Cataract By Col Rana Intisarul Haq MCPS, FCPS (AFIO)
Lens • The lens is a biconvex structure located directly behind the posterior chamber and pupil • It is the lesser of the two refractive elements in the dioptric system • The equatorial diameter in adult is about 9-10 mm • The anteroposterior width of the lens is about 6 mm • The lens has certain unusual features. It lacks innervation and is avascular.
cataract • Definition • Any congenital or acquired opacity in the lens capsule or substance of the lens , irrespective of the effects on vision is called cataract.
Classification of Cataract • According to Age • According to Morphology • According to Etiology • According to maturity • Congenital and acquired
Age Related Senile Cataract • Age related cataract is universal in persons over 70 years of age. Both sexes are involved equally. • There is considerable genetic influence. • Average age of onset of cataract is approximately 10 years earlier in tropical countries.
Age Related Cataracts senile • Presenile Cataracts Diabetes Mellitus Myotonic Dystrophy Atopic Dermatitis Neurofibromatosis-2 • Traumatic Cataract Direct Penetrating Injury Concussion Electric Shock & Lightening Ionizing Radiation
Toxic Cataracts Steroids Chlorpromazine Miotics Busulphan Amiodarone Gold • Secondary Cataracts Ch Ant Uveitis Ac Congestive Glaucoma High Myopia Hereditary Fundus Dystrophy
According to Morphology • Posterior Subcapsular Cataract • Ant Subcapsualr Cataract • Nuclear Cataract • Cortical Cataract • Mature Cataract
THE LENS CATARACT • This diagram illustrates the different morphological characteristics of cataract together with their depth and location within the lens. The following illustrations demonstrate clinical examples of these anatomical entities.
CLASSIFICATION ON BASIS OF MATURITY • IMMATURE CATARACT MATURE HYPERMATURE MORGAGNIAN
Causes • Hereditary • Age • DM • Steroids • UV Rays • Poor Nutrition • Smoking
Epidemiology • Cataract surgery is the most commonly performed surgery in elderly patient • Any Age Two peaks <10 Years >65 Years
Pathology • Depends on type of Cataract • Early Changes – tiny areas of liquefaction called morgagnian degeneration seen as cortical spokes • Progress to involve entire cortex • Later on homogeneous appearance
Etiopathogenesis of Cataract • Caused by degeneration and opacification of existing lens fibres, formation of aberrant fibres or deposition of other material in their place. • Loss of transparency occurs because of abnormalities of lens protein and consequent disorganization of the lens fibres
Etiopathogenesis of Cataract • Any factor that disturbs the critical intra and extra cellular equilibrium of water and electrolytes or deranges the colloid system within the fibres causing opacification. • Fibrous metaplasia of lens fibres occurs in complicated cataract. • Epithelial cell necrosis occurring in angle closure glaucoma leads to focal opacification of the lens epithelium (Glaucomflecken)
Etiopathogenesis of Cataract • Abnormal products of metabolism, drugs or metals can be deposited in storage diseases (Febry), metabolic diseases (Wilson) and toxic reactions (Siderosis)
Shield Anterior Subcapsular Cataract (Atopic Dermatitis)
Adv Cataract & Posterior Synechiae (Ch Ant Uveitis)
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.
Symptoms of Cataract 5. Loss or marked diminution of vision in bright sunlight or bright light beam in central posterior sub-capsular cataract. 6. Monocular diplopia or polyopia in presence of cortical spoke opacities 7. Glare in posterior sub-capsular cortical cataract due to increased scattering of light
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
Signs of senile cataract Positive findings • Diminution of vision • Anterior chamber is shallow in cases of intumescent cataract and deep in cases of hypermature (shrunken) cataract • Tremulousness of iris in cases of hypermature shrunken cataract
Signs of senile cataract 4. Lenticular opacity , grey or white opacity in lens. Iris shadow in immature cataract. No iris shadow in mature cataract 5. Morgagnian Cataract- is characterized by liquefied cortex, which is milky and nucleus is seen as brown mass, seen as semicircular line, altering its position with change in position of head
Signs of senile cataract 6. Distant direct ophthalmoscopy will reveal black shadow against red background in cases of immature cataract.
HISTORY • Age of Onset • Decreased Vision • Painless, • effecting daily routine? If the patient is bothered about his decreased vision. • Trauma • Any Ophthalmological Problems • Drugs Intake • Exposure to Radiations • Systemic Diseases • Skin disease, joint pains, etc. • Family History
Examination • GPE • SYSTEMIC EXAMINATION • OCULAR EXAMINATION • VISUAL ACUITY • ADNEXA • CORNEA • ANTERIOR CHAMBER • PUPIL • VITROUS • RETINA
Investigations • Blood Glucose • ECG • Chest x-rays (PA view) • Blood Complete Picture • Any specific relevant investigation (if indicated)
Indication for Surgery • Visual Improvement • When the patient is bothered. • Medical Indications • When cataract is adversely affecting the health of the eye e.g.: • Phacolytic Glaucoma • Intumescent Cataract • Diabetic Retinopathy • Cosmetic Indications • To restore black pupil
Optimal Post Op Refraction • If monocular correction is reqd. e.g. in contralateral dense 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
Operative Complications • Complications of Local Anaesthesia • Retrobulbar Hemorrhage • Perforation of the globe, optic nerve or sheath • Operative Complications: • Bridle Suture Perforation of the globe • Stripping of Descemet’s Membrane • Damage to ciliary body
Operative Complications(Contd) • Rupture of the Posterior Capsule • Capsular Rupture without Vitreous Loss • Small Tear • Large Tear or Zonular Tear • Capsular Rupture with Vitreous Loss • vitrectomy • Posterior Loss of Lens Fragments • Small Fragments • Large Fragments