1. LENS AND CATARACT
Mohammad Salah Uddin
M Opt; MPH(Ophth.)
Chief Optometrist
Lions Eye Institute & Hospital
2. Objective
- Know the normal anatomy and function of the
lens.
- Know the risk factors for the development of
cataract.
- Know the sign and symptom of cataract.
- Identify patients with cataract and be able to
refer patients to a centre where they can
undergo definitive treatment i.e. surgery.
- Know the complications of untreated cataract.
3. Normal crystalline lens
is transparent, biconvex
structure.
It is derived from the surface ectoderm.
It is composed of –capsule
lens epithelium
cortex and nucleus
It has no blood supply or nerve supply after
fetal development.
4. • Lies posterior to iris and anterior to vitreous.
• Suspended in position by the zonular fiber.
• It depends on aqueous humor to meet its
metabolic requirement and carry off its
wastes.
• It grows continuously throughout life.
• Measures at birth adulthood
• Equatorially 6.4mm 9mm.
• Ap 3.5mm 5mm.
• Weighs 90mg 255mg
5.
6.
7. • Functions
-to maintain its own clarity.
-provides accommodation.
-to refract light, the lens contributes
about 15-20 diopters of the refractive
power of the eye.
8. CATARACT IS CAUSED BY
OPACIFICATION AND DEGENERATION
OF LENS FIBRES ALREADY FORMED,
THE FORMATION OF ABBERENT LENS
FIBRES OR DEPOSITION OF OTHER
.MATERIALS IN THEIR PLACE
:DEFINITION
Any congenital or acquired opacity in
the lens or lens capsule is called as
cataract
9.
10.
11. Epidemiology
1. Cataracts remain the
leading cause of
blindness.
2. Age-related cataract is
responsible for 48% of
world blindness, which
represents about 18
million people
3. Cataracts are also an
important cause of low
vision in both
developed and
developing countries.
12. Cataracts
• Cataract surgery is the most frequently
performed surgical procedure
• 50% of those over 65 develop vision
impairing cataracts.
20. SENILE CATARACT
• Also called as age related cataract
• Usually above the age of 50 yrs
• Usually bilateral, but almost always one
eye is affected earlier than the other
26. Cortical cataract
• Occur on the outer edge of the lens (cortex).
• Begins as whitish, wedge-shaped opacities or
streaks.
• It’s slowly progresses, the streaks extend to the center
and interfere with light passing through the center of
the lens.
• Problems with glare are common with this type of
cataract.
28. Mature Cataract
• Lens is completely opaque.
• Vision reduced to just perception of light
Right eye mature cataract, with obvious
white opacity at the centre of pupil
32. Sclerotic Cataract
• The fluid from the cortex gets
absorbed and the lens
becomes shrunken.
• There may be deposition of
calcific material on the lens
capsule.
• The zonules become weak,
increasing the risk of
subluxation / dislocation of
lens.
33. •SUBJECTIVE CLASSIFICATION:
• GRADE 0: CLEAR LENS
• GRADE 1: SWOLLEN FIBRES AND SUB CAPSULAR
OPACITIES
• GRADE 2: NUCLEAR CATARACT AND VISIBLE LENS
FIBRES
• GRADE 3: STRONG NUCLEAR CATARACT WITH
PERINUCLEAR AREA OPACITY
• GRADE 4: TOTAL OPACITY
47. Symptoms
•A cataract usually develops
slowly, so:
–Causes no pain.
–Cloudiness may affect
only a small part of the
lens
–People may be unaware of
any vision loss.
•Over time, however, as the
cataract grows larger, it:
–Clouds more the lens
–Distorts the light passing
through the lens.
–Impairs vision
•Reduced visual acuity
(near and distant object)
•Glare in sunshine or with
street/car lights.
•Distortion of lines.
•Monocular diplopia.
•Altered colours ( white
objects appear yellowish)
•Not associated with pain,
discharge or redness of
the eye
49. •
Blurred vision
•
Need for frequent changes in your
eyeglasses or contacts
•
Trouble in driving at night (Glare)
•
Sensitivity to bright light
•
Change in color vision (yellow, orange, and red
.appear brighter and WHITE appears dull)
•
Polyopia and monocular diplopia
•
Coloured haloes
:SYMPTOMS
62. Phacoemulsification in cataract surgery
involves insertion of a tiny, hollowed tip that
uses high frequency (ultrasonic) vibrations to
"break up" the eye's cloudy lens (cataract).
The same tip is used to suction out the lens
.
63. Postoperative care after cataract
surgery
• Steroid drops (inflammation)
• Antibiotic drops (infection)
• Avoid
• Very strenuous exertion (rise the pressure in
the eyeball)
• Ocular trauma.
64. Complications of cataract surgery
• Infective endophthalmitis( infection)
• Bleeding or haemorrhage
• Uveatis( Inflammation)
• Glaucoma
• Vitreous loss
• Cystoid macula
• Retinal detachment . . .
65. Congenital Cataract
• Occur in about 3:10000 live birth.
• 2/3 of case are bilateral
• It can cause ambylopia in infants.
66. Management in congenital cataract
• Bilateral congenital cataract require urgent
surgery (lensectomy and vitrectomy) and the
fitting of the contact lens to correct the aphakia
• Uniocular congenital cataract treatment
remains controversial.
• Follow-up for children with congenital cataract
should continue because of the risk for
developing
– Glaucoma
– Amblyopia
– Strabismus
