1. Cataract

2. Objectives : Introduction : anatomy and histology
Cataract : Definition , causes , signs and symptoms
Classification
Investigation , treatment and complication of treatment

3. The lens
biconvex and perfectly transparent organ, held in position behind the iris by the suspensory ligament ( zonule ), whose fibers are composed of the protein fibrillin.
Lies in the posterior chamber of the eye between
the posterior surface of the iris and the vitreous
body.
Radially arranged zonule fibers connect between
ciliary body and lens capsule .These fibers hold the
lens in position and transmit changes in the ciliary
muscle allowing the lens to change its shape and
refractive power .
Functions : one of the essential refractive media of the eye and focuses incident rays of light on the retina.
Nourished by diffusion from the aqueous humor.

4. CROSS SECTION : 1- CAPSULE 2-CORTEX 3-NUCLEUS Histology:
1.Capsule : replicated basal lamina, formed from the basement membrane of the epithelium.
2. Subcapsular epithelium (simple cuboidal).
• lens fibre production.
• Synthesis of crystallins and membrane proteins
• transport ions and water
3. Lens fibers Lens fibers are nucleated in the cortex . As new lens fibres are added to the periphery of the cortex, lens fibers located deeper in the cortex loose their nuclei and become part of the harder nucleus of the lens.

5. **Age related changes :
The water content of the lens is normally stable and in equilibrium with the surrounding aqueous humor.
The water content of the lens decreases with age, whereas the content of insoluble lens proteins (albuminoid) increases.
The lens becomes harder, less elastic (Loss of accommodation), and less transparent.
The decrease in the transparency of the lens with age is as unavoidable.
The nucleus of the lens becomes sclerosed and slightly yellowish .

6. Definition and causes of cataract
Cataract is the name given to any light - scattering opacity within the lens wherever it is located.
When it lies on the visual axis or is extensive (transparency of the lens is reduced ) , it gives rise to visual loss.
Cataract is the commonest cause of treatable blindness in the world.
In older subjects, as a result of cumulative exposure to environmental and other influences, such as smoking, UV radiation and elevated blood sugar levels. This is referred to as age - related cataract .
More common in females than in males .

7. WHEN EYES WORK PROPERLY:
LIGHT PASSES THROUGH THE
CORNEA AND THE PUPIL TO
THE LENS. THE LENS FOCUSES
LIGHT & PRODUCING CLEAR,
SHARP IMAGES ON THE RETINA.
AS A CATARACT DEVELOPS,
THE LENS BECOMES CLOUDED,
WHICH SCATTERS THE LIGHT
AND PREVENTS A SHARPLY
DEFINED IMAGE FROM
REACHING RETINA.
AS A RESULT, VISION BECOMES
BLURRED.

8. symptoms • a painless gradual loss of vision • glare.
• in some instances, a change in refraction.
altered colours perception .
haloes around lights .
, double vision may be noted .
In infants, cataract causes amblyopia (a failure of visual maturation) by depriving the retina of a formed image at a critical stage of visual development.

9. signs Severe dense cataract cause a white pupil.
Visual acuity is reduced .
A cataract appears black against the red reflex when examined by direct ophthalmoscope .
Reduced contrast .
Severe dense cataract cause a white pupil.
Slit - lamp examination allows the cataract to be examined in detail, and the exact site of the opacity in the lens can be identified

10. Normal red reflex is : Diffuse bright red
White pupil
Slit lamp examination
Normal red reflex is : Diffuse bright red
Causes of dim red reflex : anything that interfere with the passage of light from cornea to retina
1-Corneal ulcer , keratitis .
2-Hyphemia ( Anterior champers).
3-Cataract
4- Vitreous hemorrhage .
5- NOT GLAUCOMA .
Red reflex

11. Classification Cataracts can be classified according to :
Cause : acquired vs congenital.
Anatomical : nuclear , cortical , sub-capsular.
Degree of clouding (degree of loss of the normal transparency) : Immature , mature , hyper-mature .

13. Nuclear cataract : yellowish brown black
Cortical Pos.subcapsular

14. Degree of clouding
An immature cataract has some transparent protein ( partially opaque ) .
with a mature cataract, all the lens protein is opaque.
In a hypermature or Morgagnian cataract, the lens proteins have become liquid.

15. Mature cataract
The lens is diffusely white due to complete opacification of the cortex.
Vision reduced to just perception of light
Iris shadow is not seen
lens with a mature cataract can swell and acquire a silky glitter . The increasing thickness of the lens increases the resistance of aqueous humor flow from post to ant. champer at mid dilated stage of the pupil and with it the risk of angle closure glaucoma.

16. Hyper mature cataract
Occurs If a mature cataract progresses to the point of complete liquification of the cortex, the dense brown nucleus will subside within the capsule.
This may take any of two forms:
1. Liquefactive/Morgagnian Type
When the lens capsule becomes permeable for liquified lens substances, it will lose volume due to leakage. The capsule will become wrinkled and shrunken .
The escaping lens proteins will cause intraocular irritation and attract macrophages that then cause congestion of the trabecular network (Secondary open angle glaucoma).
Cortex undergoes auto-lytic liquefaction and turns uniformly milky white.
The nucleus loses support and sinks inferiorly .
2. Sclerotic Cataract

18. investigation treatment
required if systemic disease is suspected or if the cataract is congenital or appears at an early age.
treatment
management remains surgical.

20. lens implant is calculated prior to surgery by measuring the length of the eye ultrasonically and the curvature of the cornea (and thus its optical power) optically ( keratometry ).
The power of the lens is generally calculated to provide good distance acuity without glasses (i.e. emmetropia).
The choice of implant power is influenced by the refraction of the fellow eye and whether it too has a cataract which will require surgery.
Where surgery on the fellow eye is likely to be delayed, it is important that the patient is not left with a major difference in the refractive state of the two eyes (aniseikonia), since the difference in retinal image size may not be tolerated visually.
Postoperatively the patient is given a short course of steroid and antibiotic drops.
New glasses, if required, can be prescribed after a few weeks, once the incision has healed.
Visual rehabilitation and the prescription of new glasses is much quicker after phacoemulsification.

21. Complication of cataract surgery
Corneal astigmatism
Vitreous loss
Iris prolapse
Endophthalmitis
Cystoid macular oedema
Retinal detachment.
Opacification of the posterior capsule
Irritation or infection.
increased if there has been vitreous loss.
If the fine nylon sutures are not removed after surgery they may break in the following months or years . Symptoms are cured by removal.

22. Corneal astigmatism Vitreous loss
postoperative removal of sutures that were used under local anaesthetic with the patient sitting at the slit lamp may reduce this.
Loose sutures must be removed to prevent infection but it may be necessary to resuture the incision if healing is imperfect.
Sutureless phacoemulsification through a smaller incision avoids these complications.
Vitreous loss
If the posterior capsule is damaged during the operation the vitreous gel may come forward into the anterior chamber, where it represents a risk for glaucoma or may cause retinal traction.
The gel requires careful aspiration and excision ( vitrectomy ) at the time of surgery and placement of the intraocular lens may need to be deferred to a secondary procedure.

23. Iris prolapse Endophthalmitis
The iris may protrude through the surgical incision in the immediate postoperative period.
It appears as a dark area at the incision site. The pupil is distorted.
This requires prompt surgical repair.
Endophthalmitis
Rare infective complication of cataract extraction (less than 0.3%). This is an extreme ophthalmic emergency
Patients present, usually within a few days of surgery, with:
painful red eye 2. reduced visual acuity 3. a collection of white cells in the anterior chamber (hypopyon).
Management :
Urgent sampling of the aqueous and vitreous for microbiological analysis
Intravitreal, broad - spectrum, antibiotic injection at the time of sampling (e.g. vancomycin and ceftazidime) to provide immediate cover.
Further injections are dependent on the microbiological report and clinical response. In some instances topical and systemic antibiotics are used in addition

24. Cystoid macular oedema
The macula may become oedematous following surgery, particularly if surgery was accompanied by vitreous loss or followed by inflammation.
Can produce a severe reduction in acuity.
Inflammatory prostaglandin release may play a part in this .
Treatment is with topical NSAIDs and steroid can alleviate the oedema
Sometimes it may require treatment with steroids injected into or around the eye.

25. Opacification of the posterior capsule.
Normally, the thin capsular layer, lying behind the implant, is crystal clear. However, in approximately 20% of patients clarity of the posterior capsule decreases in the months following surgery, when residual epithelial cells migrate across its surface to form an opaque scar.
Vision becomes blurred and there may be problems with glare.
A small opening can be made in the capsule with a laser ( neodymium yttrium garnet (ndYAG) laser ) as an outpatient procedure. There is a small risk of cystoid macular oedema or retinal detachment following YAG capsulotomy.
The lens implant material, the shape of the edge of the lens and overlap of the intraocular lens by a small rim of anterior capsule are important in preventing posterior capsule opacification.

26. A 60-year-old lady has just had a cataract operation
A 60-year-old lady has just had a cataract operation. Three days later she presents to her general practitioner with a painful red eye. The vision, which was initially much improved, has become blurred and she is seeing lots of floaters.
A-The GP should reassure her that the eye is settling down.
B-The patient has endophthalmitis and needs to be referred to an eye unit immediately.
C-Treatment of the condition requires steroid drops only.
D-Treatment of the condition requires intravitreal antibiotics.
E-This is a rare complication of cataract surgery.
Cataract video