NUCLEAR CATARACT PROJECT for Career growth

Nuclear

1. LENS DEFINITION:
The crystalline lens is a transparent, biconvex structure or ellipsoid structure and is
located posterior to the iris and anterior to the vitreous body in a saucer shaped depression, the
patellar fossa. It is colourless. Its diameter is 9 to 10 mm and its thickness is varies with age. The lens is
suspended by numerous fibers that together are called zonules. The ring of fibers (Zonules of Zinn)
attaches the lens to the ciliary body and is called Suspensory ligaments. The total dioptric power is 16 to
18D and the refractive index of lens is 1.39, Nuclear is 1.41 and cortex is 1.38. The lens is made up of
unusual elongated cells that have no blood supply and nerve supply but obtain nutrients from the
surrounding fluids, mainly the Aqueous humour that bathes of the lens and the waste products are
removed through these fluids. The main role of the lens is to maintain the transparency, organizer of
anterior segment, is to provide accommodation in conjunction with the zonules and the ciliary body, it
provide the focused real and inverted image of the object on the retina and preventing the damaging
rays from reaching the retina, its accounts for 35% of total refractive power of eye. The lens structure
consists of three. They are,
 Lens capsule
 Lens epithelium
 Lens fibres.
i. Nucleus
ii. Cortex.

Nucleus: It is the central part containing the oldest fibers. Slit lamp
examination of an adult lens, from within outwards may show the following
nuclei are,
 Embryonic nucleus
 Fetal nucleus
 Infantile nucleus
 Adult nucleus.
EMBRYONIC NUCLEUS:
It is the innermost part of nucleus which corresponds to the lens up to first 3 month of
gestation. It consists of primary lens fibers which are formed by elongation of the cells of posterior wall
of lens vesicle.
FETAL NUCLEUS:
It lies around these embryonic nucleus and corresponds to the lens from 3 months of
gestation till birth. Its fibres meet around sutures which are anteriorly Y-shaped and posteriorly inverted
Y-shaped.
INFANTILE NUCLEUS:

2. It corresponds to the lens from birth to puberty and surrounds the fetal nucleus.
ADULT NUCLEUS:
It corresponds to the lens fibers formed after puberty to rest to the life.
CATARACT:
Cataract is defined as the clouding or opacification or loss of transparency of tissues
breakdown and protein clumping. The word ‘Cataract’ is derived from greek word ‘Katarraktes’ which
means ‘Waterfall’. Assuming that the abnormal humour developed and flowed in front of lens to
decrease the vision. A cataract begins when proteins in the eye from sending clear images to the retina.
The retina works by converting the light that comes through the lens into signals. It send the signals to
the optic nerve, which carries them to the brain.
CLASSFICATION:
ETIOLOGICAL CLASSIFICATION:
 Congenital and developmental Cataract
 Acquired Cataract
Senile Cataract
 Traumatic Cataract
 Complicated Cataract
 Metabolic Cataract
 Electric Cataract
 Radiational Cataract
 Toxic Cataract
Cortico steroid induced cataract
Miotics induced cataract
Copper and iron induced cataract
 Cataract associated with skin diseases (Dermatogenic cataract )
 Cataract associated with osseous diseases
 Cataract with miscellaneous syndromes.
Down’s syndrome
Lowe’s syndrome
MORPHOLOGICAL CLASSIFICATION:

3.  Capsular Cataract
a. Anterior capsular cataract
b. Posterior capsular cataract
 Cortical Cataract
 Sub capsular Cataract
Anterior subcapsular cataract
Posterior sub capsular cataract
 Supra nuclear Cataract
 Nuclear Cataract
 Polar Cataract.
Anterior polar cataract
Posterior polar cataract.
NUCLEAR CATARACT:
Nuclear cataract is defined as an opacity or clouding that develops in the lens nucleus or in the
centre. Nuclear cataract is one that is located in the center of the lens. The nucleus tends to darken
changing from clear to yellow and sometimes brown.
CLINICAL TYPES:
Congenital nuclear cataract
1. Cataracta pulverulenta
2. Lamellar cataract
3. Sutural and axial cataracts
Floriform cataract
Coralliform cataract
Spear shaped cataract
Anterior axial embryonic cataract
Dendritic suture cataract
4. Total nuclear cataract.
Acquired nuclear cataract.

4. Nuclear senile cataract
CONGENITAL NUCLEAR CATARACT:
Congenital nuclear cataract is occur due to some disturbance in the normal growth of the
lens before the birth.
1. CATARACTA CENTRALIS PULVERULENTA :
Cataracta centralis pulverulenta is a type of nuclear cataract involved in embryonic
nucleus. It is also known as pulverulent nuclear cataract or central puluverlent cataract or
embryonic nuclear cataract. It has dominant genetic trait and occurs due to inhibition of the
lens development at a very early stage.