👁️ Gradual visual loss refers to progressive deterioration of vision over weeks, months, or years. Unlike sudden visual loss (a true emergency), gradual loss usually reflects chronic ocular or systemic disease. The key clinical task is to localise the problem — media (cornea/lens), retina, optic nerve, or visual pathways — and to identify conditions where early treatment prevents irreversible blindness.

📝 History (Think: Central vs Peripheral, Eye vs Systemic)

⏳ Progression
- Slow, insidious loss over months–years (glaucoma, cataract, AMD).
- Stepwise decline (diabetic retinopathy).
🎯 Visual Field Changes
- Central vision loss: difficulty reading, recognising faces → macular disease (AMD).
- Peripheral vision loss: bumping into objects, tunnel vision → glaucoma.
- Diffuse blurring: cataract, refractive error.
👁️ Laterality
- Unilateral vs bilateral (bilateral suggests systemic or degenerative disease).
🌈 Visual Phenomena
- Glare, haloes around lights (cataract, glaucoma).
- Distortion or waviness (metamorphopsia → macular pathology).
- Floaters or spots (diabetic retinopathy, uveitis).
🩺 Systemic Illness
- Diabetes → diabetic retinopathy.
- Hypertension → vascular retinal disease.
- Autoimmune disease → chronic uveitis.
💊 Drug & Social History
- Steroids (glaucoma, cataracts).
- Smoking (AMD).

🩺 Physical Examination (Localise the Problem)

📏 Visual Acuity
- Measure best-corrected vision in each eye.
- Track changes over time.
👁️ Pupils
- Check for relative afferent pupillary defect (optic nerve disease).
🔦 Fundoscopy
- Macula: drusen, pigmentary change (AMD).
- Optic disc: cupping (glaucoma), pallor (optic neuropathy).
- Retina: microaneurysms, haemorrhages, exudates (diabetic retinopathy).
🔬 Slit-Lamp Examination
- Lens opacity (cataract).
- Anterior chamber inflammation (uveitis).
- Corneal pathology.

🧠 Common Causes of Gradual Visual Loss

Cause	Typical Features	Key Tests	Management
🟢 Open-Angle Glaucoma	Gradual peripheral vision loss, often asymptomatic early	Tonometry, visual fields, optic nerve imaging	IOP-lowering drops, laser, surgery
🟡 Age-Related Macular Degeneration	Central vision loss, distortion, drusen	Fundoscopy, OCT	Anti-VEGF (wet AMD), lifestyle changes
⚪ Cataract	Blurred vision, glare, faded colours	Slit-lamp exam	Cataract extraction + IOL
🔴 Diabetic Retinopathy	Blurred vision, floaters, macular oedema	Fundoscopy, OCT, fluorescein angiography	Glycaemic control, laser, anti-VEGF
🟣 Chronic Uveitis	Blurred vision, floaters, ± red eye	Slit-lamp exam, OCT	Steroids, immunosuppression

🔎 Investigations (Ophthalmology-Led)

📸 Optical Coherence Tomography (OCT): Macula and optic nerve structure.
🧪 Fluorescein Angiography: Retinal vascular leakage or ischaemia.
📈 Visual Field Testing: Essential for glaucoma diagnosis and monitoring.
⚡ Tonometry: Intraocular pressure measurement.

💊 Management Principles

🎯 Treat the underlying cause early to prevent permanent vision loss.
🟢 Glaucoma: lifelong monitoring and pressure control.
🟡 AMD: anti-VEGF for wet AMD; smoking cessation and supplements for dry AMD.
🔴 Diabetic eye disease: strict glycaemic, BP, and lipid control.
⚪ Cataracts: surgery when vision limits daily activities.

⚠️ Red Flags (Do Not Miss)

Rapid progression despite “gradual” history.
Associated eye pain or redness.
Unilateral visual loss with optic disc pallor.
New distortion or central scotoma (urgent AMD review).

📚 Teaching Pearls

🧠 Peripheral loss = glaucoma until proven otherwise.
📖 Distortion and reading difficulty point to the macula.
👁️ Cataracts cause blur and glare but normal fundoscopy once lens opacity is accounted for.
⏱️ Gradual does not mean benign — delayed diagnosis leads to irreversible blindness.

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Causes of Gradual Visual Loss over weeks and months