Diseases Of Lens

Question 1

Factors that are responsible for clarity and transparency of crystalline Lens

Answer 1

Avascularity of Lens
Epithelium one layered
Semi permeable capsule
Lens fibres are narrow and lens cell are tightly packed
Lens proteins aquaporines
Pump mechanism of Lens fibres membrane

Question 2

What are the antioxidant mechanisms of Lens

Answer 2

Enzymatic
Glutathione , g’ peroxide, super oxide dismutase , catalase
Non Enzymatic
Vitamin b , c , a

Question 3

Define cataract

Answer 3

Opacity in the Lens or it’s capsule

Question 4

Why Lens require atp

Answer 4

For transport of ions and amino acids, to keep Lens dehydrated , for transport of protein and gsh synthesis

Question 5

Difference between congenital and developmental cataract

Answer 5

1st - occurs in embryonic and fetal.nucleus , occurs before birth
2nd - occurs in infantile and adult nucleus, after birth to puberty

Question 6

Name 4 inherited cataract with systemic disorders

Answer 6

Down
Stickler
Cerbro oculo facial
Lowe

Question 7

Maternal infections causing cataract

Answer 7

Rubella
Toxoplasma
Cytomegalovirus

Question 8

What are the metabolic disorders responsible for congenital cataract

Answer 8

Galactosemia
Galactokinase
Neonatal hypoglycemia

Question 9

Ocular diseases causing developmental cataract

Answer 9

PHPV
Aniridia ant chamber cleavage synd retinopathy of prematurity
Lenticonus post
Micropthalmos

Question 10

Classification of congenital and developmental cataract

Answer 10

Capsular - ant , post
Polar - ant , post
Nuclear - embryonic , fetal , whole , adult nucleus and cortex

Question 11

What are the 3 major morphological patterns of anterior pole cataract

Answer 11

Thickened white plaque in centre
Anterior pyramidal cataract
Reduplicated cataract

Question 12

What is reduplicated cataract

Answer 12

Also double cataract
Transparent fibres between Lens fibres that have gone opaque beneath the opaque central point of anterior capsule

Question 13

Which cataract has onion whorl appearance

Answer 13

Congenital Posterior pole cataract

Question 14

Give an example of embryonic nucleus cataract

Answer 14

Embryonic nuclear cataract

Question 15

What is the most common type of congenital cataract presenting with visual impairment

Answer 15

Lamellar cataract

Question 16

Rubella affects which nucleus o Lens

Answer 16

Fetal nucleus in 7th to 8th week of gestation

Question 17

Appearance of lamellar cataract

Answer 17

Small linear opacities like spokes of a wheel seen in equator , 2 rings

Question 18

How opacities occur in sutural cataract

Answer 18

Punctate opacities scattered around ant and post y sutures in fetal nucleus
Ant axial
Floriform
Coraliform
Spear shaped

Question 19

Rubella cataract is acquired during which trimester? Nucleus harbours virus upto what time? When rubella vaccine is administered?

Answer 19

First, 2 years, 3 months before pregnancy ( toxic to fetes)

Question 20

Rubella syndrome triad

Answer 20

Ocular defects - congenital cataract salt & pepper chorioretinopathy- micropthalmos, cloudy cornea, pupil does not dilate -
Ear defects - deafness
Heart defects ‘ - PDA, PS, USD

Question 21

Give example of cataract involving adult nucleus & cortex? Is vision affected?

Answer 21

Coronary, blue dot. They appear periphery hence vision na,

Question 22

Which type of cataract is the commonest type of acquired cataract ?at what stage it starts? What term used if it occurs before 45 years of age?

Answer 22

Senile cataract starts at 50 yrs.it is called pre-senile

Question 23

How smoking cause cataract?

Answer 23

Accumulation of pigmented molecules like 3-hydroxy Ky nurenine & chromophobes that lead to yellowing. Cyanates cause caebamylation & protein denaturation..

Question 24

Give 4 examples for pre senile cataract

Answer 24

Hereditary
DM
Myotonic dystrophy
Atopic dermatitis

Question 25

What are the 2 different types of senile cataract? Which one is associated with decreased levels in protein?

Answer 25

Cortical & nuclear. Cortical type

Question 26

What are the different stages of cortical type of senile cataract?

Answer 26

5 stages Lamellar , separation Incipient cataract - Immature - intumescent cataract (lens are swollen) Mature - ripe cataract Hypermature

Question 27

What are two different types of senile cortical cataract? List out attest 2 difference between them?

Answer 27

Cortical- cuneiform opacities extend from equator to centre give radial spoke like pattern, dark lines in Post subcapsular - saucer shaped central opacity of posterior capsule

Question 28

What are the 2 types of HMSC? Give atleast 2 differences?

Answer 28

Morgagnian - hypermature cataract - whole cortex liquify, lens Tuens into bag of milky fluid,nucleus settles afbottom Sclerotic type hypermature cataract -cortex disintegrates I lens shrink, ant capsule thickened& wrinkled, ant chamber becomes deep.

Question 29

What happens in mature nuclear senile cataract ?

Answer 29

Sclerosis of nucleus spreads to periphery thus lens become inculastic & hard.. Greyish→ yellowish → amber →black → red

Question 30

Patients with central opacities (posterior subcapsulas Cataract )→ dayblindness Patients with peripheral opacities ( cortical / cuneiform )→ vision loss delayed. Patients with nuclear sclerosis → second sight

Answer 30

① better at evening ② vision improves in bright light ③ progressive myopia as distant vision loss. Improvement of near vision

Question 31

What does iris shadow presence signify?

Answer 31

Immature, Iris shadow of pupillary margin forms on greyish opacity of lens when cortex is still clear

Question 32

Match the colour of lens with the type of cataract Nuclear cataract _ dirty white with white spots Immature - milky white Mature - pearly white HMSC(morgagnian) - greyish white Sclerotic HMSC - amber, brown.black/reddish

Answer 32

① Amber, red/ black ② greyish white ③ pearly white ④ milky white ⑤ dirtywhite

Question 33

How does partial & complete opaque lens appear in ophthalmoscope?

Answer 33

Partial → black shadow against red glow Complete →no red glow

Question 34

Where phacoanaphylactic uveitis occurs?

Answer 34

It is a complication of cataract. Occurs in HMSC. Lens proteins leak into anterior chamber. They act as ag-ab.

Question 35

Types of glaucoma caused by ① immature( intumescent) ② Morgagnian type ③ HMSC

Answer 35

.① phacomorphic - 2nd angle closure glaucoma ② phacolytic - 2nd open angle glaucoma(macrophage block Tm ) ③ phacotopic( subluxate / dislocate)

Question 36

Does senile cataract occurs early in dm?.what is the classical name for DM cataract?why it occurs? How the snowflake appears? Is it reversible?

Answer 36

'yes. Snowflake / snowstorm. Glucose metabolised by nadph dependent aldose reductase → Accumulation of sorbitol → overhydration of lens → fluid vacuoles appear underneath Anterior & posterior capsule→ in cortex. Yes it is reversible

Question 37

Inborn error of which component cause galactosemie cataract? Deficiency of which 2 enzymes can lead to this ? Appearance of opacities? Name good item that can be eliminated in diet to prevent

Answer 37

.① galactose ② GPUT & galactokinase ③ oil droplet central opacity ④ milk & its products

Question 38

Name some conditions where tetany cataract occurs? Type of cataract observed?

Answer 38

Hypocalcernia caused by removal or atrophy of parathyroid gland during thyroidectormy. Lamellar cataract (infants) Multicoloured crystals observed.

Question 39

Deposition of which compound in lens cause sunflower cataract. Name the disease in which it occur.

Answer 39

① cuprous oxide ② Wilson's

Question 40

Appearance of cataract in myotonic dystrophy

Answer 40

Christmas tree

Question 41

What is complicated cataract ? Why does it occur? Name 4 causes Type of cataract they present 5 opacities they present

Answer 41

① O pacification secondary to other intraocculas disease ② disturbance in circulation of nutrients to lens ③ anterior uveitis Retinitis pigments OSA Retinal detachment Glaucoma ④ PSC ⑤ breadcrumb Polychromatic luster Diffuse yellow haze near cortex Nuclear cataract type opacity Deposition of ca2+