Cataract

This lecture explains the general aspects of cataract, its symptoms, types, epidemiology, history, examination, investigations and other related aspects.

Outline of Lecture

• Crystalline Lens Of Eye
• Transparent, biconvex, avascular structure enclosed by a capsule(basement membrane secreted by lens epithelium)
• Approx. diameter is 10mm
• Lens measures approximately 10 mm in diameter and 4 mm thick
• Suspended by zonular fibres
• Parts Of Lens
• Capsule
• Cortex
• Nucleus
• Anatomy Of Lens
• CAPSULE
• ANT CAPSULE
• Basement membrane of ant lens epithelium
• POST CAPSULE
• Basement membrane of cell lens that have nuclei near lens equator
• Thickest basement membrane in the body
• WHAT IS A CATARACT ?
• Any opacity in the lens or it’s capsule whether developmental or acquired is called cataract
  OR
  Loss  of transparency  of  crystalline  lens is cataract
• Aging Changes
  Nuclear changes (nuclear sclerosis)
• Hardening of nucleus starts as early as 20 years of age.
• Increase in insoluble proteins
• Cholesterol level increases while phospholipid level decreases.
• Symptoms Of Cataracts
• Hazy, fuzzy or blurred vision
• Double vision
• Frequent changes in spectacle prescriptions
• Feeling of having a film over the eye
• Colours appear dull
• Glare in bright daylight, and at night from bright light sources

• Acquired Cataract
• Senile cataract
• Presenile cataract
• Traumatic cataract
• Secondary cataract
• Age Related Cataract
• Morphological classification
• Subcapsular cataract
• Anterior subcapsular
• Posterior subcapsular
• Nuclear
• Cortical
• Christmas tree
• Morphological shapes of cataract
• SUBCAPSULAR CATARACT
• Anterior subcapsular cataract
• Lies directly under lens capsule & there is associated fibrous metaplasia of anterior epithelium of the Lens
• Posterior subcapsular cataract
• Lies just in front of posterior capsule
• Associated with posterior migration of epithelial cells of lens
• Patient troubled by headlights & bright sunlight
• Near vision is diminished more than distance Vision
• NUCLEAR CATARACT
• Exaggeration of normal ageing
• May lead to temporary  myopia  from  increase  in refractive  index  of  lens so patients may be able to read again without spectacles (second sight of the aged)
• CORTICAL CATARACT
• Involves anterior, posterior or equatorial cortex.
• Opacities start as vacoules or clefts between lens fibers
• Later they may develop into radial spoke-like opacities
• CORTICAL CATARACT
• Christmas tree Cataract
• Uncommon
• Striking, polychromatic, needle-like deposits in the deep cortex or nucleus
• May be solitary or associated with other  opacities
• AGE RELATED CATARACT
• Classification According To Maturity
• Immature
• Mature
• Hypermature
• Morgagnian
• IMMATURE CATARACT
• Lens is partially opaque
• MATURE CATARACT
  Lens is completely opaque
• EPIDEMIOLOGY
• Cataract surgery is the most commonly performed surgery in elderly patient
• Any Age
  • Two peaks
    • < 10 Years
      • 65 Years
• HISTORY
• Age of Onset
• Decreased Vision
• Painless,
• Effecting daily routine?
• Trauma
• Any Ophthalmological Problems
• Drugs Intake
• Exposure to Radiations
• Systemic Diseases
• Skin disease, joint pains, etc.
• Family History
• EXAMINATION
• GENERAL PHYSICAL EXAMINATION
• SYSTEMIC EXAMINATION
• OCULAR EXAMINATION
• Visual Acuity
• Adnexa
• Iris
• Conjunctiva
• Cornea
• Anterior Chamber
• Pupil
• Lens
• Vitrous
• Retina
• INVESTIGATIONS
• Blood Glucose
• ECG
• Chest x-rays (PA view)
• Blood Complete Picture
• Any specific relevant investigation (if indicated)
• OPTIMAL POST OP REFRACTION
• If monocular correction is reqd.
  • In contralateral  dense  cataract or amblyopia
  • best post op refraction is -1DS
• If binocular correction is reqd
  • difference between the two eyes should          not be more than 3DS.
• SURGICAL TECHNIQUES
• ICCE
• ECCE
• ECCE with posterior chamber
• IOL implant
• Phacoemulcification
• CONGENITAL CATARACT
• An opacity in the crystalline lens, present at the time of birth or appears with in first three months of life
• Occurs in about 3:10,000 live births
• 2/3 are bilateral
• Most common cause is genetic mutation, usually autosomal dominant (A.D)
• AETIOLOGY
• IDIOPATHIC                                35%
• HEREDITARY                                         25%
• INTRA-UTERINE CAUSES         20%
• Maternal infections
• Rubella            40-60%
• Mumps            10-22%
• Toxoplasmosis 5%
• Cytomegalovirus
• HSV
• Varicella

• Malnutrition
• Prematurity
• Drug induced

• AETIOLOGY
• INBORN ERRORS OF METABOLISM              10%
• Lowe syndrome
• Galactosemia
• Mannasidosis
• Hypoparathyroidism
• Fabry disease
• Hypo/hyper glycemia

 

• ASSOCIATED WITH OCULAR ANOMALIES   05%
• Microphthalmia
• Aniridia
• Coloboma

• AETIOLOGY
• CHROMOSOMAL ABNORMALITIES    03%
• Down’s syndrome
• Turner syndrome
• Trisomy 13 & 18
  

• BIRTH TRAUMA      02%
• SKELETAL SYNDROMES
• Hallermann-Streiff-Francois syndrome
• Nance-Horan syndrome

• Clinical Features
• Symptoms
  • Decreased Vision
  • Glare
• Signs
  • Leukokoria
  • Nystagmus
  • Strabismus
  • Amblyopia
  • Microphthlamos

• NUCLEAR CATARACT
• LAMELLAR (ZONULAR) CATARACT
• CORONARY CATARACT
• SUTURAL (STELLATE) CATARACT
• Sutural cataract
• ANTERIOR POLAR CATARACT
• CLINICAL FEATURES
• White pupillary reflex
• Poor Visual Acuity
• Nystagmus
• CLINICAL EVALUATION

• Purpose:    To know:
• Cataract density
• Type of cataract
• Condition of retina and optic nerve
• Any associated ocular anomaly

 

• Steps:       
• Torch examination
• Examination under Anesthesia
• Ophthalmoscopy direct / indirect

• Associated ocular pathology
• Corneal clouding
• Microphthalmos
• Glaucoma
• Persistent anterior fetal vasculature
• Chorioretinitis
• Rubella retinopathy
• Foveal or optic nerve hypoplasia

• PAEDIATRIC CONSULTATION
• Dysmorphic features or suspicion of associated systemic diseases
• LABORATORY INVESTIGATIONS
• TORCH screening
• Blood Complete picture
• Blood Glucose levels
• Serum calcium and phosphorus
• Urine:
• Routine examination
• Reducing sugars
• VISUAL FUNCTION EVALUATION
• Visual Acuity
• Follows light or not
• Colour targets
• Reaction to occlusion
• Pupillary Reflexes
• Fixation Reflex 
• Visual Evoked Potentials(VEP)
• VISUAL FUNCTION EVALUATION
• Visual Acuity
• Follows light or not
• Colour targets
• Reaction to occlusion
• Pupillary Reflexes
• Fixation Reflex 
• Visual Evoked Responses (VER)
• DIFFERENTIAL DIAGNOSIS
• LEUKOCORIA
• Retinoblastoma
• Retinopathy of Prematurity
• Persistent Hyperplastic Primary Vitreous
• Retrolental Fibroplasia
• Toxocariasis
• Toxoplasmosis
• Incontinentia pigmenti
• Retinal Detachment
• Cytomegalovirus Retinitis

• RETINOBLASTOMA
• RETINAL DETACHMENT WITH A MITTENDORF SPOT
• PERSISTENT HYPERPLASTIC PRIMARY VITREOUS
• TOXOPLASMOSIS
• RETROLENTAL FIBROPLASIA
• PROGNOSIS

• Visual morbidity may result from deprivation amblyopia, refractive amblyopia, glaucoma        (10% post surgical removal), squint, secondary cataract  and retinal detachment

• Mental retardation, deafness, kidney disease, heart disease, and metabolic disorders may be part of the presentation