1. Crystalline Lens
It is biconvex and transparent lens , lies behind the pupil & iris, in front of the vitreous.
It is suspended by the Zonules, arising from the ciliary processes (ciliary body), extending centrally to attach to the equator of the lens.
Lens is surrounded by the elastic capsule which is a basement membrane secreted by the lens epithelium.
Ant. lens epithelium:
Lens fibers: arise from the epithelium at the equator.

2. Crystalline Lens

3. Lens Epithelium & Zonules

4. Diopteric (Refractive) power of the eye ≈ 60 diopter
Functions of the Lens
1. Transmits light: (transparent).
2. Refracts light: act as convex lens which converge light rays..
Diopteric (Refractive) power of the eye ≈ 60 diopter
40 d. (cornea) + 20 d. (lens)
● But the cornea is static (does not change its shape & power)..
● While the lens is Elastic & can change its shape, convexity & power in response to the changes in the ciliary muscle tone & hence zonular tension.
3. Accommodation: human eye can focus & see clearly objects at different distances.. When we look at infinity (6m).. The ciliary muscle is relaxed  dilatation of ciliary ring  stretch of zonules  flat (↓convexity) of the lens..

5. Accommodation

6. When we look at near object, the ciliary muscle will contract  ↓ diameter of the ciliary ring  relaxation of the zonules  lens will restore spherical shape due to its elasticity, and its convexity and power will ↑.
SO, If we look at an object 2 meters away, we need to ↑ lens power by 0.5 diopter [3m  1/3d. | 50cm  2d.]

7. Presbyopia
Aging process, due to ↓ elasticity of the lens with age, its ability to accommodate will ↓.
At age years, every person will need a convex lens (glasses) to assist his near vision.. The condition is progressive, so the power of reading glasses need to be increased frequently..
Earlier in hypermetropia…
Later or never happened in myopia..

8. Presbyopia

9. Congenital Anomalies of Lens
Congenital Cataract: either Hereditary. AD
or Acquired in utero, e.g..: maternal inf. (Rubella),
or Metabolic disease (Galactosemia).
Ectopia Lentis: due to zonular rupture or laxity, the lens either completely displaced (dislocation) or partially displaced (subluxation), It is either:
Hereditary
1- Marfan Syndrome 2- Homocystinuria
3- Ehler Danlos Syndrome 4- Familial (AR)
Or Acquired
1- Trauma High myopia 3- Buphthalmos

10. Coloboma of the lens: in fact it is coloboma of the zonules which are mesodermal in origin, but it appear as a notch in the lens…

11. Congenital Cataract

12. Congenital Cataract

13. Ectopia Lentis

14. Ectopia Lentis

15. Coloboma of the lens

16. Cataract الساد، الماء الأبيض
Definition: Any opacity of the lens.
N.B:
A. Not all cataracts are clinically significant: depends on:
1. Size
2. Site
e.g.: Post. subcapsular cataract versus ant. cataract
B. Opacity differ in the level,
e.g.:
Capsular  Subcapsular  Cortical  Nuclear

17. Cataract

18. Posterior subcapsular cataract

19. Anterior subcapsular

20. Capsular cataract

21. Cortical cataract

22. Nuclear cataract

23. Mature cataract

24. Aetiology:
Senile: most common
Traumatic: - blunt - penetrating
- infrared (glass blowers) XR, UV
Congenital - hereditary
- maternal dis., e.g.: Rubella (TORCH)
Secondary to syst. causes, e.g: - D.M.
- galactosemia - atopic dermatitis
- dyst. myotonica - drugs: steroid, chloropr.
Complicated: ocular diseases: - glaucoma -myopia - uveitis -retinitis pigmentosa -retinal detachment

25. Clinical Picture:
Blurring of vision: Painless, Gradually progressing.
Refractive error: Nuclear = myopia Cortical = hypermetropia
Altered color values:
Glare: strong light  scattered by the opacity
Mononuclear diplopia or polyopia
Leukocoria : dense cat. (pediatric)  white pupil

26. Blurred vision

27. Diagnosis:
this is done by:
Direct ophthalmoscope: red reflex is partially or completely obscured..
Slit lamp..

28. Devices for diagnosis

29. Evaluation of retinal functions, esp. in dense cataract: a. V.A.
b. Light perception c. Pupillary reaction (optic N.) d. 4 quadrant projection e. Color discrimination
f. US, B-scan

30. B-scan

31. Further management:
Medical:
Glasses to correct refractive errors.
Dark glasses.
Mydriatic eye drops.
Surgical:
Definitive treatment.
Indications: VISUAL, MEDICAL (DM, Optic Nerve dis. Glaucoma) and COSMOTIC
Two components: (a) Cataract Extraction + (b) Optical Correction

32. A) Cataract Extraction:
Intra Capsular Cataract Extraction (ICCE): whole lens (with caps.) is removed. - cryoprobe..
Extra Capsular Cataract Extraction (ECCE): microsurgery – anterior capsulotomy remove the nucleus and cortex, leave posterior capsule.
Phacoemulsification: capsulorrhexis, US probe (very rapid vibrating)  phacolysis, most recent and preferred.. small incision 3.2 mm, ↓↓ less wound complications..
Lensectomy:
used in congenital cataract, vitrectomy machine , lens and anterior face of the vitreous..

33. ECCE

34. Phacoemulsification

35. B) Optical Correction: High hypermetropia).. (Aphakic eye)
Glasses ≈ +10 image magnified 30%  anisoconea
Contact lens 6%
Intraocular lens, IOL (Silicon-PMMA, …etc) Ant. chamber AC-IOL 1-2% Post. chamber PC-IOL (foldable, injectable)

36. Glasses

37. Contact lens

38. Ant. & post. Cham. lens

39. Foldable lens

40. Complication of Cataract Surgery:
Surgical hyphema:
Vitreous loss:
Endophthalmitis: pain, ↓vision, hypopyon. (intravitreal AB, subconj., topical). Pars Plana Vitrectomy (PPV)
Expulsive choroidal hemorrhage:
Wound dehiscence:
Astigmatism..
Cystoid macular edema
Retinal detachment:
Glaucoma:
Corneal endothelium decompensation

41. Hyphema

42. Endophthalmitis

43. Expulsive choroidal hemorrhage

44. Retinal detachment

45. Retinal detachment