Download MBBS Ophthalmology PPT 22 Complicated Cataract Lecture Notes

Metabolic and complicated cataract

Learning Objectives

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? At the end of this class students shal be able

to :

? Classify cataract according to aetiology.

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? Understand pathophysiology of metabolic and
complicated cataract.
? Identify distinct morphological subtypes of
metabolic and complicated cataract.

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`CATARACTA'(LATIN)MEANING `WATERFALL'

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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

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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

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abnormalities.

? Diabetic cataract
Hyperglycemia

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Excess glucose metabolizes into
sorbitol
(Aldose reductase mediated)

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Osmotic over hydration

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1. Age related cataract in

diabetics

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? Early onset

? Rapid progression

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2. True diabetic cataract.

? Also called `snow flake

cataract' or `snow-storm

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cataract'

? Fluid vacuoles appear

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underneath anterior

and posterior capsules

? Bilateral snowflake-like white

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cortical opacities

Snowflake cataract 7

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Galactosemia

? Multisystem disorder

? Inborn error of galactose

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metabolism

? Anterior and posterior

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subcapsular lamellar

opacities- `oil droplet

cataract'

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Oil droplet cataract

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Myotonic dystrophy

? Fine dust like opacities

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with tiny iridescent spots

in cortex- `christmas tree

cataract'

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? May progress to stellate
opacity at posterior pole

Christmas tree cataract

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Hypocalcaemic cataract

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? May be associated with parathyroid tetany.

? Multicoloured crystals
or
? Small discrete white flecks of cortical opacities

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Wilson's disease

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? `Sunflower cataract' is
rare in such patients.

? `Kayser-Fleischer ring'

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(KF ring) in the cornea
is more common.

Sunflower cataract

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(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.

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? Ocular features
congenital cataract and glaucoma
? Systemic features
mental retardation
dwarfism

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osteomalacia
muscular hypotonia
frontal prominence.

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COMPLICATED CATARACT

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? Opacification of the lens secondary to

some other intraocular disease.

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? Inflammatory conditions
? Uveal inflammations
(like iridocyclitis, pars planitis, choroiditis)
? Hypopyon corneal ulcer
? Endophthalmitis.

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? Degenerative conditions
? Retinitis pigmentosa
? Myopic chorioretinal degeneration

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? Retinal detachment
Long-standing cases

? Glaucoma (primary or secondary)

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? Intraocular tumours
? Retinoblastoma
? Malignant melanoma

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COMPLICATED CATARACT

? Lens changes typically in front

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of the posterior capsule.
? Irregular in outline
? Variable in density
? Appearance like `breadcrumb'.
? A very characteristic sign is

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Iridescent coloured particles
`polychromatic lustre' of
reds, greens and blues.

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COMPLICATED CATARACT

? Chronic anterior uveitis

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Most common cause
? Polychromatic lustre
at posterior pole
? If persists, anterior and
posterior opacities develop

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Angle closure glaucoma

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Focal infarcts of lens

epithelium

-small grey-white anterior

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subcapsular or capsular

opacities

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`glaukomfecken'

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?Pathological myopia

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Posterior subcapsular opacities

Early onset nuclear sclerosis

?Hereditary fundus dystrophies

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Lebers: total cataract

Stickler syndrome: cortical cataract

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Toxic cataracts

1. Smoking

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2. Alcohol

3. Drug induced cataract

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Corticosteroids

Phenothiazines

Pilocarpine

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Diuretics

Amiodarone

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Allopurinol

Chloroquine

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Other types:
? Infrared (heat) cataract:
`Glass-blower's or Glassworker's cataract'

? Irradiation cataract

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? Ultraviolet radiation cataract

? Electric cataract

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MANAGEMENT OF CATARACT IN ADULTS

? A. Non-surgical measures

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? B. Surgical management

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Non-surgical measures

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1. Treatment of cause of cataract

2. Measures to delay progression

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3. Measures to improve vision in the presence of

incipient and immature cataract

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Surgical management

? Indications

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1. Visual improvement

2. Medical indications :

Lens induced glaucoma

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Retinal diseases like

diabetic retinopathy or retinal detachment

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(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

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II. Ocular examination

A. Retinal function tests
B. Search for local source of infection

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C. Anterior segment evaluation by slit-lamp
examination
D. Intraocular pressure (IOP) measurement

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Retinal function tests

? Light perception (PL)

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? Projection of rays (PR)

? Pupillary reaction to light

? Two-light discrimination test

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? Maddox rod test

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Retinal function tests

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? Colour perception

? Entoptic visualisation

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? Laser interferometry

? Objective tests for evaluating retina

like VEP, ERG, EOG, USG

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Preoperative medications and preparations

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? 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

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? 6. To sustain dilated pupil

? Anaesthesia
? LA/GA

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Types and choice of surgical techniques

? Phacoemulsification (MICS)

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? Small incision cataract surgery (SICS)

? Extracapsular cataract extraction (ECCE)

? Intracapsular cataract extraction (ICCE)

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Conclusion

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? Metabolic cataracts are due to endocrine

disorders and/or biochemical abnormalities.

? Complicated cataracts involve opacification

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of the lens secondary to some other

intraocular disease.

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? Many metabolic and complicated cataracts

have distinctive morphologies.

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Thank you

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