Lens and Cataract Terbaru

8/23/2019 Lens and Cataract Terbaru

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Lens and Cataract

Cataract and Refractive Surgery Subspecialty ServiceDepartment of Ophthalmology

Faculty of Medicine Padjadjaran University


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Topics of Study

1. CataractCauses of Cataract

Global/National distribution & populationcharacteristics of Cataract

Diagnosis of Cataract. Distinction betweenimmature, mature and hypermature

Appropriate referral of cataract patient

Outline of surgical managementVisual rehabilitation of Aphakia

Outline of cataract management in young age


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Topics of Study

2. Congenital Abnormalities of Lens

Ectopia Lentis (Subluxation & Dislocation)

Lenticonus


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Crystalline Lens

Embryology

Derived from surface Ectoderm

Ectoderm invaginates and breaks as two layersstructure

Basement membrane of epithelium forms thelens capsule

Posterior epithelium cells form the embryonicnucleus

Anterior epithelium continues to regenerate anddevelop lens fibers


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Anatomy

Lies behind the iris

Concavity in the anterior face of vitreus

called the Patellar Fossa

Suspended from the cilliary processes by

Zonules

In young patients (


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Layers (from without inwards) :

Lens capsule (thinnest at posterior pole)

Epithelium (missing from posterior

surface)

Cortex

Epinuclear Cortex

Nucleus


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Nucleus (from without inwards) :

Adults

Adolescent

Infantile

Fetal (contains anterior & posterior Y-

sutures)

Embryonic


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Physiology

Functions :

1. Refraction of light (+18 D)

2. Accomodation : ability to increase refractivepower in order to focus near objects.


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Optics

+18 D refraction. And in accomodation thispower increases

Accomodation : contraction of ciliary musclesresults in laxity of zonules, which leads toincrease convexity of lens due to its inherentelasticity

Iris controls the amount of light that enters theeye by varying the size of pupil and covers theperipher of the lens thereby cutting the optical(spherical) aberrations from it


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Cataract

Definition

Any opacity of the lens

or loss of transparancyof the lens that causes

diminution or

impairment of vision


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Classification

Etiological

Morphological Stage of Maturity

Chronological


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Etiological classification

1. Senile

2. Traumatic

1. Penetrating

2. Concussion (Rosette Cataract)

3. Infrared irradiation

4. Electrocution

5. Ionizing Radiation


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3. Metabolic1. Diabetes (Snow Storm Cataract)

2. Hypoglycaemia

3. Galactosemia (Oil drop cataract)

4. Galactokinase Deficiency

5. Mannosidosis

6. Fabrys Disease

7. Lowes Syndrome

8. Wilsons Disease (Sunflower Cataract)

9. Hypocalcaemia


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4. Toxic

1. Corticosteroids

2. Chlorpromazine3. Miotics

4. Busulphan

5.

Gold6. Amiodarone


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5. Complicated Anterior uveitis

Hereditary Retinal & Vitreoretinal Disoders

High Myopia

Glaucomflecken

Intraocular Neoplasia

6. Maternal Infection1. Rubella

2. Toxoplasmosis

3. Cytomegalovirus


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7. Maternal Drug Ingestion

Thalidomide

Corticosteroid

8. Presenile Cataract

Myotonic Dystrophy

Atopic Dermatitis (Syndermatotic Cataract)

GPUT & Enzyme Deficiencies


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9. Syndromes with Cataract

Downs Syndrome

Werners Syndrome

Rothmunds Syndrome

Lowes Syndrome

10. Hereditary

11. Secondary Cataract

Posterior Capsular Opacification (PCO)


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Morphological Classification

1. Capsular Congenital (Anterior Polar & Posterior Polar)

Acquired

2. Subcapsular Posterior subcapsular(Cupuliform)

Anterior subcapsular

3. Nuclear Congenital (Discoid, etc)

Senile


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4. Cortical

Congenital (Coronary, Coralliform, etc)

Senile (Cuneiform)

5. Lamelar or Zonular

6. Sutural

7. Others

BlueDot (Cataracta caerulea)

Membranous

Cataracta Pulveranta Centralis

Reduplicated Cataract


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Stage of Maturity

1. Immature

2. Mature

3. Intumescent

4. Hypermature

5. Morgagnian


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Chronological

1. Congenital : since birth

2. Infantile : first year of life

3. Juvenile : 1 to 13 years of life

4. Presenile : 13 to 35 years of life

5. Senile


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Pathogenesis

Two main pathogenetic processes are :

1. Hydration :

Failure of active pump mechanism Increased leakage across posterior or

anterior capsule

Increased Osmotic Pressure

2. Sclerosis


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Senile Cataract

Global

38 million people are blind41% because of cataract


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Progression

1. Stage of Lamellar Separation Hydration

2. Stage of Incipient Cataract Early opacities appear

Symptom e.g., glare, appear

3. Immature Cataract

Diminution of vision Lens appearsgrayish whitein color

Iris shadow can be seen


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Progression

4. Intumescent Cataract The lens imbibes lot of fluid and becomes swollen

Anterior chamber becomes shallow

Angle of anterior chamber may close :Phacomorphicglaucoma

5. Mature Cataract Entire cortex becomes opaque

Vision reduced to just perceptionof light

Iris shadow is not seen

Lens appearspearly white


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Progression

6. Hypermature Cataract

This may take any of two form :

Liquefactive or Morgagnian type : milky white

Sclerotic Cataract with iridodenesis Vision improves to about finger counting at 1

meter


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Clinical Presentation

Symptoms

1. Glare

2. Image Blur

3. Diurnal Variation of Vision

4. Distortion (Metamorphopsia)

5. Diplopia/Polyopia

6. Altered Color Perception7. Black Spots

8. Behavioral Changes


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Clinical Presentation

Signs

1. Visual Acuity : vision is diminishedproportionate to the degree of cataract(immature from 6/9 to finger counting close toface; mature perception of light or handmovements)

2. Leukocoria : white pupil

3. Iris shadowin immature cataract

4. Distant Direct Ophthalmoscopy (DDO): redreflexes depends on degree of cataract


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Differentiating Various Stages of Cataract

Features Immature Mature Hypermature

Vision 6/9 - FC HM - PL HM FC

AnteriorChamber

Normal (shadowin intumescent)

Normal (shallowin intumescent)

Normal to deep

Color of Lens Grayish white Pearly white Milky white(withbrowm crescent of

nucleus) or chalky

white

Iris shadow Seen Not seen Not seen

Distant Direct

Ophthalmoscopy

Black patches

againts red glow

No red glow

seen

No red glow

seen


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Complication of Cataract

1. Lens Induced Glaucoma

1. Phacomorphic Galucoma

2. Phacolytic Glaucoma3. Phacotopic Glaucoma

2. Lens Induced Uveitis

3. Subluxation or Dislocationof Lens


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Investigation

1. Visual Acuity

2. Pupillary Reflexes

3. Intraocular Pressure

4. Fundus Examination5. Blood Pressure

6. General Investigation

7. Macular Function Test8. Ultrasonography (USG B-Scan)

9. Intraocular Lens Power Calculation Biometry


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Indications for Cataract Surgery

1. Optical indications

2. Medical indication Hypermature cataract

Lens induced glaucoma Lens induced uveitis

Dislocated/subluxated lens

Intra-lenticular foreign body

Diabetic Retinopathy to give LaserPhotocoagulation

Retinal Detachment

3. Cosmetic indication


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Surgery for Cataract

Choice of Operation :

1. Extra-capsular cataract extraction with

Posterior Chamber Lens Implantation(ECCE with PCL)

2. Intra-capsular cataract extraction(ICCE)

3. Pars plana lensectomy4. Phacoemulsification with Foldable Intra-

ocular Lens(IOL)


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Intra-ocular lens (IOL) types :

1. Posterior chamber lens(PCL)

2. Anterior chamber lens(ACL)


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Principles of Various Techniques

1. ECCE

The nucles and the cortex is removed out of

the capsule leaving behind intact posteriorcapsule, peripheral part of the anterior

capsule and the zonules

2. ICCE

The lens is removed in toto


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3. Pars Plana Lensectomy

A special techniques used in very young

children The lens and anterior part of vitreous is

nibled out using an instrument called

Vitrectomy Probe or Vitreous irrigation

Suction Cutting (VISC)


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4. Phacoemulsification

It is essentially an advancement in themethode of doing ECCE

The nucleus is converted into pulp oremulsified using high frequency (40.000MHz) sound waves and then sucked out ofthe eye through a small (3.2) incision

A special foldable IOL is then inserted

Is the choice of the operation for cataract


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ECCE vs. ICCE

ECCE ICCELens removal Nucleus removed out

of the capsule and

cortex sucked out

Lens removed as

single piece within its

capsule

Posterior capsule &

zonules

Intact Removed

Incision Smaller (8 mm) Larger (10 mm)

Peripheral iridectomy Not performed Required to avoidpupillary block glaucoma

Sophisticated

equipment

Required Not required

Time taken More Less


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ECCE vs. ICCE

ECCE ICCE

IOL Implantation Posterior chamber Anterior chamber

Expertise required Difficult technique Easier to learn

Cost More LessComplications which

are increasedPosterior Capsular

Opacification (PCO)

1. Vitreous prolapse &

loss

2. CME

3. Endophthalmitis

4. Aphakic Glaucoma

5. Fibrous &

endothelial ingrowth

6. Neovasc. Glaucoma

in PDR


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ECCE vs. ICCE

ECCE ICCE

Complications

which are

decreased

All the complications

mentioned for ICCEPCO

Indications A routine procedurefor all forms of

cataract (except

where contra-

indicated

1. Dislocated Lens

2. Subluxated Lens (>1/3

zonules broken)

3. Chronic Lens Induced

Uveitis

4. Hypermature Shrunken

Cataract

5. Intraocular foreign body

Contraindications 1. Dislocated lens2. Subluxated lens

(>1/3 zonules

broken)

Young patient (


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Preoperative Preparation

1. Patient preferably admitted to the hospital onprevious evening (however, surgery can alsobe done on OPD basis)

2. Informed consent is taken

3. The eye-lashes are trimmed carefully

4. Antibiotic drops are instilled every 6 hourly

5. Pupils are dillated6. Other medications e.g., antiglaucoma drugs,

antihypertensives, etc


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Anesthesia

1. Topical anesthesia

2. Retrobulbar anesthesia

3. Peribulbar anesthesia

4. Subtenon anesthesia

5. General anesthesia


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Postoperative Care

1. Eye is cleaned routinely

2. The eye is examined : Visual acuity

Apposisition of the wound

Corneal clarity

Anterior chamber depth

Pupil

IOL

Posterior capsule Intra-ocular pressure (IOP)

3. Topical antibiotic-steroid eye drops every 4-6hourly (4-6 weeks)


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Complication of Cataract Surgery

These can be grouped as :

1. Intraoperative

2. Postoperative :

Early

Late


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Intraoperative Complications

1. Damage to corneal endothelium

2. Rupture of posterior capsule

3. Vitreous prolapse and loss

4. Hyphaema

5. Expulsive hemmorrhage

6. Dislocation of nucleus into vitreous


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Posoperative Complications

Early1. Corneal edema

2. Wound leak

3. Iris prolapse4. Shallow or flat anterior chamber

5. Hyphaema

6. Hypotony

7. Glaucoma8. Decentered or displaced IOL

9. Endophthalmitis


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Late

1. Posterior Capsular

Opacification (PCO)

2. Cystoid Macular Edema

(CME)

3. Vitreous touch syndrome

4. UGH syndrome

5. Bullous Keratopathy

6. Glaucoma


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Visual Rehabilitation After Cataract Surgery

(Aphakia)

1. Absolute high

hypermetropia

2. Astigmatism3. Loss of accomodation

4. Altered Color Perception

5. More of UV rays reach theretina


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Rehabilitation

Three methods are mainly used to

tackle the problems of aphakia :

1. Intraocular Lens (IOL)

2. Spectacles

3. Contact Lens


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Aphakic Spectcles

Physical and Optical Problems :

1. The glasses are heavy and greatphysical discomfort

2. Magnification : diplopia

3. Roving Ring Scotoma

4. Jack in the box Phenomenon

5. Pin Cushion Effect6. Spherical Aberations

7. Chromatic Aberation


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Pediatric Cataract

Main problems

1. Visual Assesment

2. Vision Deprivation Amblyopia

3. Postoperative Inflammation and

Fibrosis

4. PCO

5. IOL Power Calculation


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Dislocation of Lens

Congenital

1. Familial

2. Ectopia lentis3. Marfan Syndrome

4. Weil Marchesani Syndrome

5. Homocystinuria

6. Hyperlisinemia

7. Aniridia


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Acquired

1. Hypermature cataract

2. Trauma3. Chronic uveitis

4. Intraocular tumor

5. High myopia

6. Buphthalmos


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Treatment

1. Spectacles

2. ECCE : only 1/3 zonules are broken

3. ICCE : more than 1/3 zonules are broken4. Pars Plana Surgery


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Miscellaneous Condition of Lens

1. Lenticonus

2. Lens Coloboma

3. PCO


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Lens and Cataract Terbaru

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