During this lecturer, you are going to learn the following: Anatomy & functions of the lens Definition & classifications of cataract Congenital cataract: Causes Symptoms Signs How to assess vision in congenital cataract? Post-operative visual rehabilitation Management How to calculate IOL power in pediatric patients?

1. Dr. Abdelmonem Hamed
Fellow of Baylor of College of Medicine, USA
Professor of ophthalmology, Benha University, ARE
LENS
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‫اد‬/‫حامد‬ ‫المنعم‬ ‫عبد‬
‫بنها‬ ‫جامعة‬ ، ‫العين‬ ‫وجراحة‬ ‫طب‬ ‫استاذ‬
‫بأمريكا‬ ‫بيلور‬ ‫طب‬ ‫كلية‬ ‫زميل‬

2. During this lecturer, you are going
to learn the following
 Anatomy & functions of the lens
 Definition & classifications of cataract
 Congenital cataract:
 Causes
 Symptoms
 Signs
 How to assess vision in congenital cataract?
 Post-operative visual rehabilitation
 Management
 How to calculate IOL power in pediatric patients?

3. Lens
 Transparent, spheroid
structure
 RI = 1.39
 It does not have nerves, or
blood vessels.
 Biconvex ,
 anterior surface (r=10mm)
 posterior surface (r=6mm).
Prof . Dr. Abdelmonem Hamed
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4. Lens
 Diameter : 9 - 10 mm
 Thickness is 4 mm in
adults.
 Power= 15 – 18 D
 Its weight is about 65
milligrams at the birth and
up-to 258 mg by 80 years
of age.
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Prof . Dr. Abdelmonem Hamed
9 - 10 mm 4 mm

5. Lens
 Lens is suspended in eye by Zonules of Zinn
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Prof . Dr. Abdelmonem Hamed

6. Lens-Anatomy
1. Capsule
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Prof . Dr. Abdelmonem Hamed
 Transparent collagenese basement
membrane
 It allows a transport of molecules to & from
the lens

7. Lens-Anatomy
2. Lens Epithelium :
single layer of cells lining the anterior capsule.
It is gradually become elongated towards the
equator.
 Function of he lens epithelium:
 Formation the lens fibers
 regulate the transport of metabolites to &
from the lens
 secrete the lens capsule
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Prof . Dr. Abdelmonem Hamed

8. Lens - Anatomy
The Nucleus:
consists of
(i) Embryonic nucleus ( formed in lens vesicle)
(ii) Fetal nucleus: ( formed before birth )
(iii) Infantile nucleus: (from birth to puberty).
(iv) Adult nucleus: (after puberty).
Lens Cortex
It is located peripheral to nucleus
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i
ii
iii
iv
cortex
Prof . Dr. Abdelmonem Hamed

9. Lens - Sutures
 Anterior and posterior
Y – shaped suture lines are
formed at the junction of lens
fibers.
 The anterior is erect
 The posterior is inverted
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Prof . Dr. Abdelmonem Hamed

10. Lens - Functions
 Focusing of light rays on the fovea
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Prof . Dr. Abdelmonem Hamed
How?

11. Lens - Functions
 Focusing of light rays on the fovea
through:
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Prof . Dr. Abdelmonem Hamed
accommodationIts refractive power

12. Accommodation
 Ciliary muscle contraction, the curvature of
anterior surface , increase lens power.
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Prof . Dr. Abdelmonem Hamed

13. Accommodation
 Ciliary muscle contraction, the curvature of
anterior surface , increase lens power.

14. Lens – Functions …tued
 It also prevents ultra-violet radiation
from reaching the retina
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Prof . Dr. Abdelmonem Hamed
UV-A= 315-400nm
UV-B= 280 -315 nm
UV-A
responsible for
cataract, skin
cancer

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Lens - Crystalline
 Lens fibers contain
high concentrations
of crystalline.
 Crystalline represent
the major protein of
the lens (90% of total
protein).
Prof . Dr. Abdelmonem Hamed

16. CATARACT
Prof . Dr. Abdelmonem Hamed

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Prof . Dr. Abdelmonem Hamed
Any opacity in the lens or its capsule
is called cataract.
Cataract

18. Cataract Classification
 According to age
 Congenital
 Infantile
 Juvenile
 Presenile
 Senile

19. Cataract Classification
 According to age
 Congenital
 Infantile
 Juvenile
 Presenile
 Senile

20. Cataract Classification
 According to age
 Congenital
 Infantile
 Juvenile
 Presenile
 Senile

21. Cataract Classification
 According to age
 Congenital
 Infantile
 Juvenile
 Presenile
 Senile

22. Cataract Classification
 According to age
 Congenital
 Infantile
 Juvenile
 Presenile
 Senile

23. Cataract Classification
 According to stage
 Immature
 Mature
 Hypermature

24. Cataract Classification
 According to stage
 Immature
 Mature
 Hypermature

25. Cataract Classification
 According to stage
 Immature
 Mature
 Hypermature

26. Cataract Classification
 According to
morphology
 Capsular
(ant. & post. Polar)
 Sub capsular
(ant. & post. subcap)
 Cortical
 Nuclear
Ant. pole Post. pole

27. Cataract Classification
 According to
morphology
 Capsular
(ant. & post. Polar)
 Sub capsular
(ant. & post. subcap)
 Cortical
 Nuclear
Ant. pole Post. pole

28. Cataract Classification
 According to
morphology
 Capsular
(ant. & post. Polar)
 Sub capsular
(ant. & post. subcap)
 Cortical
 Nuclear
Ant. pole Post. pole

29. Cataract Classification
 According to
morphology
 Capsular
(ant. & post. Polar)
 Sub capsular
(ant. & post. subcap)
 Cortical
 Nuclear
Ant. pole Post. pole

30. Cataract Classification
 According to etiology
 Not associated with ocular or systemic
disease
 Associated with ocular disease
 Associated with systemic disease

31. Risk Factors for Cataract
 Senility
 Sunlight (specially UV)
 Smoking
 Steroids
 Systemic diseases:
 Deficiency of vitamin A,C, & E
 Diabetes
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Prof . Dr. Abdelmonem Hamed
5S & 2 D

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