This document summarizes information about cataracts, including their anatomy, classification, causes, and management. It describes the structure and function of the crystalline lens. Cataracts are classified as congenital/developmental or acquired. Congenital cataracts have many causes including genetic factors, infections, or metabolic disorders. Acquired cataracts include senile, traumatic, and complicated cataracts caused by local eye diseases or systemic conditions like diabetes. Surgical removal and intraocular lens implantation are common management strategies for visually significant cataracts.

1. Cataract
By: Ola S. Eldardiry

2. Crystalline lens
• Anatomy
o Transparent
o Biconvex
o Flat on ant. surface more than
posterior
o Avascular
• Approx. 18 diopters
• Refractive index
o Cortex: 1.38
o Nucleus: 1.42
• Functions
o Refracts light and focuses it on retina
by alteration of shape
(accommodation)
o Retinal protection from UV rays
o Neutralizes spherical and chromatic
aberrations of cornea

3. Structure and zones
• Made up of
o Capsule
o Lens epithelium (anterior only)
o Lens fibers
• Zones
o Cortex
• Anterior cortex
• Equatorial cortex
• Posterior cortex
o Nucleus
• Embryonic
• Foetal
• Infantile
• Adult
• Metabolism: facilitated diffusion of glucose from across
capsule

4. Cataract
(opacity of crystalline lens)
Congenital/developmental Acquired

5. Congenital/
developmental cataract
• Fairly common 1:2000 live births
• Unilateral or bilateral
• May be non-progressive and visually insignificant
• May have a marked visual impairment
• Classified either by
o Morphology
o Aetiology
o Specific metabolic disorders
o Associated ocular abnormalities
o Systemic findings

6. Aetiology
• Gestational disturbance
o Intrauterine infections
o Maternal drug intake
o Irradiation
o Nutritional
• Metabolic disorders
o DM
o Galactosemia
o Hypoglycaemia
o Hypoparathyroidism
• Trauma
o Mechanical
o Electric shock
• Ocular anomalies
o Aniridia
o Ectopia lentis
o Persistent hyperplastic primary
vitreous
o Remnants of tunica vasculosa
lentis
o Congenital anomalies of lens
• Idiopathic
• Inheritance (recessive)

7. Morphological classification
Polar
Lamellar (zonular)
Complete (total/diffuse)
Coronary
Blue dot
Nuclear
Sutural (stellate)
Membranous

8. Polar cataract
• Opacities involve Lens capsule and subcapsular cortex
• Subtypes
o Anterior polar
• Small
• Symmetric
• Non progressive
• Doesn’t impair vision
• May project into AC – pyramidal cataract
o Posterior polar
• Larger
• Closer to NP
• More visual
impairment

9. Lamellar (zonular)
• Most common type
• Bilateral
• Opacification of specific
layers/zones
• Slit lamp examination
o Layer of opacification involving foetal nucleus
surrounding clearer center and surrounded in
turn by layer of clear cortex
o Front view: disc shaped configuration
o Arcuate opacities straddle equator (riders)
• Aetiology
o transient toxic influence during embryogenesis
o Calcium and vit D deficiency during pregnancy

10. Complete (total/diffuse)
• May start as subtotal at birth then progress
• Profound visual impairment
• Requires urgent surgery

11. Coronary cataract
• Developmenta
• Manifested usually at puberty
• Club shaped opacities near periphery of lens with broad
ends towards center

12. Blue dot cataract
• Multiple small bluish dots
• Scattered all over lens
• Cause no visual disturbance

13. Nuclear cataract
• Rubella cataract
o Aetiology: maternal infection with rubella
virus during first trimester of pregnancy
o Characterized by pearly white nuclear opacification
o Can progress to complete cataract and
occasional cortical liquification
o Systemic manifestations include
• Cardiac defects
• Deafness
• Mental retardation
• Cardiac conduction
o Ocular manifestations
• Diffuse pigmentary retinopathy
• Microphthalmia
• glaucoma
• Bilateral
• May involve embryonic nucleus alone or both embryonic and foetal

14. Membranous cataract
• Lens proteins resorbed
• Only anterior and posterior lens capsules remain and
fuse into dense white membrane

15. Acquired cataract
Senile
(age-related)
Traumatic Complicated

16. Senile cataract
• Old people
• Not due to local or general disease
• Bilateral with one eye affected before the other
• Incidence
o Between 65-74 years 50%
o 75 years and above 70%
• Pathogenesis: multifactorial

17. Types Cortical Cuneiform
Cupuliform
Nuclear

18. Cortical cuneiform cataract
• Stages:
o Precataractous changes
o Incipient stage
o Immature stage
o Mature stage
o Hypermature stage
• Shrunken type
• Morgagnian
o Intumescent

19. Cortical cupuliform
cataract
• Posterior subcapsular
• Central
• Causes glare and poor vision under bright lightening
conditions
• Near vision reduced more than distant

20. Nuclear cataract
• Due to excessive amount of nuclear sclerosis
and yellowing which causes central opacity
• Slow progression
• Interferes more with distant vision than near
• Causes myopic shift (presbyopia)
• Grades:
o N1-N4: cataracta brunesecence
o N5: cataracta nigra
• Red reflex seen peripherally around central
disc of opacity appears which appears black
by retro-illumination

21. Traumatic cataract
• Perforating injury
• Concussion (contusion)
injury
o Vossius ring
o Rosette-Shaped opacity
o Subluxation and dislocation
• Radiation injury
o Ionizing radiation (X-ray)
o Infra-red radiation (glass blower’s
cataract)
o UV radiation
• Chemical injury
o Alkali (caustic) burn
o Chalcosis (sunflower cataract)
o Siderosis
• Electrical injury

22. Complicated cataract
• Due to local eye disease or general (systematic) disease
• Local eye disease
o Perforated corneal ulcer
o Iridocyclitis
o Chronic glaucoma
o Retina and choroid disease
• General disease
o Metabolic
• DM
• Galactosemia
o Endocrinal
• Hyperparathyroidism
• Hypothyroidism
o Severe anaemia
o Hypertension
o Idiopathic: systemic steroids in genetically prone patients

23. Diabetes mellitus and the lens
Increased
blood sugar
Increased
aqueous
content of lens
Increased
glucose
content of lens
sorbitol
Water influx
into lens
Lens swelling
+
myopic change
Changeinrefractive
index
• Reverse to hypermetropic change if there is hypoglycemia
• Decreased amplitude of
accommodation
o With early presbyopia
• Cataract (two types)
o True-diabetic (snow-flake
cataract)
o Senile and pre-senile cataract

24. Management
• Congenital
o Irrigation aspiration
o Lensectomy
o Correction of aphakia
• Contact lens
• Glasses
• Two pairs of glasses
• Intraocular lens implantation
o Foldable soft acrylic lens
o Iris-claw (artisan) lens

25. Management
• Adults
o Indications for surgery
• Improve vision
• Manage complications
• Manage underlying retinal disease
o Preoperative evaluation
• Systemic evaluation
• Local ophthalmic evaluation
o Pertinent ocular history
o Visual acuity testing
o External examination
o Slit lamp-examination
o Fundus examination
o Retinal function tests
• Surgery
o Under local or general anaesthesia
o Operations
• ICCE
• ECCE
• phacoemulsification