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Cataracts - Coggle Diagram
Cataracts
Aetiology and risk factors
Age-related changes
Oxidation and aggregation of lens proteins.
Medical conditions
Diabetes mellitus.
Previous uveitis.
Medications
Long-term corticosteroid use.
Lifestyle/environmental
Smoking.
Excessive alcohol.
UV exposure.
Other
Family history.
Previous ocular trauma or surgery.
Definition
Opacification of the normally transparent crystalline lens.
Causes progressive, usually painless visual impairment.
Commonly age-related.
May affect one or both eyes.
Pathophysiology
Lens structure
Composed of specialised proteins called crystallins.
Protein changes
Oxidation and aggregation reduce lens transparency.
Light transmission
Increased light scattering.
Reduced light reaching the retina.
Visual impairment
Blurred vision.
Reduced contrast and visual acuity.
Clinical features
Visual disturbance
Blurred or cloudy vision.
Reduced visual acuity.
Faded or yellowed colours.
Light sensitivity
Glare.
Halos around lights.
Functional changes
Poor night vision.
Difficulty reading.
Frequent prescription changes.
Usually painless and gradual.
Complications
Visual impairment
Reduced independence.
Difficulty with activities of daily living.
Mobility
Reduced depth perception.
Increased falls risk.
Psychological
Reduced confidence.
Social isolation.
Advanced disease
Severe visual impairment.
Rare lens-induced glaucoma.
Investigations
Visual acuity
Snellen chart.
Slit-lamp examination
Identifies lens opacity and location.
Fundoscopy
Assesses retinal health.
Tonometry
Measures intraocular pressure.
Pharmacological management
Corticosteroid eye drops
Prednisolone acetate.
Reduce postoperative inflammation.
Risks: raised intraocular pressure and delayed healing.
Antibiotic eye drops
Used according to surgical protocol.
Reduce risk of postoperative infection.
Mydriatics
Tropicamide and phenylephrine.
Dilate pupils for examination and surgery.
Analgesia
Paracetamol for mild postoperative discomfort.
Classification and types
Nuclear sclerotic
Central lens opacity.
Reduced distance vision.
Possible temporary improvement in near vision (second sight).
Cortical
Peripheral lens opacity.
Spoke-like appearance.
Glare and light sensitivity.
Posterior subcapsular
Opacity at posterior lens surface.
Disproportionate visual impairment.
Difficulty reading and bright-light sensitivity.
Associated with diabetes and corticosteroids.
Management
Conservative
Updated spectacles where appropriate.
Improved lighting.
Magnification aids.
Falls prevention.
Surgical
Phacoemulsification.
Ultrasound fragments the cloudy lens.
Lens material removed.
Artificial intraocular lens implanted.
Usually performed under local anaesthesia.
Commonly day-case surgery.
Postoperative
Prescribed eye drops.
Avoid rubbing or pressure on the eye.
Attend follow-up appointments.