cataract 21-5-2011

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12 September 2011 Smt. Kashibai Navale Medical College, Pune. Ophthalmology Department Dr. Suhas Kulkarni 2011

Human Lens And Cataract: 

Human Lens And Cataract 12 September 2011

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12 September 2011 Objectives:- Lens Anatomy Lens Physiology Lens Functions Definition of Cataract Pathology of Cataract Etiology of Cataract

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12 September 2011

Lens----------- Anatomy: 

Lens----------- Anatomy It is a highly organized, transparent, biconvex spheroid structure. It does not posses, nerve or blood vessels . 12 September 2011 Ant Post

Anatomy ----------- Lens: 

Anatomy ----------- Lens Diameter varies from 8.8 to 9.2 Antero-posterior thickness changes with accommodation. Circumference is known as equator 12 September 2011 Ant Post

Lens ------------ Anatomy: 

Lens ------------ Anatomy Lens is suspended in eye, by Zonules , which are inserted on anterior surface and equatorial lens capsule and attached to ciliary body. 12 September 2011 lens Ant Post cb cb

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12 September 2011 Lens Zonules Position of lens-------- Anatomy ciliary body

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12 September 2011 Lens Anatomy Lens Zonules ciliary body

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12 September 2011 Lens Zonules Zonules ciliary body ciliary body

Lens - Anatomy: 

Lens - Anatomy Histologically, lens consists of three major components 1)Capsule 2) Lens Epithelium 3)Lens substance 12 September 2011

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12 September 2011 1. Capsule – is a thick membrane, which is transparent, elastic, acellular- envelop, thick at anterior pre-equatorial region , thinnest at the posterior pole . equator Pre equatorial region Ant Post

Lens - Anatomy: 

Lens - Anatomy - Anterior pole contains, the epithelial cells and fibres, as a structural unit and allows, a passage of small molecules, both into and out of the lens. 12 September 2011

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12 September 2011 -The lens capsule, regulate the transport of metabolite, nutrients and electrolytes, to the lens fibres. Can – opener ant capsulotomy Continuous curvilinear capsulorrhexis ( CCC )

Lens - Anatomy: 

Lens - Anatomy 12 September 2011 2. Lens Epithelium – It is a single layer of cells, lining the anterior capsule and extends to the equator.

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12 September 2011 Ant lens capsule Post lens capsule epithelium

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12 September 2011 These cells are actively dividing and elongating to form new lens fibres throughout the life.

Lens - Anatomy: 

Lens - Anatomy 3. Lens substance : It constitute, the main mass of the lens. It is divided into- a. Nucleus b. Cortex 12 September 2011

Lens - Anatomy: 

Lens - Anatomy Nucleus: consists of Embryonic nucleus Fetal nucleus Infantile nucleus Adult nucleus 12 September 2011

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12 September 2011 Embryonic nucleus : It contains primary lens fibres, that are formed in lens vesicle. ( 1 to 3 months of gestation )

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12 September 2011 ii) Fetal nucleus : it contains embryonic nucleus and all fibres added to the lens before birth ( from 3 months gestation till birth )

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12 September 2011 (iii) Infantile nucleus : it contains embryonic , fetal nucleus together with all the fibres added up-to the age of 4 years.

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12 September 2011 (iv) Adult nucleus : composed of all fibres added before puberty.

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12 September 2011 The nucleus consists of, densely compacted lens fibres and it has higher refractive index than cortex.

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12 September 2011 c a i f E

Lens Cortex : 

Lens Cortex It is located peripherally, and is composed of secondary fibres formed continuously after puberty. It is further divided into: Deep cortex Intermediate cortex Superficial cortex 12 September 2011 NUCLEUS

Lens - Crystalline: 

Lens - Crystalline Lens fibres contain high concentrations of crystalline protein. It is a major protein of the lens 12 September 2011

Lens Cortex: 

Lens Cortex The region between embryonic and fetal nuclear core and soft cortex i.e. infantile and adult nucleus is sometimes referred to as epinucleus. 12 September 2011 Adult Nucleus Infantile Nucleus Cortex epinucleus

Lens - Sutures: 

Lens - Sutures Are found both at anterior and posterior poles. They are formed by overlap of ends of secondary fibres. These secondary fibres formed before birth ( fetal nucleus ). Anterior suture is shaped as an erect Y, and a posterior suture shaped as an inverted Y. 12 September 2011

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12 September 2011 Anterior Suture ( erect Y ) posterior suture inverted Y

Lens – Physiology : 

Lens – Physiology Function of the Lens ,and it’s transparency, is dependant on the supply of appropriate nutrients to its various structures. Metabolic needs of a adult lens, is met by the, aqueous and vitreous. 12 September 2011

Lens - Physiology: 

Lens - Physiology Lens function is dependent on the 1) metabolism of glucose to produce energy , and 2) protein synthesis. Glutathione –(anti-oxidant) is found in high concentration in lens and it protect lens from oxidative damage. 12 September 2011

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12 September 2011 Lens - Physiology

Lens - Physiology: 

Lens - Physiology The transparency is dependent on, highly organized structure of lens. By act of accommodation, it changes focusing power. 12 September 2011

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12 September 2011 The lens serves two major functions: 1) Focusing of visible light rays on the fovea 2) Preventing, damaging- ultra-violet radiation, from reaching the retina Lens - Functions

Age changes in the Lens: 

12 September 2011 Age changes in the Lens Age related changes in the structure. Overall light transmission decreases with age, lens becomes less elastic. Reducing its ability to accommodate which leads to presbyopia.

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12 September 2011 I. Subluxation It is partial displacement in which lens is moved sideways (up, down, medially or laterally), but remains behind the pupil. It results from partial rupture or unequal stretching of the zonules II. Dislocation or luxation of the lens In it all the zonules are absent or destroyed. A dislocated lens may be incarcerated into the pupil or present in the anterior chamber or the vitreous

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12 September 2011 Subluxation of the lens

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12 September 2011 Dislocation or luxation of the lens

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12 September 2011 Q

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12 September 2011 Antero-posterior thickness of Lens changes In accommodation While looking up In sleep By rubbing the eyes Ans :- 1) in accommodation

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12 September 2011 Lens is suspended in the eye by Capsule Vitreous Iris Zonules Ans :- 4) Zonules

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12 September 2011 What are major 3 parts of Lens Capsule Epithelium Substance

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12 September 2011 Lens substance is divided into two parts - Cortex Nucleus

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12 September 2011 4 parts of the Nucleus Embryonic nucleus Fetal nucleus Infantile nucleus Adult nucleus

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12 September 2011 Which is the major protein of the lens :- Crystalline protein.

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12 September 2011 What is epinucleus ? ? Adult & infantile nucleus together called as epinucleus

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12 September 2011 Which anti-oxidant is synthesized in the lens ? Glutathione

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12 September 2011 What are the functions of lens ? Focusing the rays on the fovea Protects the retina from the UV radiation

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12 September 2011 Sub-luxation

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12 September 2011 Dis-location

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12 September 2011 Cataract Definition Classification of Cataract Cataract Etiology Cataract Pathology Cataract Symptoms

Cataract -- Definition: 

Cataract -- Definition Any opacity in the lens or its capsule, whether developmental or acquired is called cataract. 12 September 2011

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12 September 2011 Developmental opacities are usually partial and stationary, whereas acquired opacities are progressive.

Pathogenesis of Cataract : 

2009 - 2010 Suhas Kulkarni 55 Pathogenesis of Cataract Cataract is caused by 1.The degeneration and opacification of existing lens fibres, 2.formation of aberrant lens fibres 3.deposition of other material in their place. 12 September 2011

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56 Any factor, physical or chemical, which disturbs the critical intra – and extra-cellular equilibrium of water and electrolytes or deranges the colloid system within the fibres tends to bring about opacification. 12 September 2011 Pathogenesis of Cataract

Pathogenesis of Cataract: 

2009 - 2010 Suhas Kulkarni 57 Pathogenesis of Cataract Fibrous metaplasia of fibres may occur in complicated cataract) Epithelial cell necrosis leads to focal opacification of the lens epithelium as ‘Glaucomflecken’ in acute angle closure glaucoma. 12 September 2011

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Abnormal products of metabolism, drugs or metals can be deposited in storage diseases ( Fabry ), metabolic diseases ( Wilson ) and toxic reactions ( siderosis ). 12 September 2011 Pathogenesis of Cataract

Pathogenesis of Cataract: 

2009 - 2010 Suhas Kulkarni 59 Pathogenesis of Cataract Biochemically three factors are evident in the Process of cataract formation. Hydration Denaturation of Lens Proteins Sclerosis 12 September 2011

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1.Hydration In the early stages of cataract or rapidly developing forms, actual droplets of fluid, gather under the capsule, forming lacunae between the fibres, and the entire tissue swells (intumescence) and lens becomes opaque. 12 September 2011

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This process may be reversible and opacities thus formed, may clear up, as in juvenile insulin dependent diabetic patients whose lens becomes clearer after control of hyperglycaemia. Hydration may be due to osmotic changes within the lens or due to changes in the semipermeability of the capsule. Traumatic cataract develops by hydration process. 12 September 2011

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2. Denaturation of Lens Proteins If the proteins are denatured, with an increase in insoluble proteins, a dense opacity is produced, a process which is irreversible . This occurs in young lens or cortex of adult lens. This type of cataract is called as soft cataract. 3. Sclerosis Slow degenerative process occurs in nucleus of the lens. This type of cataract is called as hard cataract. 12 September 2011

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12 September 2011 Part – II Cataract --Etiology --Classification --Symptoms

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12 September 2011 Etiology -Age-related -Trauma -Metabolic or secondary -Toxic due to drugs -Complicated Cataract -After cataract or PCO -Syndromes associated with cataract A B C D E F G

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2009 - 2010 A. Age-related 1. Sub-capsular a. Anterior : due to fibrous metaplasia of the anterior lens epithelium b. Posterior : just in front of the posterior capsule. It is associated with the posterior migration of the anterior epithelium of the lens Etiology 12 September 2011

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-Exaggeration of the normal aging involving the lens nucleus -Often associated with myopia due to the increase in the refractive index . - Some elderly patients with Nuclear Sclerosis may be able to read again without their spectacles, due to the induced myopia: this is called the " second sight ". 2. Nuclear Cataract 12 September 2011

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Suhas Kulkarni 67 B. Trauma : can cause cataract: concussion, penetrating injury, electric shock, lightening, or radiation 12 September 2011 Flower shaped (rosette) cataract

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Suhas Kulkarni 68 C.. Metabolic or  secondary 1. Diabetes -Senile cataract is accelerated -True diabetic cataract: associated with over-hydration. Results in bilateral snowflake posterior or anterior sub-capsular opacities 12 September 2011

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2. Galactosemia - multifocal white flakes are seen in lens (inborn error of galactose metabolism) 3. Wilson’s disease – green sunflower cataract (inborn error of copper metabolism) 12 September 2011

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D. Toxic due to drugs -Steroids: systemic cause more cataract than topical. causes anterior and posterior sub-capsular lens opacities. -Chlorpromazine: causes anterior lens capsule opacities 12 September 2011

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-Gold (used in Rheumatoid Arthritis): 50% have posterior lens opacities -Miotics: cause anterior sub-capsular opacities 12 September 2011

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Suhas Kulkarni 72 E. Complicated Cataract (due to some other ocular disease) -Chronic anterior uveitis - Retinitis Pigmentosa - High Myopia - Acute angle closure glaucoma (Glaukomfleckens) 12 September 2011

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F. After cataract or PCO posterior capsular opacity formed after cataract surgery ( extra capsular cataract extraction ) It is white membranous opacity formed by remains of anterior capsule and cortex. 12 September 2011

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G. Syndromes associated with cataract Down’s ( mental retardation ) anterior, posterior subcapsular cataract Lowe’s ( oculo-cerebro-renal ) total cataract Wilson’s disease ( hepatolenticular degeneration ) green sunflower cataract Congenital rubella total cataract 12 September 2011

Classification of Cataract (1): 

Classification of Cataract (1) 1. Developmental 2. Age related (senile) 3. Cataract associated with ocular diseases 4. Cataract associated with systemic diseases 5. Traumatic Cataract 6. Drug induced cataract 12 September 2011

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Suhas Kulkarni 76 Classification of Cataract (2) Congenital Acquired- a) Senile b) Traumatic c) Complicated d) secondary e) Toxic f) Syndromes associated with cataract 3.After Cataract 12 September 2011

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A. Morphologic B. With respect to maturity of Cataract C. Age of onset Classification of Cataract (3) 12 September 2011

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2009 - 2010 Suhas Kulkarni 78 A. Morphologic: 1. Capsular Cataract 2. Subcapsular Cataract 3. Nuclear Cataract 4. Cortical Cataract 5.  Lamellar Cataract 6.  Sutural Cataract 12 September 2011

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1. Capsular Cataract a. Anterior Capsular -Congenital: from persistent pupillary membrane -Acquired: Pseudoexfoliation syndromes, chlorpromazine, in association with posterior synechiae b. Posterior capsular: -Congenital: in association with persistent hyaloid remnants (Mittendorf's dot) 12 September 2011

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2009 - 2010 Suhas Kulkarni 80 Anterior Capsular cataract 12 September 2011

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2009 - 2010 Suhas Kulkarni 81 2. Subcapsular Cataract a. Posterior Subcapsular -Complicated (e.g. in Diabetes Mellitis, Myotonic Dystrophy, steroids, irradiation) b. Anterior Subcapsular -Acute angle closure glaucoma (Glaukomfleckens), - miotics - Wilson's disease 12 September 2011

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2009 - 2010 Suhas Kulkarni 82 Anterior Subcapsular Posterior Subcapsular 12 September 2011

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2009 - 2010 Suhas Kulkarni Anterior Subcapsular Acute angle closure glaucoma (Glaukomfleckens) 12 September 2011

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2009 - 2010 Suhas Kulkarni 85 3. Nuclear Cataract -Age-related -Congenital: Rubella, Galactosemia Nuclear Cataract 12 September 2011

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2009 - 2010 Suhas Kulkarni 86 4. Cortical Cataract -Usually spoke-like, can be anterior or posterior -Can be congenital (very common) -Usually doesn't interfere with vision Cortical Cataract 12 September 2011

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2009 - 2010 Suhas Kulkarni 87 Cortical Cataract on retroillmination 12 September 2011

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2009 - 2010 Suhas Kulkarni 88 5.  Lamellar Cataract -Congenital. Involves one lamella of the fetal or nuclear zone 12 September 2011

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2009 - 2010 Suhas Kulkarni 89 6.  Sutural Cataract -Congenital -Very common -Y-shaped opacity in the lens nucleus -No clinical significance Anterior Sutural (erect Y ) 12 September 2011

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2009 - 2010 Suhas Kulkarni 90 B. With Respect to Maturity of Cataract 12 September 2011 1. Stage of lamellar separation. 2. Stage of incipient cataract. 3. Immature senile cataract (ISC). 4. Mature senile cataract (MSC). 5. Hypermature senile cataract (HMSC).

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1 ). Lameller separation :- cortical fibres are separated by fluid. This phenomenon (lamellar separation) can only be seen with a slit-lamp and not with ophthalmoscope. The general increase in the refractive index of the cortex in old people gives a grey appearance. 12 September 2011

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12 September 2011 2. Stage of incipient cataract. In this stage early detectable opacities with clear areas between them are seen. Two distinct types of senile cortical cataracts can be recognized at this stage: (a) Cuneiform senile cortical cataract. (b) Cupuliform senile cortical cataract.

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12 September 2011 Incipient stage:- wedge-shaped spokes of opacity with clear areas between them appear in the periphery of the lens and lie in cortex, some in front of and some behind the nucleus. Lens fibres, thus producing irregularities in refraction, some visual deterioration and polyopia. The bases of the wedge-shaped opacities (cuneiform Opacities) are peripheral and they are most common in the lower nasal quadrant . Cuneiform Cataract

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12 September 2011 Cuneiform senile cortical cataract

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12 September 2011 Cupuliform senile cortical cataract. saucer shaped opacity develops just below the capsule usually in the central part of posterior cortex (posterior subcapsular cataract),which gradually extends outwards. Cupuliform cataract lies right in the pathway of the axial rays and thus causes an early loss of visual acuity.

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2009 - 2010 Suhas Kulkarni 97 12 September 2011 Cupuliform cataract posterior subcapsular cataract

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2009 - 2010 Suhas Kulkarni 98 3. Immature Cataract -scattered opacities are separated by clear areas 12 September 2011 when opacification becomes more diffuse and irregular. The lens appears greyish white but clear cortex is still present and so iris shadow is visible.

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12 September 2011 Iris Shadow

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2009 - 2010 Suhas Kulkarni 100 Intumescent cataract The lens has become swollen by imbibed water -Can be mature or immature 12 September 2011 The progressive hydration of the cortical layers may cause a swelling of the lens, thus making the anterior chamber shallow (intumescent cataract).

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12 September 2011 4. Mature senile cataract (MSC). Cortical In this stage, opacification becomes complete, i.e., whole of the cortex is involved. Lens becomes pearly white in colour. Such a cataract is also labelled as ‘ripe cataract.’

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2009 - 2010 Suhas Kulkarni 102 Mature cataract -Cortex is totally opaque 12 September 2011 Cortical

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12 September 2011 Nuclear senile cataract. degenerative changes are intensified and associated with dehydration this leads to compaction of the nucleus resulting in formation of a hard cataract. The nucleus may become diffusely cloudy (greyish) or tinted (yellow to black) due to deposition of pigments. The commonly observed pigmented nuclear cataracts are either amber, brown ( cataracta brunescens) or black (cataracta nigra) and rarely reddish ( cataracta rubra) in colour

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2009 - 2010 Suhas Kulkarni 105 5. Hypermature Cataract -Mature cataract that has become swollen and has a wrinkled capsule as a result of leakage of water out of the lens. 12 September 2011

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2009 - 2010 Suhas Kulkarni 106 A) Morgagnian Cataract: -Hypermature cataract leading to total liquefaction of the cortex making the nucleus sink inferiorly 12 September 2011 Some times cortex becomes fluid and nucleus may sink to the bottom of the lens. The liquefied cortex is milky, and the nucleus is as brown mass, altering it’s position with position of head.

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12 September 2011 (b) Sclerotic type hypermature cataract: Sometimes after the stage of maturity, the cortex becomes disintegrated and the lens becomes shrunken due to leakage of water. The anterior capsule is wrinkled and thickened due to proliferation of anterior cells and a dense white capsular cataract may be formed in the pupillary area. Due to shrinkage of lens, anterior chamber becomes deep and iris becomes tremulous (iridodonesis).

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2009 - 2010 Suhas Kulkarni 109 C . Age of onset 1. Congenital Cataract -- Present at birth 2. Infantile Cataract --- up to 1 yr of age 3. Juvenile Cataract -------- Infancy to adolescence 4. Pre-senile Cataract ------ up to the age of 40 5. Senile Cataract ------ after the age of 40 12 September 2011

Symptoms of Cataract: 

2009 - 2010 Suhas Kulkarni 110 Symptoms of Cataract 1. Blurring of vision 2. Frequent change of glasses due to rapid change in refractive index of the lens 3. Painless, progressive gradual diminution of vision due to reduction in transparency of the lens 4. Second sight or myopic shift in case of nuclear cataract causing index myopia, improving near vision. 12 September 2011

Symptoms of Cataract: 

2009 - 2010 Suhas Kulkarni 111 Symptoms of Cataract 5. Loss or marked diminution of vision in bright sunlight or bright light beam in central posterior subcapsular cataract. 6. Monocular diplopia or polyopia in presence of cortical spoke opacities 7. Glare in posterior subcapsular cortical cataract due to increased scattering of light 12 September 2011

Symptoms of Cataract: 

2009 - 2010 Suhas Kulkarni 112 Symptoms of Cataract 8. Colored haloes around the light as seen in cortical cataract due to irregular refractive index in different parts of the lens. 9. Color shift , reds are accentuated 10. Visual field loss, generalized reduction in sensitivity due to loss of transparency 12 September 2011

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Cataract risk factors Demographic RF Age- The strongest RF for cataract The risk of cataract at age 70 is about 13-fold that at age 50 Race Some types of cataracts (cortical & nuclear) are more common in african americans Sex Women slightly greater risk than men Geographic Especially prevalent in developing countries in the tropical belt 12 September 2011

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Medical RF Diabetes Drugs Miotic cholinergic compounds Cancer chemotherapy agents Diuretics Various photosenthesitizing drugs Major tranquillizers Gout medications Steroids 12 September 2011

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Environmental RF Nutrition - conflicting reports Dietary intake of riboflavin, vit C &E & carotenoids (antioxidants)- protective effect Intake of niacin, thiamine & iron- also protective Radi ation Exposure to UV--> cortical & PSC IR Smo king - increased risk of nuclear cataracts Alcohol use > 2 drinks/ day--> increased risk of all types of cataract 12 September 2011

Differential Diagnosis of painless gradual diminution of vision : 

Differential Diagnosis of painless gradual diminution of vision Chronic open angle glaucoma Macular degeneration Optic atrophy Corneal dystrophy Retinopathy associated with systemic disorders (hypertension or diabetes) 12 September 2011

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12 September 2011 Grading of nucleus for Phaco-emulsification

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12 September 2011 Examination of the Eye Visual acuity for RE / LE With or without spects For distance and near Pin hole vision Pupil dilatation Slit-lamp examination Fundus examination B-Scan A-Scan

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12 September 2011 Sac Syringing IOT Other investigations Urine and Blood Test B.P. and ECG with Physicians fitness Anaethetist’s examination and fitness

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12 September 2011 Thank You