterior
subcapsular plaque

41.  Galactosemia: anterior and posterior subcapsular
lamellar opacities- oil drop cataract
 Wilsons disease: sunflower cataract
 Parathyroid tetany:
Children : lamellar opacities
Adults: anterior/ posterior punctate opacity

42. Snowflake cataract Christmas tree cataract
Oil droplet cataract Sunflower cataract

43.  Corticosteroid cataract : posterior subcapsular
cataract
 Chlorpromazine cataract
 Miotic cataract : Anterior subcapsular cataract
 Trinitrotoluence cataract
 Other drugs like busulfan, chloroquine,
amiodarone
 Metals like iron, gold, copper

44.  Causes:
Concussion– Rosette cataract
Penetrating trauma
Heat cataract: seen in glassworkers and ironworkers,
small posterior cortex opacity with zonular
exfoliation
Radiation cataract: posterior subcapsular opacities near
posterior pole
Electric cataract : anterior / posterior iridescent
opacities with stellate pattern

45. Rosette cataract
Traumatic cataract