MR.JAYDIP J.NINAMA

LECTURERMEDICAL SURGICAL NURSING

DEPARTMENT

The lensIt’s crystalline.Histology:1. Capsule2. Subcapsular epithelium (simple cuboidal).• Synthesize protein for lens fiber

• Maintains a cation pump to keep the lens clear3. Lens fibers

Cross section:1. Capsule2. Cortex3. nucleus

Ciliary muscle•Function:• Constricts ciliary body• Relaxes tension on lens• Lens become spherical,

which increase the refractive power

Ciliary process•Attaches to the lenses by suspensory ligament (zonular fibers)•Secrete the Aqueous humor into the post. chamber

DEFINITION• Any congenital or acquired opacity(dullness)

in the lens or lens capsule is called as cataract

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.

Causes of cataract• Old age (commonest)• Ocular & systemic diseases

– DM– Uveitis– Previous ocular surgery

• Systemic medication– Steroids– Phenothiazines

• Trauma & intraocular foreign bodies

• Ionizing radiation– X-ray– UV

• Congenital– Part of a syndrome– Abnormal galactose

metabolism– Hypoglycemia

• Inherited abnormality– Myotonic dystrophy– Marfan’s syndrom– Rubella– High myopia

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Any physical or chemical cause ↓

Disturbs the intracellular and extracellular equilbrium of water and electrolytes ↓

Deranges the colloid system in lens fibres ↓

Aberrant fibres are formed from germinal epithelium of lens ↓

Epithelial cell necrosis ↓

Focal opacification of lens epithelium (glaucomflecken)

↓Opacification of lens

PATHOMECHANISM

Opacification of lens takeplace by 3 biochemical changes.

1. Hydration 2.Denaturation of 3.Slow

lens protein sclerosis

Abnormalities of lens proteins & Disorganisation of lens fibres

Loss of transparency of lens

Cataract

CataractDivided to :• Acquired cataract

Age - related cataract(Senile Cataract)Presenile cataractTraumatic cataractDrug induced cataractSecondary cataract

• Congenital CataractSystemic associationNon-systemic association

Age -related cataract It is the Most commonly occurred.Classified according to:Morphological Classification• Nuclear• Cortical• Subcapsular• Christmas tree – uncommon

Maturity classification• Immature Cataract • Mature Cataract • Hypermature Cataract

Nuclear cataract• Most common type• Age-related• Occur in the center of the lens.• In its early stages, as the lens changes the

way it focuses light, patient may become more nearsighted or even experience a temporary improvement in reading vision. Some people actually stop needing their glasses.

• Unfortunately, this so-called 2nd sight disappears as the lens gradually turns more densely yellow & further clouds vision.

• As the cataract progresses, the lens may even turn brown. Advanced discoloration can lead to difficulty distinguishing between shades of blue & purple.

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.

Subcapsular cataract• Occur just under the capsule of the lens.• Starts as a small, opaque area• It usually forms near the back of the lens, right in the path of

light on its way to the retina.• It’s interferes with reading vision• Reduces vision in bright light• Causes glare or halos around lights at night.

Posterior Subcapsular Cataracts• Begins at the back of the lens (posterior pole) & spreads to the

periphery or edges of the lens.• It can be developed when:– Part of the eye are chronically inflamed.–Heavy use of some medications (steroids).

• Affects vision more than other types of cataracts because the light converges at the back of the lens.

• Anything constrict the pupils (bright light) makes it very difficult for people with this type of cataract to see.

• Dilating drops useful in this type by keeping the pupils large and thus allow more light into the eye.

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Immature Cataract Lens is partially opaqueTwo morphological forms are seen:1.Cuneiform Cataract:– Wedge shaped opacities in the peripheral cortex and

progress towards the nucleus.– Vision is worse in low ambient illumination when the

pupil is dilated.2.Cupuliform Cataract:– A disc or saucer shaped opacities beneath the posterior

capsule.– Vision is worse in bright ambient illumination when the

pupil is constricted. Lens appears grayish white in color.Iris shadow can be seen on the opacity with oblique illumination.

Mature Cataract • Lens is completely opaque.• Vision reduced to just perception of light• Iris shadow is not seen• Lens appears pearly white

Right eye mature cataract, with obvious white opacity at the centre of pupil

Hypermature Cataract• Shrunken and wrinkled anterior capsule due to leakage of water

out of the lense.

• This may take any of two forms:1.Liquefactive/Morgagnian Type2.Sclerotic Cataract

Liquefactive/Morgagnian Type• Cortex undergoes auto-lytic liquefaction and turns uniformly

milky white.• The nucleus loses support and settles to the bottom.

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.

• Iridodonesis: Anterior chamber deepens and iris becomes tremulous.

• The zonules become weak, increasing the risk of subluxation / dislocation of lens.

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

Signs• Reduced acuity.• An abnormally dim red reflex is seen when the eye is viewed

with an ophthalmoscope.• Reduced contrast sensitivity can be measured by the

ophthalmologist.• Only sever dense cataracts causing severely impaired vision

cause a white pupil.• After pupils have been dilated, slit lamp examination shows

the type of cataract.

1. History collection 2. Visual acuity test3. Dilated eye exam4. Tonometry

Treatment• Glasses: Cataract alters the refractive power of the natural lens

so glasses may allow good vision to be maintained.• Surgical removal: when visual acuity can't be improved with

glasses.

• Surgical techniques– Phacoemulsification method.– Extracapsular method.– Intracapsular method

Pre-op assesments• General health evaluation including blood pressure check• Assessment of patients’ ability to co-operate with the

procedure and lie reasonably flat during surgery• Instruction on eye drop instillation• The eyes should have a normal pressure, or any pre-existing

glaucoma should be adequately controlled on medications.• An operating microscope is needed, in order to reach the lens,

a small corneal incision is made close to the limbus for the phaco-probe.

• It is important to appreciate anterior chamber depth and to keep all instruments away from the corneal endothelium in the plane of the iris.

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

.

Intra-capsular Cataract Extraction

Intracapsular Cataract Extraction. From the late 1800s until the 1970s, the technique of choice for cataract extraction was intracapsular cataract extraction (ICCE). The entire lens (ie, nucleus, cortex, and capsule) is removed, and fine sutures close the incision. ICCE is infrequently performed today; however, it is indicated when there is a need to remove the entire lens, such as with a subluxated cataract (ie, partially or completely dislocated lens).

Extra-capsular Cataract Extraction (ECCE)

• Extracapsular Surgery. Extracapsular cataract extraction (ECCE) achieves the intactness of smaller incisional wounds (less trauma to the eye) and maintenance of the posterior capsule of the lens, reducing postoperative complications, particularly aphakic retinal detachment and cystoid macular edema.

Postoperative care after cataract surgery

• Steroid drops (inflammation)• Antibiotic drops (infection)• Avoid

• Very strenuous exertion (rise the pressure in the eyeball)• Ocular trauma.

Complications of cataract surgery• Infective endophthalmitis– Rare but can cause permanent severe reduction of vision.– Most cases within two weeks of surgery.– Typically patients present with a short history of a

reduction in their vision and a red painful eye.– This is an ophthalmic emergency.– Low grade infection with pathogen such as

Propionibacterium species can lead patients to present several weeks after initial surgery with a refractory uveitis

• Suprachoroidal haemorrhage.– Severe intraoperative bleeding can lead to serious and

permanent reduction in vision.

• Uveitis– Postoperative inflammation is more common in certain types of eyes for

example in patients with diabetes or previous ocular inflammatory disease.

• Ocular perforation.

• Postoperative refractive error– Most operations aim to leave the patient emmetropic or slightly myopic, but in

rare cases biometric errors can occur or an intraocular lens of incorrect power is used.

• Posterior capsular rupture and vitreous loss– If the very delicate capsular bag is damaged during surgery or the fine

ligaments (zonule) suspending the lens are weak (for example, in pseudoexfoliation syndrome), then the vitreous gel may prolapse into the anterior chamber. This complication may mean that an intraocular lens cannot be inserted at the time of surgery. Patients are also at increased risk of postoperative retinal detachment.

• Retinal detachment.– This serious postoperative complication is, fortunately rare, but is more common in myopic patients after intraoperative complications.

• Cystoid macular oedema– Accumulation of fluid at the macula postoperatively can reduce the vision in the first few weeks after successful cataract surgery. In most cases this resolves with treatment of the post-operative inflammation.

• Glaucoma– Persistently elevated intraocular pressure may need treatment postoperatively.

• Posterior capsular opacification– Scarring of the posterior part of the capsular bag, behind the intraocular lens, occurs in up to 20% of patients. Laser capsulotomy may be needed.