Cataract

2
Cataract
Clinical
Definition
Punctate (Blue-dot) cataract:
A cataract is a clouding of the lens in the eye
that affects vision
• A hereditary opacity of the eye’s lens.
Bright blue dot shaped opacities are
irregularly scattered throughout the lens.
• The bluish colour is due to the effects of
dispersion of light. The visual acuity is not
affected.
Classification of cataract
-
-
Congenital cataract (or) developmental
cataract
Acquired cataract
Congenital (or) Development cataract
Cataract that presents at birth or develops
soon after the birth.
Causes of Congenital cataract
1. Chromosomal abnormalities - a missing,
extra or irregular portion of chromosomal
DNA
2. Maternal malnutrition (vitamin –D
deficiency)
3. Foetal hypoxia - fetus is deprived of
adequate supply of oxygen
4. Drug intake during the pregnancy eg.
Corticosteroids
Anterior polar cataract
-
Morphological Types
1.
2.
a.
b.
3.
4.
5.
6.
7.
8.
Blue-dot Cataract
Punctate (blue-dot) cataract
Anterior polar cataract
Pyramidal
Reduplicated
Posterior polar cataract
(Embryonic) nuclear cataract
Coronary cataract
Coralliform cataract
Zonular (lamellar) cataract
Total cataract - Soft, Membranous
-
A hereditary disorder occurring in
children, and characterized by lesions
with small white milky plaques in the
front of the lens.
Cloudy vision and near sightedness
(myopia) are common. These opacities are
stationary and rarely interfere with vision.
Posterior polar cataract
-
This is due to residue of the attachment
of hyaloid artery (A branch of the
ophthalmic It is contained within the optic
stalk of the eye and extends from the optic
Coralliform cataract - congenital cataract with round or elongated processes radiating from the center of the lens
A R A V I N D
E Y E
C A R E
S Y S T E M
3
Posterior Polar Cataract
disc through the vitreous humor to the
lens on the posterior lens capsule) on the
posterior lens capsule. This is usually dot
– like mittendorf’s dot - (small, circular
opacity on the posterior lens capsule) and
insignificant.
Coronary cataract
-
-
A common visual disorder occurring
in adults, that usually does not impair
vision. Zones of small opacities may occur,
varying in color from gray to brown,
yellow, red or blue.
The opacities are arranged radially in the
outer layers of the lens, leaving the center
of the eye clear. It does not interfere with
vision.
Zonular (lamellar) cataract
-
-
It is probably the commonest type of
development cataract presenting with
visual impairment.
It may be inherited through dominant
genes, or caused by malnutrition
during pregnancy or early infancy
- hypovitaminosis – D (deficiency of
Lamellar Cataract
vitamin D ), hypocalcaemia (presence of
low serum calcium levels in the blood )
Rubella Cataract
-
-
-
Rubella infection during pregnancy may
cause wide-spread ocular and systemic
defects.
The cataract is originally nuclear and
progresses to become total.
It is associated with microphthalmos,
nystagmus, strabismus, glaucoma,
iris hypoplasia (prevents an iris from
developing properly) and pigmentary
retinopathy (a disorder of the retina
characterized by deposits of pigment and
increasing loss of vision)
Acquired cataract is classified as follows
1. Senile
2. Traumatic
- Mechanical
- Irradiation
- Electric shock
3. Complicated (due to some other ocular
disease)
Chlorpromazine - used as a tranquillizer, and sedative; Busulfan - used to treat chronic leukemia - abnormal blood cells are
produced in the bone marrow.
Compassion Apr - June, 2016
4
-
-
-
-
-
Anterior uveitis
High myopia
Retinal detachment
Retinal pigmentosa
Glauokomflecken (gray-white epithelial and anterior cortical lens
opacities)
4. Secondary (due to some systemic disease)
- Diabetes mellitus
- Hypocalcemia
5. Toxic (due to drugs)
- Corticosteroids
- Chlorpromazine
- Miotics (long – acting)
- Busulfanb
- Amiodarone (used to help keep the
heart beating normally in people
with life-threatening heart rhythm
disorders)
- Gold
6. Syndromes associated with cataract
- Down’s - (arising from a chromosome
defect, causing intellectual impairment
and physical abnormalities)
- Lowe’s
-
-
-
Treacher Collins (a condition that
affects the development of bones and
other tissues of the face)
Wilsons’s disease (too much copper
to accumulate in the liver, brain and
other vital organs)
Fabry’s disease (buildup of a
particular type of fat)
Senile cataract
The aging lens tends to become opaque after
the age of 50 years and by the age of 70 over
90% of the population show some evidence of
cataract.
Senile cataract is divided into two types
1. Cortical or soft cataract (75 – 80%) - begins
at the outer portion of the lens, then
slowly moves inward.
2. Nuclear or hard cataract (20 – 25%)- forms
deep in the central zone (nucleus) of the
lens
Stages of cataract
1. Stage of lamellar separation (demarcation
of cortical fibres owing to their separation
by fluid).
Difference between cortical & nuclear cataract
Cortical Cataract
Nuclear Cataract
1. Usually starts at late 50s
Tends to occur earlier than cortical
2. Starts with ocular diplopia / polyopia (two or more images) or
coloured halos
No such symptoms
3. Gives rise to index hypermetropia
Gives rise to index myopia
4. Appears greyish and changes to milky
Appears yellow, brown or black with
white with the maturity of the cataract progression of cataract
5. More chance of lens induced secondary
glaucoma
A R A V I N D
E Y E
C A R E
S Y S T E M
Little chance of lens – induced secondary glaucoma
5
Difference between immature & mature cataract
Immature Cataract
Mature Cataract
A. Symptoms
1. Partial loss of vision
Total loss of vision
2. Diplopia / Polyopia
White opacity
3. Rainbow halos
noticed by the patients or relatives
B. Signs
1. Visual acuity
Vision reduced to varying degree Vision reduced to hand
movement or PL
2. Colour of the lens
Grey / greyish white
White / pearly white
3. Iris shadow
Present
Absent
4. Purkinje’s image
3rd image is seen, 4th image may be distorted
Only 3rd image is seen,
4th image absent
5. Fundal glow
Present
Absent
6. Retinoscopy
Possible
Not possible
7. Spectacles May improve vision
Does not improve vision
2. Stage of incipient cataract (the lens of the
eye is only slightly opaque, with a clear
cortex).
3. Immature stage
4. Mature stage
5. Hypermature stage (the lens proteins have
become liquid)
Investigations prior to surgery
1. A. History
B. Local Investigations
- Vision
- Perception of light (PL)
- Projection of rays (PR)
C. Action of pupil
D. Slit lamp examination
E. Intraocular pressure
F. Patency of the lacrimal passage
G. Funduscopy
2. Conjunctival swab for culture and
sensitivity tests.
3. Calculation of IOL power.
4. Macular function tests
5. Systemic Investigations
Surgical techniques in senile cataract:
1. Extra – Capsular Cataract Extraction
(ECCE)
2. Intra – Capsular Cataract Extraction
(ICCE)
3. Phaco – Emulsification
4. Intraocular lens implantation with any of
the first three
5. Glaucoma surgery with any of the first
three with or without IOL implantation.
6. Keratoplasty with any of the first three
with or without IOL implantation.
7. Keratoplasty with ECCE with IOL
implantation termed “Triple Procedure”.
Stage of incipient cataract - the lens of the eye is only slightly opaque, with a clear cortex; Hypermature stage - the lens proteins
have become liquid
Compassion Apr - June, 2016