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Definition :

  • Cataract is simply defined as opacity developed in the lens or its capsule.
  • Transparency of the lens is maintained by the regular arrangement of lens fibers.
  • Hence, it occurs either through the formation of opaque lens fibers or any degenerative process that leads to opacification of normal transparent lens fibers

Classification :

  • ETIOLOGICAL
    • Firstly, Congenital
    • Secondly, Acquired
      • Senile
      • Traumatic
      • Complicated
      • Metabolic
      • Electric
      • Radiational
      • Toxic cataract, e.g.
        i. Corticosteroid-induced,
        ii. Miotics-induced,
        ii. Copper and iron induced
      • Associated with skin diseases
      • Associated with osseous diseases
      • Associated with miscellaneous syndromes, e.g.
        i. Dystrophica myotonica
        ii. Down’s syndrome
        iii. Lowe’s syndrome
        iv. Teacher-Collin’s syndrome.
  • MORPHOLOGICAL
    • Capsular cataract
      i. Anterior capsular
      ii. Posterior capsular
    • Subcapsular cataract
      i. Anterior subcapsular
      ii. Posterior subcapsular
    • Cortical cataract
    • Supra nuclear cataract
    • Nuclear cataract
    • Polar cataract
      i. Anterior polar
      ii. Posterior polar

  • CONGENITAL :
    • Present at time of birth or may develop later.
    • Congenital- present at time of birth; embryonic or fetal nucleus affected.
    • Developmental– develops between infancy and also adolescence; infantile or adult nucleus affected.
  • Etiology :
  • Idiopathic
  • Hereditary
    • Without systemic disorders (AD inheritance)
    • With systemic disorders-Downs syndrome
  • Maternal factors
    • Malnutrition during pregnancy
    • Infections
    • Drug intake- thalidomide, steroids
    • And also radiation exposure
  • Fetal factors
    • Anoxia
    • Birth trauma
    • Metabolic disorder
    • Cataracts associated with other congenital anomalies
    • Ocular diseases associated with developmental type
    • And also Malnutrition
  • CONGENITAL CAPSULAR CATARACT :
  • Anterior Capsular cataract
    • Delayed formation of anterior chamber.
    • Underlying cortex may become opaque
  • Posterior Capsular cataract
    • Persistence of posterior part of vascular sheath- hyaloid artery
  • POLAR CATARACT
  • Anterior polar cataract
    • Involves central part of anterior capsule; due to delayed development or corneal perforation
  • Posterior polar cataract
    • Small circular opacity involving the posterior pole
  • CONGENITAL NUCLEAR CATARACT- ZONULAR CATARACT
  • MCC of congenital type presenting with vision defect
  • Etiology-
    • hereditary-AD type
    • Vit D deficiency or hypocalcemia
  • Characteristics:
    • Fetal nucleus affected
    • Usually bilateral and causes vision defect
    • Wheel-spoke opacity seen
    • Two such rings of opacity seen

 

  • GENERALIZED CATARACT :
  • Coronary cataract
    • Common during puberty- adolescent nucleus involved
    • Opacities- regular radial distribution
    • Large punctate opacities may marginally reduce vision
  • Blue dot cataract
    • Most common type of congenital cataract
    • First two decades of life
    • Opacity presents as roundish blue dots in periphery of adolescent nucleus
    • Large punctate opacities may marginally reduce vision
  • Total congenital cataract
    • MCC- maternal rubella during first trimester; can be prevented by vaccination
    • Rubella cataract-pearly white nuclear type; progressive type .
    • Moreover, cataractous nucleus can harbor virus upto 2 years

Management :

  • A. Clinico – investigative :
    • l. Occular examination
    • Laboratory investigations- intrauterine infections TORCH test, Galactosemia by urine test, Hyperglycemia, Hypocalcemia
  • B. Prognostic factors
    • • Density
    • • Unilateral or bilateral
    • • Time of presentation
    • • Associated ocular defects
    • • Associated systemic defects.
  • C. Indications and timing of paediatric cataract surgery
    • Partial cataracts and small central cataracts; visually insignificant- ignored; may need non-surgical treatment with pupillary dilatation.
    • Bilateral dense cataracts- removed within 6 weeks of birth
    • Unilateral dense type – removed as early as possible
  • D. Surgical procedures
    • Lens aspiration
    • Surgical technique
  • E. Correction of paediatric aphakia
    • • Children>2 years- PCIOL implantation
    • • Children<2 years-extended wear of contact lens
  • F. Correction of amblyopia

Age related cataract (senile cataract)

  • ETIOLOGY :
  • I .Firstly, Age. >50 years;
    • 60% by the age of 60 years, 70% by the age of 70 years, 80% by the age of 80 years, and 90% by the age of 90 years develop senile type.
  • 2. Secondly, Sex. Greater in females than males at all ages.
  • 3. Thirdly, Heredity
  • 4. Ultraviolet irradiations
  • 5. Dietary deficiency
  • 6. Dehydrational crisis in childhood 
  • 7. And also Smoking
  • MECHANISM
  • Cortical senile cataract :
    • decreased levels of lens protein, amino acids and potassium + increased concentration of sodium + hydration of the lens followed by coagulation
    • Soft lens formed
  • Nuclear senile cataract :
    • Increase in water soluble protein+dehydration and also compactation of lens
    • Finally, Hard lens formed
  • A. Maturation of the cortical type of senile cataract
  • 1. Stage of lamellar separation
  • Formation of vacuoles and also water clefts leads to demarcation of cortex.
  • Moreover it is a Reversible process.
  • 2. Stage of incipient cataract
  • Two distinct types of senile cortical cataracts can be recognized at this stage:
  • a. Cuneiform senile cortical cataract
  • Wedge-shaped opacities. Seen first in the lower nasal quadrant. Starts at periphery and extends centrally, therefore vision affected late
  • b. Cupuliform senile cortical cataract.
  • Saucer-shaped opacity gradually extends outwards. Lies right in the pathway of the rays and thus causes early vision loss
  • 3.Immature senile cataract-
  • opacification progresses further. Lens appears greyish white Iris shadow is visible. lens may become swollen due to continued hydration. This condition is called ‘intumescent cataract’.
  • 4.Mature senile cataract (MSC)
  • Opacification complete. Lens becomes pearly white. Also called as ‘ripe cataract’
  • B. Maturation of nuclear senile cataract
  • Progressive nuclear sclerotic process- decreases ability to accommodate and also obstructs the light rays.
  • Finally these changes begin centrally and then spread peripherally when it becomes mature

Clinical features :

  • SYMPTOMS
    • Firstly, Glare
    • Secondly, Uniocular diplopia
    • Thirdly, Colored halos
    • Floaters
    • Blurry and also slow detoriation of vision
  • SIGNS
SIGNS OF CATARACT

Complications :

  • Phacoanaphylactic uveitis
  • And also Lens-induced glaucoma

Diabetic cataract :

  • l. Senile type in diabetics- appears at an early age and also progresses rapidly.
  • 2.True diabetic /snowflake/snowstorm cataract occurs in young adults due to osmotic overhydration of the lens-sorbitol accumulates.
  • Fluid vacuoles appear underneath the anterior and posterior capsules which leads to bilateral snowflake-like white opacities in the cortex.
  • May resolve spontaneously or mature within a few days.

Complicated cataract :

  • Secondary to a disease
  • 1. Inflammatory conditions
  • uveal inflammations- iridocyclitis, pars planitis, choroiditis MCC-anterior uveitis
    • Hypopyon corneal ulcer
    • Endophthalmitis
  • 2. Degenerative conditions-
  • Retinitis pigmentosa and other pigmentary retinal dystrophies and also myopic chorioretinal degeneration.
  • 3. Retinal detachment
  • 4. Glaucoma
  • 5. Moreover lntraocular tumours like retinoblastoma or melanoma also leads to complicated type.

Management of Cataract :

  • A. NON-SURGICAL MEASURES :
    • 1. Treatment of cause:
    • Firstly, Control of DM 
    • Removal of cararactogenic drugs- corticosteroids, phenothiazines   and strong miotics
    • And also Removal of radiation
    • 2.Delay progression:
    • Topical preparations containing iodide salts of calcium and also potassium
    • Vitamin E and also aspirin delay cataractogenesis
    • 3.Measures to improve vision
    • Prescription of glasses for refractive status
    • Arrangement of illumination
    • Use of dark goggles
    • And also Mydriatics
  • B. SURGICAL MANAGIEMENT :
  • I Preoperative evaluation
    • Ocular examination
      • slit-lamp biomicroscopy
      • fundoscopy
    • Visual acuity should be noted- Perception of light (PL) and also Projection of light rays (PR) must be noted.
    • 2. Pupils:
    • • Light reactions and RAPD, and also
    • • Ability of the pupils to dilate adequately before surgery.
    • 3 . Anterior segment evaluation by slit-lamp
    • Cornea
    • KP
    • Cataractous lens
    • Other signs to be particularly looked for include posterior synechiae, pseudoexfoliation, iridodonesis, pigments over the anterior lens capsule, and also anterior chamber depth.
    • 4 . Intraocular pressure (IOP) should be measured
    • 5. Examination of lids, conjunctiva and lacrimal apparatus.
    • 6. Fundus examination
    • 7. Retinal/ Macular function tests
    • • Two-light discrimination test
    • • Maddox rod test
    • • Colour perception
    • • Entoptic visualization
    • 8. Objective test for evaluating retina -ultrasonic geographic (USG), ERG (electroretinogram), EOG (electrooculogram) and VER (visually evoked response)
    • 9. Keratometry, corneal topography and also biometry to calculate power of intraocular lens (IOL)
  • II. General medical examination of the patient
    • Check for systemic diseases
    • 1.Firstly, Consent to be obtained
    • 2.Scrub bath.And also the eye to be operated should be marked.
    • 3.Preoperative antibiotics and also disinfectants are required to prevent postoperative endophthalmitis:
    • • Topical antibiotics-fluoroquinolone
    • • Povidone-Iodine (10%) topical solution
    • • Povidone-Iodine (5%) solution instilled as eye drops
    • 4. IOP lowering- mechanical pressure and / or by IOP lowering drugs-mannirol or acetazolamide
    • 5. Mydriasis sustained by:
    • • Topical tropicamide + Phenylephrine 2.5% every 4-6 minutes
    • • Topical cyclooxygenase inhibitor (NSAID) td before the surgery
    • Eg. Ketorolac
  • Types of surgical procedures :
  • I. lntracapsular cataract extraction (ICCE)
    • The  cataractous lens with the intact capsule is removed
    • Indication– markedly subluxated and dislocated lens.
  • II. Extracapsular cataract extraction (ECCE)
    • Major portion of anterior capsule with epithelium, nucleus and also cortex are removed; leaving behind the intact posterior capsule.
    • Contraindication markedly subluxated or dislocated lens.
  • Advantages of ECCE techniques
    • 1. ECCE can be performed at all ages, ICCE cannot be performed below 40 years of age.
    • 2. Posterior chamber IOL can be implanted after ECCE, while it cannot be implanted after ICCE.
    • 3. Postoperative vitreous related problems associated with ICCE are not seen after ECCE.
    • 4. Incidence of postoperative complications are much less after ECCE
    • 5. Postoperative astigmatism is less with ECCE as the incision is smaller.
    • 6. Moreover, Incidence of secondary rubeosis in diabetics is reduced after ECCE.
  • Different techniques of ECCE :
    • Firstly, Conventional ECCE,
    • Secondly, Manual small incision cataract surgery (SICS),
    • Thirdly, Phacoemulsification,
    • And also Femtosecond laser assisted cataract surgery (FLACS).

Postoperative management :

  • l. Firstly, Patient is asked to lie quietly for about 2- 3 hours
  • 2.Secondly, Diclofenac sodium may be given orally for mild to moderate postoperative pain.
  • 3.Thirdly, Bandage/ eye patch is removed next morning and eye is inspected for any postoperative complication.
  • 4.Antibiotic eye drops 4x for 10-14 days.
  • 5.Topical steroids (Prednisolone) eye drops 3x for 6-8 weeks.
  • 6.Topical ketorolac or any other NSAID eye drops 2x for 4 weeks.
  • 7.Topical cycloplegic-mydriatic, e.g. homatropine eye drops OD for 10- 14 days.
  • 8.Moreover Spectacles are prescribed after about 6-8 weeks of SICS operation and 3-4 weeks of phacoemulsification.
  • 9.Finally, Topical timolol (0.5%) eye drops 2x  for 5-7 days.

 

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