Cataracts

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Cataract\: Opaci
(75% in those over 65 years old).
Lens anatomy\: Comprises the lens nucleus (middle aspect), lens cortex (outer aspect), and lens capsule (surrounding
membrane).
Types of cataracts\:
Nuclear cataracts\: Sclerosis of the lens nucleus, common in old age, symptoms include myopia and dull colours.
Cortical cataracts\: Opaci
una
Posterior subcapsular cataracts\: Opaci
steroids, cause glare and progress rapidly.
Di
Investigations\: Clinical diagnosis based on history and examination, supported by slit-lamp examination with dilated pupils.
Conservative management\: Monitor until symptoms a
exposure).
Surgical management\: Phacoemulsi
aspiration of fragments, and implantation of a new lens, often under local anaesthetic.
Complications\:
Vision loss if not managed appropriately.
Posterior capsule opaci
Endophthalmitis\: Rare, severe infection of aqueous/vitreous humour, treated with intraocular antibiotics.
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Introduction

A cataract is an opaci
Cataracts can a
people over 65 years old.
1

Aetiology

Anatomy
The lens helps to focus light onto the retina.
There are three main anatomical structures of the lens relevant to cataracts\:
Lens nucleus\: middle aspect of the lens
Lens cortex\: outer aspect of the lensLens capsule\: the membrane surrounding the lens
Figure 1. Lens function.
2
Types of cataracts
There are three main types of cataracts, classi
Nuclear cataracts
Nuclear cataracts are caused by sclerosis of the lens nucleus and are common in old age.
Symptoms include myopia (short-sightedness) and colours appearing dull.
Myopia occurs as sclerosis changes the lens refractive index. Patients experiencing this symptom will often say that they
previously needed reading glasses, but no longer require them.
Cortical cataracts
Cortical cataracts are caused by opaci
On ophthalmoscopy, the opaci
often unaFigure 3. Cortical cataract with wheel spoke appearance.
4
Posterior subcapsular cataracts
Posterior subcapsular cataracts are caused by opaci
a
Patients complain of glare when looking at lights (this can cause issues when driving at night). Posterior subcapsular
cataracts often progress more rapidly than other types of cataracts.
Figure 4. Congenital cataracts caused by congenital rubella syndrome.
7

Di

Di
Open-angle glaucoma
Macular degenerationInvestigations
Cataracts are a clinical diagnosis made following history and clinical examination.
Slit-lamp examination with dilated pupils can be used to support the diagnosis.

Management

Conservative management
Cataracts often begin small with mild symptoms and progress over several years.
NICE recommends refraining from surgical management until symptoms a
Controlling risk factors such as diabetes, smoking, steroid use, and UV exposure may slow down the development of
cataracts.
Surgical management
Phacoemulsi
The opaci
often conducted under local anaesthetic.
Prior to surgery, ocular biometry is conducted to measure the corneal curvature and the shape of the eye. It is used to
choose a suitable replacement lens.

Complications

If not managed appropriately, cataracts can cause loss of vision.
Surgical complications
Complications following surgical management of cataracts include\:
Posterior capsule opaci
seems like their cataract is returning. It is treated with a capsulotomy, where lasers are used to make a hole in the
capsule to allow light to pass through.
Endophthalmitis is an infection of the aqueous and/or vitreous humour. It is a rare, severe complication and can result
in visual loss. Endophthalmitis is treated with intraocular antibiotic injections.Related notes
Acute Angle-Closure Glaucoma
Age-related Macular Degeneration (ARMD)
Amblyopia
Ametropia
Anisocoria

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References

Investigations
Oxford handbook of clinical specialties tenth edition. Ophthalmology chapter page 446-447. Published in 2016.
Management
Sunshine Connelly (description by Ruth Lawson). L e n s f u n c t i o n . [CC BY]. Available from\: [LINK].
Johannes Sobotta. Lens anatomy (modi
Complications
Available from\: [LINK].
Source\: geekymedics.com