CATARACT Flashcards by Qúophy Calbert

Cataract

Loss of lens transparency due to opacification of the lens

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Types of cataracts

Age-related cataracts
Paediatric cataracts
Cataracts due to other causes

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Most prevalent type of cataract in adults

Age-related cataracts

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Most prevalent cataracts in children

Hereditary
Metabolic

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Onset of cataracts in adults

40 to 50 years

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Which cells does the lens develop from

Surface ectoderm

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Shape of the lens

Biconvex

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Site of the lens

Patellar fossa

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Functions of the lens

Causes refraction and focuses light onto the retina

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Parts of the lens

Lens capsule
Lens epithelium
Lens fibres
Lens zonules

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Two main parts of the lens

Nucleus (older fibers)
Cortex (younger fibers)

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Leading cause of blindness in Ghana and

Cataract

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Leading cause of reversible blindness in the world

Cataract

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Causes or aetiology of cataract

Age
Endocrine diseases
Systemic diseases
Ocular diseases
Exposure to ionizing radiation
Genetic
Drugs

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Endocrine diseases that cause cataracts

Diabetes
Galactosemia
Homocystinuria
Hydpoparathyroidism
Hypocalcemia
Wilson’s disease
Malnutrition

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Systemic diseases that cause cataract

Atopic dermatitis
Myotonic dystrophy
Neurofibromatosis type 2
HIV/AIDS

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Ocular diseases that cause cataract

Retinitis pigmentosa
Chronic anterioir uveitis
Stickler syndrome
High myopia

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most common cause of cataracts

Age

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Medications that cause cataracts

Acetylcholinesterase inhibitors
Corticosteroids

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Mechanisms of age related cataracts

Congenital cataract
Subcapsular cataract
Cortical cataract
Nuclear cataract

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Congenital cataract

Disturbances occurring at any level of lens growth

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Subcapsular cataract

Fibrous metaplasia of lens epithelium

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Cortical catarct

Cortical hydration between lens fibres

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Nuclear cataract

Deposition of certain pigments i.E. Urochrome

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Pathophysiology of cataract

Denaturation and coagulatation of lens proteins present in the lens fibres which results in loss of transparency and ultimately cataract formation.

Causes of non-age related cataracts

Photo-oxidation Trauma Chemical insults

Risk factors for cataracts

Age Socioeconomic status Race Genetic factors Cigarette smokin Alcohol Hypertension Hypocalcemia Diet UV-B exposure Type 2 DM Renal impairment

Which race has the highest prevalence of cataracts

Caucasians

Types of cataracts based on location

Nuclear cataracts Cortical cataract Posterior subcapsular cataracts Congenital cataracts

Classification of cataracts based on maturity

Mature Immature Hypermature

Mature cataract

Lens is completely opaque

Immature cataract

Lens is partially opaque

Hypermature (Morganian) cataract

Cataract is shrunken and wrinkled anterior capsule due to leakage of water out of the lens

Type of cataract associated with myopia

Nuclear cataract

This type of cataract causes difficulty distinguishing between shades of color and clouds your vision.

Nuclear cataract

Cataract caused by central opacity in the lens

Nuclear cataract

Cataract that occurs in the equator or periphery of the cortex

Cortical cataract

This type of cataract has little effect on vision

Cortical cataract

In cortical cataracts vision is worse in.......

Very bright light

People with high levels of sunlight exposure have twice the risk of developing........ cataracts

Cortical

This type of cataract starts as a small opaque area usually near the back of the lens, right in the path of light

Posterior subcapsular cataract

Effects of posterior subcapsular cataract

Interferes with reading vision Reduces your vision in bright light Causes glare or halos around lights at night.

Role of B-Scan in cataract investigations

to see retinal detachment or any vitreous pathology

Role of biometry in cataract investigatiosn

for intraocular lens placement during surgery

Tonometry

To rule out glaucoma

Fundoscopy

to rule out any vitreous or retinal pathology

Investigations in cataract

Visual acuity tests Slit-lamp examinations Ophthalmoscopy Peripheral retinal assessment B-Scan Biometry Fundoscopy Tonometry

Signs and symptoms of cataract

Blurred or hazy vision Increases sensitivity to glare Reduced color perception Double vision in one eye Need for brighter light Increased frequency to change refractive glasses

Lifestyle modifications

Quitting smoking Wearing sunglasses with UV protection Healthy diet

Surgical techniques for cataracts

Extracapsular cataract extraction Intracapsular cataract extraction Phacoemulsification

Intracapsular cataract extraction

opacified lens and capsule are removed in one piece

Extracapsular cataract extraction

Hard central nucleus is removed in one piece and then the soft cortex is removed in multiple small pieces

Phacoemulsification

The hard central nucleus is dissolved by ultrasound and then the soft cortex is removed in multiple small pieces

Drugs use pre-operatively in cataract surgery

Povidone-Iodine Cefuroxime Tropicamide with Phenyephrine and Lidocaine

Povidone-Iodine

Cutaneous peri-ocular and conjunctival antisepsis before ocular surgery

Cefuroxim

Prophylaxis of endophthalmitis after catarct surgery

APROKAM

Cefuroxime

Tropicamide with Phenylephrine and Lidocaine

Mydriasis and intraocular anaesthesia during cataract surgery by intracameral injection

Complications of cataract surgery

Choroidal hemorrhage Endophthalmitis Cystoid macular oedema Retinal detachment

Nepafenac

Prophylaxis and treatment of postoperative pain and inflammation associated with cataract surgery

NSAIDS used in cataracts

Nepafenac Dicofenac Bromfenac

Diclofenac sodium

Inhibition of intra-operative miosis during cataract surgery Postoperative inflammation in cataract surgery.

NEVANAC

Nepafenac

Bromfenac

Postoperative inflammation following cataract surgery

VOLTAROL

Diclofenac sodium

YELLOX

Bromfenac

Antibiotics used for cataracts

Fluoroquinolones Gatifloxacin Moxifloxacin Ciprofloxacin Ofloxacin

ZYMAXID

Gatifloxacin

MOXIVIG

Moxifloxacin

EXOCIN

Ofloxacin

ZYMAR

Gatifloxacin

BETNESOL

Betamethasone

MAXIDEX

Dexamethasone

Steroids used in cataracts

Betamethasone Dexamethasone Prednisolone Fluorometholone

PRED FORTE

Prednislone 1%

Nutrients which prevent against development of cataracts

Vitamin A Carotenoids Vitamin C