Download MBBS Ophthalmology PPT 22 Complicated Cataract Lecture Notes

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.

2


`CATARACTA'(LATIN)MEANING `WATERFALL'

3

Definition of cataract

? Any opacity in the lens or its capsule

4
Etiological classification of cataract
1. Age related cataract
2. Traumatic cataract
3. Metabolic cataract
4. Complicated cataract
5. Toxic cataract
6. Radiation induced cataract

5

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

8


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

9

Hypocalcaemic cataract

? May be associated with parathyroid tetany.

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

10


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)

11

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.

12


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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

15

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.

16


COMPLICATED CATARACT

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

17

Angle closure glaucoma

Focal infarcts of lens

epithelium

-small grey-white anterior

subcapsular or capsular

opacities

`glaukomfecken'

18
?Pathological myopia

Posterior subcapsular opacities

Early onset nuclear sclerosis

?Hereditary fundus dystrophies

Lebers: total cataract

Stickler syndrome: cortical cataract

19

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

21

MANAGEMENT OF CATARACT IN ADULTS

? A. Non-surgical measures

? B. Surgical management

22
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

23

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

25

Retinal function tests

? Light perception (PL)

? Projection of rays (PR)

? Pupillary reaction to light

? Two-light discrimination test

? Maddox rod test

26
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