4-lens and cataract
DESCRIPTION
4-Lens and CataractTRANSCRIPT
Lens and Cataract
Cataract and Refractive Surgery Subspecialty ServiceDepartment of Ophthalmology
Faculty of Medicine Padjadjaran University
Topics of Study
1. CataractCauses of CataractGlobal/National distribution & population characteristics of CataractDiagnosis of Cataract. Distinction between immature, mature and hypermatureAppropriate referral of cataract patientOutline of surgical managementVisual rehabilitation of AphakiaOutline of cataract management in young age
Topics of Study
2. Congenital Abnormalities of LensEctopia Lentis (Subluxation & Dislocation)
Lenticonus
Crystalline Lens
Embryology Derived from surface Ectoderm Ectoderm invaginates and breaks as two layers
structure Basement membrane of epithelium forms the lens
capsule Posterior epithelium cells form the embryonic
nucleus Anterior epithelium continues to regenerate and
develop lens fibers
Anatomy
Lies behind the iris Concavity in the anterior face of vitreus
called the Patellar Fossa Suspended from the cilliary processes by
Zonules In young patients (<35 years) lens is
adherent to vitreus by Ligament of Weigert
Layers (from without inwards) :
Lens capsule (thinnest at posterior pole) Epithelium (missing from posterior
surface) Cortex Epinuclear Cortex Nucleus
Nucleus (from without inwards) :
Adults Adolescent Infantile Fetal (contains anterior & posterior Y-
sutures) Embryonic
Physiology
Functions :1. Refraction of light (+18 D)
2. Accomodation : ability to increase refractive power in order to focus near objects.
Optics
+18 D refraction. And in accomodation this power increases
Accomodation : contraction of ciliary muscles results in laxity of zonules, which leads to increase convexity of lens due to its inherent elasticity
Iris controls the amount of light that enters the eye by varying the size of pupil and covers the peripher of the lens thereby cutting the optical (spherical) aberrations from it
Cataract
Definition Any opacity of the lens
or loss of transparancy of the lens that causes diminution or impairment of vision
Classification
Etiological Morphological Stage of Maturity Chronological
Etiological classification
1. Senile
2. Traumatic1. Penetrating
2. Concussion (Rosette Cataract)
3. Infrared irradiation
4. Electrocution
5. Ionizing Radiation
3. Metabolic1. Diabetes (Snow Storm Cataract)2. Hypoglycaemia3. Galactosemia (Oil drop cataract)4. Galactokinase Deficiency 5. Mannosidosis6. Fabry’s Disease7. Lowe’s Syndrome8. Wilson’s Disease (Sunflower Cataract)9. Hypocalcaemia
4. Toxic1. Corticosteroids
2. Chlorpromazine
3. Miotics
4. Busulphan
5. Gold
6. Amiodarone
5. Complicated Anterior uveitis Hereditary Retinal & Vitreoretinal Disoders High Myopia Glaucomflecken Intraocular Neoplasia
6. Maternal Infection1. Rubella
2. Toxoplasmosis
3. Cytomegalovirus
7. Maternal Drug Ingestion Thalidomide Corticosteroid
8. Presenile Cataract Myotonic Dystrophy Atopic Dermatitis (Syndermatotic Cataract) GPUT & Enzyme Deficiencies
9. Syndromes with Cataract Down’s Syndrome Werner’s Syndrome Rothmund’s Syndrome Lowe’s Syndrome
10. Hereditary
11. Secondary Cataract Posterior Capsular Opacification (PCO)
Morphological Classification
1. Capsular Congenital (Anterior Polar & Posterior Polar) Acquired
2. Subcapsular Posterior subcapsular (Cupuliform) Anterior subcapsular
3. Nuclear Congenital (Discoid, etc) Senile
4. Cortical Congenital (Coronary, Coralliform, etc) Senile (Cuneiform)
5. Lamelar or Zonular
6. Sutural
7. Others Blue –Dot (Cataracta caerulea) Membranous Cataracta Pulveranta Centralis Reduplicated Cataract
Stage of Maturity
1. Immature
2. Mature
3. Intumescent
4. Hypermature
5. Morgagnian
Chronological
1. Congenital : since birth
2. Infantile : first year of life
3. Juvenile : 1 to 13 years of life
4. Presenile : 13 to 35 years of life
5. Senile
Pathogenesis
Two main pathogenetic processes are :1. Hydration :
Failure of active pump mechanism Increased leakage across posterior or
anterior capsule Increased Osmotic Pressure
2. Sclerosis
Senile Cataract
Global38 million people are blind41% because of cataract
Progression
1. Stage of Lamellar Separation Hydration
2. Stage of Incipient Cataract Early opacities appear Symptom e.g., glare, appear
3. Immature Cataract Diminution of vision Lens appears grayish white in color Iris shadow can be seen
Progression
4. Intumescent Cataract The lens imbibes lot of fluid and becomes swollen Anterior chamber becomes shallow Angle of anterior chamber may close : Phacomorphic
glaucoma
5. Mature Cataract Entire cortex becomes opaque Vision reduced to just perception of light Iris shadow is not seen Lens appears pearly white
Progression
6. Hypermature CataractThis may take any of two form : Liquefactive or Morgagnian type : milky white Sclerotic Cataract with iridodenesis Vision improves to about finger counting at 1
meter
Clinical Presentation
Symptoms1. Glare2. Image Blur3. Diurnal Variation of Vision4. Distortion (Metamorphopsia)5. Diplopia/Polyopia6. Altered Color Perception7. Black Spots8. Behavioral Changes
Clinical Presentation
Signs1. Visual Acuity : vision is diminished
proportionate to the degree of cataract (immature from 6/9 to finger counting close to face; mature perception of light or hand movements)
2. Leukocoria : white pupil3. Iris shadow in immature cataract4. Distant Direct Ophthalmoscopy (DDO) : red
reflexes depends on degree of cataract
Differentiating Various Stages of Cataract
Features Immature Mature Hypermature
Vision 6/9 - FC HM - PL HM – FC
Anterior Chamber
Normal (shadow in intumescent)
Normal (shallow in intumescent)
Normal to deep
Color of Lens Grayish white Pearly white Milky white(with browm crescent of nucleus) or chalky white
Iris shadow Seen Not seen Not seen
Distant Direct Ophthalmoscopy
Black patches againts red glow
No red glow seen
No red glow seen
Complication of Cataract
1. Lens Induced Glaucoma1. Phacomorphic Galucoma
2. Phacolytic Glaucoma
3. Phacotopic Glaucoma
2. Lens Induced Uveitis
3. Subluxation or Dislocation of Lens
Investigation1. Visual Acuity2. Pupillary Reflexes3. Intraocular Pressure4. Fundus Examination5. Blood Pressure6. General Investigation7. Macular Function Test8. Ultrasonography (USG B-Scan)9. Intraocular Lens Power Calculation
Biometry
Indications for Cataract Surgery1. Optical indications2. Medical indication
Hypermature cataract Lens induced glaucoma Lens induced uveitis Dislocated/subluxated lens Intra-lenticular foreign body Diabetic Retinopathy to give Laser
Photocoagulation Retinal Detachment
3. Cosmetic indication
Surgery for Cataract
Choice of Operation :1. Extra-capsular cataract extraction with
Posterior Chamber Lens Implantation (ECCE with PCL)
Phacoemulsification Small Incision Cataract Extraction/Surgery
(SICE/SICS)2. Intra-capsular cataract extraction (ICCE) Pars plana lensectomy
Intra-ocular lens (IOL) types :1. Posterior chamber lens (PCL)
2. Anterior chamber lens (ACL)
Principles of Various Techniques
1. ECCE The nucles and the cortex is removed out of
the capsule leaving behind intact posterior capsule, peripheral part of the anterior capsule and the zonules
2. ICCE The lens is removed in toto
3. Pars Plana Lensectomy A special techniques used in very young
children The lens and anterior part of vitreous is
nibled out using an instrument called Vitrectomy Probe or Vitreous irrigation Suction Cutting (VISC)
4. Phacoemulsification It is essentially an advancement in the
methode of doing ECCE The nucleus is converted into pulp or
emulsified using high frequency (40.000 MHz) sound waves and then sucked out of the eye through a small (3.2) incision
A special foldable IOL is then inserted Is the choice of the operation for cataract
ECCE
FAKOEMULSIFIKASI
SICE
ECCE vs. ICCE
ECCE ICCELens removal Nucleus removed out
of the capsule and cortex sucked out
Lens removed as single piece within its capsule
Posterior capsule & zonules
Intact Removed
Incision Smaller (8 mm) Larger (10 mm)
Peripheral iridectomy Not performed Required to avoid pupillary block glaucoma
Sophisticated equipment
Required Not required
Time taken More Less
ECCE vs. ICCE
ECCE ICCEIOL Implantation Posterior chamber Anterior chamber
Expertise required Difficult technique Easier to learn
Cost More Less
Complications which are increased
Posterior Capsular Opacification (PCO)
1. Vitreous prolapse & loss
2. CME
3. Endophthalmitis
4. Aphakic Glaucoma
5. Fibrous & endothelial ingrowth
6. Neovasc. Glaucoma in PDR
ECCE vs. ICCEECCE ICCE
Complications which are decreased
All the complications mentioned for ICCE
PCO
Indications A routine procedure for all forms of cataract (except where contra-indicated
1. Dislocated Lens
2. Subluxated Lens (>1/3 zonules broken)
3. Chronic Lens Induced Uveitis
4. Hypermature Shrunken Cataract
5. Intraocular foreign body
Contraindications 1. Dislocated lens
2. Subluxated lens (>1/3 zonules broken)
Young patient (<35 years)
Preoperative Preparation
1. Patient preferably admitted to the hospital on previous evening (however, surgery can also be done on OPD basis)
2. Informed consent is taken3. The eye-lashes are trimmed carefully4. Antibiotic drops are instilled every 6 hourly5. Pupils are dillated6. Other medications e.g., antiglaucoma drugs,
antihypertensives, etc
Anesthesia
1. Topical anesthesia
2. Retrobulbar anesthesia
3. Peribulbar anesthesia
4. Subtenon anesthesia
5. General anesthesia
Postoperative Care
1. Eye is cleaned routinely2. The eye is examined :
Visual acuity Apposisition of the wound Corneal clarity Anterior chamber depth Pupil IOL Posterior capsule Intra-ocular pressure (IOP)
3. Topical antibiotic-steroid eye drops every 4-6 hourly (4-6 weeks)
Complication of Cataract Surgery
These can be grouped as :
1. Intraoperative
2. Postoperative : Early Late
Intraoperative Complications
1. Damage to corneal endothelium
2. Rupture of posterior capsule
3. Vitreous prolapse and loss
4. Hyphaema
5. Expulsive hemmorrhage
6. Dislocation of nucleus into vitreous
Posoperative Complications
Early1. Corneal edema2. Wound leak3. Iris prolapse4. Shallow or flat anterior chamber5. Hyphaema6. Hypotony7. Glaucoma8. Decentered or displaced IOL9. Endophthalmitis
Late1. Posterior Capsular
Opacification (PCO)
2. Cystoid Macular Edema (CME)
3. Vitreous touch syndrome
4. UGH syndrome
5. Bullous Keratopathy
6. Glaucoma
Visual Rehabilitation After Cataract Surgery (Aphakia)
1. Absolute high hypermetropia
2. Astigmatism
3. Loss of accomodation
4. Altered Color Perception
5. More of UV rays reach the retina
Rehabilitation
Three methods are mainly used to
tackle the problems of aphakia :
1. Intraocular Lens (IOL)
2. Spectacles
3. Contact Lens
Aphakic Spectcles
Physical and Optical Problems :1. The glasses are heavy and great
physical discomfort2. Magnification : diplopia3. Roving Ring Scotoma4. Jack in the box Phenomenon5. Pin Cushion Effect6. Spherical Aberations7. Chromatic Aberation
Pediatric Cataract
Main problems
1. Visual Assesment
2. Vision Deprivation Amblyopia
3. Postoperative Inflammation and Fibrosis
4. PCO
5. IOL Power Calculation
Dislocation of Lens
Congenital 1. Familial
2. Ectopia lentis
3. Marfan’ Syndrome
4. Weil Marchesani Syndrome
5. Homocystinuria
6. Hyperlisinemia
7. Aniridia
Acquired1. Hypermature cataract
2. Trauma
3. Chronic uveitis
4. Intraocular tumor
5. High myopia
6. Buphthalmos
Treatment
1. Spectacles
2. ECCE : only 1/3 zonules are broken
3. ICCE : more than 1/3 zonules are broken
4. Pars Plana Surgery
Miscellaneous Condition of Lens
1. Lenticonus
2. Lens Coloboma
3. PCO