Features
• Painless, gradual loss of vision
• Glare, especially at night (haloes around lights)
• Blurred or cloudy vision
• Loss of red reflex (seen on fundoscopy)
Causes
• Age-related (most common)
• Diabetes mellitus (early onset, "snowflake" cataracts)
• Steroid use (systemic or topical)
• Trauma (especially blunt → rosette cataract)
• Radiation exposure
• Congenital: rubella, galactosaemia, hypocalcaemia
Management
• Phacoemulsification with intraocular lens implant
Causes
• Marfan syndrome: superotemporal (upwards and outwards)
• Homocystinuria: inferonasal (downwards and inwards)
• Trauma
Features
• Monocular diplopia
• Refractive changes
• Visible edge of lens on slit-lamp
Associated risks
• Secondary glaucoma (due to lens-induced angle blockage)
Features
• Progressive difficulty with near vision (reading)
• Typically begins around age 40–45
• Due to loss of lens elasticity and reduced accommodation
Management
• Reading glasses (convex lenses)
• Image focused in front of retina
• ↑ axial length of globe
• Poor distance vision, good near vision
• Associated risks: retinal detachment, myopic degeneration
• Image focused behind retina
• Short axial length
• Difficulty with near tasks (early), may also have accommodative strain for distance
• Predisposes to angle-closure glaucoma
• Irregular corneal or lens curvature
• Blurred vision at all distances
• Corrected with cylindrical lenses
Extra Revision Pearls
• Halos at night clue → cataract or acute angle-closure glaucoma (with pain)
• Upward dislocation clue → Marfan; downward clue → homocystinuria
• Cataract risk clue → steroids, diabetes, radiation
• Hypermetropia clue → angle-closure risk due to shallow anterior chamber
• Myopia clue → retinal detachment risk (especially lattice degeneration)
• Presbyopia clue → common in middle age; convex "reading" correction
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Author & Educational Disclaimer
Author:
Dr Phillip Cockrell BM FRCP DipClinEd
Dr Phillip Cockrell is a UK Consultant Physician in Internal Medicine, currently working at Queen Alexandra Hospital, Portsmouth University Hospitals NHS Trust. He has previously worked as a registrar across Intensive Care Medicine, Gastroenterology, Cardiology, Stroke Medicine, Acute Medicine, and Respiratory Medicine.
He has held senior leadership roles including Associate Clinical Director of the Acute Medical Unit, Clinical Director of Internal Medicine, and Chief of Medicine. Dr Cockrell has over 15 years’ experience in postgraduate medical education, having lectured extensively across the MRCP syllabus and contributed to MRCP revision teaching and course development.
Dr Cockrell holds a Bachelor of Medicine (BM), Fellowship of the Royal College of Physicians (FRCP), and a Diploma in Clinical Education (DipClinEd). His teaching approach is based on structured consolidation of complex medical topics to support efficient and effective revision for postgraduate examinations.
Purpose of this content:
The material on this page is intended solely for educational purposes to support revision for the MRCP (UK) Part 1 examination. It reflects examination-relevant principles of internal medicine and is designed to aid learning and pattern recognition.
Medical disclaimer:
This content is designed for postgraduate medical examination revision and does not constitute medical advice, diagnosis, or treatment guidance and must not be used as a substitute for professional clinical judgement, local guidelines, or specialist consultation. Clinical decisions should always be made in the context of individual patient circumstances and current national guidance.
