Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Ophthalmology PPT 22 Complicated Cataract Lecture Notes
Metabolic and complicated cataract
Learning Objectives
? At the end of this class students shal be able
to :
? Classify cataract according to aetiology.
? Understand pathophysiology of metabolic and
complicated cataract.
? Identify distinct morphological subtypes of
metabolic and complicated cataract.
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`CATARACTA'(LATIN)MEANING `WATERFALL'
3
Definition of cataract
? Any opacity in the lens or its capsule
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Etiological classification of cataract
1. Age related cataract
2. Traumatic cataract
3. Metabolic cataract
4. Complicated cataract
5. Toxic cataract
6. Radiation induced cataract
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METABOLIC CATARACTS
? Due to endocrine disorders and biochemical
abnormalities.
? Diabetic cataract
Hyperglycemia
Excess glucose metabolizes into
sorbitol
(Aldose reductase mediated)
Osmotic over hydration
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1. Age related cataract in
diabetics
? Early onset
? Rapid progression
2. True diabetic cataract.
? Also called `snow flake
cataract' or `snow-storm
cataract'
? Fluid vacuoles appear
underneath anterior
and posterior capsules
? Bilateral snowflake-like white
cortical opacities
Snowflake cataract 7
Galactosemia
? Multisystem disorder
? Inborn error of galactose
metabolism
? Anterior and posterior
subcapsular lamellar
opacities- `oil droplet
cataract'
Oil droplet cataract
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Myotonic dystrophy
? Fine dust like opacities
with tiny iridescent spots
in cortex- `christmas tree
cataract'
? May progress to stellate
opacity at posterior pole
Christmas tree cataract
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Hypocalcaemic cataract
? May be associated with parathyroid tetany.
? Multicoloured crystals
or
? Small discrete white flecks of cortical opacities
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Wilson's disease
? `Sunflower cataract' is
rare in such patients.
? `Kayser-Fleischer ring'
(KF ring) in the cornea
is more common.
Sunflower cataract
(Photographs- Courtesy :
Kanski's Clinical Ophthalmology)
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Lowe's syndrome
? Lowe's (Oculo-cerebral-renal) syndrome
? Rare inborn error of amino acid metabolism.
? Ocular features
congenital cataract and glaucoma
? Systemic features
mental retardation
dwarfism
osteomalacia
muscular hypotonia
frontal prominence.
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COMPLICATED CATARACT
? Opacification of the lens secondary to
some other intraocular disease.
? Inflammatory conditions
? Uveal inflammations
(like iridocyclitis, pars planitis, choroiditis)
? Hypopyon corneal ulcer
? Endophthalmitis.
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? Degenerative conditions
? Retinitis pigmentosa
? Myopic chorioretinal degeneration
? Retinal detachment
Long-standing cases
? Glaucoma (primary or secondary)
? Intraocular tumours
? Retinoblastoma
? Malignant melanoma
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COMPLICATED CATARACT
? Lens changes typically in front
of the posterior capsule.
? Irregular in outline
? Variable in density
? Appearance like `breadcrumb'.
? A very characteristic sign is
Iridescent coloured particles
`polychromatic lustre' of
reds, greens and blues.
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COMPLICATED CATARACT
? Chronic anterior uveitis
Most common cause
? Polychromatic lustre
at posterior pole
? If persists, anterior and
posterior opacities develop
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Angle closure glaucoma
Focal infarcts of lens
epithelium
-small grey-white anterior
subcapsular or capsular
opacities
`glaukomfecken'
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?Pathological myopia
Posterior subcapsular opacities
Early onset nuclear sclerosis
?Hereditary fundus dystrophies
Lebers: total cataract
Stickler syndrome: cortical cataract
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Toxic cataracts
1. Smoking
2. Alcohol
3. Drug induced cataract
Corticosteroids
Phenothiazines
Pilocarpine
Diuretics
Amiodarone
Allopurinol
Chloroquine
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Other types:
? Infrared (heat) cataract:
`Glass-blower's or Glassworker's cataract'
? Irradiation cataract
? Ultraviolet radiation cataract
? Electric cataract
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MANAGEMENT OF CATARACT IN ADULTS
? A. Non-surgical measures
? B. Surgical management
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Non-surgical measures
1. Treatment of cause of cataract
2. Measures to delay progression
3. Measures to improve vision in the presence of
incipient and immature cataract
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Surgical management
? Indications
1. Visual improvement
2. Medical indications :
Lens induced glaucoma
Retinal diseases like
diabetic retinopathy or retinal detachment
(treatment of which is hampered by
presence of lens opacities)
3. Cosmetic indications
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Preoperative evaluation
I. General medical examination of the patient
II. Ocular examination
A. Retinal function tests
B. Search for local source of infection
C. Anterior segment evaluation by slit-lamp
examination
D. Intraocular pressure (IOP) measurement
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Retinal function tests
? Light perception (PL)
? Projection of rays (PR)
? Pupillary reaction to light
? Two-light discrimination test
? Maddox rod test
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Retinal function tests
? Colour perception
? Entoptic visualisation
? Laser interferometry
? Objective tests for evaluating retina
like VEP, ERG, EOG, USG
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Preoperative medications and preparations
? 1. Topical antibiotics
? 2. Preparation of the eye to be operated.
? 3. An informed and detailed consent
? 4. Scrub bath and care of hair.
? 5. To lower IOP
? 6. To sustain dilated pupil
? Anaesthesia
? LA/GA
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Types and choice of surgical techniques
? Phacoemulsification (MICS)
? Small incision cataract surgery (SICS)
? Extracapsular cataract extraction (ECCE)
? Intracapsular cataract extraction (ICCE)
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Conclusion
? Metabolic cataracts are due to endocrine
disorders and/or biochemical abnormalities.
? Complicated cataracts involve opacification
of the lens secondary to some other
intraocular disease.
? Many metabolic and complicated cataracts
have distinctive morphologies.
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Thank you
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This post was last modified on 07 April 2022